Control the fate of the lower control arm

[jftu105]

This could be controvertial but I do it anyway.

Of four E320's 1994-5 I have, I have to deal with the torn rubber boots of all of them. Remove the tire, and check the rubber boot condition over the ball joint of the lower control arm, most likely, they are torn. Once they are torn, dust can get it and greese can go out. Left unattended, the ball joint can wear badly to have sufficient play. This ball joint design is an unstable design because when it fails, the ball joint pops out and you lose the control of your vehicle.

So, it is important to check the condition of the ball joint of the lower control arm. Uneven tire wear is a sign. Get the tire up and shake it by holding the top and the bottom of the tire. If you have significant play, you probably need a new lower control arm, or replace the ball joint if it is replaceable.

This post is about when you don't have play but the rubber boot is torn. Over at BZ-crasyworlld, they scream: "You must replace the entire lower control arm!!!! No exception!!!!!!!!" by you know who. They claim, once the dust got in, you are dead. You can never get them out and it will wear out INSTANTLY! Wrong! Yes, you cannot get all the dust particles out but as long as it is still tight, not much dust can get under. Clean it up with fresh grease, the wear rate will be minimal, and the lower control arm can still have many years of life left. In fact, once you clean up the old grease, you can see the ball joint is still shining with a mirror finish. If it is rusty and badly scarred, it is time to change,

Today, hardly can you buy good lower control arms anymore. No Lemfoeder. You got those questionable ones. So, between putting in a Febi vs the original with fresh grease and new boot, I chose the latter.

I have done the rubber boots of six ball joints (3 cars and one to go). The ball joint is still tight and no play but the boot is torn. I only replace the boot. I remove the boot, and wipe it clean. Spray some cleaner and wipe it clean and dry again. Then I put in new grease (Mobil synthetic grease) and put in the new boot. It is not an easy job but after doing it several times, I can get one done in about 2 hours at a casual pace. I never rush the job. Take my time as it is the unwound time.

The very first one I did was about four years ago. Just check its condition and the rubber is still good. You can buy this rubber boot, Original MB only, from many on-line vendors. I found RMeuropean has the best price at $11 a piece, but you need to pay a $8.00 flat shipping. Some eBay sellers sell it at $16, free shipping. Of the ones I recently got, it actually says TRW on the boot. The MB tag is on the plastic bag and made in Germany is printed.

jftu105

 

[emerydc8]

I like the idea of having some spare boots in stock, just in case I tear one when I install new LCAs later next month. Also, IIRC the last set of "factory" LCAs I installed had a white or transparent boot that I wasn't too crazy about. Thanks for the part number.

[EDIT] Looking at the RMEuro part, they are selling the transparent boot. Does anyone know if the Naperville boot is black or transparent?

 

[gerryvz]

It's a prudent idea not to pay TOO much attention to the likes of q*baert, leftcoastgeek, Jayare and the Real1Shepster over there. Often their "diagnoses" tend to be repeated, automatic, mindless assumptions based on their supposed "knowledge" and very light on actual diagnosis and work to find the real issue at hand. So while their "advice" can be directionally good, in practice it is often not so satisfying. You would be in better hands with folks here like gsxr and Klink.

 

[jftu105]

RMEuropean and all eBay sellers used the stock pictures to show the part as made of clear rubber. However, the actual part delivered are the one I shown in the image. I used to get the clear one too, but now it is all in black, made by TRW.

Similarly, on RMEuropean, the image of their Lemfoeder engine mount has a B painted on the side and with a dome top, which was made in Germany; however, the actual mount shifted, as predicted by gsxr, is made in Xhina.

In conclusion, the on-line sellers use the stock image typically, not the image of the actual item.

jftu105

 

[jftu105]

When I shared my repairs on the BZ-Wonderland, different from the "doctrines" of those clowns, all I got were ridicules, smears, and silly new sciences (such as fluid can move from low pressure to high pressure by its own). Here at 500e, I received tremedous help from many (gsxr of course as the #1 help) to get my head gasket replaced. I can also post my findings without getting attacks.

