Postby Chappardababbar on Thu Apr 23, 2009 12:25 am
My understanding is that the procedure is quite straightforward but I need some help with the details.
So SLS is on the rear suspension. I understand that a line(pipe) has to be disconnected from each rear wheel arch and is to be left to drain into a tub.
At this point you turn the engine on and let the system pump itself dry at the reservoir.
Just before the reservoir is empty you pour SLS fluid in and continue to do so until the fluid coming out at the other end is clean.
Stop, reconnect the line and repeat for the other side.
Stop, fill up the reservoir to the level indicated on the dipstick.
What have I missed?
Seems like an easy job but what exactly needs to be disconnected? What is this return line people speak of?
Chappardababbar
=================================
Postby Prime on Thu Apr 23, 2009 1:14 am
I'm sure someone else will chime in with the REAL right way to do this, but the way you describe seems overly complicated to me. The system is a full circle. The return tube empties fluid back into the top of the reservoir where it is filtered, to be sucked out and cycled through the system again - kind of like the human circulatory system. I have "freshened" the fluid by simply detaching the return tube from the reservoir and hooking a flexible hose to the tube that allows it to empty into a container on the floor. As the level goes down, continue to add fresh fluid to the reservoir until it has cycled through the system and returns from the return tube clear. As I said, this probably isn't the approved method, and perhaps it leaves some old fluid in the shocks/spheres, but it's how I've done it.
Whatever method you choose, I'd recommend against running the system dry. Pump cavitation is not your friend.
=================================
Postby gerryvz on Thu Apr 23, 2009 6:42 pm
Yes, Prime's system for doing this is a good method. It is wise to purchase 2-3 liters of fluid. You must purchase the correct fluid - it is commonly available, but you MUST have appropriate stuff specifically for hydraulic suspension systems. It's made by a number of sources; easily available at the dealer or aftermarket Benz part suppliers.
Personally I use the "Lowtemp" oil that is sold by the gallon by John Olson, editor of the SL Market Letter. You can see it here: http://amgmarket.com/marketsquare/merce ... tm#lowtemp
I've used it since my 6.9 ownership days (the 6.9 has front and rear hydropneumatic suspension ... and a total of 5 (yes 5 !!!) accumulators in the system) and it's worked well.
Just last night I changed out the accumulators on my 560SEC, and loosened system pressure through the bleed screw on the rear suspension valve (which the leveling arm attached to the rear sway bar attaches to, to adjust system pressure and flow). I would say that between what bled out the bleed screw, and the two (shot) accumulators, it was very close to a liter of fluid -- perhaps a half-liter without the busted accumulators.
The MB factory documents say to just take the drained fluid, filter it, and re-add it to the reservoir. I decided to just add new fluid that I had on hand.
So in short, it's best to use Prime's method, for the reasons he mentioned. Less chance for damage to the system.
Cheers,
Gerry
=================================
Postby 2phast on Thu Apr 23, 2009 8:58 pm
I also flushed my system using the same method Prime mentioned.
2000 CLK32k & 1993 500E
=================================
Postby Chappardababbar on Thu Apr 23, 2009 10:37 pm
Thanks for the method Prime. Did you wash the filter or buy a new one. What is recommended.
Gerry, my car has 130k miles on the clock and I'm pretty sure accumulators are original. On average when do the spheres/accumulators need to be changed and does it make a significant difference to the ride quality (mine is a little harsh).
Depending on cost, I'll do the SLS at the same time as the spheres.
