W124 coil springs

[crt]

Just changed the front ones on my ‘95 e300d estate. In light of some comments and warnings on various forums I thought I would post some thoughts.

It is a competent diy job (as was the associated replacement of lower control arms).

Despite some of the doomsters, the ebay c. £75 internal spring compressor is fine. View seems to be, which I think is plausible, that they are probably only good for a limited number of changes before they weaken, but I expect the number of changes that a diyer is going to do in a lifetime is well within that number. You do need one of these, and I don’t really know how you would do it safely without one.

A trolley jack is useful to lift and lower the lower control arms, along with random blocks of wood.

Familiarising yourself with the spring compressor before you go into action is advisable. The plates are different and the one that goes on top has a different lug arrangement to engage the top of the screw. The plates have to go in as high and, subject to one qualification, as low as you can get them. The lower qualification is that you don’t want to go so low that the 19mm hex end fouls the hole in the lower control arm as you try to manoeuvre the compressor and spring in/out. The top plate obviously has to be low enough not to foul the top housing.

Having got the thing stuck three times out of four, I think the best way is to put the top plate in about three coils down from the top, the bottom plate about two coils up from the bottom, and then insert the centre part and wiggle around, extending or contracting as necessary until the top lugs engage, and then wiggle around to engage the bottom plate. You might have to insert the plates higher or lower and rotate down or up as necessary. I lightly oiled the plates to help with this. A light is handy to see where the lugs need to be. On reflection a dab of white paint on the plates would have helped to identify where to position the lugs.

Quite a few turns are needed to compress and release: these are long springs. A deep 19mm socket and/short extension helps.

Once the old spring is compressed, it should lift straight out but might need a little gentle leverage with a crow bar (which I did from well around the front so if it sprung apart I had the engine between me and all that pent up energy).

Put compressed spring and compressor in a vice, gripping the lower end, and gently release. At which point you will heave a sigh of relief and look forward to doing it again. And again.

Assemble new spring (remembering the hard plastic/rubber cap for the top) and compressor in the vice, having noted which is the front relative to where the bottom end of the spring has to lodge so that the thick sides of the plates are at the front for ease of removal later. Compress. Release from vice and carry what others have described as an unexploded bomb back to vehicle.

Gently put spring into top housing and, if compressed sufficiently the bottom will slide into place, making sure the bottom end is on the ring on the LCA, and the very end of the spring approximately in its recess. Raise the LCA with the jack to hold the spring in place as you begin to decompress. Then unscrew the compressor a turn or two at a time while alternately pausing to lower the jack.

Once fully decompressed you may then face the problems I had repeatedly: the bottom of the compressor gets lodged on the top edge of the LCA, with the hex bolt just inside the hole, the bottom end of the compressor clamped hard against the bottom plate, and if you are really unlucky the top of the compressor gets wedged against a coil at the top of the spring, all due mainly to the significant curvature of the spring when it is decompressed in situ. The solution is to wind the bottom plate up towards the middle of the spring and the top plate down, to unjam the bottom and to give wiggle room at the top. Once you’ve done this, the centre of the compressor will fall out and then you just have to prise out the plates (tyre levers, large screw drivers and mole grips may be required).

Repeat as necessary.

I used Sachs springs from ECP, about £80/pair.

 

[rayhennig]

I used Sachs springs from ECP, about £80/pair.

Interesting. Did they give the correct ride height? Did they match an exact MB part number related to the options on your car?

I ask because the MB points system is very specific about points versus springs.

Best.

RayH

 

[DREAMER NO2]

CRT This is a good step by step walk through for the front spring replacement on the W124 models . Thank you,,and i have printed this off to use if and when the springs on my W124 need replacing ...

 

[crt]

Re ride height, I was a bit worried when I first let the car down as it seemed high in the front, but once everything settled and I think importantly, the SLS kicked in on a test drive, it has now settled to a good, even height, better thank it has been for years. Even my wife, who hates the car, noticed it looked better. I have had the car for nearly 15 years, and I’ve not touched the front suspension in that time (it’s low mileage use), and so I expect it was all very tired, possibly original.

Re part numbers, it was all a bit of a palaver. MB had only one spring in the country, and that a long way away, and about £120 inc vat. Many of the aftermarket ones are very cheap, and you don’t get the part number, and in my case the w124 options tend not include anything beyond ‘93, but usually generic w124 parts are ok. ECP does at least attempt to be car-specific by matching to reg. I am finding that MB are stocking parts for the car less reliably these days, and certainly very rarely on the shelf.

I use the car reasonably frequently, but don’t do many miles, but if I did, I might have held out for an mb original but that could have been weeks away.

same with the lcas, which I got from parts in motion for just over £100 inc new eccentric bolts, if I did more miles I might have gone for more expensive ones. But, I will certainly be keeping an eye on the lcas: the cause of this latest round of grief was a broken n/s arm, snapped at the ball joint due to corrosion and, probably some sort of impact damage, hitting a rock or something. Fortunately it snapped in a car park rather than on the road, and getting the thing onto the trailer and home was a big undertaking involving jacks, blocks, levers and a winch. The o/s, which I replaced for good measure, had the usual surface corrosion but was otherwise solid (bad bushes of course) even though it looked original like the other one.

 

[DREAMER NO2]

crt You did change both springs yes ?.

 

[crt]

Yes both, though only n/s had broken (at the bottom), and probably before the lca snapped by the look of the corrosion, and the fact that the car had been sitting low for a while, but presumably since last mot.

 

[Doug1234]

Excellent write up, I did my w124 years ago fitting new arms etc.
The hardest part for me was levering the new bottom arms down with a long bar to get the compressed spring in and this was done by sitting on the spare wheel and then sliding my backside down so some body weight went onto the bar to keep the arm down enough to feed compressed spring in.
Always a frightening time hairs up on the back of neck with these springs when they are compressed.

 

[DREAMER NO2]

CRT yes then you knew its policy to change both at the same timer . Good job done -- now enjoy or are you like me ,,and jobs on the car never end haha

 

[LostKiwi]

R129 is the same process.
Be very very careful getting the lugs properly engaged in the plates. I had one spring fully compressed and was manoeuvring it into position when it let go. I can assure everyone the central bolt assembly shoots out with great force and the bruise on my thumb where it grazed it on its way out took a week to go down. If it had caught my hand squarely I doubt I'd have much use of it now.

 

[DREAMER NO2]

LW You were very lucky at the time,, if it had hit your hand central, it would have severely damaged it .