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bozs13
01-05-2010, 09:03 PM
Hey guys.

I'm having a brake scraping issue. :wtf: It doesn't do it all the time but there is a rhythmic scraping sound coming from my front left. Sometimes it goes away when turning to the left but not often. When I break it pulses harder and I can feel it through the pedal. Every once in a while it gets really loud.

Any ideas?

I took my wheel off, turned the car on, put it in first and listened to the caliper spin. The outer caliper is definitely touching the rotor but I can't imagine that that little issue is causing all the racket.

Every time I fix one thing something else goes wrong. This is starting to become over average. I changed the wheel bearing on that side a few months ago but no other work has been done on that side in a long time.

Thanks guys, Leo

Galcobar
01-05-2010, 09:05 PM
Sounds like a stuck caliper or uneven pad material deposition -- though the latter is often a symptom of the former.

bozs13
01-05-2010, 09:09 PM
Sounds like a stuck caliper or uneven pad material deposition -- though the latter is often a symptom of the former.

could a stuck caliper have anything to do with cold weather?

sodap0p
01-05-2010, 09:29 PM
I doubt cold weather would have any effect on your brakes.

Sticky caliper and a warped rotor. Sticky caliper will cause lots of heat (which in turn could warp the rotor).

Sort of like my siezed parking brake (seized on) so the parking brake shoes on the one side was always contacting the rotor/drum. The heat siezed the auto adjuster. I had to heat it up to break it lose, and to make things worse, it was the passenger side, so I was unscrewing it counter clock wise when it should have been clockwise. fun times...

bozs13
01-05-2010, 09:32 PM
I've searched and can't find any decent info on un-sticking...do I need to drain? Oh great

Galcobar
01-06-2010, 12:51 AM
You need to disassemble -- so while bleeding will be required you shouldn't have to drain the system if you plug the disconnected brake line.


Typically the issue is the bushings. If they slide smoothly, look at the piston. Technically you might escape having to disconnect the caliper from the lines if it is the bushings which are stuck, but it generally takes a lot of force to remove seized bushings and attempting to do so while the caliper is still attached is difficult at best.

rizin
01-06-2010, 02:06 AM
Do you have a camera to take pics from the top of the caliper.

bozs13
01-06-2010, 03:19 AM
I'm about to crash but I'll take a pic or two tomorrow. Just from the top down? With it off?

rizin
01-06-2010, 03:38 PM
With it on just want to see what the wear looks like and how it is sitting on the rotor. I am with the guys on the caliper sticking and the rotor being warped.

The rotor is suppose to be able to adjust side to side on the rotor to apply even pressure on both pads. This is beacuse the caliper only applys pressure with the piston on one side. The caliper slides on two bolts these bolts are the two that have the rubber peice on them. These need to probable need to lubed up. The bushings that they are talking about ride on these bolts. If it is the bushings I would also replace the bolts also they sometimes get worn to help cause this problem.

On the rotor you might be able to get them turned. that all depends on how thick you rotors are still. There is a minimum amount of material that has to be left after they turn the rotor.

Beano
01-07-2010, 12:26 PM
I had a really jammed piston on my rear RH caliper. Pumping the pedal with the pads removed would not shift it.
Clamp the hose near the banjo, remove the caliper and grip it in the vice. Remove pads and antirattle springs. Detatch the rubber boot from the caliper (circlip) taking care not to damage boot/dust seal. Using a curved drift through the banjo bolt hole knock the piston out (the piston is a solid machined block). You can feel the stuck-on crud in the bore of the caliper with your finger. Using very fine wire wool or wet/dry paper gently clean piston & bore of caliper, and the piston, keeping action even all round to avoid flat spots. The caliper seal is a recessed O-Ring, not a lipped seal - take care not to damage it. If you have damaged the threads in the bolt hole refresh them with a screw tap. Clean with fresh fluid and replace piston. Fill caliper to 'brim' with fresh fluid through bolt hole and carry to car. Refit hose banjo then remove clamp. Replace anti rattle springs and pads (new if necessary) fit caliper to car and pump brake pedal gently until firm. If you have followed my clamping and filling instructions there will be only a tiny amount of air in the caliper - the brake will work immediately. Bleed out the air in the conventional manner if necessary.
You could of course just buy a new caliper (your local friendly garage would do this cos its cheaper than their labour costs). If you had time in hand you should of course order a new caliper repair kit - boot, circlips and O-ring. However - my repair has performed faultlessly for two years.

KoreanJoey
01-08-2010, 07:25 AM
You guys are wrong. Wheel bearing. If it's changing noise as he changes load on that side... 99% chance.