Thanks to gerryvz for a "SAFE SPACE" here!

jftu105

 

[195910]

I agree with the preventative repair, I have also changed the boots and repacked the joints 2 years ago to prevent them from going bad.

lots of items you can save on these W124s, the parts were so high quality that preventative maintenance can keep them going with no issues.

 

[gerryvz]

JTFU,

I agree that breached ball joints can be saved, as long as they are not too far gone. It's a judgement call, and I'd also factor the overall mileage of the car (or the last time the LCAs were replaced, if they ever were) into the equation. Meaning that if my car had 200K miles on it, breached ball joint rubber that was not super fresh, I'd probably go ahead and replace the LCAs. Otherwise, if it was a fresh breach and not huge, and lower mileage, I'd probably go your route and repack & replace the boots.

How's that for a Q*baert answer?

Cheers,
Gerry

 

[jftu105]

If your answer is not an unconditional replacement of the entire LCA, you will be Q*baserted totally, piled on by all others, like vulture attacks. Asked me why I knew.

Ball joints are made of hardened steel, polished to mirror finish. If the ball joint appear rusty or badly scared, or already with play, I will replace it too. My E320's are all in 120-150,000 miles and I discovered the torn rubber as soon as possible (as I inspect them). They are still tight and with mirror finish. All of them still have grease in it, but the grease is of course dark. After cleaning, the ball joint is shinning and pretty again and still tight. When everything is back, do the tire shaking test again to make sure no play. Do the tire shaking test before attempting boot replacement.

Wear is a mechanical process, which typically takes time for proper wear resistant material. This is another reason why I don/t trust those new LCAs because they might not be as wear resistant.

jftu105

 

[gsxr]

If the late, non-replaceable ball joint has zero play, and no visible dirt/debris has entered when the torn boot is removed... it's definitely worth a try cleaning, re-greasing, and replacing the boot with new OE. If so, check the ball joint for play at each oil change afterwards. There is usually plenty of warning (i.e., measurable play) before they get anywhere near failure - at least for the OE ball joints (not aftermarket). If there is ANY play... the entire LCA is junk. And if significant dirt/debris has entered... I wouldn't risk it. Re-booting is generally a good idea if you catch it early and the tear is small.

That said, since the price dropped on new late-style OE LCA's, if the boot is torn, and rubber bushings are tired... I'd just shell out for complete new LCA's. Back when they were $500 each, yeah, I'd re-boot them (and replace the bushings with OEM Lemforder). ~$125 per side and it was refreshed, ready to roll. Now the Lemforder bushings are aftermarket (not OEM), and new OE MB LCA's are $185 each delivered from Napsterville - not worth messing with while you can still get them at these prices:

https://www.mboemparts.com/oem-parts/mercedes-benz-control-arm-1243303407
1990-2002 Mercedes-Benz Control Arm 124-330-35-07 | MB OEM Parts


Sportline versions with stiffer bushings are still pushing $400 each discount ($525 MSRP).

1990-1994 Mercedes-Benz Suspension Control Arm 124-330-36-07 | MB OEM Parts
https://www.mboemparts.com/oem-parts/mercedes-benz-lower-control-arm-1243303707




The standard late LCA's (#34/35) went NLA in June 2020; right side went NLA first.
The Sportline LCA's (#36/37) went NLA in March 2023; right side went NLA first.

Best option if you need a pair is to buy good used LCA's from a car that was not in a front-end wreck (you don't want bent LCA's!), with ball joints that have zero vertical play, and rebuild them with a new grease boot, fresh grease, and new OE/Genuine bushing kits. Don't buy the cheap Febi/TRW late LCA's, for reasons explained later in this thread.

 

[kwontumspeed]

If the late, non-replaceable ball joint has zero play, and no visible dirt/debris has entered when the torn boot is removed...

Thanks. I was in the process of typing up some questions but this closes the loop for me. Although I just flipped 260k with no play, no rip, nada, I feel like I can't ignore these prices for the whole assembly. Shirley the grease is far gone by now and the bushing are original but holding. I've always been anxious about the LCA grenading at some point even though everything look and feels copasetic.

