Question: C3 Spindle bearings

[heavyd]

I read a lengthy article about a racing crew that had great success by reducing the outer bearing spindle surface eliminating the need to press the bearings back on. I just can't remember where and am curious to research this again. Can anyone help?

 

[Vettehead Mikey]

That's one of a hundred ideas that might work well on the track but is a really dumb idea on the street.

 

[Hib Halverson]

Why is it a "dumb idea" on the street?

 

[Vettehead Mikey]

OK, it's a dumb idea for the track too. Happy? :eyerole

 

[Mike G]

Rear C3 Spindles

Back in January 1980, I drove my '69 427 Vette from Shaw AFB S.C. to Keesler AFB, Miss. I got there and wierdness set in: I would let the clutch out and the back end would squat as I took off. Coming to a stop I would push the clutch and the back end felt like it 'relaxed'. Then the squealy noises from the rear started in and I was convinced the bearing was shot. I bought a new bearing and took the car to the base hobby shop, tore the whole assembly apart and sure enough, the bearing came out in shards of metal. I used a bearing puller to take the old race off the spindle and very carefully pressed on the new one. Reassembled the whole thing and had a happy Vette from there on, doing ~90 mph on the return to Shaw.
The slight interference fit of that bearing is essential for the design. That article describing a race team increasing bearing-spindle clearance was probably a race team tactic for fast pit-stop service if necessary. Remember - race teams are concerned with reliability measured in hours, not years! They'll have a car that can be rebuilt quick if needed, which is NOT the same thing needed for us with our Vettes over YEARS.
Cheers

 

[heavyd]

Thanks for the input. I will add these to my long list of education on this. One reason I was wondering was one spindle came apart easily with the puller using only the force generated with a box end wrench. The other required a bearing splitter and about 20 tons from the 50 ton press. This seems excessive as I am sure I will have the same complication reassembling. I am convinced that the interference fit was designed in for a good reason.

 

[Mike G]

Tonnage!

20 tons on a splitter?!:W That can't be normal!
Get all the spindle dimension specifications and measure both your to be certain that they're right and not distorted, bent or affected by excess heat.
This site is a really good reference to specs and further tech research.
Happy wrenching!

 

[Vettehead Mikey]

When IRS was first introduced on the 1963 model year Corvette, the rear bearing inner races were a slip fit on the spindles, a design very similar to a typical front wheel bearing. In fairly short order a substantial number of units failed in the field causing GM to change the slip fit to a moderate interference fit which brought an end to the problem. The design remained substantially unchanged from that date until end of C3 production in 1982.

It is true that not all original slip fit bearings failed, and it is also true that some owners have modified their spindles to achieve a slip fit and have had no problems. The only possible advantage is easier removal and installation- but the service interval is approx 40K miles. I think I'd put reliability ahead of serviceability.

 

[GTR1999]

Slip fit rear bearings is a subject that comes up alot on all these forums. Some are convinced there is no concern with doing it and have done so on their own cars. Usually these are proactive people who go beyond normal maintenance and tear down the bearings frequently to check.

I rebuild these and would never slip fit a bearing. Not sure if any others will but I'll turn the job down before I slip fit them. I've found most owners are not going to tear them down and want a quailty build that lasts for years and thousands of miles of use. I would recommend you correctly build your T/A's and forget the slip fit, but that is just my opinion. Good luck.

 

[heavyd]

Slip fit rear bearings is a subject that comes up alot on all these forums. Some are convinced there is no concern with doing it and have done so on their own cars. Usually these are proactive people who go beyond normal maintenance and tear down the bearings frequently to check.

I rebuild these and would never slip fit a bearing. Not sure if any others will but I'll turn the job down before I slip fit them. I've found most owners are not going to tear them down and want a quailty build that lasts for years and thousands of miles of use. I would recommend you correctly build your T/A's and forget the slip fit, but that is just my opinion. Good luck.

Thanks for all the input. I am going to have the spindle surface checked on both and replace bearings as advised. No slip fit for me.

 

[JohnZ]

They wouldn't have recalled them and changed a blissfully simple manufacturing operation at Chevrolet-Warren (spindle assembly) into a tightly-controlled tolerance nightmare requiring additional tooling, equipment, and manpower if the slip-fit design was a good idea.

The slip-fit may work fine on a race car that's torn down and inspected reguarly, but it's a safety hazard on a normal street-driven car that gets no preventive maintenance; that's why they recalled them and changed the design. When the outer race spun on the spindle and seized and the spindle failed, the wheel came off. Not good.