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Brake vibration

joshwilson3

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On my 89, I put on 4 Wearever rotors and Wearever Gold pads.

It breaks fine. But I noticed at the last few seconds before the car is completely stopped, that I get a loud vibration that you can feel through the floor. And while completely stopped, when I start taking my foot off the brakes, I too get a loud vibration.

If I just barley ease up on the brake like when you want to inch forward, I keep getting the vibration until I press all the way down on the brakes to fully stop, or take my foot all the way off the brakes.

I replaced the front pins and anti-rattle clips, greased the back of the pads and pins, torqued everything to spec, and flushed the brake fluid.

It seems the vibration comes from the front and rear, but kinda hard to tell.

If I'm say going 40 mph, and I start braking. It brakes fine, I just get the vibration in the last few seconds before the car comes to a complete stop.

Would this sound like warped rotors? Or would it be something else?
 
New pads vibrating because of a loose fit? I had some fun with my 1988 finding pads that would fit snug like the originals. Took 3 different pads to find the right ones. Was amazed how different each pad would fit. Did not have the same issue on my 1989.
 
I agree, sounds like brake pads are not fitting/seating properly. Check pins and pad contact pattern.
 
I agree, sounds like brake pads are not fitting/seating properly. Check pins and pad contact pattern.

If the pads aren't fitting properly. Is that an install error or bad brake pads?

The pins should be fine, but I'll check it out again.

I'll see if I can see a pad contact pattern, but they only have 50 miles on them, so I don't know how much I'll see.
 
The first set of pads I tried had too much side movement (play) compared to those that I had removed. The actual pad frame size was smaller in size and installed way too easy. After trying a few different pads (different companies), I found a pair that fit perfectly. Wasted a whole day. Did not have the same issue with the rear brakes. I don't your issue was caused by you.
 
The first set of pads I tried had too much side movement (play) compared to those that I had removed. The actual pad frame size was smaller in size and installed way too easy. After trying a few different pads (different companies), I found a pair that fit perfectly. Wasted a whole day. Did not have the same issue with the rear brakes. I don't your issue was caused by you.

I think shops check brakes for free. So, I might could see if a shop could check it out for warped rotors just to rule that out. The rotors were $33 or $40 a piece.

I do seem to recall the rear pads. Maybe the outside pad didn't make 100% contact with the rotor when I was trying to seat it. I remember seeing a gap in between the pad and rotor. So, I'll pull the rear wheels off and check that out to see if that is still the case.
 
It doesn't sound like the rotors are warped to me. If that were the case you would feel a pulse or chatter at all speeds. Sounds like a fitment problem.
 
50 miles..? thats not near enough time to seat a new set. Get 200 miles at least then see how it feels.50 mile drive = 30 sec braking.

if its a set of semi-metallics that will grab a little and make more noise, thats just the nature of the brake part.

it takes some time to break them in, Semi Metallic have enough metal in the pad that it tries to grab the rotor to hold it...and it will try to hold the rotor.
 
50 miles..? thats not near enough time to seat a new set. Get 200 miles at least then see how it feels.50 mile drive = 30 sec braking.

if its a set of semi-metallics that will grab a little and make more noise, thats just the nature of the brake part.

it takes some time to break them in, Semi Metallic have enough metal in the pad that it tries to grab the rotor to hold it...and it will try to hold the rotor.

They are semi metallic. I also changed front rotors and pads on the Firebird, the rears are drums. Wagner pads and Duralast rotors. And I don't notice any problems. But it had rained recently, and I noticed some minor vibration noise when almost completely stopped, but not near like the Vette. Last few times I drove the Firebird when it was dry, no vibration at all.

So, that would tell me there is something different. I'll pull the rear wheels off and check the pad fitment as when I did it last, I noticed a slight gap between one of the pads and rotor. So, if that still is the case, then that could be the problem as maybe the pads aren't 100% flat, or maybe something else.

Though, I don't really see how the front could have a fitment problem as the pads snap into the piston and caliper. I used a couple of channel locks to make sure the front pads were all the way pressed in.
 
Let me clarify one item. When I refer to play, I mean play in where the metal frame that holds the pad touches the caliper housing, not between the pad and the rotor. In all the brake pads, shoes, rotors and drums replaced regardless of the type of car, I never needed a break in period to eliminate any type of noise or vibration.
 
Let me clarify one item. When I refer to play, I mean play in where the metal frame that holds the pad touches, not btween the pad and the rotor. In all the brake pads, shoes, rotors and drums replaced regardless of the type of car, I never needed a break in period to eliminate any type of noise or vibration.

I understand what you are saying. The metal frame of the pad was too small and didn't fit tightly. I don't think that would be my problem since I remember them fitting tightly.
 
Let me clarify one item. When I refer to play, I mean play in where the metal frame that holds the pad touches the caliper housing, not between the pad and the rotor. In all the brake pads, shoes, rotors and drums replaced regardless of the type of car, I never needed a break in period to eliminate any type of noise or vibration.


"break-in" .... was a poor choice of words. Wear-in is probably more accurate.

I was trying to say that they needed to be used or applied a few times to get the normal wear pattern established. New pads are rougher than after having been applied a few times. Once the smooth surface of the rotor and its arc get polished into the pad after a couple good applications, (more than a few seconds) the max contact area is achieved. The 2 surfaces "mate" better after a few applications. Not claiming this to be the cause of a noise, just a possibility.

I know that mine tend to "groan" if allowed to creap away from a stop if they have been soaked with detergents & water from pressure washing. The groaning can be loud and felt until the pads dry out again.
Are the caliper pins/guides in good shape?
 
"break-in" .... was a poor choice of words. Wear-in is probably more accurate.

