Rotor runout.....

H

h2ohouse

Member
Joined
Apr 19, 2008
Messages
9
Location
Philmont, NY
Trailing arms are in......calipers are on....... spring hooked up. Start it up to see them turn and OMG.....I forgot to dial in the run out. Can this be done right on the vehicle? I do not have the tools here at my house for this, but can not drive it as much as they are wobbling. I can not beleive the amount of wobble....could there be something else wrong? I can probably get a guage and a mechanic / freind to help me out.
Also would painting the face of the spindle with POR15 throw off the run out?
Thanks,
Jeff
 
yes, painting the mating surface is not a good idea.... on several cars I used a metal conditioner and a very light coat of self etching primer from a rattle can, that's about a tenth of the thickness of brushed POR15.....

You can shim it "on the car", no problem. Buy a cheap dial indicator and a magnetic base... Harbor Freight, Northern Tool, Ebay.... a quality indicator with base is about $180 (Mitutoyo, Starret)... if you only need it for this one job a $25 version will be ok .... even if the indicator isn't all that accurate, you only compare before and after shimming and as long as you get repeatable readings it's fine...

Other than that, all you need is the tools to remove the calipper and the rotor... there's no other special tools required...

good luck.
 
Thanks mybad79 for the quick response....I am sitting here freakin out and waiting to see what I screwed up now...
I did goup the POR15 on with one of those sponge brushes....I will wire wheel it of first thing and then do the run out.
Thanks again.
 
h2ohouse said:
Trailing arms are in......calipers are on....... spring hooked up. Start it up to see them turn and OMG.....I forgot to dial in the run out. Can this be done right on the vehicle? I do not have the tools here at my house for this, but can not drive it as much as they are wobbling. I can not beleive the amount of wobble....could there be something else wrong? I can probably get a guage and a mechanic / freind to help me out.
Also would painting the face of the spindle with POR15 throw off the run out?
Thanks,
Jeff
Click to expand...

Yesthe por15 coudl definately affect it

The indicator will look something like this

dial_indicator_mag_base_250.jpg
 
h2ohouse said:
I did goup the POR15 on with one of those sponge brushes....I will wire wheel it of first thing and then do the run out.
Click to expand...


Did you see the stickies in this section ? the front rotors are covered in the "rotor runout" thread, the rears are covered in the "trailing arm" thread.... good stuff :1st:
 
MYBAD79 said:
Did you see the stickies in this section ? the front rotors are covered in the "rotor runout" thread, the rears are covered in the "trailing arm" thread.... good stuff :1st:
Click to expand...
I read both of them. I guess I was just wanted to be over protective and block the rust for the future. I am no mechanic and this was the biggest job I have tried to tackle. So when I saw that wobble ......I thought the worst. Hopefully start working on it again on Saterday....
Thanks,
Jeff
 
It's probably just the thick paint... post again after your inspection/paint removal.... curious what you found and if it fixed the problem ...
 
rotor runout ....plus...

I wire brushed all the POR 15 off the spindle faces and it brought the runout into specs. Went to bleed the brakes and broke off the bleeder in it could not get it out...bought a used caliper off ebay and installed that only to have to take it back off to rebuild it. Got it down off the jack stands and took her for her first ride about 3 weeks ago. Brakes work fine, but the back end still seems to rabbit around when you hit a bumb. I did not replace the spring, just the shocks and added new linners in the spring. I am thinking of saving some cash and gettin the rear sharkbite coil over system.......any thoughts on that or would a new mono spring work just as well? I do not race....jst like the feel of cornering on the back roads, but too scared to do so with the suspension I have now......I did want to keep everything original..but now it is everything, but the suspension. I want to do the front this winter, soo I will be looking into what can be done for that.
Now I have purchased the # matching intake and carburater...I am rebuilding the carb as we speek and the intake is getting powdercoated.
Wife is getting upset over the cash flow going into it......
I need to play more poker to support the good habbit....either that or she gets a second job!!!!
 
You don't need any fancy trick parts for a street car, fix the rear suspension and you'll be fine. Check the bushings for wear,spring arch,bent strut rods, worn side yokes in the diff, bearing endplay.
 
Holy ...:eek::eek:

Numbers matching intake and powdercoating ??? Wow... build the car the way YOU want it.... a powdercoated intake in not "correct" so you might as well just buy one that performs better....

You do NOT need coilovers if you only want the suspension to function.... the stock suspension is not all that bad.... shocks make a difference, I am impressed with the Bilstein shocks, I am disgusted with KYB....

used calipper ?? A rebuilt calipper is only $65 at the "zone", stainless sleeved with lifetime warranty...

Dude... post here, ask questions before you spend money... let us help you safe money and avoid mistakes.....
 
Wow you guys are great ....I don't post in months, I put up a rant about my issues and 3 responses with in hours...THANK YOU...
I still have not gotten it alligned so that will be the first step. The bushings were good, end play was fine, the only thing I was concerned about was the spring. I did not have it resprung ...I just painted it and put it back in (stupid right). I did not think bushings or endplay would make the thing jump all over the road after hitting a bump. You hear all these people talk about 68s and their performance issues with handling and you get discouraged....
MYBAD79 as for the powder coating the intake....yeah it is kind of silly, but did not want to mess around with chipped paint later on. Something easy to keep clean and shiny. The entire reason for changing it out and putting the correct carb and intake on is that it was not running the way it should. I have had the car 3 years and still have not felt even the 300 horses that it is supposed to have. The carb that is on it is a newer rochester and has about half a dozen vacum lines either blocked off or just sucking wind......I always have that moral delema wether or not to Mod it out or keep original. If it was not a 68....it would probably be an easir decission.
 
Is your rear spring flat or does it still have some arc ? Look under the car when the cars' weight is on the suspension, if the spring is flat with no visible arc it's time for a new one.
You say the car jumps all over the road: if your rear shocks are old/worn/weak then that's exactly what happens. New Bilstein shocks will fix that problem.

I didn't say it's silly to powdercoat the intake, it's way better than paint... but you said you want it all original, that's why :D
 
The shocks are brand new AC/delco nothing special, but I thought better than the originals from 1968....The spring has a bend to it yet.
As for the powder coating ....I've been thinking all day and maybe the cash only allows a coat of paint until next year. I will look at the shocks to make sure I didnt install correctly....
Thanks.
 
h2ohouse said:
The shocks are brand new AC/delco nothing special, but I thought better than the originals from 1968....The spring has a bend to it yet.
As for the powder coating ....I've been thinking all day and maybe the cash only allows a coat of paint until next year. I will look at the shocks to make sure I didnt install correctly....
Thanks.
Click to expand...

I would change the rear spring, and use Bilsteins all around. BIG difference.
As for you HP, I would time the engine per the timing "stickey", check the end play in the dizzy, and send the carb out to a guy named Lars. At least read his instructions in the rebuilding section.
 
Made the same mistake on the front hubs. POR-15'd them and threw the runout way off. Rather than fighting with trying to remove the POR, I made several shims out of a soda can and was able to shim until I was able to get the right side to .002 and left side to .003.
 
Another thread comes back to life! Personally I'm not a big fan of shimming the rotor. You are only contacting on a couple points then and when you tighten the lug nuts your basically putting everything in a bind. I just sent my front hubs to Mike Dyer to be trued up. Hopefully no shims will be required then. By the way Mike always trues the rear spindles when he rebuilds trailing arms. Much better solution then shimming IMHO.
 
avoid shims if you can. try "clocking" the rotors to improve runout (and no, that's not the same as clocking an alternator) :smash:
 
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