Scraping noise from wheel while braking (Page 1/2)
sdgdf AUG 08, 05:28 PM
All my brakes are fresh. When I'm coming to a stop, I get a scaping noise as if a rotor is uneven or something. It doesn't happen cold, ie when I'm first driving the car. It sounds worse the harder I hit the pedal.

All my hubs are the same temp when I feel them. All my slides are in the right position. I see no scoring or any weird wear on the rotors, no weird wear on the pads. I suspect its a rear wheel, and thought to jack the rear up and have someone else give it throttle and use the brakes while I'm outside listening. But without load on the wheels it might not make the noise? I also suspect my slides might not be greased properly? I notice the grease I gave them before is now all full of brake dust. My next step might be to take it all apart clean it and put it all back together?
Spoon AUG 08, 07:41 PM

quote
Originally posted by sdgdf:

I suspect its a rear wheel, and thought to jack the rear up and have someone else give it throttle and use the brakes while I'm outside listening.



Spinning the rear wheels with the car lifted from the ground and you'll have more trouble than you can imagine. I'll let the other heavy hitters come along and give you a good scolding.

OMG....

spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

sdgdf AUG 08, 08:13 PM

quote
Originally posted by Spoon:


Spinning the rear wheels with the car lifted from the ground and you'll have more trouble than you can imagine. I'll let the other heavy hitters come along and give you a good scolding.

OMG....

spoon





What? The torque will kick it off the jack stands?
Patrick AUG 08, 08:57 PM

Where do you plan to locate the jack stands?
sdgdf AUG 08, 09:35 PM

quote
Originally posted by Patrick:


Where do you plan to locate the jack stands?





Those pink jacking points ahead of the rear suspension. That’s where I’ve been setting the stands working on the rear.
Vintage-Nut AUG 08, 10:08 PM

quote
By sdgdf
All my brakes are fresh


Meaning new pads and rotors? What type of pads (organic/semi-metallic/ceramic)? Did you grease the pins?



quote
suspect my slides might not be greased properly


Did you grease the slides?
If the slides aren't greased, this means that the calipers can't move freely, and the pads can drag on the rotors.



quote
But without load on the wheels it might not make the noise?


Drive next a 'wall' with the window open to hear if the brakes are making 'noise' as you drive.



quote
My next step might be to take it all apart clean it and put it all back together?


Did you put new rotors and pads or a shop?

[This message has been edited by Vintage-Nut (edited 08-08-2023).]

Patrick AUG 08, 11:05 PM

quote
Originally posted by sdgdf:

Those pink jacking points ahead of the rear suspension. That’s where I’ve been setting the stands working on the rear.



So you wish to raise the car with the suspension fully dropped, and have the engine driving the rear wheels while in this position? I don't know for sure, but it seems to me that this would put undue stress on the CV joints working at that angle. I think I'd prefer to have the weight of the car supported by blocks of wood under the rear lower control arms, thus allowing the suspension to be at regular ride height while the engine is driving the wheels. Maybe someone else could chip in here on this as well.
Raydar AUG 08, 11:08 PM

quote
Originally posted by sdgdf:


What? The torque will kick it off the jack stands?



If the car is lifted by the cradle, and the suspension droops, the axles can over-extend and maybe allow the tripots to do "funny things", since they're turning at an extreme angle.
Best to support the car by the cradle, and then put a floor jack under the knuckle.

Although spinning the wheels with the car in the air is kind of sketchy. (Yeah... I've done it. But it still is sketchy. )

[This message has been edited by Raydar (edited 08-08-2023).]

theogre AUG 09, 04:30 PM
Iffy Wheel/hub bearings can cause "brake noise" when using the brakes. Warning: "Old style" wheel bearing sets for 84-87 Fiero and many others can't be too loose and Can't be Preloaded either. https://web.archive.org/web...cast.net/~fierocave/ wheel bearing
Iffy Pad "Squealers" can do same thing. When ship to store you whatever they get dropped & Squealer can bend & hit the rotor way easier or never depending how their bent.

Sliders and more brake parts only get Brake Grease. Preferred is Pematex green label but even basic Silicone do it a pinch.
Any other grease "eats" brake rubber things. If used them only replace the affected rubber and clean metal to get rid of extra.


quote
Originally posted by Raydar:
If the car is lifted by the cradle, and the suspension droops, the axles can over-extend and maybe allow the tripots to do "funny things", since they're turning at an extreme angle.
Best to support the car by the cradle, and then put a floor jack under the knuckle.

Although spinning the wheels with the car in the air is kind of sketchy. (Yeah... I've done it. But it still is sketchy. )

This can happen. More so if have engine/trans mounts that have problems and move to one side of engine bay because 1 axle is pulled more and tripot rollers are near the end of travel.

Only turn the wheels by hand when car is jacked or can Destroy the axle(s).
Example: If trying to hear/feel hub(s) are bad etc, rotate the tire by hand. Often can feel bearings hanging up way before can hear noise while driving.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

sdgdf AUG 09, 09:33 PM

quote
Originally posted by Vintage-Nut:

Multiple quotes




EBC yellowstuff pads, on C4 12” rotors. I did it myself and greased the pins with high temp brake grease. There’s been so much brake dust the grease is nasty.

The sound is loud enough that I can’t tell front or rear, seems to be passenger side. Also seems like it’s towards the rear. What if I drive with a GoPro suction cupped to the side of the car?