1993 240sx: uneven brake wear question

[surreybc]

1. one of my brake pads is wearing uneven and is wearing out faster than the othe pads. I have tried replacing caliper to no avail.
I noticed that the piston is hitting a metal knob on pad . also, I have the anti noise device on the two pads on the wheel that is giving me the problem and not on the opposite wheel.

2. what should i use for anti rattle anti noise? is it sufficient just to use that stuff in the bottle and not use the metal piece. thanks.

http://i36.photobucket.com/albums/e25/vancouverbc_2008/jkkk003.jpg
http://i36.photobucket.com/albums/e25/vancouverbc_2008/jkkk004.jpg

[cdlong]

i can't see the pics (at work) so i'll have to guess a little, this is the rear, right?

but the metal knob on the pad is supposed to line up with one of four notches in the piston to keep the piston from turning when you apply the parking brake. line everything up and you should be good.

i seem to remember having a similar problem with the anti rattle clips on my old car. you can take them out since they're just for noise control. as long as a little extran noise doesn't bother you, it's fine. i don't think i noticed a difference when i took mine out.

[SilviaSR20DET]

check your alignment specs which may cause un even brake wear.

[projectRDM]

check your alignment specs which may cause un even brake wear.

Explain your reasoning behind this statement.

To the OP- You have indeed replaced the caliper? That picture is a clear cut example of a sticking caliper. Either the piston is seized or the sliding pins are sticking, causing more pressure on one side than the other.

[s14kouki44]

you could have the wrong pad

[SoguRacing]

Explain your reasoning behind this statement.

To the OP- You have indeed replaced the caliper? That picture is a clear cut example of a sticking caliper. Either the piston is seized or the sliding pins are sticking, causing more pressure on one side than the other.

I second that statement. Brakes 101.

[projectRDM]

you could have the wrong pad

Wow. I'll take 'completely stupid, useless posts for $200 please'. How would the wrong pad even fit in the caliper, much less wear unevenly?

In fact, the picture clearly shows the pads, anyone who's ever seen rear Schassis pads know what they look like.

[The Chad]

I 3rd the probable bad caliper. I had a similar problem...replaced the caliper with a rebuilt unit and was good to go. ( I added Z32's upfront while I was at it :) )

[FRpilot]

you could have the wrong pad

Wow. I'll take 'completely stupid, useless posts for $200 please'. How would the wrong pad even fit in the caliper, much less wear unevenly?

In fact, the picture clearly shows the pads, anyone who's ever seen rear Schassis pads know what they look like.


LOL :rofl:


Anyways, no one has mentioned that the OP's rotors might be warped and may need to be turned. if rotors are uneven, due to warping, it could cause uneven pad wear. a hypothetical cause or warping might be due to heavy brake use, making rotors extremely hot, then say you wash your car or run over a puddle of water splashing cold water to cool your rotors too quickly.

[SoguRacing]

LOL :rofl:


Anyways, no one has mentioned that the OP's rotors might be warped and may need to be turned. if rotors are uneven, due to warping, it could cause uneven pad wear. a hypothetical cause or warping might be due to heavy brake use, making rotors extremely hot, then say you wash your car or run over a puddle of water splashing cold water to cool your rotors too quickly.

very unlikely that would happen at all. The cause is a defective sliding caliper as PROJECTRDM stated. The slider bolts are more than likely seized and reducing caliper return movement.

[socal_kouki]

So a bigger (z32) brake master cylinder would eliminate the problem, correct?

[projectRDM]

So a bigger (z32) brake master cylinder would eliminate the problem, correct?

Fuck what? How would a larger master cylinder keep the calipers from sticking? I guess a louder stereo would help too, right? Or maybe wider tires?

The only way to fix a seized caliper is to replace it.

[socal_kouki]

Fuck what? How would a larger master cylinder keep the calipers from sticking? I guess a louder stereo would help too, right? Or maybe wider tires?

