Rear bearings - setting endplay

MYBAD79

MYBAD79

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I assembled with a .144" shim and got .025" clearance.

I assembled with a .121" shim and got no more clearance, however the spindle is easy to turn.

I am measuring with a dial indicator and I expected .002" end play with the .121" shim (.023" thinner than the other one).

This is giving me a headache :banghead:
 
I'd go with .144 and take the .025 and leave it alone...

I B really scared that when up to speed and running, that thing get very very VERY unhappy

:shocking:
 
The .144" shim is a new shim. The .121" shim was installed with the old bearings.
the difference between the two is .023", therefore the endplay should come down from .025" to .002"

I have to improve my measuring setup I guess....

This is driving me nucking futs....
 
2-4 mils is said to be cool, so you right in there on the snugger side....

I fail to see an issue from everything I have read....GARY would know for sure....

I had mine done by a vette shop when I bought the car nearly 16 years ago...

:crap:
 
Karsten, put the larger shim in there and spin the setup tool like you would spin a lapping stick. Do it for a little while and measure again. Wanna bet you find your clearance there? If not, take the SPACER and lay some sanding paper on a flat sheet and in circles of 8 motions sand it down, rotating it in your hand a quarter turn every now and then. Not everyone has a nice grinding table like Gary has. You can take a little off the spacer to get your clearance.
 
Make sure to work the bearing in with your hand by rotating the spindle tool and pulling down on it as you rotate it. Do this like ten times every time before you meausre with the dial indicator - your arm will get tired, but its a sure way to know that you are measuring the clearance correctly. Then spin it a few more times while pushing down on the spindle tool.
 
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Also make sue that you bearing support is not moving during setup. You could make a bearing support plate to hold your assembly, or use a vise and tighten it up a ton so nothing moves. If you use the vise method, be very careful when measuring the assembly - do not push too hard on the spindle tool or else you could shift the assembly and make your reading inaccurate. Another tip - make sure you push the assembly tool straight up when you are measuring endplay. What I mean is, wherever you set the indicator on the nut, make sure that it doesn't move left or right of that spot when you push up...it could affect your readings.
 
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Thanks guys. I tried a different setup and now I measured .020" end play with the .144" shim. I believe this reading to be accurate.

I need a .126" shim to get .002" endplay. The .122" shim that I have is too tight.

I assembled the second assembly and noticed that the spindle flange is f'ed up. It has a nice burr on the inboard face that touches the bearing. It's worn down so that the washer under the spindle nut is pressing on the spindle shoulder instead of the flange.... guess I need one new flange.... don't like the idea of a spacer between bearing and flange, that piece would sit right at the seal and would most likely cause it to leak.

The two flanges that I have on my '79 are fine, however I want these two arms to be complete and ready for a quick swap without having the '79 on jacks for weeks....

checking Ebay.....


:smash:
 
Karsten,

I've got a spare flange. I believe it's unused, just sitting in my parts pile. I'm going C4 suspension on my '69, so I don't have a need for C3 repair parts. The flange is free for the asking. Just let me know.

Mike
 
69427 said:
Karsten,

I've got a spare flange. I believe it's unused, just sitting in my parts pile. I'm going C4 suspension on my '69, so I don't have a need for C3 repair parts. The flange is free for the asking. Just let me know.

Mike
Click to expand...

Awesome !!!

I'm sending you a PM :-)
 
MYBAD79 said:
69427 said:
Karsten,

I've got a spare flange. I believe it's unused, just sitting in my parts pile. I'm going C4 suspension on my '69, so I don't have a need for C3 repair parts. The flange is free for the asking. Just let me know.

Mike
Click to expand...

Awesome !!!

I'm sending you a PM :-)
Click to expand...

Hope this qualifies me for entry into Bird's Christmas giveaway program. :)
 
Couple of thoughts.
First I know you have the USA bearings,and parallel shims because I supplied them. One thing I didn't do was to grind the spacer parallel(didn't have it). I've found the spacers out as much as 005"
Every rear brg setup I do, I grind parallel the shims, spacers, and flanges.Everything that fits together is flat. Now as TT said the only way you can do this at home is to lap them on a flat surface.
It's not uncommon to find 010"+ using the spacers and shims from the original setup.
I set my endplay at 002 max but usually shoot for 0015" This can only be done by grinding too close by lapping. I suppose it can be done but you have to be very careful. Also the fixturing for holding and checking the endplay is critical. I bolt the support in place and use a c clamp in addition to the mag base to hold things tight. I also use a Starrett indicator, some of the cheap imports stick or have weak return springs. You only want the setup tool to move nothing else, that's why I won't do bearings on the car as shops do.
 
I measured the spacer sleeve and it was out .004". I got it parallel within .001" but it took a long time with a file and sandpaper.
I still have to work on the second spacer, hopefully that one is better.

The .121" shim that I have is parallel within .0005". Whoever assembled these the last time had a surface grinder.

One of these TAs was assembled with slip fit bearings, that undersized spindle is what I use as my setup tool.
The spindle flange that came off this assembly is the one that is worn on the inboard side. maybe the inner bearing sleeve spun on the spindle wearing into the flange ???

Thanks for all the help.
 
MYBAD79 said:
I measured the spacer sleeve and it was out .004". I got it parallel within .001" but it took a long time with a file and sandpaper.
I still have to work on the second spacer, hopefully that one is better.

The .121" shim that I have is parallel within .0005". Whoever assembled these the last time had a surface grinder.
Click to expand...

This is strengthening my case to leave out the spacer alltogether and slip fit both bearings.
 
The spindle flange is resting on the inner bearing inner race. If you do not install the sleeve and spacer and slip fit that bearing you are forcing the inner bearing onto the outer race when you're tightening the spindle flange nut.

Are you leaving that nut loose when you're not installing the sleeve/shim ??
 
He's doing them just like the fronts and honestly I don't see a very valid reason not to if you don't overtighten it. If it's good enough for the front, it's good enough for the back IMO.

The only reason the factory uses the spacer deal is because it's a press fit and therefore you can't tighten it down till it's snug. If you slip fit the whole deal you can.
 
How do you secure the nut? Do you tighten it a little more to get the pin in or loosen it? What about bearing clearance ? I'd think it's either too tight or too loose since you have to turn the nut to fit the cotter pin ... not ?

I don't see anything wrong with it either except that IF the spindle breaks (which is not very common to my knowledge) the only thing holding the wheel on the car is the brake caliper....

I believe that if GM can save a penny they do, they even save a fraction of a penny and use Velcro instead of a plastic clip to hold a fuse panel cover on the dashboard (4th gen F-body).
They would NEVER make it a press fit if they thought it wasn't necessary. :smash:
 
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