84 300d front sway bar bushing installation? - PeachParts Mercedes-Benz Forum

GLIDEHM · #1 05-09-2011, 08:24 PM

I need to replace the inner front sway bar bushings on my 84 300d that are located beneath the brake booster and the battery tray. The new bushings are split so that they can be slipped over the bar, but I am unsure if doing this is the correct procedure? Is there any need to put them on from the upper control arm end of the sway bar? Does the car need to be on the ground or supported by jack stands? Are the original bushings split so that they will come off the sway bar, or will I have to cut them if I dont take the bar loose from the UCA? Any tips, info, or tricks would be greatly appreciated. It seems like a pretty simple job, but I dont want to be surprised in the middle of the job. Thanks!

vstech · #2 05-09-2011, 08:27 PM

beware of rust of course, but it's pretty simple.
the body mounts should have the tires off the ground.

jt20 · #3 05-10-2011, 12:38 AM

As long as both wheels are at the same level, there should be no difficulty other than getting the nuts off and prying the old rubber off (and vice versa).

For some reason I recall having to unbolt the brake booster on a W123. Is that top nut not accessible?

Diesel911 · #4 05-10-2011, 01:53 AM

I also removed the Power Brake Booster.
On member said they did it with the Booster on.

I had rust to deal with so I was better off with the Brake Booster off.

There is a locating "Bump" on one portion of the Bushing. Note where the bump is on the ones that you remove.

GLIDEHM · #5 05-10-2011, 02:36 PM

Thanks for all of the info! I am replacing my booster at the same time, so that shouldnt be a problem. Hopefully there wont be any rust issues to deal with and the job will go easily. Im going to try it with the tires on the ground, and maybe I will get lucky with the bolts coming out of the brackets easily.

vstech · #6 05-10-2011, 07:21 PM

Quote:

Originally Posted by jt20

As long as both wheels are at the same level, there should be no difficulty other than getting the nuts off and prying the old rubber off (and vice versa).

this is true for the end connectors, but the inner bushings need to have pressure off them, so the wheels need to be off the ground.

Yak · #7 05-10-2011, 07:38 PM

Quote:

Originally Posted by vstech

this is true for the end connectors, but the inner bushings need to have pressure off them, so the wheels need to be off the ground.

I'd probably lift the car - evenly with both sides on jack stands - to remove it. The UCA will be applying torque to the front end of the bar and when you remove the firewall brackets that may push the unrestrained bar backwards and upwards.

But they need to be torqued down with weight on wheels to assist in getting the proper ride height and torsion on the torsion bar. Note on the first page of that section in the FSM:

"Mount and tighten torsion bar bearing on front end and support of upper control arm on torsion bar only in the position corresponding to a condition ready for driving."

The logic seems to be if the wheels are hanging when the rubber is tightened up, then the suspension will have to fight that tension in order to settle. Tighten it at the normal ride height.

Also make sure your compression washers on the UCA portion go back in correctly if you're removing them or replacing them. A digital pic pre-repair is always helpful.

POR-15 and paint that battery tray while it's out...

vstech · #8 05-10-2011, 07:43 PM

Quote:

Originally Posted by Yak

I'd probably lift the car - evenly with both sides on jack stands - to remove it. The UCA will be applying torque to the front end of the bar and when you remove the firewall brackets that may push the unrestrained bar backwards and upwards.

But they need to be torqued down with weight on wheels to assist in getting the proper ride height and torsion on the torsion bar. Note on the first page of that section in the FSM:

"Mount and tighten torsion bar bearing on front end and support of upper control arm on torsion bar only in the position corresponding to a condition ready for driving."

The logic seems to be if the wheels are hanging when the rubber is tightened up, then the suspension will have to fight that tension in order to settle. Tighten it at the normal ride height.

Also make sure your compression washers on the UCA portion go back in correctly if you're removing them or replacing them. A digital pic pre-repair is always helpful.

POR-15 and paint that battery tray while it's out...

Good call!

jt20 · #9 05-10-2011, 11:43 PM

Quote:

Originally Posted by vstech

this is true for the end connectors, but the inner bushings need to have pressure off them, so the wheels need to be off the ground.

there is no pressure on them as long as the wheels are at the same level.

Their real function is to stabilize the steering knuckle, especially during braking.

GLIDEHM · #10 05-11-2011, 12:32 PM

Thanks for the additional info! I will follow the FSM procedure for tighening up the brackets while the car is at ride height so that there is no tension on them. I had not planned on removing the outer mounts at the UCA, does anyone know if this is necessary or if it will make the job of putting the sway bar back into the correct position any easier??????

jt20 · #11 05-11-2011, 12:44 PM

It is not necessary to remove anything else when doing these bushings. (other than stuff in the way)

Maki · #12 05-11-2011, 01:42 PM

I swapped mine out with the wheels on the ground, no problem. I loosened the booster from the firewall -- I think it saved time in the final reckoning.