Vibration when braking

[sjpitts]

Sorry for the repeat for those of you on the LCML-- but I need to figure this out ASAP.

I am getting some sort of vibration when I brake. It appears to be coming from the driver side front wheel. I feel it most just as I am slowing down to stop. At high speeds, I do not really feel anything. If I look at the tire while I am stopping, I can actually see it shake a bit as it slows down.


Also, as I was towing my boat this morning, I had to brake hard and it noticed that it pulled to the right when I braked hard.


This is a 72 FJ55, with FJ60 disc brake axles (hence my post in this forum). A year -- maybe two ago--- I repacked the birfields, and while I was at I replaced the rotors, pad and wheel bearings. The rotors came from Checker-- and I had them turned before I put them on. I did not, however, replace the knuckle bearings at the same time.


The tires are 33x12.50 MTR's. They are pretty new, just a few thousand miles on them. The wheels are new as well--- they are black steel 15x8 rockcrawlers.


I am just guessing here, but I think there are four potential causes.
1) warped rotor
2) bad knuckle bearings
3) bad tie rod ends
4) bad tire.


My best guess is warped rotor-- but I don't really feel it pulsing in the brake pedal like I thought a warped rotor would do. Maybe I just am not noticing it. Besides-- these rotors are like brand new-- maybe 10 thousand miles on them tops.


How can verify if the rotors are warped? What would have caused this?-- I mounted my wheels, so I doubt that they were overly torqued. Although now that I think about it, I did torque the lug nuts pretty tight when I was changing the rotors-- hmm, maybe that was not how you were supposed to do this.


Do you think that knuckle bearings or tie rod ends could also cause this problem? How about caliper itself?


I jacked up the tire and spun it around. It sounded like it was rubbing a little more at times than it was at others, but it was a very slightly difference.


Anyway, let me know if you have any advice.


Thanks


Jared

 

[hj60]

Stop driving my truck!
Mine's also coming from the left.
I bought new OEM pads today, will throw them on in the a.m. and see if I can figger out
what's causing it and get back to you.

 

[dd113]

I bet the rotor. Cheap rotors will warp quick and 10K is not all that quick. New pads and turn them, might also look at the wheel. I doubt it is a balance issue but it might be a bit out of round.

 

[sjpitts]

Update on this--

I had my tires rotated and rebalanced. It did not solve the problem.

It is odd, when I look at the rotor it looks like there is some variation in the thickness of the rotor-- not the overall thickness-- but in the individual sides of it-- does that make sense.

But I also think that there may be a problem with the caliper. It looks like it is not squeezing evenly-- and the two pistons definately look different.

I think I will try a rebuilt caliper first. The only downside to this is that I will once again have to do some grinding on it-- to fit my wheels. I once bought one from checker autoparts and it seemed to work ok. Does anyone else have a good source for rebuilt calipers?

Jared