The only way to fix a seized caliper is to replace it.

I thought it would since a seized caliper might be defficient in brake fluid pressure. So a bigger cylinder will keep the slider from seizing, blah blah blah... this is more on the prevention part of the solution, I guess.

Otherwise this means s-chassis rear calipers are prone to seizing...

And I think the thread can do without the stupid answers.. relevant answers make you look cooler, anyway.

[SoguRacing]

I thought it would since a seized caliper might be defficient in brake fluid pressure.

Otherwise this means s-chassis rear calipers are prone to seizing...

And I think the thread can do without the stupid answers.. relevant answers make you look cooler.

It's not that s-chassis calipers are prone to seizing...it's that they are 20 years old and have xxx,xxx miles on them. They get old, rust, and malfunction like many other mechanical parts do.

[socal_kouki]

It's not that s-chassis calipers are prone to seizing...it's that they are 20 years old and have xxx,xxx miles on them. They get old, rust, and malfunction like many other mechanical parts do.

The only reason why I'm even here is cause I've replaced my rear passenger caliper twice since upgrading in the front and each time the pads are uneven. Sorry if I threadjacked I just wanted some answers for myself.

[SoguRacing]

when and if you replace parts always use new parts. perhaps you bought a used caliper. anyways back to the uneven brake wear. Make sure you ebrake cable doesn't have tension when released and maybe you need to bleed your calipers of air. just some suggestions. brakes are simple to fix.

[socal_kouki]

I had the same problem as OP I kept buying new calipers.. I replaced the same calipers showing uneven brake wear before seizing and after a bigger cylinder it hasn't happened, correctly bleed them and maybe it'll fix it for good.... :2c:

[UNISA JECS]

1. one of my brake pads is wearing uneven and is wearing out faster than the othe pads. I have tried replacing caliper to no avail.
I noticed that the piston is hitting a metal knob on pad . also, I have the anti noise device on the two pads on the wheel that is giving me the problem and not on the opposite wheel.

2. what should i use for anti rattle anti noise? is it sufficient just to use that stuff in the bottle and not use the metal piece. thanks.

http://i36.photobucket.com/albums/e25/vancouverbc_2008/jkkk003.jpg
http://i36.photobucket.com/albums/e25/vancouverbc_2008/jkkk004.jpg

You are not seating caliper piston correctly, that cylindrical notch whatever you wanna call it, has to seat in the recessed area of the piston.

This requires you to install the pads like normal, engage the brakes and ebrake a couple of times, now remove the calipers and check to make sure the notch is still sitting in teh recessed portion of teh piston, if not use a suitable tool to turn the piston so that it is, put back together and your done.

I see this shit all the time when I do rear brakes on B13 Sentra SE-R and S13/S14 240SX.

****You could grind off the notch flush and it will elimintae the problem also, but why not just do it right....

[projectRDM]

I had the same problem as OP I kept buying new calipers.. I replaced the same calipers showing uneven brake wear before seizing and after a bigger cylinder it hasn't happened, correctly bleed them and maybe it'll fix it for good.... :2c:

A larger master cylinder did not solve your problem. The bigger cylinder could possibly increase fluid pressure, but to suggest that it would be enough to 'free' a stuck caliper is asinine.

And yes, S chassis rear calipers are prone to seizing, just as any old part on any car would be. The fact that's it's mechanically actuated as well as hydraulic puts extra strain on the caliper too.

[surreybc]

You are not seating caliper piston correctly, that cylindrical notch whatever you wanna call it, has to seat in the recessed area of the piston.

This requires you to install the pads like normal, engage the brakes and ebrake a couple of times, now remove the calipers and check to make sure the notch is still sitting in teh recessed portion of teh piston, if not use a suitable tool to turn the piston so that it is, put back together and your done.

I see this shit all the time when I do rear brakes on B13 Sentra SE-R and S13/S14 240SX.