Chaps
=================================
Postby wpirie on Fri Apr 24, 2009 1:37 am
Hi Chaps,
I changed both spheres at 145,000 miles, when I bought the car so I don't know how old they were, but the old spheres were genuine Merc parts. Ride was harsh on right rear side. You must change a broken sphere?it is the ?shock absorber? in your SLS. Without the shock absorbing facility you are stressing all rear suspension components. Coincidentally I had to replace the right rear wheel bearing soon after?maybe the failed sphere was a contributing factor? A sudden drop in SLS fluid level in the reservoir, with no apparent leaks is a sure sign of sphere failure?the nitrogen-filled rubber? bladder in the metal sphere has ruptured and the SLS fluid has moved in to fill the void. Fluid does not compress like a gas, hence the harsh ride. It?s a simple plumbing job to replace them, as long as rust is not an issue. Here is what I bought from autohausaz:
1403280215 Corteco/Febi-Bilstein
Self-Leveling Accumulator Sphere/Air Cell; Rear Left/Right
For models with self-leveling suspension system. 2 per car. $105.34
Enjoy the vastly improved ride! p.s. buy a new SLS filter, its cheap.
Ward.
=================================
Postby captruff on Fri Apr 24, 2009 2:18 am
Chappardababbar wrote:Thanks for the method Prime. Did you wash the filter or buy a new one. What is recommended.
Gerry, my car has 130k miles on the clock and I'm pretty sure accumulators are original. On average when do the spheres/accumulators need to be changed and does it make a significant difference to the ride quality (mine is a little harsh).
Depending on cost, I'll do the SLS at the same time as the spheres.
Chaps
The SLS filter is inexpensive, but if you decide to change out the SLS fluid reservoir it comes with a new filter. I recently helped another member change the SLS fluid and reservoir and there was a tremendous amount of sediment that had accumulated at the bottom of the reservoir, so if it within your budget, I would go ahead and change it out while you are there.
Jeff
=================================
Postby gsxr on Fri Apr 24, 2009 4:21 am
Here's photos of the SLS hydraulic fluid. The MB part number is on the rear of the bottle.
Here's a photo of the aftermarket fluid bottle:
:wormy:
=================================
Postby gerryvz on Fri Apr 24, 2009 5:08 am
There is no difference between the SLS and the spheres. The SLS is the overall system, and the spheres are the "shock absorbers" or damper elements in the system, working in conjunction (high-pressure hose) with the hydraulic rear struts and rear springs. Self-leveling is essentially a benefit of the SLS system, along with the damping. The system consists of the following elements:
- Fluid reservoir (located underhood in front of the engine)
- hydraulic pump (located on front of engine)
- hydraulic lines (run to back of car)
- rear leveling valve (mounted to rear underside of car with an arm extending to rear sway bar)
- two rear hydraulic struts
- two rear accumulators (black spheres located inside spare tire compartment)
There's no prescribed mileage to change the spheres. I just changed them on my SEC last night and that has mileage of 178K - I think it was perhaps the second time it was done (I will look in my records).
Basically you will be able to tell because the car will give you a rather jarring ride particularly over uneven pavement, cracks, speed bumps (taking speed bumps with a bad SLS even at 2 MPH will just about rattle your teeth out of your head) and so forth. You will feel even the SMALLEST cracks and imperfections in the pavement - driving over something as small as a garden hose will be very noticeable with a bad SLS.
The test to tell whether the spheres are bad (most people don't really watch their hydraulic fluid that often) is simple -- just go to either or both rear corners of the car. Push down HARD on the corner. If the SLS is working, it will go down a couple of inches and then back up in a smooth damping motion. If it's bad, you will only be able to force it down about 1/4-1/2 inch and it will feel very rubbery. Or use the speed bump test at 5-10 MPH. If your teeth fall out of your head, your SLS is definitely bad.
After I bled the SLS on the 560SEC, I took it for a test drive along a notoriously rough road near my house. Wow ! I thought to myself, "Cool, my SEC is back !"
The systems on the 560SEC and the E500 are very very similar, though they use different spheres and struts. But operationally, they are identical.
BTW, Ward is VERY correct that an SLS system with bad accumulators will eventually "blow out" the rear struts, simply because the struts and spheres are filled with fluid and there's no place for it to go except out the seals when the suspension is trying to absorb bumps. The struts are er .... rather expensive .... so be warned. However, I do believe they are rebuildable, but most folks just purchase new ones. At today's prices, they're gonna run ya about $400 bones -- EACH.
