190D Rear wheel bearing, what is involved in changing it?
 

Hearing a louder and louder growl from the rear, suspect it is the rear wheel bearing. I picked one up, it is one big sealed bearing, what is involved in the install?

Thanks,
John :cool:

Elbow grease:

Markus and his Radlager

Rust and frustration
 

one of two ways:

On or off the car

Caliper and rotor off, center hub nut off.

On the car, special slide hammer the hub out of the bearing after removing the axle shaft retaining nut, remove snap ring then special fixture for the slide hammer again to pound the bearing out of the hub


Off the car, is a pressing matter.

Caliper and rotor off, center hub nut off, parking brake shoes off, 3 5-mm hex nuts that hold the backing plate off, all five links at the hub, off. This is a 1 hour job for the less rusty, more if heat and penetrate is needed. The magic trick here is to ensure the backing plate is broken loose from the hub center and spins freely, this will make link removal very easy. (bolt head access is simplified.)

Remove the entire carrier from the links. DO NOT loosen the middle forward link from the body, this is your toe adjustment for the rear axle. The head of the bolt has a fixed eccentric washer. A good mix of long Snap-On wrenches are helpful.

Once the hub is off the car with the brake plate, it's time for pressing. The better choice is a Benz dealership if you don't have an import centric independent shop that knows how to press it apart without snapping off the caliper ears. Some would argue cutting off the backing plate is helpful in the pressing process to simplify supporting the hub as you press, but the mercedes shops have the tooling to press the hub and bearing out without smashing the backing plate. Good luck with that one.

202 420 14 44--This is the plate for your car.

The hub is pressed out of the center of the bearing first, then the bearing is pressed out of the carrier after the snap ring is removed.

Press the new bearing into the carrier, slide the brake backing plate on the center of the carrier, then press the hub into the center of the bearing.

Reinstall the carrier in reverse.

Good luck!

Thanks for the replies, the first post was helpful seeing pic, looks like the first half was pulling the old one out, final group of pics was pressing the new one in.

Thanks for the explanation Mark, I really have to get a good look at the rear. What torque should the center hub nut be torqued to?

Beyond that, how does the hub go back on? Does it slide into the inner race of the new bearing, get tapped in with a hammer?

The old hub needs to be pressed into the center of the new bearing and the whole assembly then pressed into the carrier. I've heard tell of those that have pounded it back in, but I've had too much corrosion in the hub--Also, its and interference fit of a couple thousands of an inch so hammering could bung up the new bearing pretty easy.

OK, so the hub is first pressed into the bearing, then that whole unit pressed into the carrier?

The fellow in the pics must have pressed the hub into the bearing after it was in the carrier, no?

I have a press, bearing separator, and a couple flat plates along with an assortment of large sockets. Hopefully I will be able to complete this with those tools.

Any other tips you have would be great, thanks.

-John

201/124 Bearing installation!
 

Actually, the bearing is pulled into the hub using its' outer diameter as the point of applied force. Then with the bearing installed and the clip in its place the hub is installed into the center of the bearing. To do this the screw acts on the hub's outer edge and the bearing's inner diameter. That is the only way the interference fit between the hub and the bearing inner diameter can be accomplished without destroying the bearing itself. If it is attempted the other way around the actual bearings between the outer and inner races/diameters of the bearing's shell will have force applied to them and will fail. This is precisely why the bearing is destroyed when the hub is pulled from the wheel carrier, the bearing's inner diameter/race seperates from the outer diameter/race. When pulling the hub with a slide hammer be prepared for a struggle as the bearing takes quite a bit of force to come apart sometimes. Once apart part of the inner diameter/race will likely be stuck on the hub's inner part, this is most easily removed by grinding it almost through and then using a cold chisel to break the last bit. Early wheel carrier installation used some adhesive and may need a judicious heat applied to soften this up to allow the bearing's outer shell remainder to be pulled/pushed from it. Good luck!

Here's a short video showing the process using the SIR B90-M tool:

http://www.youtube.com/watch?v=vxcRUKYsTG0

The German page makes it sound like they used the axle and nut to pull the hub in, but think it was more likely pressed back in using a socket or similar race support on the inner race of the bearing from the back.

Ok, I got the hub nut off, parking brake shoes off (I dont know how they are going to go back on, tough to squeeze behind the hub) backing plate unbolted and loose, all 5 link nuts/bolts loose, but the parking brake cable through the back of the carrier is through a circle hole, and the end of the cable has a pivot mechanism that is not going to fit through it! Any ideas? Thanks

Yes, the pivot pin in the little arm on the end of the cable slides out and the arm on the end of the cable comes off. I forgot about the park brake, a channel locks, small punch and hammer will loosen the cable housing from the back of the hub. With regard to reassembly, the bearing into the carrier, the hub into the bearing. Far as the parking brake reassembly goes, GOOD LUCK, you will need it. Without a doubt, the CRAPPIEST job on a Mercedes IMHO. The biggest deal is resetting the retainer springs, Sir tools sells a neat little tool for this expletive generating task.

Thanks! Excellent timing. Heading back to the garage now. Will keep you updated.

-John

PS--the spring tool is a M0021 from SirTools.--The also make a on the car bearing tool a B-90 M for $341. No press or air tools required, comes with a manual as well. neat rig.

Update,
the parking brake pin came out easily, then pressed hub out, and bearing out of carrier, no problem.

BUT, the [only] bushing in the carrier is worn, how does that come out? Two jaw puller?

What is it called, I want to call the Mercedes dealer and see if they have it.

Thanks, John

Too bad you are on the wrong continent. I have this tool for sale on sleezeebay right now.

http://farm4.static.flickr.com/3549/...b9767568a4.jpg

This looks like the part, would a 2-jaw puller remove it?

http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1986@@1986&makeid=63@@MERCEDES-BENZ@@63&modelid=6121%3AMBC|1482%3AED|10000093%3ASM|169@@190D+2.5&catid=241464@@Suspension&subcatid= 241504@@Control+Arm+Bushing&applicationid=W0133-1625602&mode=PA