 

[gsxr]

If you plan to keep a 124 long term, I'd consider hoarding a pair of the Genuine MB late LCA's at the current pricing. Never know when they will either go NLA, or the price will go back to where it had been previously. But yeah, if the joint is tight & sealed and the bushings are decent, I'd keep using them until something actually needs replacement (unless restoring a vehicle, replacing most of the suspension, yadda yadda...)

 

[kwontumspeed]

If you plan to keep a 124 long term...

Done and done. Now that I'm keeping her, wanting to refresh the whole front end with new shocks(200K), fresh 1 dots, sway bar bushings(036) and odds and ends. With fresh new LCAs to round things off I won't be fretting on any part of the system for a long while.

 

[Bogeyman]

Dave: Will these fit my '87 TDT?

 

[gsxr]

Dave: Will these fit my '87 TDT?

Yup! The late LCA's fit all years/models of 124 chassis. IMO they are an upgrade, as they allow wider selection of front brakes, and the late ball joint seems to last almost indefinitely if the boot is not compromised (at least on OE LCA's). I have several with 200-250k miles and zero play in the BJ.

Edited to clarify mileage.

 

[IslandMon]

The late ball joint seems to last almost indefinitely if the boot is not compromised (at least on OE LCA's).

Does anyone know of a good product to treat the boots with to prolong the life of the rubber?

Asking for a friend that bought the OE control arms that dropped $200 each after spending $400 each... haha ouch

 

[jftu105]

Good to know these new LCAs are good. However, 200 km is really not that much, which is about 125k miles. It is considered low milage. The three rebooted LCAs I recently did are all about 125 to 140,000 miles.

When W124 were plentiful at the junk yards, about five to six years back, I witness almost all LCAs on those cars had torn boots. Rubber cannot last 200 km but hardened steel of ball joints can last much longer when properly lubricated. In comparison, tie-rods wear out a lot sooner. Tie-rods have smaller ball joints, i.e. higher contact stress for the same force.

I used to reboot the tie-rods too because I don't want to do the alignment for additional $100. Boy, how I was vultured over at the BZworld when I announced my rebooting effort.

The boot costs about the same as a tie-rod end. Now, I just replace tie-rods and then do the DIY alignment. My tires have been wearing evenly.

jftu105

 

[IslandMon]

Good to know these new LCAs are good. However, 200 km is really not that much, which is about 125k miles. It is considered low milage.

He said 200k miles. I do agree that is a lot of miles/time for a dust boot to survive for.

 

[jftu105]

My fault, somehow, I read it as 200 km.

jftu105

 

[gsxr]

Klink has stated in the past (on the forum, somewhere) that some aggressive wheel cleaners, or other "detail" products, can radically degrade rubber items like ball joint or tie rod boots. In general I'd apply any dressing that claims to prolong the life of rubber items. From memory, some Wurth product was recommended, at great cost.

I've found far more tie rod boots failed than ball joint boots. The V8 tie rod assemblies aren't cheap, and alignments are usually $150+ at the dealer. If you can catch the tie rod boot failure very early, so it's just barely started to split, these can often be re-booted safely (again, assuming zero play, no dirt/water entry, etc). If the boot has been split for a long time - i.e., split most or all the way around - time to buy all new steering links and shell out for a dealer alignment; after checking any other items that could be alignment-affected.

 

[samiam44]

I'm not apposed to rebooting. If you check them at oil changes.. get them before they rust. Polished steel against a polymer plastic won't wear the metal. But at some time, depending on road conditions the plastic will fail.
The tie rods see heat and that is their demise.

 

[samiam44]

Any rust pits in the radius of the ball to shank.

 

[kwontumspeed]

Now the Lemforder bushings are aftermarket (not OEM)...

What's the indicator that these are not OEM? If not made in Germany?
I have a bushing kit in my stash bought while diagnosing an issue with the 036. Bought the kit, never used it, but bought them >10 years ago.
Correct PN: 124 330 06 75 (made in Brazil) - individually marked 124 333 42 14, 8018(2), 124 333 43 14, 8011(2)

Crap?