Cheers,
Gerry
Here's an exploded view of the rear hydraulic strut:
Here's the level control valve and how it attaches to the rear sway bar:
Here's the hydraulic oil tank and the two accumulators in the rear:
=================================
Postby Chappardababbar on Fri Apr 24, 2009 5:43 pm
Thanks for that Gerry,
Check this out, the ASR and ABS lights have been on, on my car for a while - ever since I bought it 9 months ago. I took it to a Porsche specialist who told me it was to do with an electrical problem to the injectors, which is why I bought a new harness and didn't really think anything of it.
Yesterday I took the car to an ex-MB technician who has just started his own enterprise who told me it was due to a fuse that had blown out (no. 10, a red one). He replaced this you won't believe the difference it made. It seems as though the entire system had locked out and had become unbearably harsh. I hope I didn't do the car too much damage during this time as I'm sure the chassis has progressively become looser as a result of the lack of any damping.
Anyway, much better now, but still not ideal. I think I'll replace the SLS reservoir as I'm changing the brake fluid reservoir and coolant tank as per Dave's suggestion anyway. Accumultors are ?110 each. They look perfectly fine but I'll make a decision based on how the ride improves after I replace the rear strut mounts (26 and 29 in your diagram I believe)
Chappardababbar
=================================
Postby gerryvz on Fri Apr 24, 2009 7:04 pm
You will be amazed at the ride with the new accumulators. Again, just give it the speed bump test, and you'll be converted. The stock E500E actually has a VERY nice ride.
Cheers,
Gerry
=================================
Postby Chappardababbar on Sun May 10, 2009 5:28 pm
Just changed out my fluid...but not using the method above.
I picked up the car after it had a new power steering pump fitted and whilst driving home I looked across at a traffic light and this woman was pointing at my car. I nodded back thinking "yeah baby, I know" but she became more frantic and I realised something was wrong. Pulled over and there was fluid gushing out from under the car. Heart attack moment.
I switched off the engine and opened the bonnet to find a hose had burst. Just below right intake tube. I didn't know what the hose was for but luckily I noticed the SLS reservoir was completely dry so I figure that a change in pressure due to new P/S pump caused it to split. luckily I had a whole bunch of hoses plus SLS fluid in the boot so I put one on and filled up.
Not quite a flush but good enough. Just need to figure out part number for the hose now.... Moral of the story is change SLS and P/S hoses in engine when changing pump.
Chappardababbar
=================================
Postby gerryvz on Sun May 10, 2009 8:44 pm
Wow, that must have been an experience ! Glad to hear you had the parts on hand to fix it. Not a bad thing to replace hoses - in fact most everyone's hoses are now overdue for replacement - heater, cooler, oil cooler, trans cooler, whatever. The ALL need to be replaced folks !
I was on the my way to my son's swim meet yesterday about 6:30 AM (hardly any traffic) and driving my 1989 560SEC about 5 miles to the pool. I was at a stoplight when I see smoke drifting up from either side of the front of the car. As I was about a mile from the pool I just continued on and parked in the lot, and walked him to the pool office to prep for warmups. Went back to the car and there was a puddle of fluid underneath it about 8 inches in diameter. I turned the engine back on to see where it was dripping from, and then turned it back off. Confirmed via the finger & nose test that it was indeed motor oil. :loser:
At 1PM, after the swim meet was over, I drove back home (carefully) and pulled the car into the garage, where I drove it up on a set of ramps. Got underneath (luckily had lined the garage with cardboard under the car to catch oil spill) and turned it on again. Finally with the help of a trouble light I could see where it was leaking from -- very strong drip stream. It was coming from one of the bolt holes that attaches the oil filter canister to the side of the block. Yikes ! This was a left-over bolt from my change of the lower wiring harness the night before (the bolt also held a small thin metal plate that had a plastic cable retainer on the other end of the plate) -- I searched where that bolt went and couldn't for the life of me find the hole under there, so I just put it on my workbench to check out the next time I was under the car. Well, the problem found me ! Needless to say, five minutes later the problem was solved, and a few shots of BraKleen (cleans up grease and oil fast) was enough to clean up the underside of the car. Whew!
