124 rear wiggle. - PeachParts Mercedes-Benz Forum

babyjames · #1 11-14-2009, 11:46 PM

Man, this thing is starting to frustrate me! Subframe bushings?? They look suspect. The PO did NOT take care of this car. Let everything get so bad it wore everything out in the rear end.

I've replaced control arms 202 350 02 06 (lower center), 210 350 33 06 (upper front), 210 350 34 06 (upper rear), 210 350 38 06 (lower front) on both sides. They were definitely all either shot, or getting that way and I have noticed improvement each time I replaced some (did this in stages, used new hardware pretty much everywhere - kept the hex bolts in places where it was tough to get the triple square bit into, re-used bolts were of appropriate diameter).

The diffy bushings are bad, what's left of 'em. I'm thinking the ones on the subframe are too. Lurches (sways, swings, jumps, call it what you will) when on the brakes, when going over a bump which quickly loads then unloads the rear suspension, and when accelerating hard, especially uphill. One important note, the problem is worse when there is weight - cargo, passengers, fuel - in the rear. Did the upper rear and lower middle on the R side this morning and then went out for a cruise with my four-year-old. Everything was pretty cool until we stopped for fuel. With 3/8 tank, I was feeling pretty good about myself. At 3/4 the a** end starts jumping! AAARRGGHHH!

Most logical next step? I'm leaning toward front rear subframe bushes. How hard - possible?? - without the press? I'm looking at Samstag right now!

Jay.

babyjames · #2 11-15-2009, 01:02 AM

Not the first time I've asked that question, and I'm sure it won't be the last!

I used new bolts (M12) on the upper and lower front arms, but didn't put a bushing in the bolt holes on the wheel carrier. I'm thinking I might have screwed up there?? Working from memory, those had a long bushing that extended through the hole on the arm, into the carrier. I think I had to use a dead-blow to remove the arms after I got the bolts out.

I just want this thing to handle right so I can go throw it around a little!!!!!!

Second guessing is what I do best! I hope I can sleep tonight.

Jay.

Billybob · #3 11-15-2009, 01:07 AM

Unless you can definitively see the subframe bushings have failed your logical next step if the four strut arms are solid would be the rubber bushings at either end of the rear lower control arm. There is an upper/inner one between the LCA and the subframe and the lower/outer between the LCA and the wheel carrier. The one at the wheel carrier seems to wear out sooner than the upper one.

The subframe mount bushings are the most robust and they are almost completely enclosed so that helps them last longer I’d guess. If you get to the point where every thing else is done and you decide to do them they can be a bear. The way to do it is to hang the caliper, compress the spring, loosen or disconnect the shock and rear sway bar, then loosen all the four subframe mount bolts some, then remove the subframe mount bolts on one side with something to control the dropping of the sub frame when you do!

Then remove the old and install the new making sure you get the new mounts completely seated into the subframe “cups” into which they fit. Then lift the subframe back up into its precise position, look from below so that you can see the threaded hole into which the subframe mount bolt will screw into. Carefully start the bolt by hand being carful to hold the bolt straight and avoid cross threading the very fine threading on the bolt. You might need to lever the subframe around to get it where you can line up the bolt straight and get it started. You definitely want to take your time and “feel” the bolt into the threads with your hand, I use a socket on the end of an extension for a little leverage to angle it and get it started. The bolt originally had blue threadlock, clean the old stuff off on a wire wheel or with a wire brush and use new stuff it will be easier to start that way. Cross threading these bolts is a major problem to remedy and most likely you will never get the bolt completely installed if you cross thread it, you’ll rip the threaded tubular stud into which it threads out of the chassis’s sheet metal trying. Turn the bolts about half way in and then move to the other side and follow the same procedure, torque the bolts into place, reattach the shocks, the sway bar, decompress or install the spring, and reinstall the caliper.

The subframe mounts can be difficult bordering on impossible to remove and install, often times people burn the rubber loose heating the subframe cup with a torch. Unfortunately that just makes installing the new ones harder because of the burnt stuff inside the cup not to mention paint on the subframe is then trashed and will be rusting soon afterward.

If you get to the stage where you’re going to do the R&R of the subframe mounts I have the Klann tool for rent in the tool rental program. I bought it after the first 124 rear- subframe-mount- R&R-palooza experience I had! With the tool and a tube of KY Jelly it’s a task rather than a life and death struggle!

