arielb1

Thanks for the help. I am stumped.

GOOD KARMA to you.

I have a 4X4 4Runner 1994 110k miles. Awhile ago my steering wheel would shake as I applied the brake. I also feel my brake pedal shake, it fact, the entire car would shudder. So, I took it to a mechanic to change the front brakes. He turned the rotor and put new pads. The problem was resolved only for a short time like 3 months or 10K miles. The problem returned again and I took it to the same mechanic. This time he changed the rotors and pads to new ones. I got charged full price and it hurt really badly.

Well, shortly after, the problem returned about 7000 miles. The exact symptoms and issues. I was told it could be a front end problem. If it was a front end issue, would I not experience the same problem even after the brakes were replaced. Why does it go away when the brakes are new? Is it possible because I did not use OEM parts? If it is a front end problem, could it have something to do with a thunk noise I would hear towards the front as I go into reverse after the truck sat for awhile. It is a one thunk sound as I start to reverse with my stick shift.

Thanks you!!!

UNR.Grad

Make sure your lugs are being torqued correctly and evenly when put back on. Have your rear drums been looked at recently, if they're not adjusted properly the fronts do pretty much all of the work and the increased heat can lead to warping.

GregStevens

Not sure about the thunk...I'm assuming you've got a manual? If so, I'm thinking that just a transmission thing and not related. (may be another issue though, can't say for sure).

It's sure odd that you have the shakes return after completely new brakes. Sounds like to me the rotors were warped. Turning them can help, but if they are really bad, you have no choice but to replace them...which you did.

This leads me to believe that the hub(s) was not replaced back to factory torque settings. And are now a little, tiny bit loose and will shake, especially upon braking. It might happen at other times, but I'm thinking that while braking, the looseness is exacerbated and gives you the shakes.

So I'd make sure all the gizmos that attach the the rotors are snug and to spec. I'd start there...I don't think this sounds like a front end problem since it only happens under braking. I could be wrong, but that's what my gut tells me.

I'm sure others will chime in, as well...

arielb1

Thanks for the help. I will look into these suggestions. Anyone else have ideas I can look into? The thunk occurs somewhere in the front end. I am, however, more concerned with the shaking. I thought I would take the rotors and see if it is needs to be turned again. If it does, then I would just replace everything with OEM and torque everything to specs. Great ideas so far.

nunsa

A thunk in reverse is usually caused by a U-joint going Tup!
If you feel a shudder it's most likely your rotors, now, I know you replaced them, but if you get some of those "cheapies" it will be good for awhile and then it will return to the shudder. Check your rotors for warpage and check you front wheel bearings and the tie rods, if it's a FE problem most likely it's one of these FE components, I've even seen tires and a bad FE alignment cause the probs you described!
Good Luck!

k-bomb

These rotors are attached to the hub via the studs. Wish I had a picture to explain that better. Anyway, when a new rotor is attached to the hub there are two important procedures to prevent rotor pulsation. One is that the hub is thoroughly cleaned of all rust and debris of any kind before attaching the new rotor to the hub so the the two seat up flush. The second important thing is that the new rotor should be turned on the lathe as a whole assembly. In other words he should turn the rotor/hub assembly together. This will ensure that the rotor is turning true with the hub assembly. Failure to follow these steps is the most likely cause to the rotor vibration.

However, the rear brakes being out of adjustment is also a very likely cause as well.

As far as front end problems causing a rotor vibe? Not really possible. However, front end issues can exagerate a rotor vibration into more serious shaking, but it is not atually a cause of rotor vibration.

The clunking in reverse sounds unrelated to the rotor pulsation problem.

fustercluck

you should also check that the rear brakes are taking the load percentage they were designed to have. if the load placed on the front is too much, they will heat up and warp. check with the dealer tech to find out the percentage of load for front vs. rear and make the adjustment as per the manual.

the rotors you have being that newly turned, you should get at least until the next brake job before you'd need to mess with them again. all other factors being eliminated (front end parts etc.), i'd be willing to bet this is your problem.

arielb1

WOW!!! I recall the mechanic did not turn the new rotor with the hub. In fact, as soon as the new rotor arrived, he attached the hub and put the entire assembly back together again. I never knew that a new rotor had to be turned again with the hub. I am learning so much tonight. Meanwhile, I am also researching the tup and how to fix a u-joint problem. It appears challenging so far. From what I am reading above, the shaking of the brakes and the tup are two different issues. I think I will take the brakes apart and have the hub and rotors turned together as one piece, inspect the tie rods and bearings, and install new pads. I haven't formulated a plan yet for repairing the u-joint problem. I really appreaciate your help guys.

GregStevens

Right, the rotors are attached to the hub via studs, but I'm talking about the, in particular, the 52mm (I think it's a 52) nut that is on the very outside of the axle. I was thinking that may be loose and was causing the shimmy.

Could be, I still think...but there are other great suggestions here. Don't listen to me, I've been drinking.

arielb1

I really have to invest in a helms manual. I am learning so much from this forum. I think the helms will put it all together for me.