To access the inner bearing, the caliper must be removed.

 

Thanks, next step is there any info on this forum on how to remove hub/calipers and reinstall both bearings? I have searched with no success. Still playing with the dust cap, pretty tight..

 

This is all I have access now and hope you find it useful.

You use a screw driver to pry out the dust cap. The "official" tool is a slide hammer, I think.

 

A very large pair of channel-lock pliers works well on the dust cap, if you're having trouble with the screwdriver trick.

 

Thank u all I will report progress and may be some pics. Good info

 

Front Wheel Bearing Replacement with pics

OK, here we go. After 2hours, 15 Minutes, I changed my front wheel bearings.

The are 3 scenarios:

a. Bad bearings- need replacement
b. Loose bearing nut, need adjustment
c. Repacking of bearings

In my case I decided to replace the bearings anyway although I only needed tightening. In all cases ensure you ensure all parts are clean and are genuine MB parts. This is not a hard job but a bit messy. Most importantly observe all safety precautions.

1. Orders the parts-correct part numbers. Bearings(2 per side-inner and outer). The bearing pack from autozone comes with dust cap, seal,rotor nut etc. Parts cost $50 for both front wheels.
2. Buy correct grease from local MB dealer- $8.99 a tube
3. Tools required- screw driver, plastic hammer, 17mm socket, 18mm socket to remove 2 nuts holding calipers, jack,5.5mm allen socket, etc
4. Jack up the car, take off the lug bolts using 17mm socket
5. Remove the calipers using 18mm socket- 2 bolts located at the back of the caliper then secure the calipers to ensure hoses are not strained

6. Remove the dust cap- its very tight use a screw driver to pry it off along the edges. I placed a metal object in the dust cap groove and hit it with a hammer outwards and it came off easy.
7. Remove clamping nut using allen key and remove the bolt holding the outer bearings in place.
8.Remove the outer bearing and pull the rotor/hub assembly out.
9. To remove the inner bearing use a screw driver and drive by the outer edges of the seal. Pop the seal out and the bearing comes out.
10. Take out all grease inside hub assembly. I sprayed the maf cleaner and used a rug to clan it thoroughly
11. Grease all bearings with mercedes 'green'; grease. Grease inside hub assembly as well
the shaft.
12. Turn the rotor assembly and Insert inner bearing
13. Drive in the new seal- use plastic hammer or in my case place a 2x4 across the seal and gently hit it in until it sits well
14. Insert the hub/rotor asssembly into the shaft
15. Insert outer bearing after greasing it well
16. Tighten the wheel bearing nut, quarter turn beyond hand tightening. Turn the rotor assembly to ensure it moves freely and theres is no resisistance. Hold the rotor assembly at noon and six oclok positions and rock to ensure there is no movement. There is no torgue speficied for the bearing nut, unless u use special tools to ensure you are within allowable 'play' per WIS
17. Replace the caliper(tighten two,18mm bolts)
18. Replace the dust cap. I added some grease on the cap
19. Insert the wheel, tighten to required torquee
20. Done. Ensure you clean the rotor to ensure there is no grease on the surface.

 

16. Tighten the wheel bearing nut, quarter turn beyond hand tightening. Turn the rotor assembly to ensure it moves freely and theres is no resisistance. Hold the rotor assembly at noon and six oclok positions and rock to ensure there is no movement. There is no torgue speficied for the bearing nut, unless u use special tools to ensure you are within allowable 'play' per WIS

You did back it off a bit after tightening it, right? The tightening is to seat the bearings. Then it is essential to back it off to get the proper adjustment. There is supposed to be a bit of movement.

 

Good point. Correct, I backed it off a little bit and rocked the rotor again to ensure free movement. For lack of better tools, I used the manual 'rotor spin test'. Hope i did not overtighten.

 

Nice shots...I trust you packed the bearings and didn't just coat them with grease?

Something makes me think I'd like to see that grease under a UV light.

Good luck with it.

 

Packed means

packed. You really need to slop it in and with latex gloves push the grease into every race and bearing. Push push push.
Very nice write up,Good job.
For those that go by the wis,you can pick up a magnetic dial indicator at harborfreight tools to get the balls on dead set accurate play method.
Old school method as your case works great also:thumbsup:
Did you remember to tell people to inspect the spindle for galling?
That is for the people that ignore the signs of a bad bearing and just keep driving till the front wheel falls off

 

I think I did the best I could but I am sure I could have done better. My first time you know. I learnt a lot in the process though. Hope they last.

 

I fill my palm with grease, and run the larger edge of the bearing cage against my hand to push the grease through the bearing. Once it starts coming out the other side, you're almost done.

Make sure the bearings are clean before you start. Use some sort of solvent, then dry with compressed air. But NEVER spin the bearing with compressed air. Be sure that the parts stay still.

 

Excellent. I repacked my bearings on my 300SDL some time ago...The tightening of the locking nut as far as you can go is important in order to seat the bearing, then back off 1/4 - 1/3 of a turn. If you haven't done this, you can do it now - just take the cap off, loose up the nut and do it...