 

[gsxr]

OEM Lemforder bushings years ago were made in Brazil and had the MB part numbers stamped in the rubber, identical to OE/Genuine bushings.

The new version (circa 2018) are made in Spain, have NO part numbers on the rubber, and are heavily scented of Harbor Freight.

 

[kwontumspeed]

Looks like I'm good. Not sure what I'll do with these but let em keep the other parts company....

124 333 43 14:

124 333 42 14:

 

[jftu105]

The ball joints of LCAs or tie-rods are made of metal, both the ball and the socket, not metal and plastic. The lower control arm ball joint has to sustain a pulling force (recoil of the coil), which is about 1/4 of car body weight on each tire. It is actually lower but we can design it with safety factors to assume 1/3 of car weight for each LCA ball joint. The force is pulling the ball joint of the LCA off; therefore, the wear is between upper semi-sphere of the ball and the top portion of socket. this is actually a good news because the dust particles can be cleaned more effectively on the upper portion. The ball joint is also a surface contact, which reduces the contact stress, for a lower wear rate. In comparison, ball bearings have point contacts with high stress concentration, while roller bearings (wheel bearings) have line contacts. Wheel bearings are surprisingly long lasting, considering the force, rotation (and slip), and heat they have to deal with.

Tie-rods and LCAs are seeing similar heat conditions, near the engine but not close. The forces on the tie-rod are along the tie-rod axial direction, which means that the wear is on the side of the ball and the socket. The forces are related to the steering when making turns. People like to drive fast during cornering will wear out their tie-rods sooner.

Whatever people choose to do, replacement or rebooting, we have two LCA boots, four tie-rod boots, and two more of the center link boots, together 8 boots to watch for. I might have missed some. These boots ain't cheap and the labor is not cheap either.

Other rubber parts to worry about include:
1. Exhaust hangers
2. Rubbers of engine mounts and transmission mount
3. All bushings
4. The rubber boot of the main drive shaft (it failed on me once to cause noise when the car is moving)
5. Belt tensioner
6. Serpentine belt
7. Harmonic balancer (very expensive repair)
8. Differential mounts
9. All cooling hoses
10. All fuel hoses
11. All brake hoses
12. Flexible couplings (two of them)
...

I am getting scared if I keep going. It seems that every car is a disaster waiting to happen.

jftu105

 

[gsxr]

samiam44 cut apart an OE and aftermarket ball joint... the metal ball sits in a plastic shroud, which is then encased in the metal outer shell. But there is a plastic piece separating the metal ball from metal housing, in all directions. Link:

https://www.500eboard.co/forums/index.php?threads/late-lcas-oe-vs-trw.4618/post-66491

About the tie rod boots... I generally re-boot on vehicles (not E500E's!) I'm trying to avoid sinking $$$ into, if the linkages are tight and tire wear is normal. For "keeper" vehicles (E500E), I generally end up replacing almost every suspension item (especially front suspension/steering, and rear subframe bushings) and shelling out for a dealer alignment - once. Alignments are too expensive to have to get one every couple years if you wait for the next part to wear out. Preventive/predictive maintenance will cost more up front but save money in the long run.

 

[gerryvz]

That's a nice list of "chassis rubber" JF .... replacing this oft-overlooked, worn-out collection of rubber is a core tenet of my "GVZ $5K / $10K Deferred Maintenance" that all V-8 W124 models carry, depending on their mileage.

 

[jftu105]

Link to your deferred maintenance kit, GVZ $5k/$10k?

jftu105

 

[jftu105]

gsxr: the metal ball sits in a plastic shroud, which is then encased in the metal outer shell. But there is a plastic piece separating the metal ball from metal housing, in all directions.

I learn something new every time I read gsxr's posts. I am amazed that the ball joint of LCA is a metal ball covered by plastic and then encased by a metal housing. I cannot believe how long this plastic can last. I would think that they might choose compatible metals to reduce wear. My camera tripot ball joints are made of metal entirely. I can understand that it sits on a piece of plastic because the force is pulling, not compressive. But also against a piece of plastic on the upper sphere?

