Rear End ride Height

[n/a]

My 280sl's rear end seems as if it is sagging. When new, the rear end was higher than the front, with the two rear tires canted inward (tops outward, bottoms inward). In order to get this back to new specs is this a problem with the shocks and/or springs, and how can you determine which??

[Tom]

I regrettably have a lot of experience in this area...

The springs are not likely the issue-but the spring pads.  You should replace the rubber pads with the same part number pad that came off as these are keyed to the specific springs (each set of springs is different and color coded-see stripes on side of spring).  To compensate for possible spring compression over the years, you might step up the pad width by one level.

Pad part numbers may have changed over the years so check the Big Blue Book.

My car has slight positive camber due to new, stiffer progressive rate springs.  Have you owned the car since it was new?  It is interesting that you note that the new car had slightly positive camber-I assume this is with the hard top off.  Perhaps the geometry of the suspension is set with the top on, which reveals slightly positive camber with the top off.

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1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
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[jeffc280sl]

While Bilstein shocks are pressurized they should have little or no effect on ride height front or rear.  All three rear springs have rubber pads on both ends.  On my car both top coil spring pads were compressed some.  The rubber was in good shape because they areprotected from road salt and grim.  The bottom pads were deteriorated so that only small pieces remained.  Same goes for the compensating spring pads.  The compensating spring pads come in two thicknesses 3 and 6 mm.  The top coil spring pads come in a variety of thicknesses and the bottom comes in one thickness.  I would check the lower coil and compensating springs pads as a first step.  Replace as needed and see if the ride height is improved.  While you replace the lower coil spring pads you might as well do the top.  You will need to remove the original top pad to determine the correct thickness or use the BBB and color coding on your springs to determine pad thickness.

Jeff C.
1970 280SL 4-speed

[hauser]

From what I have read up on this matter I also believe it to be worn out pads.

My question is, how does one determine what size pads to use?  We may also have to keep in mind that Mercedes offered different springs such as the heavy duty for towing.  Is there a way of finding this out other than the data card?

1969 280sl 5 spd        1999 ML320          Gainesville,Fl.

[n/a]

Tom,
No I did not own this car from new, I just have completed about 90% of a total restoration. I remember seeing these at the M/B factory as they were coming off the assembly line, and noticed that they all had positive camber.
Since my car was first shipped to South Africa, and had the bottom skid plates installed, I would venture a guess that the springs were HD. I will take it to my alignment shop and see if they can check the pads- hopefully the springs are still color coded.
Thanks for the info- I will keep you informed.

[n/a]

I've seen so much discussion on this subject over the years and much controversy. Look at any sales brochure for any W113 and you'll see what the standard ride height is supposed to look like. I see many of these cars sitting too high, like they're ready for a safari. I have a 230SL sales brochure and the car almost looks lowered. The rear wheels will never be vertical, but close.

tom in CA
2003 C320 Coupe

[jeffc280sl]

Gents,

There is a table in the BBB which describes rear spring and pad sizes for 280SLs.  Both normal and harder suspension setups used the same rear spring part number.  

The harder suspension setup springs are color coded with white, red or blue stripes and called for 20, 14 and 8 mm pads respectively.  The quantity of a particular color stripe determined notch position of the spring disk. One stripe meant position 1, 2 strpes meant position 2 and so on.  There is a note in the harder suspension chart which says it is for bad road conditions ( higher vehicle level)

The normal suspension setup springs are likewise color coded with  red or blue stripes and called for 20, 14 mm pads respectively.  The quantity of a particular color stripe determined notch position of the spring disk. One stripe meant position 1, 2 stripes meant position 2 and so on.

The compensating spring is color coded as well.  White means 6 mm pads on both ends. Red means 6 mm on one end and 3 mm on the other.  Blue means 3 mm pads on both ends.

Rear spring pad thickness is not measured atthe thickest point on the pad. It is actually measured on the left side of the pad with the spring end notch facing towards the measurer.

I don't know if this helps anyone.  Let me know if you have any questions.

Jeff C.
1970 280SL 4-speed

[jeffc280sl]

Hauser,

ps. A condition of using this information is that you agree to swap your 5 speed with my 4 speed.  I'm sure you will agree.  Right??

Jeff C.
1970 280SL 4-speed

[hauser]

For those intrested in the spring markings and shock tower markings  go to www.dearbornauto.com  Check out the 1970 Ivory 280sl. There is also a nice looking brake reservoir in this car.

Jeff as far as my 5 speed goes, no can do.

