A$$ End Wiggle - 87 300D - PeachParts Mercedes-Benz Forum

a2t · #1 12-18-2008, 09:17 AM

(1987 300D Turbo, 283,000 miles)

I heard a peculiar new noise today.

Peculiar old noises are fine, but peculiar NEW noises are particularly concerning in this car (based on years of experience). Since I was 30 miles away from work on my lunch break picking up parts I had to get back. So I turned up the AM radio and forgot about it for a while. On I-285 I was again reminded of the peculiar new noise. This time the radio couldn’t drown it out so I moved over to the far right lane and brought it down to legal speeds, and got into crash position. Soon after, the right rear tire let go in cloud of smoke and debris. As I was putting the spare one on I tightened the lug nuts a bit with the car raised and was surprised to see the rear tire move fwd a good inch or so by the torque of the lug wrench. Upon closer inspection I can see the whole rear tire is able to move pretty freely fwd because the torque arm (the upper front arm) has no bushing left in it at the subframe mount. You can almost touch the rear tire to the front of the fender well!

This 10 degrees of free play could explain the ass end wiggle Ive complained about for the last 10,000 miles. Im not a scientist, but it seems likely…

When I got it home after work I took the rear tires off. Thank God I even made it home. The tire on the left rear is corded on the inside over a 6 inch area, and the torque arm on that side is in the same condition. The other bushings look to be in OK shape (meaning they are there and don’t seem to have much play in them). I loaded 2 lug bolts into the hubs and used a crow bar to pry on each rear wheel hub to try to move it fwd or aft. They move fwd very easily but wont move aft at all.

So Im thinking I can get by with new torque arms, which are relatively cheap.

Are there any tricks to removing and replacing these? I was going to give it a go tonight, it looks pretty tough to access the bolt at the subframe, so I will probably need to remove the swaybar mount. I hope none of the bolts are cone shaped, especially at the rear wheel carrier because I do not want to have to press this out like a tie rod. I guess if worse comes to worse I’ll bring it to a shop. Any and all advice on this job will be greatly appreciated!

Jeremy5848 · #2 12-18-2008, 06:28 PM

Best to check all five of the arms that hold the rear suspension and replace any with bushings that look worn. You had the good sense to slow down and move over before the tire let go; something like that could kill.

a2t · #3 12-18-2008, 06:45 PM

No I dont have any sense, its been loose for 10k and it took this for me to get off my lazy ass and look at it. Dont wanna look too close at this car, theres alot wrong...

Can I put a jack on the diff and lift it in the middle so I can work on both sides at once? Wheres good spot for jack stands on rear?

Thanks,

Chris W. · #4 12-18-2008, 08:27 PM

If I'm not mistaken, you want to tighten the torque arms with the suspension in the normal loaded position, not with the wheels hanging down as they do when the car is up in the air.

IMHO the best way to do this is to put the car on jack stands and then jack under the wheel (or the hub) to get it up to the loaded position. You can do one side at a time.

You'll have to establish a reference measure point when the car is on the ground and jack the wheel or hub back up to that point.

Rgds,
Chris W.
'95 E300D, 258K

a2t · #5 12-18-2008, 08:57 PM

yeah thats a good point. it does say that over and over in the fsm, not to tighten them down unless the axle is level.

so can i jack on the diff to raise it?

babymog · #6 12-18-2008, 09:51 PM

Don't jack the diff, use the body. There are jack pads under the jack holes.

The torque arms come off pretty easily, probably the easiest part of the rear suspension to change. You'll need the updated bolt kit with the new arms.

sixto · #7 12-18-2008, 10:23 PM

I'd be surprised if your carrier bushings are anything more than ghosts of their original selves -

124 carrier bushing R&R

Sixto
87 300D

a2t · #8 12-19-2008, 06:11 PM

why do i need new bolts?

i dont know about carrier bushings, any way to tell?

a2t · #9 12-19-2008, 06:14 PM

and wheres a good place to put the jack stands if im jacking on the jack pads?

on the bmw's ive worked on we jack on the diff and use the jack pads for the stands.

sixto · #10 12-19-2008, 07:18 PM

You can't see the carrier bushings until you release the LCA from the hub carrier. If the rear end creaks when you get into or out of the car, you need new carrier bushings. If the wheel shifts as you torque the lug bolts, you probably need new carrier bushings.

I jack by the LCA under the spring and use the jack pads for jack stands.

Sixto
87 300D

a2t · #11 12-20-2008, 08:00 AM

Ok thanks, I will do that Sixto.

So can anyone confirm if I need new bolts? I know the early 86 models had an eccentric bolt in there but since mine is 87 I thought I had updated bolts ... ?

jnc19610 · #12 12-20-2008, 11:04 AM

Put a block of wood on your jack, and jack behind the jack pad, then put the stand on the pad.

AFAIK.... if your car is making noises, it's telling you something. Bad noises mean fix it. rattling noises in the suspension is always a SAFETY issue. Please don't ignore your safety, and safety of others. In PA, we have a stupid inspection system.... Personally, I wish they would get rid of it, but stories like yours is why we have it.

Sounds like you're a Darwin candidate. (no offense meant)

a2t · #13 12-20-2008, 12:58 PM

Wow you came to that conclusion quick, and you havent heard 1/2 my stories

Dont worry about offending me, Ive got thick skin.

OK so I got the torque arm out (after LOTS of psi on the air gun).

The old bolt on the carrier side is too big to fit thru the new arm. Beautimus. Guess I do need updated bolts for the carrier. Should replace nuts as well, those things got beat to sh..t

I will take pic of the torque arms that came out. No rubber left.

a2t · #14 12-20-2008, 04:56 PM

For all you Darwin award winners...

Update, and I'll post a final write up on how to do this once Im finished (still learning)...

Got bolt kit from dealer (2 ea) 1 for ea side. + 2 sleeves. It seems the updated torque arms have smaller ID on the wheel carrier side, so you need a smaller bolt. But the wheel carrier bore is then too large, so you have to press in a sleeve.

Then, the bolts they give you in the kit are now internal triple squares instead of external hex. As if it wasnt hard enough to grip the heads of those bolts, hidden up in subframe or behind the overengineered dust shield.

All this will make you want to beat someone with a hammer. F#$ckin stupid.

Anyway, 1 side done, I will work on right side tomorrow. Hopefully wiser from having learned, though being a Darwin award winner probably not...

lvfast1 · #15 12-20-2008, 05:19 PM

a2t, I am also about to tread on this repair due to worn bushing in the rear of my 300d..I would appreciate any extra info on this you can provide IE the tool or socket needed for the new bolts any specific tips or shortcuts so i dont have to learn this all the hard way..and hopefully i can provide some info also when i get mine done due to i think my car needs two links on each side one being the one you just replaced and another... both of the front facing links
Thanks in advance
Arlo