I am even more scared now. No febi or TRW for sure. I better go buy a few of those OE LCAs in the links provided in gsxr.

jftu105

 

[jftu105]

As I was surprised by the plastic bearing used in the ball joint of the LCA, I did more digging on the ball joint design. I came across this patent by Mevotech, US 8,757,648 B1, and it describes nicely the OEM design of ball joint and their new invention.

Here are some key description. As the figures below. The first one is the lower control ball joint and steering knuckle. The second one, as prior art, is the OEM design, in which a polymer bearing (#16) is used to mate with the steel ball. The third figure is the new design of Mevotech, in which the seat is sintered metal (#22) and the socket is the hardened steel (#21). In the fourth figure, it shows that the new invention with metal bearing will have much lower wear.

I am still surprised by the use of polymer bearing and how long the ball joint actually last. The major threats are the heat from the rotor and the brake dust.

Below are some texts from the patent:

US 8,757,648 B1​

​

An example of accelerated wear and deterioration is seen in the Suspension and steering system of a vehicle having a control arm forged or cast of a lightweight non-ferrous mate rial such as aluminum where the outboard end includes a ball joint mounted in a socket with polymer bearings. Various factors of the OEM design contribute to accelerated wear, premature failure and repair expenses.​

​

Polymer bearings deteriorate in high heat conditions. The abrasive brake dust penetrates into the ball joint and is captured in the lubricant between moving parts which causes increased wearing of the polymer bearings.​

The choice of polymer bearings for the ball joint combined with increased exposure to heat and dust from braking there fore has resulted in premature failure. Brake dust, road salt and sand particles can penetrate the seals of a ball joint and mix with the lubricant grease. The wear experienced by the polymer bearing is accelerated and causes excessive axial and radial play in the ball joint.​

dd weight or both. For example, the aftermarket parts industry has improved ball joint lifespan and durability by using sintered metal bear ings manufactured from metal powder which have advan tages over polymer bearings. Sintered metal bearings are porous and the lubricant penetrates the bearing surfaces improving lubrication of the Surfaces of adjacent moving parts. Sintered metal is more durable at lower temperatures better than polymers and withstands high temperature envi ronments better than polymers. Sintered metal has better wear characteristics than polymers and sintered metal does not degrade due to chemical incompatibility with grease formu lations like polymers. Replacement of sintered bearings for the polymer bearings of an OEM control arm assembly is relatively simple when done by a replacement parts manufacturer.​

a ball joint having: a steel housing with an externally threaded surface and an inner chamber; a ball stud with a partially spherical ball head upwardly restrained within the inner chamber and a shank extending upwardly through an upward opening in the housing; and a bearing having a partially spherical inner Surface engaging the ball head and having an outer Surface engaging the inner chamber; wherein the housing has a laterally extending collar with a lower contact Surface that engages the upper mounting Sur face of the control arm when the threaded surfaces are fully torqued together; and wherein the ball head has a center of rotation laterally adjacent an upper portion of the outboard wall, the upperportion having an upper wall thickness greater than or equal to a lower wall thickness of a lower portion of the outboard wall. To avoid direct contact betwe​

ssembly 8 where a socket is machined in the outboard end to house polymer bearings 16. The spherical ball head 15 is secured in the socket with a closure plate 17 and the stud shank 18 extends to be connected with the bolt 13 to the hub carrier 4 as indicated in FIG. 3. The minimum wall thickness W determines the imaginary operating envelope 19 within which the control arm assembly 8 rotates about the ball head 15 and likewise determines the OEM clearance C shown in FIG. 3. FIG. 6 shows the example embodiment of the invention with a slightly larger imaginary operating envelope 20 which consequently provides a slightly smaller clearance dimension C" shown in FIG. 4. However within the confines of the operating envelope 20, the maximum wall thickness W has been found to have sufficient load resisting capacity to allow use of a steel threaded housing 21 and sintered metal bearings 22, as better shown in FIG. 7. FIG. 7 shows a close up view​

