SLS Delete

[500AMM]

Installation of rear Koni's
Test Drive: I'm actual very happy with the results, the car has much more feeling with the road and it's actual still comfortable.
So I'm planning deleting the SLS, installing a 400E/500SEL pump and remove the old pipes.

Hi Dan.

So, then you are almost done with the SLS-delete, looks OK.
How is your camber with that low ride height at rear?

Are you sure about deleting the hydraulic tubes all the way from the SLS-valve to the pump and oil reservoir? I think you have to cut them apart to get them off, which means you get a comprehensive job if you or a future new owner reconsider to add the SLS function again. I will leave those pipes oil filled and blinded on the car. The threads on the fittings on the supply and return lines are M12x1, which is not so common to find blind plugs for. So one option is to leave the SLS-valve in place connected to the tubes, but with plugged ports to the struts, they are M10x1. Instead of the copper washer plug type, you get plugs with conical sealing face inside if wanted.

Cheers

(BTW, I have decided to go for Bilstein B8. Will be done during the winter hibernation.)

 

[jhodg5ck]

Thanks...The beauty of Mercedes is 9 time out of 10 you will find a Very nice finish under what ever grease/grime is lurking.. I find that to be the case all around the car.

Yes, that is a fender lip roller..which if you Really push it will flare the fenders just a bit more. That and a body dolly to get some of the Hard edges does a nice job

Jonathan

 

[borring]

I got a Power steering pump from a from a 1992 500SL - so i can delete the SLS for good.
Has anyone replaced a steering pump on a 500E before? is it a hard job?
And is there any parts i should consider replace while im at it?

 

[Egreaves20]

Do you really need to replace the steering pump? My SLS has a leak below the rear passenger door area and the reservoir has been empty for years, with no power steering issues.

http://slsconversion.com/How_To_Install.html

"Disabling the SLS System: All of the SLS lines, supply bottle and other components can be left on the vehicle just in case you decide to return the vehicle to stock configuration. The SLS pump on the w124 vehicles is incorporated into the power steering pump. To disable the SLS function of the dual pump, simply replace the banjo bolt the provided bolt into the banjo fitting which will not allow hydraulic fluid to be pumped into the system."

 

[Egreaves20]

SLS Conversion sent me a SLS hose delete plug (bolt) for the 500e tandem pump. Seems like a good alternative to swapping PS pumps from the 400e.

 

[Jelmer]

You're going through with the SLS-Delete?

 

[Egreaves20]

Yes, will update once done.

 

[500AMM]

Do you really need to replace the steering pump? My SLS has a leak below the rear passenger door area and the reservoir has been empty for years, with no power steering issues.

http://slsconversion.com/How_To_Install.html

"Disabling the SLS System: All of the SLS lines, supply bottle and other components can be left on the vehicle just in case you decide to return the vehicle to stock configuration. The SLS pump on the w124 vehicles is incorporated into the power steering pump. To disable the SLS function of the dual pump, simply replace the banjo bolt the provided bolt into the banjo fitting which will not allow hydraulic fluid to be pumped into the system."

As for the tandem PS pump with dual functions - it is two separate pumps on the same shaft, sealed off in individual chambers. So if the SLS is emptied, the PS pump is still operating, or vice versa.

The reason I wouldn't run with blocked ports on the SLS pump is simply the risk for a pump breakdown due to missing lubrication. Keep in mind that the SLS pump is still running and it needs lubrication. Even if the SLS pump and reservoir is emptied, it's always some residual oil left in the cavities, but is it enough to maintain a satisfactory lubrication of the internals and withstand any heat build up?? Well, IMO it's not.

Another option is to dismantle the SLS pump by taking out the pump internals, see enclosed image. The parts at right is the SLS pump internals, except for the part down right which is the shaft sealring on the front end (installed in the bottom on the pump housing on the image).

 

[Egreaves20]

Understood. The new banjo bolt replacement from SLS Conversions will keep the SLS fluid from being pumped through the lines to the rear of the car. The SLS reservoir will still be in place with some fluid in it to ensure the SLS side of the tandem pump has some lube.