Cheers,
Gerry
My understanding is that the procedure is quite straightforward but I need some help with the details.
So SLS is on the rear suspension. I understand that a line(pipe) has to be disconnected from each rear wheel arch and is to be left to drain into a tub.
At this point you turn the engine on and let the system pump itself dry at the reservoir.
Just before the reservoir is empty you pour SLS fluid in and continue to do so until the fluid coming out at the other end is clean.
Stop, reconnect the line and repeat for the other side.
Stop, fill up the reservoir to the level indicated on the dipstick.
What have I missed?
Seems like an easy job but what exactly needs to be disconnected? What is this return line people speak of?
Chappardababbar
=================================
Postby Prime on Thu Apr 23, 2009 1:14 am
I'm sure someone else will chime in with the REAL right way to do this, but the way you describe seems overly complicated to me. The system is a full circle. The return tube empties fluid back into the top of the reservoir where it is filtered, to be sucked out and cycled through the system again - kind of like the human circulatory system. I have "freshened" the fluid by simply detaching the return tube from the reservoir and hooking a flexible hose to the tube that allows it to empty into a container on the floor. As the level goes down, continue to add fresh fluid to the reservoir until it has cycled through the system and returns from the return tube clear. As I said, this probably isn't the approved method, and perhaps it leaves some old fluid in the shocks/spheres, but it's how I've done it.
Whatever method you choose, I'd recommend against running the system dry. Pump cavitation is not your friend.
=================================
Postby gerryvz on Thu Apr 23, 2009 6:42 pm
Yes, Prime's system for doing this is a good method. It is wise to purchase 2-3 liters of fluid. You must purchase the correct fluid - it is commonly available, but you MUST have appropriate stuff specifically for hydraulic suspension systems. It's made by a number of sources; easily available at the dealer or aftermarket Benz part suppliers.
Personally I use the "Lowtemp" oil that is sold by the gallon by John Olson, editor of the SL Market Letter. You can see it here: http://amgmarket.com/marketsquare/merce ... tm#lowtemp
I've used it since my 6.9 ownership days (the 6.9 has front and rear hydropneumatic suspension ... and a total of 5 (yes 5 !!!) accumulators in the system) and it's worked well.
Just last night I changed out the accumulators on my 560SEC, and loosened system pressure through the bleed screw on the rear suspension valve (which the leveling arm attached to the rear sway bar attaches to, to adjust system pressure and flow). I would say that between what bled out the bleed screw, and the two (shot) accumulators, it was very close to a liter of fluid -- perhaps a half-liter without the busted accumulators.
The MB factory documents say to just take the drained fluid, filter it, and re-add it to the reservoir. I decided to just add new fluid that I had on hand.
So in short, it's best to use Prime's method, for the reasons he mentioned. Less chance for damage to the system.
Cheers,
Gerry
=================================
Postby 2phast on Thu Apr 23, 2009 8:58 pm
I also flushed my system using the same method Prime mentioned.
2000 CLK32k & 1993 500E
=================================
Postby Chappardababbar on Thu Apr 23, 2009 10:37 pm
Thanks for the method Prime. Did you wash the filter or buy a new one. What is recommended.
Gerry, my car has 130k miles on the clock and I'm pretty sure accumulators are original. On average when do the spheres/accumulators need to be changed and does it make a significant difference to the ride quality (mine is a little harsh).
Depending on cost, I'll do the SLS at the same time as the spheres.
Chaps
=================================
Postby wpirie on Fri Apr 24, 2009 1:37 am
Hi Chaps,
I changed both spheres at 145,000 miles, when I bought the car so I don't know how old they were, but the old spheres were genuine Merc parts. Ride was harsh on right rear side. You must change a broken sphere?it is the ?shock absorber? in your SLS. Without the shock absorbing facility you are stressing all rear suspension components. Coincidentally I had to replace the right rear wheel bearing soon after?maybe the failed sphere was a contributing factor? A sudden drop in SLS fluid level in the reservoir, with no apparent leaks is a sure sign of sphere failure?the nitrogen-filled rubber? bladder in the metal sphere has ruptured and the SLS fluid has moved in to fill the void. Fluid does not compress like a gas, hence the harsh ride. It?s a simple plumbing job to replace them, as long as rust is not an issue. Here is what I bought from autohausaz:
1403280215 Corteco/Febi-Bilstein
Self-Leveling Accumulator Sphere/Air Cell; Rear Left/Right
For models with self-leveling suspension system. 2 per car. $105.34
Enjoy the vastly improved ride! p.s. buy a new SLS filter, its cheap.