PS: If you take off the wheel and turn the hub with the rotor on, you're going to hear it hit the pad, the rotor is partially held in place by the wheel/lug nuts. Without the lug nuts in place, and torqued down the rotor floats and pretty much goes where ever the hell it wants.

bozs13
01-08-2010, 02:36 PM
I highly doubt that it's the wheel bearings since both are brand new and have been doing fine. It doesn't sound like a wheel bearing. Here's a sound clip of me going down the driveway and towards the end me slowing down.

http://www.youtube.com/watch?v=8lFlQ31mcBs

I've had ZERO time to do anything and take pictures as I am in and out of school/work all the time and then hit the sack (working now). Maybe I can take pics this weekend.
It's getting snowy down here and I can't trust my car when it makes this sound...

85gtsblackman
01-08-2010, 02:45 PM
make sure the bearing didnt go again, you could have a bad race which means u would need a new hub

other than that sounds like your due for a brake overhaul

rizin
01-08-2010, 04:36 PM
85gtsblackman on the 5th gens the bearings and races are in one unit that gets pressed in. I listened to the audio sounds like the scrper is making the small chirp. Which normally means the pad it worn low. Everytime you brake is the loud noise when it is grabbing hard.

KoreanJoey
01-09-2010, 06:46 AM
Backing plate of the brakes? That' seems likely as I think that's what they sound like (I've done it more than once while doing brake jobs). And yeah, you're right, that definitely doesn't sound like a wheel bearing.

PS: That's more of a squeaking/creaking noise than a scrapping noise by the vid.

Galcobar
01-09-2010, 08:40 AM
Bent the lip on the backing plate enough to scrape?

Beano
01-11-2010, 09:14 AM
Ahh - squeaking-scraping sound? I had an anti rattle spring break up at the beginning of a long journey - drove me nuts worrying about the noise - stopped and crawled under the car a few times during the journey but couldn't pinpoint the noise (except identifying the brake it was coming from. Upon arrival at destination (daughter's house) I took off the wheel and caliper and removed the offending pieces of anti rattle spring (actually a complex thin sheet of stainless steel pressing, not a 'conventional' spring) I drove the car (silent again) to the nearest main dealer for a set of new springs and fitted them that afternoon. Only tools required were Jack, wheelbrace and 14mm ring spanner. Springs set was very reasonably priced too!
Beano

bozs13
01-11-2010, 12:29 PM
Hmm...that could very well be it! The sound went away for 3 days but now it's back? Would it do that?

bozs13
01-11-2010, 12:31 PM
85gtsblackman on the 5th gens the bearings and races are in one unit that gets pressed in. I listened to the audio sounds like the scrper is making the small chirp. Which normally means the pad it worn low. Everytime you brake is the loud noise when it is grabbing hard.

I checked the pads and they're fine :)


Backing plate of the brakes? That' seems likely as I think that's what they sound like (I've done it more than once while doing brake jobs). And yeah, you're right, that definitely doesn't sound like a wheel bearing.

PS: That's more of a squeaking/creaking noise than a scrapping noise by the vid.

How in the world would the backing plates do that? We are talking about those plates that go in between the caliper and brakes...like a thing metal piece right? Cause both are just there loosely.

Galcobar
01-12-2010, 02:35 AM
No, what you just described are shims. Specifically, brake pad shims.

And please: brakes. Not breaks. You brake your car, it stops. You break your car, you spend a lot of money fixing it.

Backing plates are the large metal plates mounted between the hub and the axle carrier/knuckle on the rear wheels. The caliper bracket (aka torque plates) mounts to the backing plate. These plates also mount the parking brake hardware, or the drum brake hardware if your car is not equipped with rear discs.

This term is also sometimes applied to the very similar plates on the front brakes, though Toyota likes to refer to the front versions as dust covers as they do not mount any hardware.

If the dust cover is touching the rotor this can easily cause the higher-pitched scraping sound.

Just be sure it's the wheel you think it is; get the car up on jacks and spin the wheels by hand. Often you can trace the vibration to the source by feeling for it.

Beano
01-12-2010, 09:05 AM
'Shims' are designed in various thicknesses to adjust clearances - not necessary on brake pads, since the piston(s) in the caliper compensates for wear automatically.The complex shaped thin stainless steel 'shims' on our caliper are designed to be a firm 'sprung' fit into the caliper recess and exert very light pressure on the edges of the metal part of the brake pad to prevent the pads flopping about loosely causing a rattling sound - hence, anti-rattle springs. Aftermarket pads instead of OE Toyota parts may not fit snugly enough into them.
In the case I mentioned, because of the complex shape of the 'spring' it was not able to fall out, although it had broken in two pieces and one of the 'clips' that secure it to the caliper body had broken off completely, but part of it was loose enough to be able to scrape against the disc (rotor, as you call it). The noise was more aparent when the brake was applied - a metal to metal sound, confusing when checking by eye because I could see the pads were almost unworn. Only after removing the pads was the problem aparent.

rizin
01-13-2010, 12:35 AM
I would say first thing to do is go get your rotors turned if they can be. That is why you are feeling the pulsing in the brake pedel. Then start finding the squeak. You need to make the car safer as soon as possible.