****You could grind off the notch flush and it will elimintae the problem also, but why not just do it right....

Thanks for the help, guys:) I have already put new calipers and rotors on the rear in an attempt to fix this problem. There is uneven wear but also the outside pad is wearing out twice as fast as the inner and is wearing out faster than all the pads on front and rear. It's always the driver side rear. My best guess is that the inner liner of rubber brake hose is collapsing . Might be more than one of the issues people of identified.

There is slack in the ebrake. I double check for air and sticking caliper. Thanks again for your participation.

[undesiredshoe]

I had the same problem as OP I kept buying new calipers.. I replaced the same calipers showing uneven brake wear before seizing and after a bigger cylinder it hasn't happened, correctly bleed them and maybe it'll fix it for good.... :2c:

Thats like saying, "Oh my car wouldnt start so installed my Nardi steering wheel and now my car starts fine."

[UNISA JECS]

You see the shinny mark where you wrote "see this is wear the pistons hits"....that is your first clue that your not aligning the piston correctly, this is what sucks about the rear brakes and seems luck wasn;t on yoru side. The notch thingy shoudl be untouched.

[SilviaSR20DET]

Well i had uneven wear on the rear pads because my toe was waaay off. The inside of the pad seemed to wear worst then the outside pad which i can conclude was my toe that caused excessive wear. Another reason would be that the caliper could of been frozen or seized which was stated above^^^

[UNISA JECS]

Toe, camber, caster or anything related to suspension has nothing to do with brake pad wear EVER.

[SoguRacing]

Well i had uneven wear on the rear pads because my toe was waaay off. The inside of the pad seemed to wear worst then the outside pad which i can conclude was my toe that caused excessive wear. Another reason would be that the caliper could of been frozen or seized which was stated above^^^


lol! making such a statement..how ignorant..

[cdlong]

when you replaced the caliper did you check the slide pins and slide pin boots? if the boots aren't sealed, it will allow water to get in and rust the pins, freezing them and causing exactly the wear you've got. the caliper can over come the increased friction, but when it is supposed to back off, the outer pad continues to ride on the rotor, wearing it out faster.

to check the pins, take the caliper and bracket off. the pins should be clean and smooth and greased with a heavy high temp grease. to check the boots, push the pin all the way in to collapse the boot, then pull it out to full extension. the boot should be sealed well enough to keep a vaccum for at least a few seconds. if it doesn't, either the boot is torn, or the sealing surface isn't clean.

[surreybc]

when you replaced the caliper did you check the slide pins and slide pin boots? if the boots aren't sealed, it will allow water to get in and rust the pins, freezing them and causing exactly the wear you've got. the caliper can over come the increased friction, but when it is supposed to back off, the outer pad continues to ride on the rotor, wearing it out faster.

to check the pins, take the caliper and bracket off. the pins should be clean and smooth and greased with a heavy high temp grease. to check the boots, push the pin all the way in to collapse the boot, then pull it out to full extension. the boot should be sealed well enough to keep a vaccum for at least a few seconds. if it doesn't, either the boot is torn, or the sealing surface isn't clean.

Yikes, I dont think I ever checked the pins for some reason. I think you might get the prize.

[projectRDM]

Yikes, I dont think I ever checked the pins for some reason. I think you might get the prize.

Post #4. I said that already.

[socal_kouki]

A larger master cylinder did not solve your problem. The bigger cylinder could possibly increase fluid pressure, but to suggest that it would be enough to 'free' a stuck caliper is asinine.

And yes, S chassis rear calipers are prone to seizing, just as any old part on any car would be. The fact that's it's mechanically actuated as well as hydraulic puts extra strain on the caliper too.

I understand your reasoning but the reasoning behind my prevention is undeniable. I may be wrong but oh well... the op is happy and so am I.

Thats like saying, "Oh my car wouldnt start so installed my Nardi steering wheel and now my car starts fine."