I was trying to say that they needed to be used or applied a few times to get the normal wear pattern established. New pads are rougher than after having been applied a few times. Once the smooth surface of the rotor and its arc get polished into the pad after a couple good applications, (more than a few seconds) the max contact area is achieved. The 2 surfaces "mate" better after a few applications. Not claiming this to be the cause of a noise, just a possibility.

I know that mine tend to "groan" if allowed to creap away from a stop if they have been soaked with detergents & water from pressure washing. The groaning can be loud and felt until the pads dry out again.
Are the caliper pins/guides in good shape?

Yes, I would call it a "groan".

I noticed it is no where near as bad, in you can barely hear/feel it when going in reverse.

I replaced the front pins and anti rattle clips with a set from Napa. I also greased them. For the rear, I cleaned the old grease off the pins, and regreased them.

It brakes fine, so it probably wouldn't be worth it to go replacing parts to see what that does. If I did take the wheels off to check them out, I probably wouldn't be able to tell anything.
 
Yes, I would call it a "groan".

I noticed it is no where near as bad, in you can barely hear/feel it when going in reverse.

I replaced the front pins and anti rattle clips with a set from Napa. I also greased them. For the rear, I cleaned the old grease off the pins, and regreased them.

It brakes fine, so it probably wouldn't be worth it to go replacing parts to see what that does. If I did take the wheels off to check them out, I probably wouldn't be able to tell anything.

The wear parts have to mate and they do when used. BUT, depending on the material that might take longer then others. I know full metalics can screech all the time, good news is things will wear out fast on those pads so the noises have a limited lifespam.

I was told that the new ceramic pads did not grab & hold as well as semi-metallics, but they don;t dust the wheel down with brake wear dust...which is a nice bonus. whatever you install, it may take a week or two but you will get comfortable with them soon and even learn to like how they perform.
 
The wear parts have to mate and they do when used. BUT, depending on the material that might take longer then others. I know full metalics can screech all the time, good news is things will wear out fast on those pads so the noises have a limited lifespam.

I was told that the new ceramic pads did not grab & hold as well as semi-metallics, but they don;t dust the wheel down with brake wear dust...which is a nice bonus. whatever you install, it may take a week or two but you will get comfortable with them soon and even learn to like how they perform.

The semi-metallic pads and rotors were installed probably 3 weeks ago. I'd say now I've probably got 100 to 150 miles. I guess time will tell if the "groan" goes away, or doesn't. I know I don't have any groan when I did semi-metallic pads and rotors on the Firebird. But then again I used a different brand pad and rotor on there.

I would have figured if it was something that would go away when they wore in, that I'd have other problems or noises as everything else performs fine.

I may ask a shop what they think since they check brakes for free. I guess I should have gone ceramic as the price was around the same. The reason I didn't was because I heard cermaics eat rotors more than semi-metallic.
 
The semi-metallic pads and rotors were installed probably 3 weeks ago. I'd say now I've probably got 100 to 150 miles. I guess time will tell if the "groan" goes away, or doesn't. I know I don't have any groan when I did semi-metallic pads and rotors on the Firebird. But then again I used a different brand pad and rotor on there.

I would have figured if it was something that would go away when they wore in, that I'd have other problems or noises as everything else performs fine.

I may ask a shop what they think since they check brakes for free. I guess I should have gone ceramic as the price was around the same. The reason I didn't was because I heard cermaics eat rotors more than semi-metallic.

I've been told that the ceramics have their own set of issues... being a cleaner pad that leaves less dust is the advantage. Wear or noise might be the trade off.
 
It doesn't sound like there's been enough aggressive driving to warp a rotor, unless they were bad out of the box. Are you getting similar stopping distance to the old pads? I was thinking maybe a piston isn't engaging completely. Also, the first time I did my brakes, I found extra shims between the rear pads and pistons (my rear's didn't look like they engage evenly either). Since you changed the rotors as well, you might just try removing / re-installing everything to see if somthing was missed or not fitting quite right.
 
It doesn't sound like there's been enough aggressive driving to warp a rotor, unless they were bad out of the box. Are you getting similar stopping distance to the old pads? I was thinking maybe a piston isn't engaging completely. Also, the first time I did my brakes, I found extra shims between the rear pads and pistons (my rear's didn't look like they engage evenly either). Since you changed the rotors as well, you might just try removing / re-installing everything to see if somthing was missed or not fitting quite right.

I don't recall what the stopping distance was before. But it seems to stop fine to me right now.

I believe a shop will check brakes for free. So, I'll just let a shop check the rotors to see if they are warped, as that will rule that out.

My rear caliper pads didn't have any shims on them when I pulled the old ones.

I'm pretty sure I did everything correct, unless there was a special way to do something that isn't in any of the writeups. I spent all day on it, not really sure if I want to spend an entire day taking everything apart just to put it back together. As the front pads are hard to remove/install.

The only thing I can think of, is I did have some trouble getting the front pads on as I had to use channel locks. I had to snap in one side at a time on the front piston side. So, I had to rock the pad on by squeezing one end, and the other piston would pull out some, then I'd squeeze that end and go back and forth until the pad was all the way seated.

But it does seem like the noise is from the front and back from what I can tell, so that is why I was thinking rotors since I've read of the cheap China rotors being warped out of the box.

I may get a helper to do the brakes while I put my scope on the front calipers. Will be tricky, but shouldn't take long to know what calipers are making the vibration/noise. For the rears, I'll probably have to lay on the ground and put the scope on the knuckle as if there is vibration from the rear, then it will travel through the knuckle anyways. Or I might could put the scope on the rear control arm in front of the tire. That might be easier since I could walk with the car as it moves forward some.
 

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