70 L-46/M-21 pilot bearing removal.

[Mike F.]

The pilot bearing was the needle bearing type. It self destructed. How do I get the outer shell of this bearing out of the crank? I've tried three different pilot bearing pullers (Advanced Auto, Auto Zone & Harbor Freight) with no luck. Any suggestions?

Thanks,
Mike

[Mike G.]

Re: 70 L-46/M-21 pilot bearing removal.

I used a puller known as a "blind hole bearing puller". Essentially a 3-finger expanding collet, with a slide hammer. What a PITA.

[Monte M.]

Re: 70 L-46/M-21 pilot bearing removal.

Mike,
This is a solution of last result. If you have a mill or way to shave down a bolt or wooden dowel, it is much easier. The bottom line is you are trying to find a dowel, that is the same size as the opening in the inside of that outer race.

Once you have a bolt or piece of dowel that is a very close fit, pack the bearing with the heaviest grease you can find. Get every air pocket out of behind it you can. Put the dowel just inside the hole and hit it pretty hard with a hammer. As the force of the dowel drives the grease in, it will drive the bearing out. The bearing race will gradually work its way out with each hit.

Wood works best in that it will not damage the crank at all. If by chance you use a metal dowel, put a piece of rubber against the crank so the dowel will bounce off of it when it is driven in.

I hope I made this clear enough for you to get the general idea. It is primitive, but it does work like a charm. If I need to explain it better, just let me know.

Best of luck,

Monte

[Joe L.]

Re: 70 L-46/M-21 pilot bearing removal.

The pilot bearing was the needle bearing type. It self destructed. How do I get the outer shell of this bearing out of the crank? I've tried three different pilot bearing pullers (Advanced Auto, Auto Zone & Harbor Freight) with no luck. Any suggestions?

Thanks,
Mike

Mike------


As you've found, this is going to be a difficult extraction. At this point, the thing I would try is to use a bolt that will "self-thread" into the remaining shell. Fabricate from steel stock a "u-shaped" bracket with a hole larger than the bolt in the center. Then, pass the bolt through the hole and "self-thread" it into the bearing shell. Hopefully, by turning the bolt you'll be able to pull the bearing remnant out of the crank. However, this will work only if you're able to get a really good "bite" of the threads into the bearing shell and, most likely, you won't be able to do so.

The only other thing I could suggest would be cutting the bearing shell with a sharp chisel or a Sawzall with a thin blade. Then, you could collapse the bearing shell enough to pry it out. Even if you "nick" the crankshaft in the process, there won't be any really serious damage done.

By the way, the problem you're having is just one of the reasons I have repeatedly recommended against the use of the needle bearing pilot bearing. This bearing will experience the problem you have encountered if there is even slight misalignment and slight misalignment is the case more often than not. In addition, there is really very little, if anything, gained by using the needle bearing piece. It's way more sophisticated and, thus, "seems like" it should be better but, in reality, it's not.

[Mike T.]

Re: 70 L-46/M-21 pilot bearing removal.

This wasted GM roller bearing was in my 66 L79 for a little less than 5K miles.
Used a Harbor Freight Blind Bearing Puller to remove the remnants and replaced it with a GM Bronze Bushing.Mike T in Prescott AZ

[Dan D.]

Re: 70 L-46/M-21 pilot bearing removal.

Beware of some of the repro bushings. They contain iron. Test it with a magnet. If it is magnetic, don't use it. It need to be Bronze only.

-Dan-

[Edward J.]

Re: 70 L-46/M-21 pilot bearing removal.

Mike, I like Joe's method, I have used this before and it worked, however I packed the hole tightly with thick wheel bearing grease and this will aid as you thread the bolt in hydraulic pressure will push the bearing out, As A note GM roller bearing really never work good on a older shaft as the surface has to be micro smooth other wise this what happens to the rollers. the bronze bushing is the only way to go. and be sure to use some sort of grease to coat the shaft and bearing surfaces . One other note is if you have a slide hammer with a shaft dia about the same as the pilot bearing try threading that into hole.

[Mike F.]

Re: 70 L-46/M-21 pilot bearing removal.

After four straight days I finally got the pilot bearing out. Had to grind, sawzall, chisel, etc.. It was in so tight that even after knocking 1/3 of it loose and out, the other 2/3rds needed to be chiseled out.

Got it all back together today, but something isn't right. Lots of knocking when releasing the clutch from a standstill. It need to come apart again.

[Bill L.]

Re: 70 L-46/M-21 pilot bearing removal.

I know the pilot bearing is out but thought I might share my experience.

I used play dough. Found a wood dowel close in diameter, packed the play dough in the hole and kept adding as I tapped the dowel with a hammer. The Play Dough pushed the bearing right out without the mess of grease.

Make sure the new pilot bearing is non magnetic and the throw out bearing is the correct size and installed correctly. Service manual has a good picture of correct installation.

I am pretty sure it was either Duke or Joe that suggested I also have the new flywheel and pressure plate balanced as an assembly. Used the Luk part number(s) per Joe L.


Bill