 

[borring]

I can confirm that the H&R springs for 500E SLS is not working, they are simply to soft to take the load from the Koni's and they are 10mm short.

rear spring our of 29855HA
wire diameter: 13,50mm
free length: 295mm
total number of coils: 10,0
sprign rate: 85N/mm

Last night I mounted a w210 E55 AMG spring which is much stronger (with w210 pads), the only problem is they are too long, of cause they can be cut off, so I investigated H&R for the w210.

Here´s the data. Please note that 52724 is a spring set exclusively for H&R USA (E55 AMG) which is not available in Europe.

rear spring our of 29724 HA
wire diameter: 14,50mm
free length: 305mm
total number of coils: 9,25
sprign rate: 80N/mm

rear spring our of 52724 HA
wire diameter: 14,50mm
free length: 305mm
total number of coils: 9,25
spring rate: 90N/mm

These springs are exactly 10 mm longer, the wire diameter is also stronger, but can someone explain the spring rate impact for me?

 

[500AMM]

Dan,

The formula for linear springs called the Hooks law: F= kX where F is the force, k is the specific spring rate, X is the compressed length. If we put in the numbers when the springs are compressed say 60 mm, which is close to what the spring actually is from free length to the car is resting on the springs:
F= 80 N/mm x 60mm = 4800 N
F= 90 N/mm x 60mm = 5400 N

F=mg where g=9,81 and converting to more understandable values in kilograms:
4800/9,81 = 489 kg
5400/9,81 = 550 kg
This is the difference in the weights needed to compress those two springs 60mm

How to compare the springs
If your car compresses the strongest spring say 60mm, how much does the weakest spring compress until it reaches the same resistance as the strongest:

F will be equal in both cases so F₁ = F₂ giving k₁ X₁ = k₂ X₂

X₂ = (k₁ X₁)/k₂ = (90x60)/80 = 67,5 mm

In percent: 100% - 67,5/60 = 12,5 % more compression
This is linear springs so it can be shown directly using the spring rates: 100% - 90/80 = 12,5%

So at a given length the weakest spring compresses 12,5% more.

My 2 cents

 

[borring]

Thanks for the explanation.
If i want to compare these two to understand if it will fix my problem, what are the numbers as the wire diameter is different?
At least my option is 1 cm longer and the wire diameter is also stronger (if the steel is same) but how can it be less stiff?

My curremt ones (29855HA) which is to shot and soft:
wire diameter: 13,50mm
free length: 295mm
total number of coils: 10,0
sprign rate: 85N/mm


Compared with ones from the w210 (29724 HA)
wire diameter: 14,50mm
free length: 305mm
total number of coils: 9,25
sprign rate: 80N/mm

 

[500AMM]

Those spring rates may seem contradictory, but it is only 6,25% difference. The spring rate is a result of the entire design of the spring, where every geometrical change will count. Supposed that the parent material is the same - which I belive it is since it is the same brand, it is the design on the springs.

Those two designs are quite close, but it is two main factors counting, the pitch and the wire diameter. The steeper/higher the pitch is, the stiffer the spring is. And the larger the spring wire is, the stiffer it is. So that spring factors looks odd.

However, do keep in mind that the springs will soften over years, so it is a big difference between new springs compared to a say 5-6 seven year old springs. So comparing a used spring of one type, with a new unused spring of another type, with that small difference in spring rate, will likely give abnormal measures. At least you should let the new springs settle on the car for a month or so to get a correct comparison. Based on the images you Emailed me yesterday, my guess is just the age on those two spring types.


-a-

 

[gsxr]

29-855-HA springs are progressive (coil spacing differs along the length - see photo below). It's not stated if 29-724-HA and 52-724-HA are also progressive, but i bet one or both are, since the specs are identical except for the spring rate. I believe that can only be possible with the coil spacing varied (progressive spring rate).


Dan, what you need are the 30-230 springs, but I believe they are NLA / out of production. See if H&R can provide specs for the 32-230 rear springs, and then choose which of the W210 springs are closest to that spec.

 

[Egreaves20]

I have Koni yellow sports set on full soft all the way around, with the factory SLS springs. The car sits level, and handles beautifully. Very happy with this combo. I tried the H&R non-SLS springs with the Konis and the car just sat too low for daily driving.