In the embodiment illustrated, the housing 21, ball head 15 and shank 18 are made of steel. The partially spherical upper bearing Surface of the housing 21 and a matching portion of the ball head 15 are case hardened for enhanced wear resistance.​

Enjoy.

jftu105

 

[gerryvz]

Link to your deferred maintenance kit, GVZ $5k/$10k?

jftu105

https://www.500eboard.co/forums/ind...-157kmi-30k-diamond-bar-ca.12825/#post-178338


https://www.500eboard.co/forums/ind...-420-or-going-back-to-volvos.6086/#post-92421

https://www.500eboard.co/forums/index.php?threads/buying-low-miles-money-pit-e500es.5655/#post-85366

https://www.500eboard.co/forums/index.php?threads/wtb-1994-e500-under-20k.12510/#post-175202

https://www.500eboard.co/forums/ind...-ebay-west-memphis-arkansas.8384/#post-125483

 

[Melville]

I am getting scared if I keep going. It seems that every car is a disaster waiting to happen.

If any owner of a 25 year old high performance German machine intends to keep that machine in proper condition and does not say this to himself with regularity, he probably doesn't have the sense to accurately understand his situation.

 

[gerryvz]

No febi or TRW for sure.

If I remember correctly, TRW makes an "aftermarket" line of LCAs, and is also (or at least, has been) the OEM for MB's own 124 LCAs as well. They have made two different quality lines of products, with the MB LCAs being the better quality line.

You have to remember that Febi is NOT a manufacturer, they are merely a re-boxer of other companies' products. In 90% of cases, Febi re-boxes chinese junk parts. In a few documented cases, such as the SGF flex discs, they do re-box quality/OEM products that MB uses. But, you MUST be judicious in your research so that you don't get burned. This site has generally documented cases where Febi boxed parts are safe, but they are very rare.

This is where this site's wisdom dramatically eclipses the "experts" such as Q*baert over at Banzworld 124. Q*baert is going to tell you if you have a bad LCA, reflexively, that you are using "eco-junk" wiring and that you MUST replace your wiring harness before touching your suspension, or any other part on your car.

 

[Melville]

This is where this site's wisdom dramatically eclipses the "experts" such as Q*baert over at Banzworld 124. Q*baert is going to tell you if you have a bad LCA, reflexively, that you are using "eco-junk" wiring and that you MUST replace your wiring harness before touching your suspension, or any other part on your car.

This is not technically accurate Gerry. The first response is always to change the OVP. I've looked at threads for my wagon where someone is asking something that I exactly want to know. The discussion doesn't even touch on that question and instead talks about OVPs. More times than I can count.

 

[samiam44]

There is nothing new in a cast iron seat with a hardneed steel ball. But, to be longer life they must get regular fresh grease. This is the moog problem solver design for the past 30+years. The oe''s found that the majority of the owners did not grease. Polymor does fine except in overload situations like hitting a bad pot hole.

Didn't grease.

Product lines. I didn't realize the division until a friend from Behr explained they reverse engineer aftermarket parts. If mb paid for initial development and tooling. Aftermarket is probably made in a different factory.
The finger design is much weaker and that one had failed which was cut open. I did the reboot and grease to a factory joint. There are press in grease ftgs and you could add one to help purge the old grease and fill it. I never tried it with the drop in control arm prices.
Oe control arms may use a trw joint, but the welded assembly could made by any mb approved vendor.

 

[gerryvz]

This is not technically accurate Gerry. The first response is always to change the OVP. I've looked at threads for my wagon where someone is asking something that I exactly want to know. The discussion doesn't even touch on that question and instead talks about OVPs. More times than I can count.

That is also a "go-to" catch-all, most certainly. There are a few others common "fixes" prescribed there, too.

I always enjoy the threads there where they tell LH V-8 W124 owners to change their OVP. I miss the days when Clark Vader used to get into it with them.

 

[samiam44]

Do you expect the same fan belt life between the continental made in Germany vs china? It is much cheaper, but some of that lies in the specs and not just mb markup.

