bearing buddy to pack wheel bearings??? - PeachParts Mercedes-Benz Forum

odie · #1 10-28-2004, 12:11 PM

I'm getting ready to repack my front wheel bearings.

I was wondering if you could use one of those bearing buddies or "Red-eye" wheel bearing caps that are available for boat trailers?

I think all greasable wheel bearings are basically the same design. An inner & outer bearing, inner seal and outer dust cap.

With boat trailers you back into the water while the bearings are still hot and the sudden cooling can cause water to get sucked in past the seals. The special grease caps have a grease fitting so you can grease the bearings after you pull your boat out of the water at the end of the day. This pushes the old grease out the inner seal and any water out with it and replaces it with fresh grease without having to take the hub apart everytime.

Why can't this be done with wheel bearings on a car? If the special bearing caps don't fit why can't you drill and fit a zerk fitting onto a Mercedes bearing cap and squirt away with the old grease gun?

This would save a couple of hours labor and you could regrease anytime you wanted.

boneheaddoctor · #2 10-28-2004, 12:16 PM

problem is you have to weigh the bearing before and after greasing it to be sure you get the right ammount of grease in the wheel.

I think it calls for a total of 75 grams grease total more and it doesn't circulate right too little and ................

either way your bearings are toast.

Take the right steps and I see no reason it won't work.

Habanero · #3 10-28-2004, 12:30 PM

I am probably going to get flamed on this, but I think the whole weighing the grease thing is a little silly. I myself have repacked probably close to a thousand bearings and I hate to guess how many Dad and my brother have packed in their respective shops and never once has any of us weighed the grease we were using. There is obviously some technique involved in getting the grease into the bearing, but if it is full, it is full. Now unless there is something magical about Mercedes bearings, I can't imagine they are that much different than any other bearing. Guess I will find out as I need to do mine in the next month or two, and I don't plan to weigh the grease.

tangofox007 · #4 10-28-2004, 12:31 PM

Putting grease in through the dust cap will blow the cap off before the grease gets past the outer bearing. And if that was not a factor, you would wind up way too much grease in the hub. And then you would likely blow the inner seal out. Then you would have grease all over your brake rotor and caliper. At least your brake pads would last longer!

boneheaddoctor · #5 10-28-2004, 12:36 PM

I just reread the original post.....

..I correct my original assesment. I thought it was a bearing packer, I misread it, one of those thgreasible cap things would be bad. It would force grease though the backside by poping the rear seal a very bad thing.

Would force out water contaminated grease on a boat trailer without brakes, a good thing, on a mercedes a bad thing.

odie · #6 10-28-2004, 12:39 PM

I would think that if you pumped a good amount into the bearing cap you will hear or see the grease pop out the seal on the other side. Pump a few more times for good measure if you like. any mess from the grease pushed out past the seal you can either scoop up or wipe off with a paper towel. Or just let it have there until it falls off driving down the road.

How would having too much grease in the hub be a problem? The Red-Eye style beearing buddies are spring loaded. You over fill the bearing caps with grease and as the old grease seeps out past the inner seal overtime, fresh grease is feed into the bearings. The "red-eye" pop out when you has pumped enough grease. when the red-eyes disappear it's time to add more grease.

What do you mean by grease circulating? I know that the big rigs have oil in the driven axles. The have a clear cap on the hub that you check everyday. Had to do that at truck driving school. I though that wheel bearing grease was thick and heavy so it stays in place and doesn't run off when it gets hot.

Forgive me if I don't know squat about grease. It's messy and few people really want to know anymore about it than they have too. That's why 99% of the cars on the road are way overdue for repacking. LOL

boneheaddoctor · #7 10-28-2004, 12:42 PM

grease actually does circulate, slowly but it does, think a mixer with cake batter in a bowl.

To get grease past the inner seal, the seal would unseat through hydraulic force.

How do you plan on scooping it out, there is a dust cover?

brake dust would get in, grease would sling out through centrifical force and grease your disks. None of that any good.

