GORDO77

I have a vibration in my 77 have checked or replaced every thing that turns. had car up on jack stand and runing .looks like more than 1/8 run out . these are origanl rally wheels. thanks in advance for any help . :smash: :seeya

jerryp58

If I'm reading this right: you put the back of the car up on jack stands, put it in gear and observed the wheel or tire "wobble" about 1/8 in. ?

I'm not sure what that would tell you. I don't know if tires are balanced well enough to eliminate all movement/wobble when they're hanging in the air like that.

As far as the vibration, do you think you've isolated it to the rear? If so, you could rotate the tires front-to-back and see if the vibration follows the tires. If it does, you would have isolated the problem to a bent wheel, improperly balanced tire problem, separated tire ply, or something similar. If it doesn't follow the tires then, you may be dealing with a rear bearing problem, an imbalanced driveshaft or halfshaft, or something along those lines. Has any work been done on any of these components recently?

BTW, I'm not sure that running the car on jack stands with the rear wheels hanging like that is a good idea.

GTR1999

If you want to check runout you need to do it with a dial indicator wiht the wheels off and not running. .005" I think is the max runout, but check a manual first. Running with the rear 1/2 shafts hanging down runs a high risk of binding them and breaking something very quickly. You might be able to level the t arms off but I still wouldn't try it.
Gary

KJL

You have a couple of things going on. There is bearing end-play,which is hard to determine with the half-shafts connected, and rotor run-out. Jack up the rear and put car on stands. Now remove the tires and place at least 3 of the nuts back on the rotor and snug, this will hold rotor tight against spindle flange. using your jack carefully jack up the trailing arm so it is close to normal operating position. Put trans in neutral and find a place to stick a magnetic base dial caliper (harbor frieght) on the trailing arm. Place needle agains rotor close to the outside edge. Turn the rotor (do not push or pull) and observe the readings. See where the high and low spots are. Mark the rotor and remove. Place shim washers (special) at these locations and replace rotor and recheck. Yes, it takes a little time to dial it in. Instead of washers I used aluminum duct tape and just built up the layers until I got it right. After you have dialed it in, make sure you mark the rotor so you will always put it back on the same way. If you tire still has a wobble have a shop check the rim and tire out. You may also want to disconnect the half-shafts fron the spindle flange and check your bearing run-out.

Good luck

Matt Gruber

i use a dial indicator, about the most i can tolerate is .045" , anything under .030" is great!
i check lateral and radial runout without a tire on
good luck, i sold some great looking Creager SST's 'cause of .060"

bob myers

Gordo,
I have a 63 roadster {yeah, I know what am I doing here?] that suffered from a vibration I could not track down. I have two complete sets of wheels and tires and both sets had an identical vibration at 55-60 mph. I was getting ready to tear everything apart when I read a thread about a professional brand wheel balancer. It is made by the Hunter Company and is the model 9700.. the balancer, with a good operator, can determine radial runout, side to side run out, and can even determine if the wheel would benefit from the tire being mounted in a different position on the wheel. I had my first set done and this car runs smooth as silk now.
I suggest you call the better alignment shops in your area and ask if they have a Hunter 9700 wheel balancer. They can tell you all about it. Good luck, Bob Myers NC

GORDO77

Thanks drives61 and bob myers ,this is the info i needed,as bearing were just rebuilt by bair's and rotor runout is less than .003 thanks again :seeya :seeya