Repacking wheel bearings...What cleaner and what grease? - Page 2 - PeachParts Mercedes-Benz Forum

rwthomas1 · #16 01-20-2006, 08:24 AM

My prefered method is to use Kerosene as a solvent in a bucket or the oil drain pan. Cleaning the bearings thoroughly is easy with an old toothbrush. Cleaning them thoroughly is the only way to see if the rollers are damaged in any way.

I fail to see how blowing them out with compressed air will damage them. As long as you do not spin the cages with the air stream theres no problem doing this and they are ready to be packed when you are done. This is how they taught me in VoTec years ago.

I always hand pack the bearings. The MB grease is nice but I use Mobil 1 or Amsoil synthetic in all my vehicle bearings. Never had a problem. Both of them will meet or exceed any spec you can provide.

The most important part is to correctly set the preload on the bearings. Do a search on this. It has been discussed before and there are several ways to do it and get it right.

RT

dannym · #17 01-20-2006, 10:11 AM

I found that Carb Cleaner works very good cleaning bearings.

Danny

Habanero · #18 01-20-2006, 11:23 AM

Biodiesel is also a great solvent for cleaning up almost anything greasy. Nontoxic and smells good, too. Finally got Dad to switch from kerosene to biodiesel in his solvent sink last fall.

I also hand-pack bearings. That is how Dad taught me to do it, and I hate to think about how many bearings he packed in 25 years as a mechanic. However you get the grease in there, as RT mentioned, preload is the key important factor.

Also of note is if you are switching from regular to synthetic grease, be sure to get absolutely all the old grease out first. I don't know how much of an issue it is with the newer synthetics, but in the early days of synthetic greases they weren't miscible with all petroleum-based greases. So if you contaminated the synthetic with petroleum grease, you ended up with a mess that had very little lubricating power. Like I said, I don't know so much about newer synthetics, but you should be cleaning the bearing and hub well enough to get all the old grease out anyway.

Mike J · #19 01-20-2006, 07:10 PM

I ran to the local MB store and bought their grease. Must be good stuff, I can't read the Deutsch on the tube.
It better be great stuff, at the price, $13.41.
10% materil and labor discount for MBCA card-carriers. That will be next.

Bearings cleaned easily with mineral spirits, then rinsed with acetone. I'm satisfied. I hit them with Sweet Thang's hair dryer....

... and repacked.

The only really messy part was getting into the brake dust and cleaning up the hub bolts. I don't mind clean grease on my hands.
Thought my hands were clean and picked a bearing out of the mineral spirits and wondered where all the black stuff was coming from.
"Oh! My thumb!"
There is a lot of brake dust by the time you get down to 10-15% of pads left.
Oh, yeah. I think she'll be wanting a new toothbrush, too.

New rotor is on hub with blue loc-tite, with inner bearing and seal in place, and ready to reassemble in the A.M.
Funny, outer bearing is Japanese, while inner bearing is German. Hmmmm, wonder about the races....

Caliper bolts broke loose real easy. Had blue loc-tite at one point, but apparently not used the last time they were off and on.

What I really love about working on the car is the total lack of rust and corrosion on anything I have touched so far. Kinda like working on a fairly new vehicle.

DieselCJ · #20 01-20-2006, 10:50 PM

NC240D76 · #21 01-20-2006, 10:58 PM

I always heard that diesel fuel or kero was great for washing parts and gasoline left a residue that formed a layer around the part and kept grease from coating the bearings.
If the red and sticky you are asking about is the Lucas grease then use it, great stuff but it will take some extra hand washing after hand packing. (which I would recommend).

MarkM · #22 01-20-2006, 11:54 PM

I dont see a problem washing bearings with min. spirits, gasoline, or even soap and water (maybe a little slower with soap and water). Acetone is an excellent choice for the final rinse due to its very high volatility enabling its easy removal by air drying and/or blowing out with compressed air. Acetone is especially recommended if you use soap and water because acetone and water are miscible, and the acetone will get rid of the water (when I used to work in bio. research labs, we used acetone as a drying agent to remove water from freshly cleaned glassware). A previous comment indicated that acetone penetrates the skin and does all kinds of nasty stuff to your body. Actually, acetone does not readily absorb through your skin and enter your blood stream....it does disolve fats out of your skin after repeated use (like most organic solvents)and will cause drying/cracking of the skin, but skin absorption is not a major worry. It is very volatile, so if used in an enclosed area with little ventilation, inhalation may be hazardous, but acetone is not very toxic, so this is not a major worry under most circumstances. (Note that acetone is the primary ingrediant in nail polish remover, which consists of acetone (30%?) with water, a relatively benign product). The major worry about acetone is that it is a class 1A flammable liquid, so eliminate all ignition sources nearby when using it...this stuff is a real nasty fire hazard. Use it in a well ventilated area.

I do understand the rationale behind not washing bearings, and just repacking with grease, pushing out the dirty stuff in the process. What I dont like about this, though, is that you are bound to leave some dirt in there with this process. I cant see going to all the trouble of repacking bearings, and not making the extra effort to completely remove all the dirt. I say start with mineral spirits, finish with acetone, blow out with air, and then re-pack with the grease of your choice by hand.

(I dont see much worry regarding all the talk about leaving residues from gasoline, and so forth, in the bearings....in the end, you are just going to cram a bunch of grease in there and everything will be fine...as long as you did remove all the dirt and grit!!!)

Mark

Mike J · #23 01-21-2006, 07:40 AM

NC240D76,
Yes, it's the Lucas grease, "Red and Tacky." not "Sticky."
Well, between that and the DuraBlend, I have grease for the other vehicles.

MarkM says:
"I do understand the rationale behind not washing bearings, and just repacking with grease, pushing out the dirty stuff in the process. What I dont like about this, though, is that you are bound to leave some dirt in there with this process. I cant see going to all the trouble of repacking bearings, and not making the extra effort to completely remove all the dirt. I say start with mineral spirits, finish with acetone, blow out with air, and then re-pack with the grease of your choice by hand."

The mineral spirits flushed out the grease in moments, and the acetone was so quick and easy to work with, I can't imagine NOT cleaning the bearings everytime, for the peace of mind that the bearing is clean, and the opportunity to give a good inspection.
There's plenty to do during the drying time. On the passenger side I will be working on the ball joint and tie rod, cleaning hub, during bath and drying time.

And thanks to all who answered my original post.

pmckechnie · #24 01-21-2006, 08:19 AM

I'm sorry, but sometimes I make statements and don't explain myself enough.
I don't wash bearings before repacking them IF I am just doing maintaince. If the bearings are noisy, dry, look worn or dark colored, etc then I will clean them VERY good using whatever method I have at hand at the time. If the old grease looks like it is still doing it job, is reasonable clean and not dried out then I will only repack them. The reason I do it this way is because the more you MESS with something the MORE likely you are to MESS it up.