Rick Miley · #8 10-28-2004, 12:52 PM

More than you ever wanted to know about grease is here. Boy, do I miss TCane. If you have time, do a search on his posts. He brought a tremendous wealth of information here, but was run off by another member.

Pete Burton · #9 10-28-2004, 01:16 PM

a simple bearing packing tool is available at many places. It's basically 2 dished plates, one threaded in the middle. you put bearing in and pump with grease gun. Works very well, but this can be done well with patience by hand too. Depends on what you like. The bearing buddy solution doesn't really work for a car, because there are 2 bearings separated by several inches. Greasing the outside one while ignoring the inside is NG. Too much grease causes unnecessary drag and elevated temperatures. Grease is used where an oil bath (which is mode efficient) is impractical, like in auto wheel bearings and driveshafts.

odie · #10 10-28-2004, 01:24 PM

I think your right about the seal blowing out. The seal is tapered to the inside. It would be hard for grease to make it's way out.

So how does it work for a trailer?

Why not just a grease fitting on the grease cap and a give it 2-3 pumps every oil change? A little fresh grease to replace what is slowly consumed, but not enough to blow the seal out either?

I had a couple of trailer kits with greasable berings that the manual said to add a couple pumps every few thousand miles.

boneheaddoctor · #11 10-28-2004, 01:30 PM

grease isn't consumed.....

#12 10-28-2004, 01:38 PM

I agree w/ Habanero on the issue of weighing grease.

As far as packing method goes. There's nothing quit like a good hand job.

It may not be as fast as one of the cool little packing plate deals, but it's a lot more fun getting your hand a little dirty. Besides, by the time I get to the point where I'm pulling the bearings out of the hub I have wash my hands before I can repack them anyway.

I'm a firm believer in keeping it simple. More tools just means more to pick up when I'm done.

Brian Carlton · #13 10-28-2004, 02:14 PM

Quote:

Originally Posted by Habanero

I am probably going to get flamed on this, but I think the whole weighing the grease thing is a little silly. I myself have repacked probably close to a thousand bearings and I hate to guess how many Dad and my brother have packed in their respective shops and never once has any of us weighed the grease we were using. There is obviously some technique involved in getting the grease into the bearing, but if it is full, it is full. Now unless there is something magical about Mercedes bearings, I can't imagine they are that much different than any other bearing. Guess I will find out as I need to do mine in the next month or two, and I don't plan to weigh the grease.

I agree completely. I've never weighed the grease before, nor do I ever intend to.

JamesStein · #14 10-29-2004, 09:44 AM

Quote:

Originally Posted by cmichalik

As far as packing method goes. There's nothing quit like a good hand job.

It may not be as fast as one of the cool little packing plate deals, but it's a lot more fun getting your hand a little dirty. Besides, by the time I get to the point where I'm pulling the bearings out of the hub I have wash my hands before I can repack them anyway.

I'm lazy. I recently replaced the inner and outter bearing on one side and repacked the other. On the repack, I didn't really feel like using a solvent to clean all the old grease out of the bearings. Since I didn't do the packing job last time around I had absolutely no idea what kind of greases was in there. After 20 minutes of me trying to force the old grease out while forcing the new grease by hand I gave up and bought on of those bearing packing kits and 2 tubes of redline bearing grease.

I pumped the redline into the bearing continually until it flowed clear red and I was done. That whole process took about 3 minutes. The time it took to clean up the packer and everything was still less than it took me to 'fail' to repack it by hand.

Habanero · #15 10-29-2004, 11:59 AM

JamesStein, that is a very dangerous practice you describe. Just because the new grease looked clean coming out of the packer, that does not necessarily mean all the old grease was removed. Bearing packing is not like flushing a cooling system. You really need to be sure you clean all the old grease out of the bearing using a proper solvent. If the two greases are incompatible, they will separate and you will end up with steel on steel inside the bearing. Cleaning the bearing before repacking is the first commandment of bearing packing and you are really taking a huge risk by not following it. In fact, one could argue you would be better off not touching the bearing at all than performing the procedure you describe.