Tell them to buy the uro ovp relay.

 

[gerryvz]

Continental belts (and rubber products in general) are not what they used to be 5-10 years ago. I saw the quality of the Conti belts go south when I lived in Texas, and my shop-owner friend confirmed it with regard to the belts he used on customers' cars. The Texas heat took its toll -- rapidly -- on the Conti rubber belts.

 

[gerryvz]

Tell them to buy the uro ovp relay.

I used to tell nocfn to buy KAE products.

 

[samiam44]

Makes you wonder what changed

My dealership friends still get good belt life to the factory belts. Next time, it will be one with the star.

 

[JC220]

Gates belts are what I am using now myself. They are an OE supplier to MB. My S430 W220 had its original gates belt with 145 ish K miles on it still serviceable. But I installed a new Gates belt anyway.

A note on Febi - yes they get / got bashed for Chinese parts. But more recently I am getting lots of German made OE parts in Febi boxes - in nearly all cases actually. I have a large stash of spares on the shelf and in there are some new Febi boxes items. (Brake parts, bearings, transmission filters, transmission seal kits + rad caps etc) I will post photos of those parts so all can see soon on the parts quality list on here.

In my opinion Febi may no longer belong at the bottom of the w124 parts supplier list. And Lemforder should drop, or likely will have to soon since they are pedalling Chinese engine mounts..... just sayin. Where Lemforder were a sure cert for OE quality parts their offerings are for sure getting sketchy.

 

[samiam44]

Oh, maximum steering forces are induced when parking with a speed @0.0mph. Always creep when turning. Teach your kids in an old car without ps.

Gates purchased continental product line.. correct?
I buy mainly oe. The dissatisfaction of doing a job over out weights the saving 95% of the time.

 

[jftu105]

The steering force and the turning torque at the wheel are two different things. When you try to turn the tire, parked, you are simply rotate the tire and the friction keep it from turning easily but your car is not cornering, no lateral force. When you are cornering, you have to change direction. The direction change comes from a lateral force generated by the tire slip angle. This directional change is also the result of the centripedal acceleration, which is m v^2/R. Higher speeds or shaper turns need higher lateral forces. This steering force is actually forming a counter torque, becasue it is behind the center of the tire contact patch. When you make a turn and then let go the steering wheel, it rotates back due to this counter moment. The feel at the steering wheel and the actual force at the tire and the tie-rods are different.

jftu105

 

[samiam44]

You never exceed 1g lateral acceleration on the street. Mechanical forces on the joints are higher. Now the ball joint and suspension sees higher loads in turning events.
Have you ever driven an America rwd car or truck without power steering? Your hypothesis of the loads being higher are incorrect. Suspension loads yes, steering no.
I truly appreciate the effort it requires to r&r the boots. Kink is correct, rubber doesn't hold up to alkaline wheel cleaners..
If the lower ball joint got so hot to have any issues from braking, you would be able to keep paint on the wheels.
Tapered wheel bearing are very lowly loaded compared to their ultimate dynamic rating. Flex disc, I think are 20:1 according to the sgf design manual.

Just trying to give my opinion and correct things as a structural engineer whom put hiself through school turning wrenches.

 

[jftu105]

If you actually do a force analysis, you will know what I am referring to. You can turn a wheel when parked. While turning, you experience high torque to overcome friction, but once turned, it reaches its equilibrium and no force anymore, despite the tie-rod may looks like pulling one side big time. A four-bar linkage can reach different positions but forces are not related to the position. When you are corning at high speeds, the lateral force needed to make the turn is huge. Let's say that you make a sharp turn, requiring 0.5 g centripetal acceleration, then the force is equivalent to half of the car weight, or 1500 lbf for a 3000 lbf car (not that uncommon). These forces are distributed to all four tires, but you are still looking at 400 lbf forces at each tire. Of course, this force is not taken by the tie-rod entirely, but by the entire tire structure/suspension/steering mechanism, mainly through the ball joint of the LCA. However, this force is not at the center of the tire, as I stated in the last post, and the tie-rod is needed to sustain the resulting moment of the steering force.

