Do I need to compress spring/strut to do tower/mount? (w124)

[ps2cho]

My strut tower/mount has cracks in it for my 1987 260E. I saw at the junkyard what "looked" like I do NOT need to compress anything at all, only to raise the front and let the suspension go to full extension.

Anybody done this before?

I don't want to unbolt it and have it shoot up or anything. I don't think it will based on what I observed, but I just want to double check.

Thanks,
Robert

[pawoSD]

I've been wondering this same thing, as the mounts on my 300E need replacing....

[compress ignite]

Detach the Nut securing the top of the Shock absorber/strut with the chassis
on the wheels ,Nothing happens.
BUT,If you then start raising one side or the other of the chassis the Springs
will be subject to Escape...until they reach full extension.

SOME have claimed to be able to place a jack under the LCA s and control the
extension process.
(Once the chassis is raised far enough to enable full extension of the springs AND the top of the SA is "Freed")

I've come to HATE Emergency Rooms and extended Involuntary Hospital Stays.
[The Drugs ARE great,but the physical cost negates any benefit.]
(Too much time as a Guest of Northside,Crawford Long,Piedmont and St.Josephs
in the late '80s and early'90s...One brief sojourn with the Mayo system in JAX
in '97 for cardiac plumbing)
[AND the terrible thing about your own funeral...You can't even enjoy a drink!]

SO I'll either rent or buy the REAL spring Compressors.

[pawoSD]

Sounds scary....guess I will hold off for now!

I started to post how this can be done, but given the danger of this operation if not done by someone with the right skill set and equipment, I hesitate. I don't want to encourage someone to do something that might get them hurt.

[Ivanerrol]

This is not a dangerous job if you go about it the right way.
Jack the car up and support the body on solid jack stands.
Remove the wheel and then put a good quality hydraulic jack underneath the control arm.
Go about removing the strut.
Replace the strut mount.
Use all new bolts that are provided with the new Bilstein strut and strut mount.

The spring will not come off even if the control arm is extended as far as possible. The spring is too long. Just be carefull and support the arm. If the axle slips and extends as far as possible you will ruin the rubber bushings - ask me how I know.

You can do this job in 30 minutes. The hardest part is undoing the lower bolts on the strut if they are corroded on.

You need to use the proper spring compressor if you need to remove the control arm.

[ps2cho]

So I need to physically remove the strut to do the tower mount?
Sorry I am a little confused.

I am not replacing the strut. The tower mount just has a crack in it and is allowing the strut to move slightly which is a problem so it needs to be replaced. I have the new tower mount in hand ready to go.

[Ivanerrol]

You don't need to remove the strut to remove the strut mount.

Raise the car - put the body on sturdy mounts.
Remove the wheel, put your hydraulic jack under the control arm so it doesn't move downwards.
Undo the nut on top of the strut. you will need a 22mm ring spanner + a either 7mm or 8mm allan key (depending on whose strut is installed).

Pull the strut piston down from the strut mount (do this in the wheel arch).
You need to loosen the rubber cover.
The strut mount has three bolts holding it in and will need to be removed via the wheel arch.
If the strut piston is easy to compress then the strut is cactus. If there is a leak from the top of the strut the strut is cactus.
The bump stop will be probably cactus. You should get a new one with the strut mount kit.
Replace everything in order of removal.

Doing the bounce test on a W124 will not give an indication of the condition of the strut. To ascertain the condition, MB workshops should remove the strut and measure its compression on a tester.

A strut should give considerable pressure when trying to compress the piston. If its soft - it's had it. In my experience if the strut mounts are split then generally the strut is stuffed also.
If your car has 100,000 K's up the struts will be at the end of their life.

[glenmore]

As mentioned, have a new rubber boot ready as the old one is probably shredded. My bumper stops were fine and I reused them. They seem pretty sturdy so you may not need new ones, but then again you don't want to do this again. I did this once with worn shocks and the pistons were easily compressed and held so you had plenty of time to slip in the new mount and boot. I later replaced the shocks with new Bilsteins and then later had to change one of the mounts again. Compressing and holding the piston on a new shock is a lot tougher. You might try tying it with some rope. I controlled the spring by resting the weight of the car on stands under the LCA.

glenmore
1991 300CE
2000 C280

[pawoSD]

How far does the car need to be raised/the control arm need to be lowered in order to get the mounts in and out? Is the spring still safely in place? Or is it nearing the "I'll jump out at you and take you for a ride!" position?

[glenmore]

To get the mount out you are primarily compressing the shock piston and slipping the mount off.

Here are the steps I took. If you are not confident that you have all your ducks in a row, best to leave this to a shop. I have done it a couple of times and it is nerve racking even though I am pretty sure to have covered all the bases.

Jack up car under jack pad and remove wheel. Place a jack stand under the control arm and lower the car so the entire weight of car sits on the stand and the other three wheels. Position the stand so that there is no way it can slip off. I test by giving the car a good shove from different positions. No worries yet because the spring is contained by the shock still being bolted at both ends. Remove large nut at top of shock while holding the piston with allen. Remove nuts holding mount to body. The mount is now only held on by the pressure from the piston from underneath. Now if your shocks are worn, the following is not that hard. Reaching under the fender, compress the piston and the mount will fall off in your hands. Slip a new rubber boot on, check the bumper and put the new mount in and release the piston, guiding it thru the mount. If your shocks are relatively new, then it's a bit tougher. I had to tie down the piston with rope. Extra hands come in handy. Have someone compress from above as you pull down and tie off. The shock is free to swivel about but as long as the weight of the car is on the LCA, the spring is contained. Put nuts on mount studs. Release piston and hope it goes thru the center of the mount. Put big nut on the piston rod while holding with allen and you are done.

glenmore
1991 300ce
2000 c280

[pawoSD]

My ducks are in a row, and look cool while doing it.



That does not sound difficult at all (compared to some of the epic projects I've done), I will probably look into replacing my mounts soon, as they are in bad shape...

[babymog]

I wanted to test this theory, so here's what I did.

'89 300E in a junkyard, with the suspension intact, car raised and wheels off.

Removed nut from top of strut tower, allowed the suspension to fully extend un-restrained (BANG).

The sway-bar holds the lower control arm from extending too far, so I released the strut from the other side also (again: BANG). Still not extended far enough, interference between the swaybar and control arm, so I disconnected the swaybar.

Now the control arm is able to move down further, the spring still hanging in there, I stood and bounced on the control arm to extend it down as far as possible, the spring still will not budge.

I attached a strap to the center of the coil spring, pulled outward as hard as I could without mechanical assistance, broke the strap, spring still in there. I tried prying the inboard coil from the control arm (getting daring), still no joy.

Now I went back in with the spring compressor, oops, the spring is arced too much to fit it easily, a little help from an external spring compressor (I took three different spring compressors in).

Quite a bit of compressing was necessary to release the spring from the completely un-restrained control arm, I don't think it was going to hop out on its own.

All of the time the strut top was waving in the wind, at least once the swaybar was released.

Is this a safe thing? To replace the strut without a spring compressor? To tempt fate as I did? I would recommend at least using some type of spring compressor to contain the spring as you lower the suspension, but my experiment indicates that it isn't easy to extract a spring from this car with the control arm installed and no spring compressor.

This car apparently had pretty good control-arm bushings, and they were tight. It might have come apart if I had loosened the control-arm bushings allowing the control-arm to pivot further than 90*, didn't look easy.

[ps2cho]

Thanks for all the info guys. I will hit it this weekend the let you know how it went.

[pawoSD]

The spring must go into too tight of an arc while held inside the cups at either end....thus preventing it from popping out without being compressed.