I have been living with a suspension issue on the front right corner of my wagon. It started with a slight scrapping turn on sharp left turns. So naturally, rather than address the problem, I postponed and just started compensating by taking turns at a snails pace... Lately thoughit has started to nosedive when braking and I think the inevitable can no longer be put off. So I brought the car in to the mechanic and according to him shocks and springs are soft. After doing some reading I'm preparing to tackle the job. I've found several great threads on the subject:
1. Get the car up on stands and remove the wheels. Stands should be placed under the lower control arms directly below the springs.
2. Remove the wheels
3. Remove the top nut on the shock
4. Remove the three lower nuts on the shock
5. Replace the shock mount at the top
6. Install the new shock (together with new bumper and boot) in reverse order.
7. Install the spring compressor
8. Remove spring
9. Install the new spring (with new shims)
Q. What is the torque spec for the shock's top nut and three lower nuts?
Q. Is the order of my steps right or should I remove the spring before installing the new strut (7 and 8 before 6)? Would this provide easier access? It would mean that both the strut and spring would be out at the same time. Is that OK?
Q. Also, since I am using the spring compressor anyways, is it safer to install it before removing the strut (7 before 3)? This way I am sure that it won't pop loose on me.
Q. I have also read that the stands should be used on the frame of the car, and that a jack should be used to support the lower control arm below the spring. Is there an advantage to this approach?
I haven't don't the job on a W124 myself but that is the correct spring compressor. I cant believe how cheap they have become. I think I paid $120 a few years ago.
Personally I would remove the springs before messing with the struts. The jack under the LCA is just to keep the spring from becoming to stretched.
I jack up the car by the front crossmember and rear diff and put the jackstands on the factory jackpoints. Don't put the jackstand under the spring or you will not be able to insert the spring compressor through the arm and into the spring. The jack under the control arm is a quicker way to get the job done w/o using the spring compressor if you don't need to remove the spring, but you're going to replace the spring pad anyway. You're still going to want the jack under the arm when doing the job. Removing tension from the spring first is the safest way to do the job. You don't need to remove the spring from the car; you just need to compress the spring enough to expose the top and replace the pad. When I did that on the rear of my car, I put the bottom plate under the control arm so it would be secured and not spin around.
MAKE SURE THE SPRING COMPRESSOR SHAFT IS COMPLETELY AND CORRECTLY KEYED INTO THE PLATES BEFORE HANDLING THE SPRING. First time using the MB spring compressor I thought it was in, but it wasn't fully. There was a fair amount of tension on it when it clicked into place, and it scared the living shit outta me.
The torque spec is 83 lb-ft for the lower bolts and 44 lb-ft on the strut mount according to the installation instructions that came with W201 Bilstein B8s, double check for your application.
You may or may not be able to remove the spring with the shock in place. You'll have to see when you're in there, but you said you're replacing both the springs and shock, right? Use the spring compressor to take tension off the spring first; then remove the shock. Then there will be plenty of room to get the spring out. If you're not replacing the shock, you'll probably just need to undo the nut at the top to be able to move the control arm low enough to get the spring out of the mounts if it's preventing it from going. Get the plates of the compressor as close to the top and bottom of the spring for your best chance of this.
You can just raise the front of the car.
They state what the bungee is for in the instruction next to the pic: To prevent the brake line and knuckle from damage. You won't have to tether them if you keep the jack under the control arm since you're removing the springs because the force of the spring is what would be cause the damage, but it's still not a bad idea. Just make sure to have the spring compressor on the spring before removing the shock bolts.
you also should check the condition of the bushings in the front end, and ball joint. badly worn control arm bushings could be causing your wheel dive, more likely than struts.
I agree with LCG. You are glossing over an important point: Whether springs and shocks will cure your problem. Obviously I haven't seen it, but I am going to go out on a limb and say the springs aren't your problem unless you have 500K on them or it is broken. At the very least, I would swap the struts and mounts first and see if it helps (new struts never hurts anyway and it is easy). Definitely replace the top strut mounts. I'm not saying new springs would hurt, I just don't see that being the source of your problem and given that it is a pain, dangerous, and an added cost, I would hold off. Unless of course you simply wanted new springs or to lower your car.
I recently replaced my front control arms. It isn't fun, but totally doable. Going from memory when removing the springs, I think I left the struts in place but obviously unbolted them at the bottom. I am pretty sure I also separated the tie rod ends from the control arm as I really had to make as much room as possible. You may also find that even after the control arm is all disconnected, there may still be a decent amount of resistance to lowering the control arms.
Of course, if your springs are really that bad, maybe they have sagged so much it will be easy. But I can't really imagine springs, short of breaking, sagging so much it causes the symptoms you describe.
If you do decide to swap springs, if it was me, I would absolutely change your control arm bushings and ball joints at the same time unless they have been replaced recently.
I'm not sure how someone can tell that your springs are 'soft' without removing them. It can also be difficult to tell much about the condition of the shocks, unless there are obvious leaks. As a rule, if your shocks haven't been replaced in the last 30k or so miles, consider them in need of a change.