Beano
01-13-2010, 09:59 AM
Re the parts diagram - OK so we have anti squeal shims and anti squeal springs shown here - 'anti-rattle' in old UK terminology. On my Celica rear brakes (and many other brakes I have worked on (car and motorcycle) the anti squeal shim as it is called in Toyota Speak is a complex pressed stainless steel item incorporating two sprung clips (top and bottom)which clip it securely to the caliper body. The edges of the metal backing of the pads is in permanent light contact with these 'shims' to prevent them flopping loosely against the Rotor (disc) and rattling or squealing. I suppose it is referred to as a shim because it takes up clearance at the edges of the pad - (not between the back of the pad and the piston). Some of these 'spring shims' incorporate a tag which will scrape against the rotor/disc when the pads are worn and make a nasty noise (wear indicator tag). Other makes have this tag as an integral part of the pad - or as is shown in the toyota diagram, as a separate 'clip-on' on the pad. I used to have a P6 V8 Rover 3.5 which had 'electric' wires moulded into the pad, connected to an idiot lamp on the dash. When the pads wore sufficiently to expose this wire, it earthed against the rotor/disc and the lamp lit every time you applied the brake. - But I digress!
Beano (UK)

KoreanJoey
01-15-2010, 05:08 AM
What he means by backing plate would be the metal dust cover around the entirety of the brake assembly. Check that it hasn't been bent and is now making contact with the rotor.

http://www.montemania.com/images/nosgenuinegmparts/brake_backing_plate_shield.jpg

Galcobar
01-15-2010, 06:15 AM
Weird, I'm not seeing my post where I linked the parts diagram...

Try again: http://www.celicatech.com/imagearchive/bgbonline/93celica/br/frontbrake.pdf

bozs13
01-15-2010, 07:21 PM
Well It's not the part pictured above. I checked. Here's a vid I snapped before I had to get to work. It looks like the rotor is warped. It is wobbling and my WHEEL is wobbling too. Does it look like it to you guys too? Also, would that wobble coming through that shaft be related to the warped rotor or is that another issue?

http://www.youtube.com/watch?v=CFgd9BImq5Q

Galcobar
01-15-2010, 07:57 PM
Hmm....I'm going back to Joey's original suggestion, bearing issue.

Or at least something related to the suspension and steering -- warped rotor is unlikely to produce wobble through the entire setup given the warping is at the pad contact point.

Could be something as simple as improper installation of the wheel bearing.

bozs13
01-15-2010, 09:01 PM
I think you might be right.

http://www.youtube.com/watch?v=BUv9nezpjpE

KoreanJoey
01-18-2010, 01:49 AM
I know you said you did the wheel bearing recently, but was the hub also replaced? I did a wheel bearing on my car and thought the hub was ok, lasted a whopping 1200 miles before it went out again.

Zabimaru
06-22-2011, 04:04 PM
Joey & Galcobar,
I've got a similar sound on my 94gt and had a mechanic tell me it was the front backing plate (dust cover, what have you). Is there any concern for removing them and not replacing? Getting them off myself seems like it maybe more trouble than I can get into now and I don't actually want to pay some one right now. Any thoughts on taking metal shears to the offending parts until I can get that hub off by my own hand or a paid professional?

Galcobar
06-22-2011, 11:33 PM
Front backing plate doesn't rotate, it just keeps the road gunk away from rather important parts of the car such as the CV joint and steering bellows. I'd not want to remove it, but generally if it's scraping against something (rotor usually) it's because it hit something and bent.

Usual solution to a bent dust cover is a pair of pliers and some swearing.

KoreanJoey
06-23-2011, 03:19 AM
I just use a prybar and push it away from the rotor. If your mechanic can't manage that, find a new mechanic.

Zabimaru
06-24-2011, 04:47 AM
Thanks Guys,
I bent it out some before I posted, but scraping is merely less than constant. I guess I'll just crawl back under next week and try to identify remaining contact points. Is brake cleaner probably the best thing to spray down there, or is there something else that might help clear out the corrosion and flaky bits?

Galcobar
06-24-2011, 04:56 AM
Brake cleaner works great as long as you don't get it on rubber or paint, but I generally use a rubber-safe degreaser so I can scrub without worrying about flying droplets.

KoreanJoey
06-24-2011, 07:32 AM
So bending it did change it? Just wanting to make sure we get it nailed down as to what exactly the source is.