Turbo-Jet

Interference fits are used for a number of reasons, all which improve reliability:
-ensure concentricity and cylindricity
-permit thermal expansion
-maintain radial play
-prevent creep

Versus a transitional fit, a press fit requires slightly less precise size specs on both parts= cheaper for the mfr.

I support your desire to experiment with parts moving at 100 mph, but one or two successful tests does not prove anything in terms of reliability.

Matt Gruber

i'd use a little jb weld

theandies

Exactly. You'll need really accurate tolerances for slip fit applications. Very expensive for manufacturers. If you can get your yokes etc. within a few thousands all the way around with a dermal tool (or whatever you used) without precise measurement tools then you are GOOD.

mandm1200

Certain things may be alright without being pressed in under high power. I would think the universal joint should be done that way. I don't think slipping them in would be suffiicient nor a light tap of a brass hammer. I am thinking a few medium taps with a 4 pouder would do. Slipping fitting the rear spindel bearings without the spacer and shim is not a good idea. I could understand someone honing the bearing slightly for ease of removal later, but they should still require a light pressing to install. In my opinion, you want to remove material from the item that is changed as a maintance item. As an example, remove the material from the universal caps not the flange or yoke.

tictocdok

ujoints should not be a slip fit, they should be tight so the cap doesn't rotate in the yoke and wear thru the yoke.
rear spindle bearings can be a slip fit if you use a spacer and shims, get the right end play, and torque the nut to 100ft lbs.

norvalwilhelm

I have had lots of practice replacing U joints over the last 40 plus years and once my son taught me the trick to removing the old pressed on ones and slip fitting new ones I have not had a problem ever. Sure a few of mine actually go on with just pressing with the thumb but where is it going to go. The circle clip keeps it from walking out and the only thing it could possible do is spin in the yoke and then hopefully seize and the needles actually start working again.
I have used up to 12 ton to remove an original and then pressed new ones on. That is wrong because the caps get deformed causing the needle rollers to no longer follow a round path.
Honestly in the 14 years I have driven my vet and I have destroyed both axles and never had a single problem with the universal, grease joints and all.

norvalwilhelm

To slip fit I only use a flapper wheel for less then 15 seconds, just polish the inside of the yoke. What do you guys think a press fit would be. How about .002 or .003??? That would totally destroy any roundness in the cap. A press fit can be under .001, You are only trying to keep the cap from rotating, not deform it. And why should the cap rotote when it has lubed needle bearings inside on a precision ground surface. The needles want to rotate and it doesn't take alot of force to prevent the cap from rotating.
I have always driven 4 wheel drive vehicles for my daily driver and they have always been slip fit after the originals seize and my life after slip fitting exceeds the originals. My ford F150 eat universals every 13 months until I said enough and skipped warranty and slip fit them myself.

CGGorman

I have to agree with Norval and Turtle. As long as there is no slop, I don't see the issue. The retaining ring holds the joint from coming apart and it won't ever see significant loads axial to the bearings, so failure of the retaining rings is beyond the point of concern. I think Norval's point of excessive interference and out of round bores is a larger concern.

Anybody know what the machining tolerances on the OD of the bearing and the ID of the yoke bores are? I bet the low end stack up gives an interference of .001".

Twin_Turbo

I did the same thing with the flapper wheel to make pressing in the control arm bushings a bit easier, this way there's much less chance to collapse the arm, yet I left enough interference to keep the shells from popping out too easily. As for the u joints, where do you get those tiny flapper wheels?? EDIT.. standard abrasives probably has them eh?

comp

if he has made to much "slip" would GREEN lock-tite help,,, isn't that
stud&bearing mount ????

Turbo-Jet

Loctite 620, 638, 641 or 680 will work here. 641 is the best because can be disassembled and cleaned more easily

Fevre

I slip fit my brain, pops right in and out.

redvetracr

"slip fit u-joints" ...NOT on my race car ..NO WAY NO HOW!!
....redvetracr

comp

so is that the green Stud& Bearing mount ?????

jlch

-and heat transfer..

I always want some type of resistance while installing. If they just slip in, I replace. I have had many high torque race cars/trucks and my experience is that when they are loose, it's just an indication of falure on it's way.

NHvette

I did mine just the way Norval describes, but I used some 600
wet-or-dry sandpaper and my finger to clean them up.
There is still a slight interference fit, but not enough to require
a press or BF hammer. Pressing in/out can also bend the flanges
or ends of the halfshafts. Not any more.

Turtle, if the cap rotates freely, I hope you do something to help
keep them in place (rotationally). A machine shop may be able
to knurl them up - like reconditioning a valve guide. Other than
that, maybe the loctite will work ... dunno.

turtlevette

please pop it back in before you post again.

i picked up some locktite green today. Its the type that creeps into tight areas. Should work perfect to prevent the cap from turning.

Turbo-Jet

yellow I think. Loctite has many retaining compounds, most are a green liquid, but they differ widely in application. best to learn them by product number, not color.

DJ Dep

BAH! You're just ol' fashioned! Just bore out the yokes with a brake cylinder hone and slipity-slop those caps in. Then bring out the Crazy Glue and you're all set

Crazy Glue...you can do some CRAZY things with it.

Dep

jimiscnc

If Turtlevette slip fit his u-joints and has years of real data that it works well, I'll buy that.

I dont think its advisable to slip fit the rear axle or pinion gear for a 63 to 82 vette, however.

I think the first 63 vettes came from the factory with slip fit rear spindle bearings and there was a design change early on to press fit.

with u-joints one of the main factors is that the axle, spider? is only rocking back and fourth maybe 10 to 20 degrees per revolution. It isn't spinning complete 360 degree revolutions like a pinion gear or rear spindle. Makes the slip fit more forgiving and the needle bearings allow the axle, spider? to move, not the bearing housing in the yoke. takes much less torque to function properly than have the needle bearings transmit torque to the bearing cap and turn in the yoke, in other words.

I had a bent flange, out about 5 degrees from straight and put a u-joint back in and it lived fine, although it was a bad thing to do.

therefore, u-joints are a hell of alot more forgiving on the slip fit than other bearings on our vettes.

I never did figure out how a slip fit is just fine on the front wheels, but illegal on the rears?

I had an inner bearing on the front walk/orbit and make the spindle shaft undersize. I glued it back in with the right loctite and it never gave me any problem. Hot metal spray and re-grinding to size is more expensive than replacing the spindle!

-Jim