ry57pont

help school me here.. So i am planning on doing my rear trailing arms next week. i see how people use the bearing set up tool to measure endplay before pressing the assembly together.
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My Question: can you turn down the axle (spindle) and slip fit the bearings and use that way? why do they need to be press fit? - Ryan

GUSTO14

Good question and one that has been debated here more than a few times. Some have done this and experienced no ill effects, while others are of the opinion that GM engineers know best.

I would suggest it is probably a discussion you should engage in with the folks at Bair's or Vansteel (as well as some others) who rebuild these trailing arms professionally and have years of real world experience with them.

I would just point out that there are more than a few vehicles on the road as well as off-road that utilize slip fit bearings in similar circumstances.

Good luck... GUSTO

plaidside

I believe in 63 they were slip fit but GM later went to press fit. There must have been a good reason for the change.
My theory is that with a slip fit there is a chance of the inner race spinning on the shaft causing irreparable damage to the shaft.
Joe

wombvette

Do a search here and the C3. You will have much reading.

I am in the absolutely not camp.

jim lockwood

Early '63 was a slip fit and later '63 was a press fit. There was an intermediate iteration on bearing fit also but I don't know what it was. I don't claim to be an expert on rear spindles at all.

I agree, Joe, with your assessment..... there had to be a good reason to change.

Jim

ry57pont

i know GM does everything for a reason. and i will most likely press fit. but inquiring minds are still curious on the technical reason. kind of like "trust but verify" - RB

MikeM

GM posted a service bulletin about the timing and the reason for the change. I don't have it here. Like Jim said, there were three variations of axle/bearing setup in '63. I don't remember what the interim was.

You can bet GM recognized a problem early on as it didn't take long after start of production for them to go to press fit and continue that way through the rest of C2, C3 production.

I've heard that there were instances of the inner bearing race spinning on the axle as noted above. See the service bulletin.

Plasticman

Yes, I did it when I had to replace the bearings (and spindle shafts) at less than 70K miles, on both sides on my 70 Vette. Daily drove the Vette for a total of 247K miles without ever having to touch them again.......easy to set up the "perfect" .001" end play, and regrease or repair if needed.

I did it at the suggestion of racer John Greenwood.

Plasticman

MikeM

TDB thread:

Read Michael Hansen's posts and Wayne Womble's.

http://www.ncrs.org/forums/archive/i...p/t-30154.html

JohnZ

Here's the story on the '63 rear spindle machining changes - note that although the production change was made in December '62, the TSB wasn't issued until June, 1963. Recalls for safety issues weren't required by law until late 1966.

The November and December changes resulted from field reports of rear spindles/wheels departing the vehicle.

wombvette

Those pictures were long gone. I will try to repost them here.


Typical failure where bearings are slipping on the shaft.


Both of these failed and the wheel fell off after the caliper mounts broke.

John BX NY

When I did mine more than a few years ago I used the slip fit method described in the NCRS restorer.

Basically its a light interference fit and the bearings are installed on the shaft with locktite bearing mount. The idea is later service would be easier.

It seemed like a good idea at the time and I had easy (free) access to highly skilled machinists. Not sure I would do it today but it's been trouble free for years.

Anyone else try that method ?

6T7L71CPE

I had a backyard "Corvette Mechanic" replace the rear bearings in my '71 when it was my daily driver back around 1980. A few years later they were too loose to have an alignment. I took them apart and found he had used a belt sander to make the "Slip Fit"! I sent them off to one of the rebuilders and surprisingly wasn't charged for the useless cores.

66since71

Guldstrand also recommended it for racing setups, where bearings were serviced frequently. I've had good luck with slip fit bearings on 4 different C-3/4s. But GM had a much bigger sample of cars when they went to press fit!

Of course I do repack them regularly. I wouldn't panic if yours are slip fit. Just plan to repack them when you do the fronts.

Harry