 

I just added some grease to my bearings last month (190,000 miles). One wheel had some play and that is what started it.
Mercedes bearing seem to last even 1,000,000 miles without repacking, while most of trailers require bearing repacking every year/30k.
Bottom line, I just wiped off the dirty grease around the nut and put lot of new grease on the nut. Pushing the dust cover force the grease to go inside and lubricate inner bearing as well.
There are special "Bearing buddies." that give the grease constant pressure in dirty situation like boat trailers or off road equipment.

 

Bearing replacement parts

Quick check:

There is no washer between the locking collar and the outer front wheel bearing on the W210, right? At least there wasn't one mine...
Just checking because some detail views show one(?).

 

Quick check:

There is no washer between the locking collar and the outer front wheel bearing on the W210, right? At least there wasn't one mine...
Just checking because some detail views show one(?).

It does look like there is something triangular between the collar and bearing...

 

Great write up and detail information!

What I didn't hear is that how did you guys drive out/in the inner races on the bearings? Aren't they usually driven into the hub and requires a puller to get the races out? (Not to be confused with the part of the bearing that holds the rollers)

Perhaps they just come out by pulling it with your hands?

Please clarify,

Thx!

 

Did you change the flange as well?

 

You would usually only change the flange if it is damaged.

 

Sorry guys, at mercy of sounding like an idiot... Which part is the flange?

 

You need to push them out with brute force, that's what my mechanic did, with a long shishel type and the hub on a vice. They pop out. Then you need the tool to put the new one in, like large washer, to be sure its centred and sat properlly with a " ting" noise, that mean its all the way through.
Olivier

 

Update:

Actually, I'm pretty sure that the bearing and bearing race should be replaced as a pair. (even if it looks fine) The two parts wears together and it doesn't make sense to mate old part with new.

So I used a punch to drive out the old races. Notice in the second picture that the old bearing race has scoring marks - replacement is a must.
I used the old races to drive in the new ones. Didn't hear any "ting" noise, but you can definitely tell if the races are fully seated.

Oh and the 5lb sledge worked best :thumbsup:

 

You can use an appropriately sized sockect to fit in against the underside of the race and then hammer it out. You can also use a drift, moving it around the circumference as you hit, but be careful not to scratch the hub or get the race cocked. You can also by a bearing race driver.

 

Oh, thanks Matt. I'm sure the mechanic called it the flange?

 

No ting Just kidding.
Well done :thumbsup:

 

Should the bearings be replaced at a certain mileage?

What are indicators that it is time to perform this entire process?
Someone had mentioned that MB bearings seems to last a 1M miles...any truth to that?

 

What are indicators that it is time to perform this entire process?
Someone had mentioned that MB bearings seems to last a 1M miles...any truth to that?

I'm sure someone can chime in on the actual service life of the front wheel bearings.

I was experiencing front wheel vibrations starting at 75mph, and gets progressive worse at +120 mph

I went ahead and replaced:
Lower control arm bushings (both sets - on both sides)
Inner tie rods
tie rod ends
lower ball joints
and finally bearings.

Now! it rides like it's made for the Autobahn.

My car has 87k miles on it and the larger bearings were made in Japan, the smaller ones were made in England. I suspect a previous owner (2 other) had the larger bearings replaced. (I've never seen a German car oem uses Japanese parts)

 

Kaister, you're correct about replacing the races with the bearing. It is typical. But actually, if the race is in good shape, you could probably reuse it with new rollers. But never mix used parts. If they were ever run, they need to only run against the same parts.

There are bearing packers which hold the entire bearing and force grease from one end to the other. Using one before installing the big race would work pretty well. These have a grease-gun fitting. I agree that you won't effectively get it through the hub, and even if you could, you don't want the hub packed full of grease. That would make a mess.

 

I think what I'm eluding to is that if you spend the time / labor to repack old bearings, spend the extra $60 (both sides included) and install new bearings. You may spend a extra 15mins (per side)punching out the old races. The key to driving out the old races is to punch with convection. Pull the punch tight against the inner race lip and focus in on where you will drive the 5lb sledge. (Oh you may smash your hand if you don't concentrate )

 

Bearing removal pin

I noticed in G-AMG's writeup on bearing removal, the "bearing removal pin" found in the kit that comes with the car is used. I dont quite understand what its for...does it aid in getting the rotor off?

 

I noticed in G-AMG's writeup on bearing removal, the "bearing removal pin" found in the kit that comes with the car is used. I dont quite understand what its for...does it aid in getting the rotor off?

When reading and posting, it's important to be ACCURATE especially if you are quoting. It's also helpful to link to the picture so that others don't have to spend lots of time trying to figure out what you mean.

That is NOT a "BEARING" removal pin and G-AMG does not represent it as such. It is a wheel removal pin that is part of the tool kit. Since MB uses lug bolts instead of nuts, many find it useful to help reinstall and align the wheel. I've used mine once, since then I ignore it. To use it, you remove a lug bolt, thread the pin in it's place, then remove the other lug bolts and slide off the wheel. You'd remove it before removing the rotor, then reinstall before putting the wheel back on.

For others looking at this thread, this is what Trek is asking about: