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Tires, Brakes and Suspension

W109 rear brake bearing replacement
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I think I got it now. I mean I replaced the slide bearings and the felts. No problems at any stage. The bearing housing seems to be firm prior to greasing already but the test drive will show if the maintenance helped.

On assebly I disconnected the closest parking brake support bracket so I could easily install the lower half of the bearing housing. Also I took off the brake rotor just to get better clearance when working.

Of course I lubricated all parts prior to installation; actually used MoS2 grease on the slide bearings and spray vaseline on the rubber seals.

Kari Pykäläinen

1971 6.3 #5581
1980 6.9 #7201
1981 380 SL
1987 560 SEC
1996 C180 A
1998 ML 320
1995 Tahoe 350cid
1980 Stingray SV175 boat
Thanks Art. The seals are included in the kit, I bought the same kits that you had. The spacers seem to be ok on my car.

The rubber seals are in very healthy condition; soft and no damages at all. The shop manual says that you can do the slide bearing overhaul having the shaft in place if you do not replace the rubber seals. In such a case the seals have to be in good condition, no wear and tear. Mine seem to be in good condition.

Of course I will use new felt rings as the old ones were worn out.

Kari Pykäläinen

1971 6.3 #5581
1980 6.9 #7201
1981 380 SL
1987 560 SEC
1996 C180 A
1998 ML 320
1995 Tahoe 350cid
1980 Stingray SV175 boat
65mm is correct. You should be OK. Sounds like the main problem was water and dirt contamination of the bearing. Proper greasing and new seals should prevent recurrence. I presume the seals are in the kit. The problem is to get the new seals over the hub if you have not removed the axle.
Art
Just a quick update. I have measured the following with my vernier caliper:
Axle tube diameter 65 mm
Bearing housing diameter 70 mm
Thicness of the old slide bearings approx 1.9 - 2.2 mm
Thickness of the new slide bearings approx 2.4 mm

So I might be lucky just with replacing the nylon slide bearings. I will try to do this first. If there is still excess play I need to figure out how to decrease the bearing housing diameter.




Kari Pykäläinen

1971 6.3 #5581
1980 6.9 #7201
1981 380 SL
1987 560 SEC
1996 C180 A
1998 ML 320
1995 Tahoe 350cid
1980 Stingray SV175 boat
Okay. I have dismantled the RH side bearing. I removed the brake caliper and was able to wiggle out also the bottom half of the bearing housing. I need to clean and wash all parts before I can start to analyze where the wear is.

The bearing halves had a tight fit on the axle tube. There were already self-made shim plates between the housing and the nylon bearings; three stripes of thin sheet metal where the middle one seemend to cover the grease groove.

Everything was dirty and rusted, the gunk had no lubrication properties any more.

I studied the Shop Manual. I could not find any measurements there, only the dismantling and reassembly instructions.

I measured the axle tube has a diameter of 65.0 mm. I need to try with the new bearings if it is still loose. The old bearings seemed not have been worn, the thickness is even and they look the same as new ones in the kit.

How I can determine if the wear is in the axle tube or in the bearing housing?

I think perhaps I have to go for tailor made slide bearings, like here: http://www.detrading.se/en/products/slide-bearings/compound/

I was planning to buy a pair of those and have to machine the right thickness.

But I will clean all first and then try to find the problem.




Kari Pykäläinen

1971 6.3 #5581
1980 6.9 #7201
1981 380 SL
1987 560 SEC
1996 C180 A
1998 ML 320
1995 Tahoe 350cid
1980 Stingray SV175 boat
Absolutely OK[:)]. The purpose of all the pictures and text is to help people keep their cars running. Just tell them that I am not a mechanic. Justin is and some of the others involved have high quality skills. I am just the "scribe" and photographer.
Art
I have ordered the repair kits with part number A109 420 00 78. The price in Finland is EUR 51 per kit.

I linked some of Justin's pictures to out local web forum because my buddies did not have a clue what kind of system my car has, if that is OK Art?

Kari Pykäläinen

1971 6.3 #5581
1980 6.9 #7201
1981 380 SL
1987 560 SEC
1996 C180 A
1998 ML 320
1995 Tahoe 350cid
1980 Stingray SV175 boat
The tolerances are discussed on page 8 of that thread with contributions from Chris Johnson and Paul Jermy. You are right, Justin did the final bearing assembly when I was not there to take photos[:I]. However, I did take some pictures showing the bearing half in place temporarily to show how it fits with the outer spacer rings. They have to be a tight fit, no sideways play at all. Do not make the mistake that he made of replacing the axle before doing the hold down bearings. You can see in the thread that he put the axle back in with the hold down bearings and seals not in place. He was very "lucky" to manage to stretch the rubber seal rings for the bearings over the hub, so it can be done with the help of a lot of rubber grease and elbow grease[;)]. I would not recommend it.
Art
Thanks Art. I have been reading that topic but had forgotten there was the bearing also being refurbished.

When I bought the car there was already some play in the bearing and the anti-dive arm had some sideways play already. I changed the rubber bushings that come under the rear seat and could live with the car for few years. I guess greasing the bearing helped me.

Now for the last two years the bearing vibrates when reversing. I checked under the car that the bearing is massively worn out. The arm is moving few centimeter sideways at the end.

I was hoping to change the bearing nylons by just removing the housing, and of course the brake caliper etc. that is on the way.

I bough the nylon bearings few years ago, now it seems only the complete repair kit is available. I need to order the kit as I do not have any seals etc.

Where could I find the tolerances to measure the axle tube and the housing?

In your topic there was no pictures taken during the bearing assembly, that is a pity [:)]

Kari Pykäläinen

1971 6.3 #5581
1980 6.9 #7201
1981 380 SL
1987 560 SEC
1996 C180 A
1998 ML 320
1995 Tahoe 350cid
1980 Stingray SV175 boat
Have a look in the 6.3 Forum in the threads I made sticky at the top for "Justin's 6.3 project" or words to that effect and go to page 7. Doing this job starts towards the bottom of page 7. There are some important points. Often, the wear is in the steel of the axle housing tube, not the nylon, so you need to carefully measure the diameter of the bearing section of the axle housing to ensure it is within specs. If it is not, it will be necessary to replace the axle housing or have the bearing surfaces built up and reground. The rubber seals are also very important to keep dust out of the bearing. It is very difficult to get the seals on unless the axle and its hub is removed from the axle tube. The tolerances for the bearings, both for lateral movement and thickness are in hundreths of a millimetre, hence the range of thicknesses supplied for repair. And so on... This is a job that should be done with the axle out of the axle housing tube which is when you would replace the axle bearings and the various rubber bushings.

This all has nothing to do with the brake calipers themselves, whether they float or not. I am not sure what you mean when you say the whole system is very loose. Even with the usual wear in the bearing caps, if they are properly greased, there should be little or no play and nothing should be visibly or palpably loose.
Art
300 SEL 6.3 has "floating" rear brake calipers. The bearing on the right side is in poor condition and on reverse it vibrates a lot when braking. I checked underneath that the whole system is very loose.

I did buy the plastic bearing parts (bearing halves) already years ago but never replaced the parts.

I had a look on the EPC but could not find the bearing parts, I saw the bearing housing and a repair kit. I remember there should be sone shims rings also?

Anyhow I need to do it now, is there anything special I need to know? I just remember the shim rings, is there any adjustement to be done.

Kari Pykäläinen

1971 6.3 #5581
1980 6.9 #7201
1981 380 SL
1987 560 SEC
1996 C180 A
1998 ML 320
1995 Tahoe 350cid
1980 Stingray SV175 boat
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