Warped Rotors And/Or....?

[Mustangman66]

Grab your camera, see if u can get it on video

 

[Dalmus]

What about the tranny fluid?

I've ruled out warped rotors, because the brake vibration is only occuring when I'm coming down from highway speeds. If I spend 20 minutes driving 30-40 mph, everything is relatively smooth from the ride to the braking. I still notice some shudder, but not nearly as bad as at certain HWY speeds.

After I've been at HWY speeds for a few minutes, I really notice the shudder, and only then do the braking vibrations occur. If I slow back down from HWY speeds and cruise for a few minutes, the shudder is gone and braking is once again smooth.

I'm wondering if maybe I should change out the transmission fluid? I've got ~128K on the beast, and it was last changed out at ~65K when the dealer had to replace the clutch packs.

Burnt fluid can cause similar issues, right? At least it would be a cheaper alternative, and necessary maintenance anyway, than having someone take the diff apart and inspect it.

 

[tower]

Front wheel bearing starting to go, I had the same thing changed out both front bearings and good as new. Jacking the truck up may not tell you unless they are totally gone and if they where the noise would be much louder. Does the feel/noise change when making a turn (at speed)?

 

[Dalmus]

Front wheel bearing starting to go, I had the same thing changed out both front bearings and good as new. Jacking the truck up may not tell you unless they are totally gone and if they where the noise would be much louder. Does the feel/noise change when making a turn (at speed)?

Both I an my mechanic have had the thing up in the air, and we get absolutely no play in any of the wheels, and no noise when I spin the fronts. I did replace the driver's front bearing about 10K miles ago, so I guess the passenger could be going, but wouldn't I feel it in the steering wheel as well as the brake? Oddly, I didn't have any shuddering before I replaced that bearing.

With no play and no noise, I'd hate to just throw $250 at each wheel to see if that fixes it...

But to answer your question, I don't notice any change in noises or feel when I make turns at speed. BUT, now that you mention it, on the rare occasion I need to crank the wheel hard left and make a tight (slow) turn, I sometimes get a hop, but no noises. I always thought this was the on-demand 4x4 kicking in because of the difference in speed in such a tight turn.

 

[tower]

Yea the hop would be 4X4, I did not really hear mine but did feel it in the wheel. When we put my truck in the air you would not get any free play and both seem to spin ok but changing the bearings fixed it. May not be what your peoblem is but it was mine.

Good luck keep us updated.

 

[edwx]

I had a vibration it the pedal (& whole vehicle for that matter) while braking, and it turned out to be a caliper slide pin that was seized. If the caliper isn't moving freely, there is no damping, and the vibration will be felt. My pin was "almost" totally seized and I finally got it out and cleaned it up ( should have replaced it) and the vibration was gone.

 

[jmanolop]

Have you tought about changing the brake's fluid?
Maybe the fluid gets hot after, more less, then minutes, and one of the seals for the booster is leaking.

 

[Dalmus]

Slight update...

I checked the rear calipers, and they seem to be moving freely... I watched the driver's side while I pumped the brakes twice, and watched the passenger side while someone else pumped the brakes. They also moved smoothly back in when I recompressed them with a C clamp.

While I had the calipers off, I swapped in new rotors. I don't know if it was just a placebo effect or not, but, while the vibrations are still there, they DO seem a little more muted.... Its hard to explain. If this were a SOUND, it would have gone from a "thump thump thump thump" to a "thuff thuff thuff thuff."

I'm thinking about the brake fluid suggestion. If the seal for the booster was leaking, would I have any other signs, such as the resevoir level gradually lowering?

Somebody told me that its possible that the transmission isn't disengaging properly, and the pulsation I feel while braking isn't really from the brakes, but from the transmission still wanting to provide power. I wonder if it would be worth changing the tranny fluid?

 

[edwx]

Did you remove, clean and regrease all 8 caliper slide pins, 2 per caliper.

 

[Dalmus]

Did you remove, clean and regrease all 8 caliper slide pins, 2 per caliper.

Those are the two long bolts in rubber boots that you remove in order to remove the caliper from the rotor, correct?

The lower pin on the right rear was harder to remove than the other three (only did the back wheels). It only seemed to fight me on the threaded part... I'll pull the wheels again clean all the pins. I'll check the fronts, too.

Thanks!

 

[edwx]

The bolts and the pins are different. There are 2 bolts and 2 heavily greased (with blue hi temp. grease) slide pins per caliper. The pins are hollow and are attached to the caliper by the boots. The bolt goes through the hollow of the pin, and bolts the pins to the caliper holder. The caliper slides back and forth on the pins. The pins and bolts don't move.....just the caliper moves on the pins. The pins are usually what I have the most problem with. I think I have a stuck one now. I'm getting a shudder when I brake.

