My bike has been parked for about a week, pending receipt of the Haynes manual I ordered so that I could do a much needed replacement of the rear pads.
I got the new pads a few days ago, got the manual today, and went to town.
Here's the problem:
I got the old pads out after taking out the springs and pins, and they were VERY tight in there.  It took some serious muscle to get them pulled out of the caliper.
Looking at them, there is no pad whatsoever on them...they are pure metal. 
The new pads that I got have a metal backing that is the same dimensions all around as the old ones...but there is pad on them.
So, of course, they are no where CLOSE to fitting into the caliper in place of the old pads.

My question is this:
Since I know I have the right pads (they were specifically listed for a GS500 and the profile is identical), is my caliper adjusted wrong?  It really looks like someone may have tightened things up in there in order to make the bike stop on completely worn out pads (I bought it used about 2 months ago).  If so, how the heck do I adjust it back to where it's supposed to be so that I can install pads that will actually do their job?

Here's a pic.  The one on the left is what I just took out of my bike; the one on the right is the new pad.
That CAN'T be what a brake pad is supposed to look like...can it?  I mean, that thing's had nothing but metal grinding on metal stopping this bike for God knows how long.
But the new one is nowhere close to fitting in the space that held the old one REALLY tight.

Just did mine, were in basically the same shape.   You have to get the pistons pushed back into the bores to be able to fit the new pats in.   It can be a bear, but be careful not to scratch the pistons/bores/housing.   I padded a set of channel locks w/ fuel line around the jaws, and used the old pad to push the pistons back.   You have to push them back evenly all around, and they will slide right back.   If the pistons get cocked or pinched/pressured all one  one side, they won't go back into the bores.

new to bikes but on cars i use a C clamp with the old pad to push it back...sounds easier then going all the way around little by little.

I used some bar stock I had lying around, maybe 1/8th inch thick and about 1 1/2" wide. Probably 4 feet long. I bent it using my bare hands at a 45 degree angle, to clear the seat plastic.

Then I just used it as a lever against the brake rotor, making sure that the bar was pressing somewhere near the center of the piston. It helps if you loosen the bleeder valve, so you're not fighting the hydraulic pressure. What I did there is put a piece of hose on the bleeder valve and gave it a single pump, so maybe 2" worth of brake fluid came out, then left the valve cracked 1/8th inch: Just enough for fluid to come out, but not enough to suck air in.

The rear rotor flexed A LOT, which worried me, but eventually those pistons went back in. Everything's back together and I've ridden 200 miles, no problems. It's funny how much you stress about the project you're doing.... your bike feels broken. Then you go for a ride and in an instant, you no longer care about those goobered up threads, or that overtightened bolt

I wonder if your rotor is any good.  Have you measured it?

Measured?

Sorry for the ignorance.  This is my first bike.

There is a minimum thickness for rotors.  For the rear it is 5.5mm 

Since there is quite a bit of metal missing from the old pads, you can assume there is quite a bit of metal missing from the rotor as well.  If you can get your hands on a micrometer, measure the rotor thickness.  If you can't get a micrometer, take the rotor off and bring it into an auto parts store.  They will have one. 

U may as well bleed the breaks if u haven't in awhile when doing this.. it will make the pad change a lot easier.. my front pad looked like your bare metal one too, lol.

I've had the bike about two months, and from the looks of this project and the oil change I did last night, the previous owner never did ANY maintenance to it.

Quote from: murf425 on October 08, 2008, 07:12:34 PM

Holy shnikey...!

I'd be surprised if the rear rotor is any good after that.

Prying against the rotor or the brake arm is a bad idea. They weren't meant to be pried against, and while everything may look fine, there may be stress cracks. You don't want stress cracks on anytihng, especially a part of the braking system.

Howto do it ? Here:

Remove the pins that hold in the brake pads, place em in a pie tin. You just ate that pie, and it was deeeeeeeliciouse , so you can afford expending a few calories on fixing your fooken brakes, right ? Cool.

Remove the cotter pin (you bess have on there !) on the brake arm that holds the nut snug and the caliper from falling off.

Gently pry the brake line holder away from the swing arm just enough to clear the brake line. GENTLY you behemoths !

Remove the two bolts that hold the brake caliper to the swing arm/axle/doo-hickey.

Gently pull up on the caliper, watch as your old crusty pads fall out, crap all over the place. Yeah !