I’ve got a few 124 cars and a couple 201 cars and the thing I learned is in the long run it is simply easier to drop the entire subframe, replace every rubber piece that can’t be EASILY replaced with it in place and then just reinstall the whole thing. The access to remove some of the strut end fasteners with the sub frame in place takes the patience of a Buddhist monk (and even he would be swearing and gritting his teeth). With the subframe on the ground you can do all four struts in less than an hour, the LCA bushings are ten minutes each, the diff bushings the same, subframe bushings the same. I give the subframe the once over clean it, rust treatment and paint if needed and it’s like new. A couple hours and it’s ready to go back in.

I actually made a tool to even make the reinstallation easier, I took four subframe mount bolts cut the heads and about 1” off, welded those to 12” sections of 3/8” allthread. I thread the tools into the subframe mount bolt receptacles, get the subframe underneath and lift it up threading the allthread extensions down thru the sub frame mount holes, then throw a big washer on each and a 1” long allthread connector nut on each. I can then get the jack out from underneath and use a box wrench to consecutively run the nuts up the allthread lifting the entire subframe into the precise position. Then one by one remove the tool and replace it with a clean bolt with new threadlock.

This way I don’t have to wrestle the 300 pound subframe unit from underneath or with it overhead trying to get it into the exact position while trying the get bolts threaded. It make it easier with the car on stand and a floor jack or with the car on a lift you can maneuver the heavy thing with ball park accuracy and then screw it into exact position nice and easily.

babyjames · #4 11-15-2009, 01:57 AM

I'm not 100% certain on the bushes, Billybob. Thanks for the input. Just checked the EPC and that put my leaving-out-shims fears to rest. No M14 bolts - except that one that was 14mm on the arm end, and M12 through the wheel carrier. Nope! That would have been too easy.

Why is the waggle worse when there is weight in the tail? Might be time to take the car over to MBI and get them to have a peek! I'm tired of throwing parts/MONEY at this thing. FWIW I replaced the LCA/inner bushings on both sides. The outer pivot/ball joint-ish "bushing" (LCA at wheel carrier) seemed pretty o.k., L + R.

I feel good about everything I've done so far, I mean these parts were definitely bad! Heck, everything rubber on the rear of the car is bad. Those subframe mounts are BEEFY! But, dude, if you'd driven this thing before I started in to replacin', well, it wouldn't surprise me if the even the burliest of bushings got wore out!

Cheers!

Jay

babyjames · #5 11-16-2009, 12:07 AM

Which tool do you have, Billybob? I'm looking at Samstag p/n KL-0356-1. According to the description of the tool, it is possible to R+R the bushes with the subframe in place. Is this the same one you have? Is the description inaccurate? With the tool you have for rent it IS necessary to drop the subframe??

Linky: http://www.samstagsales.com/mercedes.htm#suspension

Thanks!

Jay.

Billybob · #6 11-16-2009, 12:30 AM

Yes that is the tool I have, their description of how it’s used is a little misleading. The entire subframe does not need to be completely dropped, as I mentioned in my earlier post but you do need to drop one side at a time so it hangs down enough so that you can get the tool in place above the subframe bushings.

babyjames · #7 11-16-2009, 12:44 AM

How much to ship the tool to 97217? Do you require a deposit? Have the press for the diffy bushes, too? Might as well get it all over with!

Jay

Billybob · #8 11-16-2009, 10:17 PM

Quote:

Originally Posted by babyjames

How much to ship the tool to 97217? Do you require a deposit? Have the press for the diffy bushes, too? Might as well get it all over with!

Jay

PM sent!

babyjames · #9 11-17-2009, 11:09 PM

First, if your mother-in-law or kids are around, go into the bathroom and close the door.

Now, pinch your tongue between your thumb and index finger and say the following, "I am sofa king we Todd Ed."

That's how I feel right now. I replaced what I will call the "toe link" (210 350 21 53) and INSTALLED THE LITTLE CHEESEBALL SHIMS IN THE BOLT HOLE ON THE WHEEL CARRIER FOR THE OUTSIDE END OF THE THRUST LINK. Yup.

Freakin' dialed! Feels great.

Eatin' crow. That's MY game!

Jay.