 

[bobbaloo38]

I just joined seeking some help with my 02 explorer. It was acting the same way, no pulsing in the steering wheel, yet once warm, it would make a clicking noise coming out of the back tires. I started to install new rotors and pads today, my brother slapped them on for me, we put the lugs on with the tires off and found that the rotors had a lot of play. It rained before we could do any more investigating. Bob

 

[Dalmus]

Alright, I went through and greased all the pins... It did seem to help with the vibrations while not braking slightly (possibly a placebo effect), however the pulsations while braking still showed up after a few minutes of driver.

Here's what else I found:
- The inner brake pad on the front diver's side doesn't move freely in the slipper. The outer pad, and the two on the passenger side of just a little play. So it seems possible that as the rotor heats up from driving, it expands and the lack of play in the slipper causes intermittent contact.

- The front passenger hub doesn't seem to spin quite as freely as the driver's side. There's no noise coming from the hub though. This was with the caliper off. I had the driver's side hub replaced about 6 months ago, so that could be the reason... But with no noise, could the hub still be going bad?

 

[edwx]

Hmmmmmmm............sounds like things are working properly. How many miles did you say you had on those rotors?

 

[Dalmus]

Hmmmmmmm............sounds like things are working properly. How many miles did you say you had on those rotors?

Only 12,000 miles or so on the front rotors. Less than 200 on the rear rotors.

 

[Blrob]

I would suggest checking the u-joints. They can give a vibration at most speeds. I just replaced 1 on a F150 with vibration at street and highway speeds. Found it was the rear u-joint. Changed it out in about an hour and re-installed, all is quiet. Warped rotors and pads wouldn't give you the vibration that you can feel as well as hear.

 

[Dalmus]

I would suggest checking the u-joints. They can give a vibration at most speeds. I just replaced 1 on a F150 with vibration at street and highway speeds. Found it was the rear u-joint. Changed it out in about an hour and re-installed, all is quiet. Warped rotors and pads wouldn't give you the vibration that you can feel as well as hear.

Both the tire shop and my regular mechanic did a visual inspection, and said that the u-joints looked fine. I suppose the only way to really be sure is to pull the drive shaft and physically move them in all four directions?

Could bad u-joints lead to bad pinion seals? I have some leakage on both the front and rear seals.

Assuming I can get the drive shaft off, it looks like a pretty simple job to replace the u-joints... For the cost of the parts, maybe I should just go ahead and replace them anyway. Is it likely I'll be able to get the bolts off without air tools?

 

[aatomicdawg36]

Both the tire shop and my regular mechanic did a visual inspection, and said that the u-joints looked fine. I suppose the only way to really be sure is to pull the drive shaft and physically move them in all four directions?

Could bad u-joints lead to bad pinion seals? I have some leakage on both the front and rear seals.

Assuming I can get the drive shaft off, it looks like a pretty simple job to replace the u-joints... For the cost of the parts, maybe I should just go ahead and replace them anyway. Is it likely I'll be able to get the bolts off without air tools?

So, what was the end result? Did you ever find the problem ?? Dude, this thread was one of the most interesting ones I've ever read. Looks like you had some good suggestions. Just wondering how things turned out. Thanks

 

[94Eddie]

I had a vibration on my Mustang once that was giving me fits trying to find the cause. I checked the balance, warping of the rotors, wheel bearing, slipped belts in the tires etc. It turned out to be a worn tie rod end that let one front tire wobble when braking. Especially at highway speeds. Check your steering components too.

Usually a U-joint problem will be present when accelerating and decelerating independent of braking. A bad U-joint can be very hard to detect. I have had them appear find and once taken out and removing an end cap had rust and bearings fall out.

 

[Dalmus]

So, what was the end result? Did you ever find the problem ?? Dude, this thread was one of the most interesting ones I've ever read. Looks like you had some good suggestions. Just wondering how things turned out. Thanks

Thanks for the interest!

It turned out to be the left rear bearing hub. It wasn't bad enough to cause the wheel to wobble when I stopped and the mechanic got the vehicle in the air, but after I started hearing intermittent "chirps" from the left side of my vehicle while driving down the road, I bit the bullet and insisted on replacing the rear hub (the front left was replaced about two years ago).

Bingo... no problems since. At least not the vibration after driving for a time... Plenty of other issues developing with this beast a 135K... But those are for another post.