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Grooved Rotors and Pulsing Pedal by chucks85fastback
Started on: 04-15-2015 11:45 AM
Replies: 8 (168 views)
Last post by: chucks85fastback on 04-17-2015 02:31 PM
chucks85fastback
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Report this Post04-15-2015 11:45 AM Click Here to See the Profile for chucks85fastbackClick Here to visit chucks85fastback's HomePageSend a Private Message to chucks85fastbackEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hi guys, I did some searching on my issue and didnt come up with much (has the search changed? it doesnt seem as useful as it used to be.)
My issue is that i feel a pulse in the brake pedal, and after driving about an hour last weekend and going down a long steep hill, it started to pull to the right and the brakes felt hot on the front passenger side. But driving back and forth to work it barely pulls at all, and is hardly warmer than the rest.

I replaced the rubber lines with stainless ones from TFS last summer, so thinking those arent the problem.

The rotors have some fairly deep grooves in them, both sides of the car and both sides of the rotor. How does that happen? I never let my pads get low enough for the rivets to touch the rotor.

The car was sitting all winter so I'm going to at least lub the sliders tonight. I'll have to double check the thickness of them too, but i think they are still good according to the Ogre's info.

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dobey
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Report this Post04-15-2015 12:08 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Maybe something got trapped between the pads and rotors? If the grooves are deep, you probably need to replace rotors and pads all around, and then do a proper bed-in procedure (which can take quite a long time if you don't drive the car much).

You'll have to pull the pads and rotors off to see what the likely cause was. Sounds like your rotors are maybe a bit warped too, if you get a pulsing feel in the pedal when stopping.
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chucks85fastback
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Report this Post04-15-2015 12:36 PM Click Here to See the Profile for chucks85fastbackClick Here to visit chucks85fastback's HomePageSend a Private Message to chucks85fastbackEdit/Delete MessageReply w/QuoteDirect Link to This Post
How do you do a proper bed-in?
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dobey
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Report this Post04-15-2015 02:18 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by chucks85fastback:

How do you do a proper bed-in?


Depends on the pads/rotors, but usually a few hundred miles where the brakes are only used more gently/lightly than normal. The pads should come with documentation which states the recommended procedure for them. The EBC GreenStuff I installed on my truck last year with new EBC rotors came with such instructions, at least. I suppose some cheap pads from AutoZone/etc… might not. I don't recall what the recommended procedure is for the OEM brakes on the Fiero.
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chucks85fastback
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Report this Post04-15-2015 05:28 PM Click Here to See the Profile for chucks85fastbackClick Here to visit chucks85fastback's HomePageSend a Private Message to chucks85fastbackEdit/Delete MessageReply w/QuoteDirect Link to This Post
Seems like the problem is a stuck caliper after all. I can barely turn it by hand. There are some grooves on the rotor but nothing that can really catch my fingernail. The grease on the pins even looks fresh still. There is some play left to right, seems like a bushing or something on the tie rod, where it connects to the steering rack. Any advice on that?
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chucks85fastback
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Report this Post04-15-2015 05:32 PM Click Here to See the Profile for chucks85fastbackClick Here to visit chucks85fastback's HomePageSend a Private Message to chucks85fastbackEdit/Delete MessageReply w/QuoteDirect Link to This Post

chucks85fastback

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Only on the passengers side
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Report this Post04-15-2015 05:35 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Rebuild the calipers and get the rotors turned unless they are trashed, in which case you should replace them. Also replace the pads, and do the recommended bed-in for the pads.
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Report this Post04-16-2015 12:09 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Pulsing pedal then most likely has "warp" rotor(s). Warp mean the rotor will fail paralleling spec. The test hard to do for most DIY and even mechanics. An minimum You have to take thickness at several spots and can be a false results because the small amount to measure. 0.0005" is too small for many tools available cause only read to 0.001. Some digital mics will read 0.0001 but anything tiny bit off including user error can cause false results.

Warp rotors are often sign of pad dragging cause by bad caliper(s) or hydro problems.

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chucks85fastback
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Report this Post04-17-2015 02:31 PM Click Here to See the Profile for chucks85fastbackClick Here to visit chucks85fastback's HomePageSend a Private Message to chucks85fastbackEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks for the help guys,
I replaced the bad caliper and the pads, feels 10x better. I realize now that what i thought was the brake pedal pulsing was actually the bad bushing in the steering rack, so thats next. I read up on it on an archived thread a little bit, and I'm going to order Rodney's replacement. Is there just one bushing to replace? Because the driver side isnt showing any play.
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