Replace bearing or whole "knuckle"? - PeachParts Mercedes-Benz Forum

vito · #1 08-06-2008, 05:46 PM

I have what I believe to be a bad bearing on the driver side front. I have a parts car that has good ones. Would it be easier to replace the whole knuckle? Or just replace bearing? Never done front end work. Thanks

pjc · #2 08-06-2008, 06:22 PM

Bearing or ball joint? The bearings are in the hub; the steering knuckle contains the lower ball joint.

I'll assume you mean ball joint, in which case the answer is: It's easier to simply swap knuckles. You have to remove the knuckle either way, and installing the new ball joint requires a special tool that costs $350 or so. (You can, however, knock the old ball joint out with just a BFH if you're careful.)

Some on this board claim you can install the new ball joint with an ordinary C-clamp, or with a ball joint press available from Autozone, but based on personal experience I find that difficult to believe. I tried it with a very nice K-D Tool ball joint press and couldn't get it to work; there's not enough clearance. Best bet is to bring the knuckle and new ball joint to an indy who has the tool and pay them to press it in.

It's possible to get the knuckle off the car without compressing the spring if you put the car on a jack stand and use a hydraulic jack under the lower control arm. But these springs are very dangerous, so the safer approach is to compress the spring using a proper Mercedes-style compressor. Disconnecting the LCA from the ball joint can also be difficult; best done with a large cone-style ball joint separator.

Be certain your old ball joint is bad, and the replacement good, before you perform this job. It's not something you want to do for no good reason. Nor do you want to do it twice.

tangofox007 · #3 08-06-2008, 06:34 PM

Quote:

Originally Posted by vito

Would it be easier to replace the whole knuckle? Or just replace bearing? Never done front end work. Thanks

The easiest option would be to swap just the hubs. (Unless the bad bearing damaged the axle.)

vito · #4 08-06-2008, 06:58 PM

Quote:

Originally Posted by tangofox007

The easiest option would be to swap just the hubs. (Unless the bad bearing damaged the axle.)

this would not require compressing the springs correct?

tangofox007 · #5 08-06-2008, 07:04 PM

Quote:

Originally Posted by vito

this would not require compressing the springs correct?

None of the suggested options requires the use of a spring compressor. If you are going to remove the knuckle, you can leave the weight of the vehicle on the lower control arm.

Removing a front hub is only slightly more involved than changing a flat tire. But even that can turn into a disaster for those who are unprepared or ill equipped.

winmutt · #6 08-06-2008, 08:32 PM

Pull the hubs inspect the spindles and if they are not smooth or look worse than the parts car, make the swap. I would swap both at the same time. Probably about 8hrs of work,

pwogaman · #7 08-06-2008, 08:51 PM

Quote:

Originally Posted by pjc

Some on this board claim you can install the new ball joint with an ordinary C-clamp, or with a ball joint press available from Autozone, but based on personal experience I find that difficult to believe.

Believe it or not I did it. There are a few old threads here with loads of pictures and lots of flaming on the topic. The Autozone tool cost me nothing to borrow.

bgkast · #8 08-06-2008, 10:43 PM

New bearings are what, $20. Just buy a new one!

Diesel911 · #9 08-06-2008, 11:55 PM

If you swap the whole Steering Knuckle you may need to have a front end alignment done. If you only replace a ball joint there is a good chance your alignment will be OK.
If it is a Wheel Bearing as said previously; if there is no damage to the spindle just replace the bad bearing and the race. Or, swap a good hub from the other vehicle but be sure to keep the origional bearings with that hub.

vstech · #10 08-07-2008, 01:18 AM

... get 126 hubs from somewhere and change up to vented brakes!
but the simplest thing is to swap hubs over 5 minutes work tops.
I would just put in new bearings. that way I know I'm not doing work that will need to be done again soon. look to spend 4 hours changing bearings. you will need your preferred method of driving out the races from the hub, you will need to grease the new bearings, and you will need a race setter to put the new races in.
parts should cost at most $20 for both sides bearings and seals. and you will spend a lot of time banging and cleaning.
swapping hubs over is a piece of cake in comparison.

vito · #11 08-12-2008, 04:50 PM

Just wanted to say thanks for the replies. Over the weekend I pulled the hub, the inner bearing was the culprit, all loose, brown grease (very little). So we swapped the whole hub off the parts car, which had brand new bearings. Drives smooth as butta and NO MORE NOISE!

Hatterasguy · #12 08-12-2008, 06:37 PM

I was going to say I just did a front wheel bearing on my SDL with one of Phil's kits. If it took me an hour and a half its because I was drinking beer and BS'ing with my friend.

These cars are so easy to work on!

My dad did one on his F150 last year and was like, damn MB did it right.

charmalu · #13 08-12-2008, 08:09 PM

Reading through this, I didn`t see anything mentioned about the preload on the bearings, I thought this was an important step when doing mercedes bearings.

Charlie

Oracle12345 · #14 08-12-2008, 08:47 PM

Quote:

Originally Posted by charmalu

Reading through this, I didn`t see anything mentioned about the preload on the bearings, I thought this was an important step when doing mercedes bearings.

Charlie

IT is and if you dont you will wear the bearings out prematurely....