Put a C clamp where those old crappy pads were, and gently push the piston back into the caliper's bore.

GET YOUR EYES OFF MY BISCUITS ! Them biscuits are for MY eating, not yer eyefulls ! You just had a whole damned pie ! Sheesh !

clean that mess up with a dry paintbrush. no need to spray it with anything. thanks.

put the mess back together, don't leave out the cotter pin in the brake arm assembly.

If you can't work a c- clamp, get yer neighbor's 8 year old and he'll figure it out for ya, but laugh at you every time you leave the house.

torque it all to spec, use some BLUE loctite, and enjoy the ride. take it easy till the pads conform to your FOOKED rear roter's ridges from those FOOKED old crusty pads you let run down past their sell-by date.

done. (assuming you know you should bleed your brake lines, both front and back anytime you do this)

Quote from: ohgood on October 09, 2008, 01:41:03 PMPut a C clamp where those old crappy pads were, and gently push the piston back into the caliper's bore.

I retract the pistons with the old pad in place; I find they're easier to get a grip on.  YMMV.

OMG its the Wiki!!!




http://cgi.stanford.edu/~sanjayd/gs500/Upgrades/BrakePads

To replace the rear brake pads.....I can do it with the rear caliper staying attached as well as the rear wheel..correct?
That is how it's shown in the GS500 Wiki.....http://cgi.stanford.edu/~sanjayd/gs500/Upgrades/BrakePads    (but the rear wheel is off)

I do not want to take off the caliper for sure....the job is simple enough as it is with the caliper in place. I'm waiting for the new brake pads to come in.

2. It's a 2007 and I'm changing the pads on it... ....the problem.....I can see the rotor disc is really worked...the pads were rubbing against it constantly and eventually wore out. Is it possible the piston is stuck? Will I be able to move it back for sure?..to make more room for the new pads...
With the bike on the centerstand and rotate the rear wheel freely...I can hear the contact of pads and disc.....no major warps in the disc though
I'm just going to change the pads, push the caliper back and put the cover back on....should I look out for anything else regarding my problem?

bummmp pls helpp...duno why the brakes were constantly rubbing the disc causing the brake pads to wear outtt...its an 07! takes much longer than that to change brake pads, thr front are more than fine

Quote from: vorBH on March 07, 2009, 10:10:36 AM
To replace the rear brake pads.....I can do it with the rear caliper staying attached as well as the rear wheel..correct?
That is how it's shown in the GS500 Wiki.....http://cgi.stanford.edu/~sanjayd/gs500/Upgrades/BrakePads    (but the rear wheel is off)

I do not want to take off the caliper for sure....the job is simple enough as it is with the caliper in place. I'm waiting for the new brake pads to come in.

2. It's a 2007 and I'm changing the pads on it... ....the problem.....I can see the rotor disc is really worked...the pads were rubbing against it constantly and eventually wore out. Is it possible the piston is stuck? Will I be able to move it back for sure?..to make more room for the new pads...
With the bike on the centerstand and rotate the rear wheel freely...I can hear the contact of pads and disc.....no major warps in the disc though
I'm just going to change the pads, push the caliper back and put the cover back on....should I look out for anything else regarding my problem?

Take your caliper off the bike and have a look. It is really not that hard to take it off and just flip it to the outside of the bike without taking the brake line off... Check to make sure your caliper isn't sticking. Also, if your brakes really are rubbing all the time, check to make sure your rotor is still good. If it rubs all the time, it could overheat and warp, or get grooves in it. If you put new pads on the bike with a grooved rotor, they will get grooves right away and when you finally do replace the rotor, you'll also have to replace the pads again or the grooved ones will squeal like freakin' crazy and drive you insane.

Thanks for your reply! Phew, good, I didn't want to take off the brake line....Ok so if it is sticking, I need to lube the piston at least right?
I found a product at Walmart...a Brake Cleaner, like $4.44 CDN...says it is applicable to all parts of the brakes and caliper etc..can I use this to make a piston smooth?

Also, the rotor is pretty worked up rough from all the rubbing....should I have it machined at the mechanic?...but this requires taking off the rear wheel etc...a headache....but a must do??

There are minor warps in the rotor..you can hear contact.....but it rotates freely....possibly because there is no padding left..I think when I put in the new pads it won't rotate as freely because it'll be contact actual brake pad...any suggestions??

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.