Failed Pilot Bearing

[Peter Ansted]

I was surprised to see a trashed pilot bearing sitting at the end of the crank in my 63 340 car. I put in a new LUK clutch 3 years ago and assumed I used the bushing supplied. Apparently, I popped in the pilot bearing at that time. It was installed properly and the engine/trans hookup occurred while the engine was out of the car and it went in very smoothly. It sure looks like the
GM 14061685 bearing I just picked up yesterday. The casing of the bearing is all that is left - the rest is a tangled mess behind the bearing. The input shaft on the 4 speed has a small groove in it from spinning on the trashed bearing. Is a bearing puller needed to remove or will the grease/ water trick work? Can the tranny be poorly aligned resulting in this problem? I cannot find any archive covering a failed bearing - it sounded like they are bullet proof. Thanks

[Joe L.]

Re: Failed Pilot Bearing

Peter----

The GM #14061685 is a needle bearing type pilot bearing so, based upon the information you provided, I assume that type bearing is what you used when you replaced the clutch. Your description of what happened to your bearing is EXACTLY the reason that I don't use this type bearing. The needle bearing-type pilot bearing works VERY good PROVIDING that the engine block/bellhousing/transmission are in perfect alignment. Very often, they're not. In that case, you're better off with the oilite bronze bushing.

With an oilite bronze bushing, if there is very minor misalignment in the system, the bushing will "wear-in" to compensate and still function very well and with a long service life. With a needle-bearing-type pilot bushing, the slightest misalignment will cause the bearing to "self-destruct" in short order. That sounds like what happened to you.

[Mike M.]

Re: Failed Pilot Bearing

agree with joe 100%. put a bronze bushing in the crank as you rebuild and your grandkids will need to replace it in 50 years. merry christmas, mike

[Mark #28455]

don't pound in the bearing

The needle bearings are a precision-machined part. They can be damaged if installed with a spare socket and large hammer and will then eat themselves (even if perfectly aligned).

[Joe L.]

Re: don't pound in the bearing

Mark-----

The best thing to use to install the bearing is an old transmission input shaft which has a pilot shaft diameter the same as the bearing is designed to accept (or Kent-Moore tool J-38836, if one happens to have one). However, there's no practical alternative to using impactive force to install the bushing if the crankshaft is installed in the engine.

[Paul B.]

Re: don't pound in the bearing

I put over 46,000mi and still going on two of those in two different Corvettes in the last ten or so years-seemed the bearing bushing worked great for me in both cars.

[Mark #28455]

Re: don't pound in the bearing

I didn't mean to say that you shouldn't drive them into place, only wanted to emphasize that precision parts are ruined when Bubba gets a big hammer and does it in one or two hits.

[David B.]

Re: Failed Pilot Bearing

Be careful of new pilot bearings being sold now. A lot of them are not oilite. It you go to an auto parts store, pick up one of the magnetic pickup tools they sell and test the bearing. If it sticks to the magnet, leave it alone - it's junk. The good ones cost a little more, but its better to wear out your pilot bearing than the input shaft of your trans. The imported steel ones are coated to look the same as oilite, but they will wear out your input shaft if mis-aligned and do not posess the lubricating capability of oilite bushings.

David B.

[bruce11495]

Re: Failed Pilot Bearing

I've heard nothing good about the needle bearing ones. It seems a that the "old" technology is more compliant and able to stand up to some mis-alignment.