W123 squirrelly handling. Rear end bushings worn? - PeachParts Mercedes-Benz Forum

whyameye · #1 02-25-2015, 05:09 PM

My 1985 300D is suffering from squirrelly handling. I've checked all the parts in the front and everything seems tight and OK. The problem feels like it might be coming from the back anyway so i'm wondering if the rear subframe bushings or trailing arm bushings are worn.

Nothing feels loose in the back but as everything is under tension even when the back is lifted I don't think that means much. Do these pictures make it seem like my bushings are worn?

t walgamuth · #2 02-25-2015, 06:21 PM

Have you checked the sway bar links?

Adriel · #3 02-25-2015, 06:32 PM

Mine was super bad in the wind especially, and it was the idler bushing. It looked alright, but manipulating the tie rods you could see it move.

Hope this helps.

whyameye · #4 02-25-2015, 07:01 PM

I replaced the sway bar links and the clunking in the back went away but the handling wasn't much better. I also replaced the idler bushing in the front even though it didn't seem to move much. That didn't help either. Good suggestions though.

Adriel · #5 02-25-2015, 07:20 PM

Quote:

Originally Posted by whyameye

I replaced the sway bar links and the clunking in the back went away but the handling wasn't much better. I also replaced the idler bushing in the front even though it didn't seem to move much. That didn't help either. Good suggestions though.

Bummer, that must be frustrating.

So tie rods have no movement, like the rest of the front suspension? If so, time to grab a pry bar and find where in the rear it is loose.

whyameye · #6 02-25-2015, 07:43 PM

Quote:

Originally Posted by Adriel

Bummer, that must be frustrating.

So tie rods have no movement, like the rest of the front suspension? If so, time to grab a pry bar and find where in the rear it is loose.

Yep the tie rods have no movement and the front suspension seems tight to me. A pry bar in the back is probably a good idea.

Phillytwotank · #7 02-25-2015, 07:50 PM

How are the shocks?
I had one rear shock fail and it felt "squirrelly"

Adriel · #8 02-25-2015, 08:59 PM

Quote:

Originally Posted by whyameye

Yep the tie rods have no movement and the front suspension seems tight to me. A pry bar in the back is probably a good idea.

Believe it is in a manual, as seem to recall a picture. So, can't take credit!

Quote:

Originally Posted by Phillytwotank

How are the shocks?
I had one rear shock fail and it felt "squirrelly"

Interesting Phillytwotank! With the S.L.S., didn't notice this. Be good place to go, checking for oil leakage, check for looseness and clunks in the rear, damper bushings, then pull the dampers and check as the last.

Diesel911 · #9 02-25-2015, 09:44 PM

Any abnormal Tire Wear?

Too much end play in the Rear Hubs?

Junkman · #10 02-25-2015, 10:00 PM

I have had other cars steer like crap with no parts obviously in bad shape. I replaced every bushing & steering part on a Datsun Z including new shocks and springs. It now corners like on rails. I plan on doing something similar to the SD this summer because it is sensitive to road crown and really doesn't steer like a luxury car. I wonl't change easy stuff like tie rods if they are obviously tight but ball joints, control arms/bushings will all be new and high quality.

whyameye · #11 02-26-2015, 01:30 PM

Tires are wearing fine, but this is a recent problem. The shocks seem OK to me when I try "the bounce test" by pushing down on the back end with my own weight. I don't detect any play in the rear hubs.

The symptoms are hard to explain: steering feels tight and handling feels good. Then suddenly the entire car is swerving ever so slightly .25 degrees in one direction or another with everything still feeling tight. The steering gearbox seems tight to me and the front wheels seem very sensitive to changes in the wheel.

The odometer reads 280K and it isn't original so who knows? In any case, my point is that there's a good chance I'm looking at original bushings in many cases and maybe one plan of attack is ignore this annoyance until the summer then change every bushing the way Junkman did to his Datsun.

t walgamuth · #12 02-26-2015, 02:01 PM

did you check the sway bar links yet?

BillGrissom · #13 02-26-2015, 02:51 PM

By no means an expert, but I think the rear end would have to be really worn to cause straight-ahead wander, and you would probably hear clunks on turns and bumps. Have you checked "toe in"? Even a little toe-out can cause wander. Too much toe-in causes excessive tire wear.

With steering wheel centered, sight along each tire w/ a straight-edge at the rears. Should view a point ~1" off the rear tire, on both sides, if about right. Even better, use a tape measure across the fwd & aft sides of the front tires, going as high up as you can (but equal on each side). Should be 1/16 to 1/8" more across on the aft side.

Maxbumpo · #14 02-26-2015, 03:28 PM

Quote:

Originally Posted by whyameye

The symptoms are hard to explain: steering feels tight and handling feels good. Then suddenly the entire car is swerving ever so slightly .25 degrees in one direction or another with everything still feeling tight. The steering gearbox seems tight to me and the front wheels seem very sensitive to changes in the wheel.

Classic description of worn bushings in your first picture, first post. The rear end is trying to steer the car.

Pain in the butt to replace, but at least you don't have to take too much apart. This job can be done with a floor jack and a short piece of 1/2 inch all-thread with appropriate nuts / washers.

If your car has been exposed to salt / has rust, be prepared for a real fight. The big bolt that holds the rear subframe to the frame via the bushing may have become one with the bushing, so consider getting new bolts with the new bushings.

barry12345 · #15 02-27-2015, 12:16 AM

Rear steer usually responds to coming on the fuel and letting off. If you have it a steering correction is always required usually in each state.