Brake Pulsation/Shuddering Driving me Nuts

[bosszhp]

Ok, so when I got my ZHP about a year ago there was only a very faint brake vibration. 2 weeks after I bought it I hit a massive pot hole (thanks PA) and cracked one of my control arms. That was replaced and solved most of my brake vibration. Fast forward a few months and it came back, so I replaced the front rotors. Went away for a few weeks and came back. So I replaced the FCAB's. Again, went away for a few weeks and now it's back again and seeming to get worse. Tried bedding the brakes yesterday, seemed to help but sure enough it came back rather quickly. What could possibly be the case now? I'm going to flush the brake fluid before checking anything else just to make sure that isn't the problem (probably also what's causing my red brake light to come on). What other things cause this? Only other thing I can think of is RTAB's or possibly suspension? Could a sticking handbrake cause this? The shoes are new but my Indy suggested a new handle or something along those lines (can't remember). One last thing I want to note is something my previous Indy had mentioned which was replacing something that was throwing the alignment out, but said it wasn't necessary to replace them immediately. Oddly enough no other Indy has mentioned this. :dunno

Running out of ideas (and money lol) and this is seriously becoming a nuisance.

[spoonerDee]

The vibration is in the front? If so I don't see how the emergency brake would affect it since it activates the rears. Long shot but maybe a wheel is out of balance? Typically when I've seen shuddering its ball joints, control arm bushings, warped rotors, wheel balance, new pads old rotors.

[bosszhp]

The vibration is in the front? If so I don't see how the emergency brake would affect it since it activates the rears. Long shot but maybe a wheel is out of balance? Typically when I've seen shuddering its ball joints, control arm bushings, warped rotors, wheel balance, new pads old rotors.

Yes it seems as if the vibration is coming from the front. You mentioned new pads on old rotors, how about old pads on new rotors? This came to my mind but if that was the problem I think bedding my brakes yesterday would have solved the problem. It did but only for about ~10 miles!

[spoonerDee]

As far as I know (someone correct me if I'm wrong) it's usually new pads on old rotors. That being because the rotors have grooves and what not in them and a new smooth pad will chatter against them. Don't really see/remember any issues with new rotors and old pads.

[nozhp4u]

Usually new Rotors AND Pads installed at the same time will correct brake pulsation. Old pads on new rotors can lead to undesirable results. If the old rotors had uneven pad deposition, the surface would not have been flat. That would lead to those pads developing a non-flat surface. If you put those old pads on new rotors you may hear some chatter. I would think that after a proper bed in that should take care of itself though. I have had considerable brake noise from new pads on resurfaced rotors in the past. That is why I just replace and not resurface rotors (not worth the hassle/risk imo).

You could also have a stuck caliper. I don't suppose you have larger than normal amounts of brake dust on one of your wheels? Unbalanced or bent wheels can absolutely create vibration. You said you hit a pothole. Have you had your wheels on a balancing machine to see if they are bent/damaged?


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[3ZHP]

I would recheck the FCAB and Balljoints. If they were installed incorrectly it could create an issue. Jack up both front wheels and have someone move/shake the wheels from the front and back and look closely for movement in all of the suspension joints. If you don't see movement, place jack stands under the control arms having them support the weight and repeat the same procedure.

You also need to lift the wheels up and down while freely suspended to check for ball joint movement. A long 2X4 or pipe under the tire should work.

http://youtu.be/kuOvH4Z6mDY

You can also check the rotors for runout with a dial indicator. One with a magnetic brace may work.


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[bosszhp]

Today was my first semi-long trip after the FCAB's and I noticed a slight vibration at around 70-80 mph so I think that rules out any braking components. Had an alignment back in August when I got my PSS's, might get it checked again just to make sure everything is OK there. Whatever it is it is greatly amplified when breaking.

[BustedBoat]

Check for tie rod play maybe? My car had quite a bit of looseness while driving when my tie rods went. I believe the easiest way to check for this is to jack up the front of the car, lock your steering wheel and see if it wiggles from side to side. If there's a lot of play, they have gone bad.

[bosszhp]

Check for tie rod play maybe? My car had quite a bit of looseness while driving when my tie rods went. I believe the easiest way to check for this is to jack up the front of the car, lock your steering wheel and see if it wiggles from side to side. If there's a lot of play, they have gone bad.

Yeah that's the next thing I was going to check, pretty sure that's the culprit because I started noticing the car wants to dive to the right a little on hard breaking.

[spoonerDee]

Now this really reminds me of my e36. When I first got it, it drove fine, except when I hit like 65-70mph or higher then suddenly it shook harder than my wife on a cold winters night.

I replaced the ball joints, control arm bushings, had an alignment and balance which fixed it 99%. There was still a very slight vibration at high speed but not like before. It originally was so bad the whole car would vibrate and hum like going over rumble strips. Scary stuff.

[BustedBoat]

Good thing you got that fixed then!

[spoonerDee]

Indeed.

[bosszhp]

Now this really reminds me of my e36. When I first got it, it drove fine, except when I hit like 65-70mph or higher then suddenly it shook harder than my wife on a cold winters night.

I replaced the ball joints, control arm bushings, had an alignment and balance which fixed it 99%. There was still a very slight vibration at high speed but not like before. It originally was so bad the whole car would vibrate and hum like going over rumble strips. Scary stuff.

Yeah that's exactly what I'm experiencing right now, lets see if the tie rods take care if it...

[bosszhp]

Tie rods were fine so I took it to my Indy. They put it on the lift and checked all the front suspension and braking stuff, all of which was good. However, they found play in the one steering column bearing (the one on the upper U joint or something like that). Apparently, that little bit of play is what makes my steering wheel violently shake from side to side upon braking and at highway speeds. They quoted me $500 to replace it; anyone ever have this issue before? Sounds very rare.