It is possible to remove the spring using a jack and avoiding having to purchase a compressor, but if you haven't done it before it can be a touch unnerving. If you're not confident, a compressor is definitely the way to go.
I'd agree with others who have said that changing the shocks may not solve your problem. The springs, if changing like for like, won't are unlikely to deliver a massive difference. I'd therefore suggest changing the bushes and ball joints at the same time. I've done exactly this job on my MY94, but had to replace the whole control arm as the ball joints are not separable. Whilst in there, and depending on mileage, take a good look at the tie rods and steering dampner. It's worth getting all of this stuff out of the way in one go whilst you have the springs out. Check your brake pads whilst you're in there!
Just changing shocks wouldn't require alignment. If you're changing other stuff, like springs and spring pads, tie rods, etc, you should get an alignment done.
the spring PADS are more likely to be an issue than the springs themselves.
note that mercedes customizes the springs and pads for the set of options on your car, they have 3-4 spring weights, and 3-4 different thickness pads, there's a scale of points you add up for car options (this is all in the EPC), and the final score correlates to which spring and pads to use.
The springs are usually fine and you don't need spring compressor to change the shocks. The reason is the anti-roll bar will hold the spring in place even if the shocks are removed. If you want to be safe, you can certainly have a jack under. Press your front end down by hand when the car is parked to see how firm it is and how it bounces. If it bounces a lot, the chance is the springs are fine but the shocks are out. If your car apparently is sagging down when parked, both the springs and shocks are out.
Just change the shocks should be fine. If that does not solve the problem, you can then change the springs.
The bushes, tie rods, and ball joints should be checked before replacement. Just life the car with tires in place and check if you have any looseness.
Finally, check the shock mounts, which hold the top of the shocks. If they are cracked, you need to replace them. They usually are out when the shocks are out. I had to replace all shock mounts of all my E320s along with all the shocks, but never the springs.
To be honest I'm just going on the word of the mechanic. We recently moved to a new area and have not found someone I trust. If anyone knows of a good MB mechanic in the Detroit area (Oakland county) please let me know. So, I took it to a general Euro garage. They had a few 124s in the lot and seemed generally competent but I was not happy with wait. They quoted me for $900 including alignment... But like I said, after doing some reading I feel comfortable tackling the job myself.
I went out and had a closer look. Putting some weight on the front right corner it is totally dead, no bounce at all. The front left corner on the other hand still has some spring to it. So I am planning to go ahead and order everything to do both shocks and springs. I will post pics when the job is complete (later this week or weekend). Is it safe to drive the car around in the meantime?
How would I check the bushes, tie rods, and ball joints as mentioned? What type of movement am I looking for?
To check tie rod and lower control arm ball joint, you jack up the car with the tire off the ground. You shake the tire horizontally, if it moves loosely, you have tie rod problem. Then, shake it vertically, if it moves loosely, you have lower control arm problem. Next do a visual inspection to check on the rubber boot conditions of the tie rod and the control arm.
Finally, I am not convinced that the springs are bad. When the tire is off the ground, look at the gap between the spring coils. Put the tire back on the ground, and check the gap between the coils again. The coils should not collapse to nearly touching. Check both side. When you said, one side is dead and the other side is bouncy, the dead side probably still has a good shock and a good spring if the dead feeling means that it is hard to push down and it bounces back slowly.
At parking, the car weight pretty much is supported by the springs, not much by the shocks (about only 50 lbf or rebounding force for a shock when not moving). The shock provides a huge damping force when the car bounces, thus as vibration absorber.
If you don't need to replace the springs, the job becomes so much easier and no coil tool is needed.
Good advice above. When inspecting the tie rods, any damage to the boot - the rubber thing that covers the ball joint - and you'll want to replace. The parts are cheap - Pelican parts will help. Around $15-20 per side probably.
Changing the tie rods is easy enough. You will need a ball joint separator to do this job. Good enough ones on amazon for about $15-20. I think pelican parts may even have a 'how to' on their website. They can go off with a bang when separating them; just so your warned. It can't hurt, but it'll shock the first time!
Whilst you're in there, I'd consider changing the steering dampner. If the tie rods and shocks are gone, odds on it's shot also. Changing it is the easiest job in the world.
I'd wholly agree that absent a break, the springs are almost certainly fine. As noted, the dead side is probably the good side.
You can drive the car as it is.
Are you seeing any unusual tire wear on the front? It may give you an idea of what's going on.
Just wanted to update and thank everyone for advice. Job went smoothly except for having received the wrong springs from AutohausAZ. Apparently the problem is with Bilstein who has them mislabeled. Had to order from Lesjofors...
Car feels much tighter and no longer scrapes/knocks on turns. Probably just from having new shocks. In hindsight probably could have left the old springs as consensus seems to be that they last forever, and there was no visible signs of damage to them.
Only negative is that I still have issues. Turns out that the scraping sound when braking is not from nosediving, but rather because the break pads are completely worn out on that same corner. Tackling that job now. Thanks!
While you're in there on the pads and rotors, check the pad wear sensors. The break wear warning light on the cluster should have illuminated well before the pads started eating on the rotor.
Good luck
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