Ward.
=================================
Postby captruff on Fri Apr 24, 2009 2:18 am
Chappardababbar wrote:Thanks for the method Prime. Did you wash the filter or buy a new one. What is recommended.
Gerry, my car has 130k miles on the clock and I'm pretty sure accumulators are original. On average when do the spheres/accumulators need to be changed and does it make a significant difference to the ride quality (mine is a little harsh).
Depending on cost, I'll do the SLS at the same time as the spheres.
Chaps
The SLS filter is inexpensive, but if you decide to change out the SLS fluid reservoir it comes with a new filter. I recently helped another member change the SLS fluid and reservoir and there was a tremendous amount of sediment that had accumulated at the bottom of the reservoir, so if it within your budget, I would go ahead and change it out while you are there.
Jeff
=================================
Postby gsxr on Fri Apr 24, 2009 4:21 am
Here's photos of the SLS hydraulic fluid. The MB part number is on the rear of the bottle.
Here's a photo of the aftermarket fluid bottle:
:wormy:
=================================
Postby gerryvz on Fri Apr 24, 2009 5:08 am
There is no difference between the SLS and the spheres. The SLS is the overall system, and the spheres are the "shock absorbers" or damper elements in the system, working in conjunction (high-pressure hose) with the hydraulic rear struts and rear springs. Self-leveling is essentially a benefit of the SLS system, along with the damping. The system consists of the following elements:
- Fluid reservoir (located underhood in front of the engine)
- hydraulic pump (located on front of engine)
- hydraulic lines (run to back of car)
- rear leveling valve (mounted to rear underside of car with an arm extending to rear sway bar)
- two rear hydraulic struts
- two rear accumulators (black spheres located inside spare tire compartment)
There's no prescribed mileage to change the spheres. I just changed them on my SEC last night and that has mileage of 178K - I think it was perhaps the second time it was done (I will look in my records).
Basically you will be able to tell because the car will give you a rather jarring ride particularly over uneven pavement, cracks, speed bumps (taking speed bumps with a bad SLS even at 2 MPH will just about rattle your teeth out of your head) and so forth. You will feel even the SMALLEST cracks and imperfections in the pavement - driving over something as small as a garden hose will be very noticeable with a bad SLS.
The test to tell whether the spheres are bad (most people don't really watch their hydraulic fluid that often) is simple -- just go to either or both rear corners of the car. Push down HARD on the corner. If the SLS is working, it will go down a couple of inches and then back up in a smooth damping motion. If it's bad, you will only be able to force it down about 1/4-1/2 inch and it will feel very rubbery. Or use the speed bump test at 5-10 MPH. If your teeth fall out of your head, your SLS is definitely bad.
After I bled the SLS on the 560SEC, I took it for a test drive along a notoriously rough road near my house. Wow ! I thought to myself, "Cool, my SEC is back !"
The systems on the 560SEC and the E500 are very very similar, though they use different spheres and struts. But operationally, they are identical.
BTW, Ward is VERY correct that an SLS system with bad accumulators will eventually "blow out" the rear struts, simply because the struts and spheres are filled with fluid and there's no place for it to go except out the seals when the suspension is trying to absorb bumps. The struts are er .... rather expensive .... so be warned. However, I do believe they are rebuildable, but most folks just purchase new ones. At today's prices, they're gonna run ya about $400 bones -- EACH.
