Replacing Rear Brake Pads

[joshr08]

our bike is known for brake squeeking

[John0]

when i hear people's brakes squeaking on their cars, i kinda judge them in my head that they're lazy and just don't care about their car.  I can't but think that other people who hear me are doing the same thing about me.  I dont like to be perceived the wrong way, even by people who i'll never see again.  but i suppose i can live with it.  I was just hoping that there was some sort of quick fix.

[vorBH]

Minor sqweeks are okay my neighbor mechanic said....I have a practically new 07 cbr125.....the brakes still touched a bit and it was new....but when it prevents rotation of the wheel etc that's a problem.


Anyways, I checked my rear rotor...the area where the pads press against it is eaten away maybe 1mm?? There's no padding left on the pads...is the piston seized? I pushed apart the pads but it made it worse because it pushed from the top of the pads, causing the bottom of the pads to invert inwards on the rotor...BUT the purpose was to see if the piston would move...and its moving
I realigned the wheel, its much better now...BUT the rotor is ruined and I need to have it machined

Heres the concern...I'm going to get the new brake pads...so I'll take out the worn ones and try to push the piston back to put in the new pads....when it's all setup again though and I pump the brake again to push the pads in closer to the rotor....will the pads get killed again because of the condition of the rotor both through use and non-use?

Really need some help, thanks guys

[sledge]

There is a simple test that will determine if you have sticking piston. Place a thin feeler gauge between each pad and the disc. Then stamp hard on the brake pedal and try and pull the feeler out, if to does come out the piston is sticking, if it doesnt the piston is free.
As for your disc.....Suzuki quote a service limit thickness of 5.5mm, not much when a new one is about 6.1mm and if you have lost 1mm off each side you are well outside tolerance even before getting it skimmed.

[vorBH]

Oh ok...well it's not 1mm I've lost, just an estimate...I'd say .4 of a mm I don't really know.........all I knwo is that I am probably going to be machining the rotors (both sides) to get it back to a normal smooth surface

[fred]

Oh ok...well it's not 1mm I've lost, just an estimate...I'd say .4 of a mm I don't really know.........all I knwo is that I am probably going to be machining the rotors (both sides) to get it back to a normal smooth surface

Good luck with that. From what I've seen though, as soon as the rotor isn't smooth anymore, it is worn too thin to be machined back in to place. Even if you could barely squeak by and machine it just inside of tolerance, you'd just have to replace it anyways in a short time... Sounds like time to go rotor shopping to me. Changing the rotor isn't that bad, the hardest part is getting the wheel aligned and the chain tension right when you're done, but if you do the chain slack adjustments when you should, you'll already be able to do this...

[vorBH]

Ok cool, thanks for the info...I guess I'll measure the rotor thickness (5.5mm minimum), and see where it's at.

In the meantime...where can the rotor for cheap price?
Do I have to get the same one? Or will something else thats cheaper fit? (a 4 bolt pattern)

[joshr08]

heres prolly the cheapest youll find unless you go with someone elses gs take off
http://gstwins.com/gsboard/index.php?topic=46773.0

[vorBH]

Thanks! I sent him a PM

[joshr08]

ok thats prolly the best deal youll find on that rotor.

[allaussiegrown]

My rear brakes squeak quite a bit anytime i step them.  is this something I should be worried about or should I just let it go?  would changing the pads help any?  could it be possible that at one point the pads were down with the wheel being a lil crooked and now with it straight its squeaking?  I've felt the rotor, i havent felt any grooves.

Do you still have braking response? (dose it take alot of effort for the brake to stop the bike)
If your not getting much stopping power than it think it is time for a change. I just changed my back one after they were squeaking when i applied them at low speeds. i had next to no pad left on them and couldn't stop with the back brake very well at all.

[vorBH]

So as described before....my 2007 gs500F....rear rotor is all rubbed down by the pads, no pads left...right down to the metal plate of the brake pads....is the caliper seized?

What should I do to fix it? Open the caliper....lube everything in there (piston)?....and then go ahead and install the new pads?

Which brake/caliper lube should I use?


ALSO, may it be the case that the rotor is not straight, ie. running on an angle....but if the chain tension indicators on both sides are equal then the wheel must be straight along with the rotor....


When I spin the wheel...at half the spin there is no resistance.....the other half the rotor resists and rubs the pads...

[fred]

So as described before....my 2007 gs500F....rear rotor is all rubbed down by the pads, no pads left...right down to the metal plate of the brake pads....is the caliper seized?

What should I do to fix it? Open the caliper....lube everything in there (piston)?....and then go ahead and install the new pads?

Which brake/caliper lube should I use?


ALSO, may it be the case that the rotor is not straight, ie. running on an angle....but if the chain tension indicators on both sides are equal then the wheel must be straight along with the rotor....


When I spin the wheel...at half the spin there is no resistance.....the other half the rotor resists and rubs the pads...