Unless one is willing to sit down and draw a proper free-body diagram, the discussion of forces is quite futile. Interestingly, engineering students after four years learning, many of them (over 90%) cannot draw a correct free-body diagram. Feeling could be very misleading when it comes to forces. When you brake, your body moves forward. The feeling is that there is a force to push you forward, but in fact, the force is to slow you down in the opposite direction. Therefore, if we want to discuss the force to the tie-rod ball joint, let's draw a free-body diagram and go from there, not citing the experiece of turning the steering wheel.

jftu105

 

[samiam44]

jftu105,

Interesting notes, and I DO FBDs every day as a stress engineer with many years of experience. The spindle end with the line of force action is a distraction to the topic. Yes, you are welcome to measure the spindle geometry- got one laying in my shed. You can solve either unknown by knowing the other as long as you have enough equations. 400 lbs at the tire. But the steering force, that a person can sustain for long periods is fixed by human factors(There's a nasa handbook on human factors). For a limited time, as in parking, it is a higher value. This creates a moment (lb-ft) in the shaft which is multiplied by the steering box. Output is a torque which is applied to the steering gear arm (distance) which produces the total maximum load on the tie-rod.
So it's not antidotal, but attacking it at an end for the common reader. The steering force is measurable(without PS) and is greater due to the static coefficient of friction of the tire to the road. When it is rolling, the force is reduced.

This all started out friendly and I think it's out of control. Simply pointed out statements which were false in the beging about the construction of the ball joint*BECAUSE* I was the one which dissected the ball joints to dispel the previous belief on this forum that the OE and OEM TRW joints were identical.

Sincerely,

Michael

 

[jftu105]

We are still talking about two different things. The torque to turn the steering wheel and the force acting on the tierod are not always directly related. If you are cornering, at 0.5g, the tie-rod needs to take up the steering force so that the tire stays in the same angle. You are not turning the wheel. If you are parked, there is no force acting on the tie-rod if the tire is turned at a fixed angle. In the mean time, if you are parked and you want to turn the tire, you need to overcome the friction between the tire and ground. The friction force has nothing to do with the steering force needed to make a turn.

I will send you a FBD analysis privately so that we don't bother everybody on the 500E board.

jftu105

 

[Gatorblue92]

I recently did a full rebuild of the front steering and suspension parts on my 93 400E and ended up using some NOS Lemfoerder parts for the tie rods and the idler arm bushing. I did roll the dice on some TRW branded lower control arms since I'm trying to keep this car going on the "cheap" I also figured that even with the possibility of these only lasting a few years they are still far better than the ones I removed which were barely still holding together.

 

[JC220]

I recently did a full rebuild of the front steering and suspension parts on my 93 400E and ended up using some NOS Lemfoerder parts for the tie rods and the idler arm bushing. I did roll the dice on some TRW branded lower control arms since I'm trying to keep this car going on the "cheap" I also figured that even with the possibility of these only lasting a few years they are still far better than the ones I removed which were barely still holding together.

Have you installed the TRW LCA's yet? If not, I would be very interested to see pictures posted of TRWs current aftermarket 124 control arms when they get there etc if you don't mind. I know that my recent Febi control arms had addressed the crap clear boot issues.

 

[gsxr]

I recently did a full rebuild of the front steering and suspension parts on my 93 400E and ended up using some NOS Lemfoerder parts for the tie rods and the idler arm bushing. I did roll the dice on some TRW branded lower control arms since I'm trying to keep this car going on the "cheap" I also figured that even with the possibility of these only lasting a few years they are still far better than the ones I removed which were barely still holding together.

If you haven't installed them yet... send 'em back. I don't know how cheap TRW-branded LCA's are, but at $185 each for Genuine MB delivered, there can't be enough savings to make it worth the gamble.

BTW - the OE LCA's now have clear boots, but are otherwise identical to the original LCA's. I don't think it matters if the boot is clear or not, as long as it stays in place through full range of motion.