Cheers,
Gerry
Here's an exploded view of the rear hydraulic strut:
Here's the level control valve and how it attaches to the rear sway bar:
Here's the hydraulic oil tank and the two accumulators in the rear:
=================================
Postby Chappardababbar on Fri Apr 24, 2009 5:43 pm
Thanks for that Gerry,
Check this out, the ASR and ABS lights have been on, on my car for a while - ever since I bought it 9 months ago. I took it to a Porsche specialist who told me it was to do with an electrical problem to the injectors, which is why I bought a new harness and didn't really think anything of it.
Yesterday I took the car to an ex-MB technician who has just started his own enterprise who told me it was due to a fuse that had blown out (no. 10, a red one). He replaced this you won't believe the difference it made. It seems as though the entire system had locked out and had become unbearably harsh. I hope I didn't do the car too much damage during this time as I'm sure the chassis has progressively become looser as a result of the lack of any damping.
Anyway, much better now, but still not ideal. I think I'll replace the SLS reservoir as I'm changing the brake fluid reservoir and coolant tank as per Dave's suggestion anyway. Accumultors are ?110 each. They look perfectly fine but I'll make a decision based on how the ride improves after I replace the rear strut mounts (26 and 29 in your diagram I believe)
Chappardababbar
=================================
Postby gerryvz on Fri Apr 24, 2009 7:04 pm
You will be amazed at the ride with the new accumulators. Again, just give it the speed bump test, and you'll be converted. The stock E500E actually has a VERY nice ride.
Cheers,
Gerry
=================================
Postby Chappardababbar on Sun May 10, 2009 5:28 pm
Just changed out my fluid...but not using the method above.
I picked up the car after it had a new power steering pump fitted and whilst driving home I looked across at a traffic light and this woman was pointing at my car. I nodded back thinking "yeah baby, I know" but she became more frantic and I realised something was wrong. Pulled over and there was fluid gushing out from under the car. Heart attack moment.
I switched off the engine and opened the bonnet to find a hose had burst. Just below right intake tube. I didn't know what the hose was for but luckily I noticed the SLS reservoir was completely dry so I figure that a change in pressure due to new P/S pump caused it to split. luckily I had a whole bunch of hoses plus SLS fluid in the boot so I put one on and filled up.
Not quite a flush but good enough. Just need to figure out part number for the hose now.... Moral of the story is change SLS and P/S hoses in engine when changing pump.
Chappardababbar
=================================
Postby gerryvz on Sun May 10, 2009 8:44 pm
Wow, that must have been an experience ! Glad to hear you had the parts on hand to fix it. Not a bad thing to replace hoses - in fact most everyone's hoses are now overdue for replacement - heater, cooler, oil cooler, trans cooler, whatever. The ALL need to be replaced folks !
I was on the my way to my son's swim meet yesterday about 6:30 AM (hardly any traffic) and driving my 1989 560SEC about 5 miles to the pool. I was at a stoplight when I see smoke drifting up from either side of the front of the car. As I was about a mile from the pool I just continued on and parked in the lot, and walked him to the pool office to prep for warmups. Went back to the car and there was a puddle of fluid underneath it about 8 inches in diameter. I turned the engine back on to see where it was dripping from, and then turned it back off. Confirmed via the finger & nose test that it was indeed motor oil. :loser:
At 1PM, after the swim meet was over, I drove back home (carefully) and pulled the car into the garage, where I drove it up on a set of ramps. Got underneath (luckily had lined the garage with cardboard under the car to catch oil spill) and turned it on again. Finally with the help of a trouble light I could see where it was leaking from -- very strong drip stream. It was coming from one of the bolt holes that attaches the oil filter canister to the side of the block. Yikes ! This was a left-over bolt from my change of the lower wiring harness the night before (the bolt also held a small thin metal plate that had a plastic cable retainer on the other end of the plate) -- I searched where that bolt went and couldn't for the life of me find the hole under there, so I just put it on my workbench to check out the next time I was under the car. Well, the problem found me ! Needless to say, five minutes later the problem was solved, and a few shots of BraKleen (cleans up grease and oil fast) was enough to clean up the underside of the car. Whew!
Cheers,
Gerry
