gbarmore

My neighbor is a mechanic and he took my new Timken bearings, races, seals and TA parts to his shop with my bearing set-up tool, and set up both TA's within spec. He said he got them right around .003 on one and .006 on the other. I got them home and installed them on the car. The body is off, and the arms are only bolted into the frame at the pivot point, I do not have a diff or half-shafts attached at this point.

While trying to get my rotor runout dialed in, I noticed that if I tried to rock my rotor left and right I could actually see my inner axle flange move left and right and I could feel the movement side to side. I set up my dial gauge and measured the play at the spindle edge with the rotor off and it was about .003-.004. Is this normal if the end play was set correctly? Is it more noticeable because I don't have any of the drivetrain hooked up yet?

I assume this play will be much worse at the wheel edge once installed as it is much farther from the center 'axis'. If my neighbor did set the end play right, and this is not normal, what else can I look for? Any help or experience is greatly appreciated!

Steve2147

That sounds right. If the spindle can move in or out .003 the outer edge of the rotor will rock more than that because of the lever effect. If you're concerned put your dial gauge on the end of the spindle and measure the end play yourself.

Steve g

birdsmith

Van Steel (Pfahnstiel) may chime in here ; in his book he recommends grabbing the tire and checking with 1/8" at the outer edge being the limit. Not sure exactly how he came up with that but he is definitely guru when it comes to TA's...

Mike Ward

Sounds normal. Make sure that you've got the shaft loaded in one constant direction when you're measuring rotor runout so that bearing play doesn't influence the reading.

drwet

Okay, I don't consider myself an expert, only having done this a couple of times, but I don't remember that much play. I do recall that once the bearings were greased, I couldn't feel the play that was there when they were dry. Did the tech pack the bearing with grease?

gbarmore

We'll I talked with Paul from Van Steel and he was a great help. Bottom line is that there are so many variables to deal with when setting up the TA's that it's mind boggling. One thing I did not do before I took everything apart was measure the spindle runout. He said this is important as a starting point and should be done to aid in tracking down potential variables with measurements after the rebuild.

Variables include but of course are not limited to:
1) are the spindle bearing mounting surfaces worn?
2) is the spindle true, both at the face and the shaft?
3) are the races fully seated?
4) is the rotor warped?
5) was the end play set with or without grease in the assembly?
6) Temperature of the parts when assembled?

The list goes on and on.....

I'm going back out to the garage to try to eliminate some variables that Paul and I discussed and determine what's next.

Bottom line is I may end up starting over with this rear end re-build and do my best to get end play to .001 or less. This means destroying both sets of new bearings, more headaches, and more time spent on these than I ever imagined. IT's worth it but with so many other things to do on a frame off, this may be one thing better left to the pro's like the folks at Van Steel.

To Be Continued......

gbarmore

The bearings were set-up with a light coating of lube to keep from scoring anything, no grease until they were put in the assembly.

Mike Ward

I'd measure actual end play before disassembling anything. There's no need to go to less than what you said you've already got. Zero end play on a tapered roller bearing is not a good thing. Don't confuse spindle end play with radial runout. Two different unrelated animals.

Steve2147

With all due respect to the Salesman at Van Steel, you're being sold. You called him with a shortage of confidence in a job they didn't get and he's throwing everything he can at you to shake your confidence further.

Runout has absolutely nothing to do with the movement you are measuring at the outer edge of the rotor. Doesn't matter if the rotor is bent 90 degrees, the movement at the outside edge doesn't change. For runout to be significant, the spindle has to be turning.

Temp? Really? Yes, if one part was in the freezer and the other sitting on the wood stove in the shop, but I'm betting all the parts were stored in the shop at the same temp. Then it doesn't matter if they're all 30 below or 100 above. Those are the temps they may be called to operate in and the will all expand and contract at the same rate.

There could be wear on the spindle and the inner race not tight on the shaft, but you won't be able to feel it now. Once the nut has been tightened the inner races, spacer and shim are all tightened together. Under extreme force they might move, but that's certainly not what you're feeling. And it's a basic part of the job for every mechanic changing a wheel bearing of any kind. Check the spindle. Same with the outer races moving in the support. When you drive in the new one you kind of notice if it falls in.

This isn't even a procedure thing. This is simple physics.
with a tapered bearing when there is end play there is sideways movement.

If it were a straight roller bearing or bushing it doesn't matter how far from the centre you take your measurement it will always just be the end play. But that's not what we have.

Double check your end play. Check your runout with the rotor on and correct it with the appropriate shim. It does not matter how much the face of the spindle is out, the face becomes square when the rotor is shimmed square assuming you are using a good quality rotor that's mounting face is parallel to it's brake surface.

Steve g

gbarmore

We'll, I've noodled on this for a couple of days now because I haven't had time to actually work on the car. All of the input has been good and sparked more internal debate about what to do here. I do have to agree with Steve2147 and others that say there needs to be some end play and therefore some 'rock' to the assembly. Part of me says just get it back together, drive it and see what happens, an experiment if you will. It's not the end of the world if I have to pull it apart again and if I get the rotor run out in spec i'm not worried about pumping air into the brakes. I do have to say that I don't think the gentleman at Van Steel is trying to sell me, he's a racer and former shop owner and is inherently **** about tolerances, I get that and I can appreciate it. Perhaps it goes above and beyond what is necessary here, but we all have things that we get carried away with on these cars right!?!

Whatever I do I will post results, it would be interesting to get one side down to .001-.002 of end play and see how that affects the 'rocking' i'm concerned about. My neighbor brought me some of those 'Brake Align' shims from his shop that they don't use anymore and I am going to try those to true up the rotors. They don't mess with shims anymore and throw everything at the on-car lathe. Sure would be a lot easier if it's possible for our c3's.

Mike Ward

It is possible, and is preferable to using shims.

Steve2147

Not always better. In many cases the runout is in the face of the spindle with the mounting surface and brake surface of the rotor parallel to each other. So the runout from the hub transfers to the brake surface. If you turn the rotor on the car you will correct the brake runout, but you will leave the mounting surface for the wheel with runout. This leaves a wobble in the wheel. A tapered shim takes the runoout out of both the brake surface and the wheel mounting surface. I just went through all this. 4 Brand new rotors and excessive runout on all but one when mounted on the hub/spindle. Poor quality rotors was my first thought, although they came from a reliable Corvette supplier. It wasn't. The runout was in the hub face and spindle face.

gbarmore, this is not/should not be an experiment. Recheck your end play. If your endplay is correct the side to side movement is correct. There is no spec for it, but it's an inherent and fixed to the amount of endplay. No mystery, no guessing.

Check the runout forcing the spindle all the way in one direction so the endplay is not affecting your reading. Measure the face of the spindle and mark the stud where the high spot is. Mount your rotor and check the runout there. Mark the high point. If the runout is excessive make sure the highpoint for the rotor and spindle are opposite one another.

Steve g

Mike Ward

Yet this is exactly how GM manufactured all C2s and C3s. The runout of the wheel mounting surface did leave a potential wobble in the wheel, but given the sloppy lateral and radial runout specs given to Kelsey Hayes for manufacture of the steel rally wheels, a few thou of hub runout paled in comparison.

I don't think there's any intention here to reinvent the wheel. (sorry)

mark6669

Every one always over thinks these things factory spec is .001-.007 I try for .003-.005 but if its within factory specs never any problems. I think there is to much hype from the rebuilders scare tactics.
Mark