Topic: rotors runout
in Forum: C3 Engines, Driveline and Handling
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I got new rotors and I rebuilt my calipers. When putting it back together, I found out that there's a pretty good runout in the front (both). I don't have the measurement, but lets just call it really bad. I don't need a measuring tool to tell this one; it's just obviously crooked.
Now, I don't know (yet) if it's the rotors themselfs or the spindles (should I call it hub for the front?). I think I had the problem before the new rotors and brake rebuilt; since I did notice vibrations when braking and really uneven brake pads wear.
From a perspective that I'm planning to redo the suspension (and take care of the spindles (and hubs?)) this winter; I'm thinking that the best way to quickly take care (temporarely) of the problem is to get a dial indicator and add shims (beer can's cutouts) between to rotors and spindles to make it close to straight.
I can't find any dial indicators (at least at a decent price anywhere in my neck of the wood), but I found some for 40$ or so on eBay.
What do you guy's think; would that be a good 40$ investment and a half-decent solution given than I will only drive like that less than 20 miles?
And what about the rotors themselfs; even if I had this dial indicator; how can I measure the rotor by itself; how can I "fabricate" a true flat spinning surface to test it?
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Former Member
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Fayetteville, NC - USA
Joined: 2/13/2005
Posts: 244
Vette(s): 1968 Corvette Convertable, 4 spd, 350 SB, Daily Driver
Have a mchine shop test it to ensure it is square on both sides. They can put it on a rotor lathe and check it out in a jiffy. If it is straight, then shims shouldget you close. If you can see drastic run out with the naked eye, then something is way off. I recomend having a set of indicators. The brakes need adjusted a lot if you drive it regularly. An o-ring kit can help with the air pumping problem and reduce the need to have your rotors perfect.
Former Member
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Yelm, WA - USA
Joined: 7/12/2007
Posts: 356
Vette(s): 1979 L82 4 speed Scat 383 crank 190 cc Procomp Aluminum Heads 202 160 stainless valves GM Powder metal rods Speedpro H860CP Hypereutectic pistons 280 cam hydralic HEI Pro comp 1.6 roller rockers Mighty Demon 750 Sanderson CC1AP Hedders.
Yes take them to a machine shop to have them checked, I've had new rotors that were kicked back before because they were bad right out of the box. They can turn them so they are "true" and check for bearing runout for around $10 a rotor. I'm doing my suspension right now and I took mine to a local corvette shop and they are saving me some change on my trailing arms.
This is my first vette rebuild but I have a lot of experience with this from my 4x4 trucks's. I've had a front hub actually go out driving down the road, and it's not a lot of fun. If it wasn't attached to the axle I'm sure my tire would have kept on going down the road without me. If the bearing cup/race spins out in the hub you will have to replace everything. Especailly for the front, it's fairly cheap to do it right the first time and save some headaches down the road.
Thanks...Good stuff.
I'll get my rotors to a shop and I'll buy that dial indicator even if I won't have much use for it after. But you never know; I could get a call from a friend one day asking me to calibrate his microwave turn table.

in Forum: C3 Engines, Driveline and Handling
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