Your comparison is to a cosmetic upgrade in contrast to a bmc that would increase stopping performance, go back to square one. Don't answer to this post either.

[ex_rabbit]

my pop's Maxima was doing the same thing.. whats up with that, Nissan? :-( lolz

[surreybc]

the pins seem to slide fine. the rubber boots compress down to about 17 mm long.

this is what the piston head looks like after driving car for about 100 kms with new pads. The entire head was rusty when i was replacing pads.
http://i36.photobucket.com/albums/e25/vancouverbc_2008/brakes006.jpg

the notch seems to have paint rubbed off it.
http://i36.photobucket.com/albums/e25/vancouverbc_2008/brakes008.jpg

if the piston wants to turn, you would think it would turn until the notch falls into one of the slots in the head of piston?

[cdlong]

Post #4. I said that already.

yes, but my answer was longer and therefore better.

[UNISA JECS]

You need to re-read my post thats all imma say.

[projectRDM]

yes, but my answer was longer and therefore better.

True. Ass.

OP- that caliper looks like it came off a sunken ship. If that's new I'd be questioning your judgment of what 'new' means.

[surreybc]

You need to re-read my post thats all imma say.


Yeah, I'm almost certain the unevenness is caused by the piston hitting the knob. It's just odd that it only happens on that one wheel and that the pad is so warn compared to the other pads.

The pins seem to be almost a milimeter different in height so I will take them out and check that out as well. I measured because one boot fold was less folded. I appreciate your help.

[cdlong]

well, the slots in the piston certainly aren't lined up. they should be at 3, 6, 9, and 12, not 2, 5, 8, and 11. fix that first. i'm not sure that could cause your wear problem, but if the pad is making the caliper sit crooked, it may bind the pins.

[surreybc]

Does anyone know why the pins are different. One of the pins has an interior boot.

http://i36.photobucket.com/albums/e25/vancouverbc_2008/getimage.jpg

[racepar1]

HOLY CRAP this thread is full of uber fucking fail! A bigger master is the supposed solution!!!??? The toe is off is another possibility!!!??? I mean, SERIOUSLY!!!??? Where the fucking hell did you fucktards get those ideas from? Look at the pic of the caliper, it looks like it has been stored in saltwater for like 10 yrs! There's your problem. The supposed "new" caliper has highly doubtfully been actually new for years. Uneven wear like that is generally caused by stuck caliper slider pins. Those pins should be lubed with EVERY brake job EVERY time. The other place that could be sticking to cause wear like that is on the shims on the caliper bracket that the pad actually slides in. Those should also be lubricated with EVERY brake job. If those shims are damaged it can also cause one side of the pad to stick. Where the hell do you people come up with this bullshit? This is a simple, common problem with a simple, common answer.

EDIT: Oh, and in ALL the s-chasis rear brake jobs that I have done (which is a shit ton) I have never had to manually align the notch in the piston with the alignment dowel in the pad. Pump the brakes and pull the e-brake a couple times after it is all back together and it should line itself up, as long as your calipers are functioning correctly and you aren't an un-lucky motherfucker that is.

[projectRDM]

HOLY CRAP this thread is full of uber fucking fail! A bigger master is the supposed solution!!!??? The toe is off is another possibility!!!??? I mean, SERIOUSLY!!!??? Where the fucking hell did you fucktards get those ideas from? Look at the pic of the caliper, it looks like it has been stored in saltwater for like 10 yrs! There's your problem. The supposed "new" caliper has highly doubtfully been actually new for years. Uneven wear like that is generally caused by stuck caliper slider pins. Those pins should be lubed with EVERY brake job EVERY time. The other place that could be sticking to cause wear like that is on the shims on the caliper bracket that the pad actually slides in. Those should also be lubricated with EVERY brake job. If those shims are damaged it can also cause one side of the pad to stick. Where the hell do you people come up with this bullshit? This is a simple, common problem with a simple, common answer.