 

[borring]

Reply from H&R:

Sorry, but there is no 30-230 and there has not been a spring like this during the last 15 years.
I do not have any data for these. This is not one of our usual numbers, so I doubt that it shall be a H&R number...

and on my follow-up:
This seems to be an old H&R USA spring which we/ they do not have anymore and of which I have no data, sorry.

 

[gsxr]

Good thing we had the photos to prove we're not crazy, eh? Bummer they are NLA with no specs available.

 

[Jim]

Hydraulic Strut Replacement

I have been meaning to post this brief information for a long time...

My first 500E had the SLS struts deleted and the pump disabled.

It was fitted with Sachs Super Touring
Part Number 106 878
I thought the part number might be useful to someone.

It was drivable but a little low I recall...it's about 8 years ago now...

I tend to go with OEM design and parts so finding the SLS deleted was bad news...this was my first 036 and so knew little about the car when I brought it.

Anyway it is all OEM now...but the Sachs parts above came off my car in good condition, no idea how long they had been on the car;
I still have the struts (see picture) carefully stored in the boxes that the replacement SLS struts came in.

 

[Christian_K]

Re: Hydraulic Strut Replacement

Hi Dan.

So, then you are almost done with the SLS-delete, looks OK.
How is your camber with that low ride height at rear?

Are you sure about deleting the hydraulic tubes all the way from the SLS-valve to the pump and oil reservoir? I think you have to cut them apart to get them off, which means you get a comprehensive job if you or a future new owner reconsider to add the SLS function again. I will leave those pipes oil filled and blinded on the car. The threads on the fittings on the supply and return lines are M12x1, which is not so common to find blind plugs for. So one option is to leave the SLS-valve in place connected to the tubes, but with plugged ports to the struts, they are M10x1. Instead of the copper washer plug type, you get plugs with conical sealing face inside if wanted.

Cheers

(BTW, I have decided to go for Bilstein B8. Will be done during the winter hibernation.)

Thats awesome. I'll do it the same way most likely. So you plug the holes in the SLS leveling unit, that goes normally to the struts and spheres with a M10x1 Plug. What did you used to plug the "other side", means the threaded ends of the actual steel lines? With this method, is it then a looped system? Or will the Tandem pump "fight" against unlimited resistance?
Thanks for your input.

After installing my Koni's, the rear end lowered ~3 cm more.
(The car has H&R, Koni's + 1-point pads at the the rear and 4-point at the front)
View attachment 11676View attachment 11677

Test Drive: I'm actual very happy with the results, the car has much more feeling with the road and it's actual still comfortable. So I'm planning deleting the SLS, installing a 400E/500SEL pump and remove the old pipes.

Hi, I think it would look "OK" if you use the 3 point pads in the rear, do you agree?

I can confirm that the H&R springs for 500E SLS is not working, they are simply to soft to take the load from the Koni's and they are 10mm short.

rear spring our of 29855HA
wire diameter: 13,50mm
free length: 295mm
total number of coils: 10,0
sprign rate: 85N/mm

Last night I mounted a w210 E55 AMG spring which is much stronger (with w210 pads), the only problem is they are too long, of cause they can be cut off, so I investigated H&R for the w210.

Here´s the data. Please note that 52724 is a spring set exclusively for H&R USA (E55 AMG) which is not available in Europe.

rear spring our of 29724 HA
wire diameter: 14,50mm
free length: 305mm
total number of coils: 9,25
sprign rate: 80N/mm

rear spring our of 52724 HA
wire diameter: 14,50mm
free length: 305mm
total number of coils: 9,25
spring rate: 90N/mm

These springs are exactly 10 mm longer, the wire diameter is also stronger, but can someone explain the spring rate impact for me?

Hi again,
what you mean that springs are to soft for taking "the load from the konis" ? I don't understand that. Was the car driveable or not with the shorter H&R SLS Springs?

My plan is leaving the H&Rs for SLS in place and use 3 point pads with stock gas struts in the back.
What do you think? Driveable or not?

Thanks for all input.