W126 sagging in the rear
 

Is it a DIY'er to change the rear spring on a w126 420sel? It seems to be sagging in the rear. How much is it to do at the shop for the two rear spring?

Thanks,

John

John,

You could do this yourself depending on your level of mechanical competency but the MB spring compressor really must be used for safety reasons and that tool is hideously expensive, over $900 if memory serves me correctly. Also, when changing rear springs you need to replace the pads which will be one of three thicknesses. You might also check the subframe mounts too.

Do you live in Georgia or California?

Unless you've been hauling bricks in your trunk, I'd be surprised if your springs are bad. Have the subframe and differential mounts been changed? I think that it's generally the rubber and not the steel parts that go bad.

Len

IF that car is sagging in the rear IT would be the SPRINGS!! Very common on the W126 chassis.

At dealer we charge 3 hrs on that car & the springs(116-324-08-04) list for $126.each

I gladly then defer to your expertise. I was basing my answer on my experience with the 123 chassis.

Len

I replaced mine a few months ago, my brother has an Asian import shop and we used one of his internal styled spring compressors. It wasn't too bad of a job but you need to have a clear head while doing it, a simple mistake could get extremely dangerous. It didn't change a thing so I guess my rears weren't in that bad of shape after all.

If you wanted to boost the rear springs up cheaply you could get some of those cast aluminum twist-in spacers. A chain store parts house would probably have an ample supply of them. I put some on a ratty 380 SL one time, the owner, a friend was a real cheapskate but I must say it made a big difference.

Hours
 

Is the 3 hours for both rear spring?

John

For my 2 cents: 126's do have rear spring problems. They are often regarded as "ass sitters". Over time the springs do collapse.

Replacing the rear springs is not that big a deal for someone who knows how to do it. I would HIGHLY recommend that you use your car's VIN # (Chassis #) and check with a dealer for the correct spring part #. Why? Over the years, depending on the car's option content etc, different springs were selected. It is easy to get a spring that is close but not the exact one needed.

I have done four cars: 2 123's, a 126 and a 124.

I have used the spring knuckles and they are a fast and what I would regard as a temporary solution ..... The best is the the right set of springs..... makes all the difference in the world.

haasman

Re: Hours
 

I'm sure that is the total for BOTH springs. ;)

Yes, 3 hrs for BOTH rear springs. And since the rear shocks must be removed to install the springs you should think about replacing them as well!!

Sagging
 

Definately the rear springs and not fun to change at all, you will need the internal spring compressor and they are about $600, without it the job is nearly impossible and borders on dangerous.

You will need to lift the car, remove the rear seat completely, unbolt the sway bar and remove the rubber snubber stops on the chassis. The upper shock mounts are accessed through holes behind the seat back and are two 17mm nuts jammed together. The spring compressor has two plates which are placed inside the coils of the spring, one top, one bottom, a threaded rod is inserted into the plates and turned to compress the spring. Once compressed the spring can be withdrawn upward and reward past the point where the snubber was mounted. Famous text: "Installation is the reverse of removal"

The compressed spring has a great deal of stored energy and if you get a finger in the wrong place and things give way...You will loose it. Because of the way the spring is mounted only a KLANN KL-0025-1K spring compressor should be used although I believe that MOOG made a copy at some point.

At the end of the day unless you or a friend owns the tool, just pay the 3 hours and be done with it.

Chris

I couldn't justify the cost.
 

I used some spacers called "spring knuckles" . You jack up the rear. push them in, and twist them. I used two on each side for about 3/4 inch lift. About $5.00 at Autozone. I could tell no difference in ride quality, but it sure looks better. That left me $400 bucks to spend on something that really matters.. Like a fuel pump, and new belt tensioner..

Jay

Knuckles
 

Better left at Autozone, now the springs are stressed at the point where the bits were jammed in, unfortunately if it were that easy they would sell them at Mercedes. Will probably work for a while but you are risking breaking a spring now... There are few quick fixes... The knuckles are sold right next to the extended shackles designed to lift 4x4's which throw off the camber, steering and tend to break under side load in offroading, one shelf down you can find the "engine rebuild in a can" and the "Stop leak"... Best of luck but if you intend to keep the car, fix it right...If you like the car put H&R springs in and suddenly it will handle!

Re: Knuckles
 

Oh well.. Don't tell anyone, but sometimes I get the wine that's in a box too:D .. I did the spring knuckles about a year and a half ago.
Bet 5 yrs from now they will still be working. I do however agree that it's not the best way to solve the problem. But certainly a cheap solution that in my opinion does not cause a safety hazard.

It would be EASY to spend a lot of money on this car, and yet never really increase its' market value