EDIT: Oh, and in ALL the s-chasis rear brake jobs that I have done (which is a shit ton) I have never had to manually align the noych in the piston with the alignment dowel in the pad. Pump the brakes and pull the e-brake a couple times after it is all back together and it should line itself up, as long as your calipers are functioning correctly and you aren't an un-lucky motherfucker that is.

You must have forgotten where you were. This is a 240SX forum, remember?

[racepar1]

You must have forgotten where you were. This is a 240SX forum, remember?

I just have problems accepting how retarded 90% of the population is. This thread is a whole new level of retardedness though.

[surreybc]

HOLY CRAP this thread is full of uber fucking fail! A bigger master is the supposed solution!!!??? The toe is off is another possibility!!!??? I mean, SERIOUSLY!!!??? Where the fucking hell did you fucktards get those ideas from? Look at the pic of the caliper, it looks like it has been stored in saltwater for like 10 yrs! There's your problem. The supposed "new" caliper has highly doubtfully been actually new for years. Uneven wear like that is generally caused by stuck caliper slider pins. Those pins should be lubed with EVERY brake job EVERY time. The other place that could be sticking to cause wear like that is on the shims on the caliper bracket that the pad actually slides in. Those should also be lubricated with EVERY brake job. If those shims are damaged it can also cause one side of the pad to stick. Where the hell do you people come up with this bullshit? This is a simple, common problem with a simple, common answer.

EDIT: Oh, and in ALL the s-chasis rear brake jobs that I have done (which is a shit ton) I have never had to manually align the notch in the piston with the alignment dowel in the pad. Pump the brakes and pull the e-brake a couple times after it is all back together and it should line itself up, as long as your calipers are functioning correctly and you aren't an un-lucky motherfucker that is.

The caliper has around 15,ooo miles on it. I don't know why it is so rusted now. The point is that this is the second caliiper and the problem still persists. I do tend to agree with you that you shouldnt have to align the notch because I have never had to on the opposite wheel. Lets try to keep the discussion friendly.

[xdumbxguyx]

this happened to my dads car as well on a 98 accord. those pins above where the caliper is bolted on to rusted out on one side. i had to pound the shit out of it to remove it. i cleaned it up used some sand paper and regreased it now its fine again

[cdlong]

being 0 for 2 is no big suprise, the rear calipers on the 240 suck. try a fresh rebuilt one. and clean up the pins.

[singlecamslam]

its common for any old car. When i back out in reverse my car makes a noise like a dying giraffe due to the seized caliper. Eventually i'm gonna replace it, and thats what you should do.

[racepar1]

The caliper has around 15,ooo miles on it. I don't know why it is so rusted now. The point is that this is the second caliiper and the problem still persists. I do tend to agree with you that you shouldnt have to align the notch because I have never had to on the opposite wheel. Lets try to keep the discussion friendly.

Sorry, I'm not nice or friendly on the intraweb. I am however honest and knowledgeable about almost everything that I decide to comment on. Me and russ (projectRDM) tend to :rl: noobs/morons. Please excuse us but this shit gets old fast. Back on topic, there is something wrong with the caliper. Replace it with a known good one and lube the pins/shims like I said.

[surreybc]

My pins are not rusted and move fine but basically have no lubrication on the bottom half. The pins on opposite wheel have lots of lubrication. Looks like the caliper boot is coming out too per the picture. I guess the dry pins destroyed two calipers. sticking pins would explain the accelerated wear and the uneven wear. Thanks for the help.


http://i36.photobucket.com/albums/e25/vancouverbc_2008/gghh002.jpg
http://i36.photobucket.com/albums/e25/vancouverbc_2008/gghh001.jpg

[surreybc]

Definitely was the pins. Only drove a few miles and the rust from piston is now transferring to the pad. My previous 100 mile drive left no marks on the pad.

http://i36.photobucket.com/albums/e25/vancouverbc_2008/ggggg001.jpg

so, grease those pins even if they move freely.