loud noise and vibration when braking in reverse w109

[WANT '71 280SEL]

When backing up, there is a loud vibration with accompanying "vibration sound" upon braking. It only does this in reverse, mind you. It's definitely coming from the LR. It's very noticeable to all passengers, maybe even outside the car. It almost feels like the brake caliper has one bolt missing and it's slowing pivoting with the wheel. I checked this and it's not the case. There's no clear movement in the wheel with the car off the ground.

If I remember correctly, isn't there some anti-dive design specific to the w109 rear-end? There seems to be a sort of collar at the end of the axles that looks like it pivots on the axles. I can't tell very clearly, but is there a bushing in there that when bad could cause this noise?

Any advice or insight on this? I'm dedicating a full week to do a BUNCH of work to the car and would like to address as much as possible.

Thanks!

David

[Pooka]

You might check the M-100.cc site, but this sounds like a rear wheel bearing.

There are grease zerts back there for these bearings since they are a rather old type of bearing. The loud noise in reverse is a classic example of the sound you hear when when these bearing have worn out.

[JMela]

Check this thread, this might be it:

M-100 Message Board - Strange (new) 6.3 sounds

[WANT '71 280SEL]

JMela, thank you. That's definitely my issue. Unfortunately it looks like it's almost impossible to eliminate. The thread mentions having shims custom made but I think that's getting over my head, especially when it comes to installing the shims.

Thanks,

David

[JMela]

Originally Posted by WANT '71 280SEL

JMela, thank you. That's definitely my issue. Unfortunately it looks like it's almost impossible to eliminate. The thread mentions having shims custom made but I think that's getting over my head, especially when it comes to installing the shims.

Thanks,

David

Might be worth a phone call/ email to these guys, different thread said they had developed a kit for 6.3's w these symptoms:

Home - Star Motors NY - Star Motors NY

[WANT '71 280SEL]

I checked their website but didn't see anything mentioned about it. I'll give them a call Monday and see what they have to offer.

Thanks,

David

[cth350]

crawl down in there and look for the grease fittings and give them a good shot of grease and the situation should get better.

The repair kit for each side is two plastic bearing shields that look like a half-pipe along with rubber seals. All the air suspension W109 cars need them eventually. Severe wear will require shimming the plastic shells to account for an out-of-round condition.

-CTH

[WANT '71 280SEL]

Charlie (or is it Charles?),

Have you done this specific repair before? I did some reading on m100 and it seems the shims might not be the best repair for it as it makes the rear ride rather hard. Then again, it may only be the case when shimmed too much. If you have done this before, how involved is it? I assume the axle shafts have to come out so the whole rear end should come out of the car?

Thanks,

David

P.S. I'm surprised there isn't more on the forum about this as it seems rather common to W109's. There are a few posts on M100.org but I didn't really see anything here. Oh well, I guess there aren't really many 109 owners on this forum.

[68_280SE]

When I rebuilt the rear axle on my W109, the nylon bushings on the brake bearings where worn and the axle tube had some slight pitting. I cleaned up the axle tubes with some very fine emory cloth and installed new nylon bushings. That was over a year ago and I not had any noise or chatter when braking in reverse. After 40+ years most W109 cars will need to have these bearings replaced due to wear and lack of proper greasing. There are grease nipples on each bearing that are very easy to miss. This job can be done without having to remove the entire rear axle from the car.

If you do decide to replace the nylon bushings yourself you'll need 2 of these repair kits from mercedes 1094200078. This kit includes new nylon bearing shells, two rubber seal rings and two felt seal rings

You'll have to remove the brake caliper, rotor and backing plate to get access to the bearings. There are 4 bolts holding the bearings together and at least one more large bolt holding the bearing to the brake support arm. One word of caution. The rubber seal rings that seal the bearings will probably have to be replaced. To be able to fit the new rubber rings over the axle housing, you have to pull the axles out. The upside to pulling the axles out is that you can clean and repack the rear wheel bearings and replace the inner and outer wheel bearing seals. There is a repair kit available from benz that has both seals, gaskets, and bearing lock ring 1113500068. Also the big blue mercedes shop manual for W108, W109, W111, and W113 cars has all of the detailed information about replacing the bearing shells and R&R of the rear axles.

From my experience I wouldn't say this job is impossible, but time consuming and very rewarding when fixed properly.

John

[WANT '71 280SEL]

Hi John,

Thanks for your in-depth write up. It sounds like this repair is probably beyond what I'd want to do myself, but I'm curious: do you have to open the rear differential to pull out the axle shafts as with most American rear ends?

Thanks,

David

[WANT '71 280SEL]

Also, I spoke to Star Motors about their kit. It's $290 and supposedly includes everything you'd need. What makes their kit special is that they special machine the bearing to oversize 1 and oversize 2 depending on how bad your car is. He said you'll need to measure your axle end with everything apart to determine which kit you'll need. Cars from rusty parts probably need the second oversize while others can use the first oversize. I guess the Mercedes kit only does the standard size, thus why Star may be the right way for some people.

I'm not sure which way I'll go. Because the MB kit is around $40 with my discount I may start with it and order the kit from Star if the MB one is too loose. With the bearings installed, supposedly you should be able to twist the carrier by hand. If not, you went too big. If it's sloppy, which is sounds like a lot of them are with the standard MB bushings, you'll want to go the Star route.

Hopefully this helps someone with this same issue (i.e. any w109 owner).

Thanks,

David

[68_280SE]

David,

You do not have to open up the differential housing to remove the axle shafts. The axle shafts are held in place by a plate that is bolted to the axle housing with 6 nuts and washers.

Here is a link from the Pagoda website with some pictures showing axle shaft removal. Rear Wheel Bearing Tour

Also if you do decide to pull the axle shafts yourself, there is a procedure you have to go through to engauge the snap ring on the right axle shaft with the slip joint when you reinstall the right axle shaft. The forum on the M-100 board has tons of information on this procedure and its in the blue factory shop manual. I'm not exactly sure when the factory changed the right axle shaft to include the snap ring, but the rear axle in my 1970 300SEL 2.8 didn't have the snap ring. My guess is that it was only on the later cars.

John