Front Bearing Race Removal

[slomove]

This is Birkin specific, but maybe you Caterhamistas know how to do this, anyway:

I found a front bearing a bit lose and when opening saw a lot of rust in the grease, probably water got in there. Took it all out and ordered new bearings but the inner/larger bearing race baffles me. How do I pull this out of the aluminum hub? It is completely recessed and I can barely get a fingernail behind the inner edge.

The outer bearing race should not be a problem (I hope) since it has a protruding ledge that i can get to with a brass punch.

Thanks

[rzempel]

I was told once, by a World Superbike mechanic, that the way he used to pull bearings races like that was to run a weld bead around the bearing face. As the weld bead cools, it supposedly contracts and shrinks the bearing, allowing the bearing to literally fall out.

I've never tried it myself, but it may be a possibility.

[BMWRACER]

You might try welding a couple of bolts to the race, then using a slide hammer.

I'm surprised they make no provision to remove the race.

[Doug Liedblad]

Gert

Running the welding bead inside the race works great. I've done it several times.

You may not have to run it all the way around, I only used an inch or two of bead

Sometimes the race will fall out, other times it needs only a small encouragement. Welding a bolt to help pull it out should do the trick.

Do it on both sides as it will press out much easier.

You can also heat the entire hub up a bit as the aluminum will expend more than the race.

I use the oven, generally when the wife is not around.


I have a mig welder if you can't find one closer.

Doug

[slomove]

Whew. The welding did the trick and I got the races out. I still broke the jaws of a cheap slide hammer puller but a pilot bearing puller holding on to 3 weld beads broke them loose.

Now I need to find the unobtainable grease seals with 53mm OD (52mm or 54mm is easy). So far I only found Dichtomatik in Germany making them or maybe the Birkin importer has such unusual parts.

[Sean]

Now I need to find the unobtainable grease seals with 53mm OD (52mm or 54mm is easy). So far I only found Dichtomatik in Germany making them or maybe the Birkin importer has such unusual parts.

Maybe try Timken? Might be worth a shot.

[slomove]

Yes, I tried Timken as well as Federal Mogul, SKF and other usual suspects. all of them have seals for 40mm shaft and either 52 or 54mm OD. Some of them even 7mm thick and with the closed metal housing. But, other than Dichtomatik nobody has 53mm OD. Now I can either:
- get one from the importer (probably an arm and a leg)
- motivate relatives in Germany to buy me a set (if really available and not just catalogware)
- Use 52mm and goop them in with silicone (no way)
- turn out the hubs to 54mm and use the bigger seals

At least there are options.

Since I am at it I am also considering rebuilding the entire front suspension. I.e. disassembling, stripping and powder coating everything, replace the ball joints and bushings, maybe even new calipers (upgrade?).

[Doug Liedblad]

Gert

Can you turn a spacer that fits the into existing hub that a seal can then press into? 52 mm ID, 53 mm OD. A light press fit is all you would need.

That way you don't have to change your hub.

Doug

[slomove]

Hm. Interesting Idea.

I probably can not turn such a piece because with 52 ID and 53 OD the wall would be only 0.5 mm. But maybe I just get some 0.5mm shim stock strip and bend a bushing ring. The remaining small gap could indeed be sealed with some goop.

So, another option and quite cheap. Like it!

Gert

[Doug Liedblad]

McMaster Carr has it in .5 mm or .020" which should be close enough.

In Titanium too!

If you can form it Ok I'd hold it in with Loctite. The green stuff.

Heat will get it out if you ever need to.

Let me know if it works.

I corrected my 54 mm to the 53.

[Jim F.]

Gert, I would suggest biting the "small" bullet and have your hubs turned..... that way, wherever you are in your travels, if a bearing problem arises again you'd have many choices for a quicker, easier bearing replacement w/o having to deal with a multi-process of shims, goo, Loctite or whatever. As usual, sometimes it's better to keep things simple (uncomplicated) to avoid a failure from one or more of the processes (snowball effect). I'm not trying to meddle but hopefully can offer what I believe to be the correct decision. I don't know what the shop rates are in your part of So. Ca, but I'd be more inclined to use a precision machine shop rather than a tire/wheel/brake shop. Hope I've helped w/o offending.....

[BMWRACER]

If you decide to do any machining. I have a very good machinist in West Los Angeles

[Doug Liedblad]

I agree that turning it is the best way if you have access to a lathe or pay a shop to do it.

The bit that uses the shim is only the grease seal, not the bearing race so it's not as critical.

I know that Gert is about as cheap as I am, maybe more so. The precision shim will work just fine. Probably. YMMV

Worth a try for a few minutes work to make the shim. You'll know soon if it won't hold up.

Doug

[GWise]

The precision shim will work just fine. Probably. YMMV

hahaha! I agree with you. Probably.

[slomove]

I called Dick Brink who imports the Birkins and there are good news and bad news:

- good news is he has the proper 53mm seals and at $10 each they are cheap enough even for me :)

- the bad news: he almost convinced me getting a wide-track suspension instead of re-building what I got. Better handling, quick-adjust camber, sealed ball joints and no hassle chasing odd parts, stripping/coating etc. And I can keep the rotors, shocks, springs, calipers and axles. But at $1600 not exactly cheap anymore.

Decisions, decisions....what should I do now?