1969 280sl 5 spd        1999 ML320          Gainesville,Fl.

[Tom]

The nice, fresh (white) brake reservoir helps identify this as a true low mileage car.

_____________________________________________

1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
_____________________________________________

[mulrik]

I'm sorry but I have to correct one saying that new Bilstein shock absorbers do not affect the height. This winther I installed new bilsteins in all corners, and it DOES make a difference in height. I agree though that pads are the most significant contributor whereas the springs very likely are in excellent shape.


'67 250 SL Papyrus White 113043-10-000023

[jeffc280sl]

Mulrik,

I have been considering new Bilsteins.  Mine are still pressurized but do not have enough pressure to lift the car.  Can you describe how much force it takes to compress a shock during installation?

Thanks

Jeff C.
1970 280SL 4-speed

[Bob G]

In the process of changing over to the John Olson springs and rebuilding the rear and some front suspension bushing. I also installed new bilstein shocks all the way around. I have not done the front springs and suspension yet, but the rear has gained an inch in height from 25/3/4 to 26 inches this may be due to the fact that I installed 24 MM pads in the rear vs the 18 MM pad that came out with the stock springs. The ride is much more tauntwith new trailing arm bushing and I cannot wait to finish the front and have the alignment done.
I do feel that spring pads are responsible for the ride height of the car. I also noted in the BBB in the rear suspension section under alignment about an ajustment to the spring perch that can rasie or lower the car. There was also a note about steel shims and a part number. I need to fine an alignment shop that understands these old Mercedes suspensions so they can set it up right. Any recommendation would be well comed.
Over all I am quite satified and I will report more as this project progresses.
Bob Geco
1968 280SL

[n/a]

"SL Classics" has recommended changing out both the front and rear pads to 30mm ones. Does anyone have any experience going to this thick of a pad? Also when posters refer to motor mounts, are they referring to "sub-frame mounts" or are these different?
Thanks

[jeffc280sl]

Their recommendation seems odd to me.  I think if one size pad worked for all, MB would have used 30mm pads on all SLs.

Jeff C.
1970 280SL 4-speed

[A Dalton]

They reccommend 30mm pads when not matching the pads to the springs cuz all old springs sag from age.  The thick pad just helps get the height back to normal
 Just the same way with the comp sprng pads .. you always get the 6mm unless you get a new spring.
 The factory matches the different springs to different pads , but with old springs, you get the max.
  Don't forget, the sag rear is sagging weak springs.  The thicker pads just change the height for better camber .... they do not fix the weak springs.. they just change the height. and the higher the chassis is , the higher the differetial top  hanger support is off the ground.
 As the support position raises , the camber becomes more positive.
 But.. you still have weak springs.....with improved geometry due to proper ride height.

[George Davis]

FWIW, my car currently has the 30 mm rear spring pads, but it still sags are the rear.  By semi-calibrated eyeball, I'd say it had about 1-2 degrees negative camber.  Just for fun, I made some 10 mm spacers and installed them yesterday.  This reduced the negative camber, but the camber is still slightly negative.  I think a 10 mm lift is fairly significant, but to get all the way to the factory spec of 1.5 degrees positive camber, the spacers would have to be on the order of 25 mm thick... which would make me extremely nervous... and I don't recommend the 'additional spacer' approach.  I think I'm looking at new springs as a winter project.

Each car and set of springs is going to be different, and what you can do will depend on (a) amount of sag (and how much lift you need to correct it) and (b) which thickness pads are already in there.  If you have the 18 or 24 mm pads, and a 6 or 12 mm lift will do the job, that's the easiest approach.  They aren't that hard to change.  If you need more lift than thicker pads can give you, new springs are probably the answer.  First research project is to see which pads you've got.

A Dalton's point is good, too.  Sagged springs are probably no longer on spec for spring rate.  Trouble is, if you put in new rear springs, you probably new need fronts as well.  Rats, my project just got bigger...  maybe negative camber is ok after all, I'll just replace the rear tires frequently... sigh.

George Davis
'69 280 SL Euro manual

[Malc]

Funny, everybody is going on about pads, spacers etc. Yes they can rot and colapse, but springs will sag eventually, plus they can break, usually near the top and bottom and it can be difficult to spot untilk you take them out.
If you take them out check the free standing length and if you can find somebody get them checked with hydrualic spring tester to check the poundage.
Finally watch for either the upper or lower platforms deforming/rotting away causing the springs to disappear into the bodywork, not as daft as it sounds I have seen a couple of BMW2002 with this problem
Malc