Hmm, that sounds like all kinds of not good. If your rotor is rubbing things while the wheel is straight, I'd first suspect that it is warped. If you have a seized caliper, it is not at all difficult to imagine that riding around with the brakes rubbing all the time warped the heck out of the rotor by overheating it. If the rotor is mounted wrong, I guess it could be wobbly without being warped, but if it has been on there long enough to eat through all of a brake pad, it is probably toast no matter what the root cause of the problem was. If I were you, I'd probably replace the rotor, get new pads and rebuild the caliper. When you install the new rotor, make sure the mating surface on the wheel is very clean and flat and doesn't have anything there that would cause your rotor to not seat correctly.

I just rebuilt my front caliper on Tuesday and I can tell you with confidence that it isn't hard. You will probably need a source of compressed air to remove the pistons (heed the warnings in the service manual, they really do shoot out quite violently!) but no other special tools are needed. It did take me a few hours of scraping and an entire can of brake cleaner to get all of the corrosion and dirt out of the seal grooves that caused my seals to go bad in the first place, but that was more tedious than it was hard. Once you've cleaned the cylinders and pistons and convinced yourself they're not worn beyond spec, just stick new seals in and reinstall the pistons. For lubrication, you just use clean brake fluid. Also, if you don't have stainless brake lines and haven't changed your brake lines in the last couple of years, now would be a really good time...

[bill14224]

Fred, I'm amazed how many folks are having such problems with almost new bikes.

I would strongly guess the root cause here is he has been adjusting his chain tension incorrectly, leaving his rear axle crooked, causing his back brakes to wear-out prematurely and f$$king-up his rotor in the process.

People, when you adjust your chain, leave a little slack in it, and MAKE SURE THE AXLE IS ALIGNED EVENLY ON BOTH SIDES.

[fred]

Yeah, it could be a poorly aligned wheel, but if he's confident the alignment is right on, the next likely candidate is a stuck caliper. A stuck caliper is probably a pretty easy problem to end up with if the bike sits for a very long time and the fluid and lines aren't changed often enough... It is weird that people have problems with new bikes though. My '94 with about 88,000 miles on it doesn't have such problems. I wonder what's going on. I guess it could be any one of a few things: quality could be decreasing, all the bikes that were built wrong in the 90's have long since died horrible deaths just like these new ones, or perhaps this kind of thing happens all the time to GSs that sit, but only people with newer bikes complain while the guys with older bikes just chock it up to old age and fix it. I don't know...

[vorBH]

I would strongly guess the root cause here is he has been adjusting his chain tension incorrectly, leaving his rear axle crooked, causing his back brakes to wear-out prematurely and f$$king-up his rotor in the process.

This is wrong...I bought the bike in November..put it away until March (now)....(its an 07)..when I bought it the chain had too much slack in it...in early March I tightened the chain to have ~1.2 inches slack....and both ticks on the chain adjuster to align the wheel are even.

SO, the previous owner f%&ked it up, I don't WHAT the f**k she did and it kinda pisses me off....anyways.....I'm going to take it to a mechanic, have the rotor machined, and open the caliper and re-grease it etc...and then re-install everything with the new brake pads.

I opened the rear brake resevoir and the fluid is clear and clean.


What do you mean by "For lubrication, you just use clean brake fluid"...you mean actual DOT brake fluid to lube all the parts in the caliper?

[fred]

Yes, you use DOT brake fluid to lubricate the inside of the caliper. You don't want anything in there that isn't brake fluid. Also, you can't machine motorcycle rotors. They aren't thick enough. The difference between a new rotor and a worn rotor is .7mm max! By the time you've got a problem, you've already worn the rotor beyond limits. Time to just get a new rotor.

[vorBH]

Hmm Out of curiousity...what happens if I don't get a new rotor?
So I would just open the caliper, get it unstuck, replace the pads, make sure the wheel is definitely straight........if the rotor is below recommended thickness, will it warp, or? whats the problem with it being under a certain thickness?....I'm thinking to just leave it since I rarely use the rear brake....

Will the current rough surface of the rotor (currently it is very rough on the inside of the rotor) ruin the new brake pads??

[sledge]

....I'm thinking to just leave it since I rarely use the rear brake...

You have been given answers to this issue by several people but are ignoring them and instead looking for justification for not doing what is being recommended  With this in mind I am not too surprised to read the above comment...........If you dont use the rear brake why not take the whole thing off, junk it and solve the problem that way???!

Your pads are worn, there is no friction material left...replace them.

Your disc is worn and is below what Suzuki says is a safe limit, it could warp even shatter in use and the damaged surface will rapidly wear out new pads. If you carry on using it and you are putting yourself and more importantly OTHERS at unnecessary risk....replace it.

Something could be out of alignment or your caliper could be seized or the pads could be hung up on the pins, no-one knows for certain because no-one has actually seen it and from your description its impossible to say with certainty. Your pads could simply have had a hard life from new and died a natural death. It will become obvious if something is siezed when an attempt is made to replace them and at the same time alignments and chain tension can be setup and checked.

OR........you can carry on asking the same questions and ignoring the facts/advice until some Numpty comes along and gives you the answer you WANT to hear.

[vorBH]

You Numpty obviously don't understand the simple concept of a Forum...a place to ask questions and discuss things...we're all at different knowledge levels
With your attititude, go take a hike