GPZ500 Rear Brake Pads

[upanddown22]

How are the brake pads on the rear brake held on?

I've just had the wheel out to replace the tyre, it's my first time doing it and when I went to put it all back together one of the pads fell out of the caliper and I wasn't quite sure how it goes back in.

Can any one enlighten me?!!

GPZ500 1995

Thanks
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Kawasaki GPZ500S 1995

[stinkwheel]

They are held on by blind luck and wishful thinking.

They sit inside the calliper frame and are held in place because they can't get back out of the frame on account of being trapped between the disc and the calliper.

it is not unheard of for them to be spat out during use once they are worn down a bit. It's happened to me twice.

Slot it back into place, pump the brake a few times to push the brake piston out which ought to trap it between the calliper and the disc.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[upanddown22]

[stinkwheel]

There is an anti-rattle spring in there but it doesn't do anything to hold them in place as such.

If you still have the wheel out, probably best to fit the wheel then slide the calliper over the disc rather than trying to slot it in with the calliper attached. Pushing the piston back in a little will make this easier.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[upanddown22]

Yep wheel is now in so I was thinking I'll take the caliper off the bracket and try and slot it all back in.

Thanks Stinkwheel
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Kawasaki GPZ500S 1995

[upanddown22]

Well I managed to get them back in last night, and I'm glad I had problems as I removed the pads and it turns out one of them only had a wafer thin amount of material left! Strangely the other pad looked had absolutely loads on, hence why I thought they were ok when I checked them.

Is this normal?
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Kawasaki GPZ500S 1995

[DrDonnyBrago]

[upanddown22]

[stinkwheel]

Everything about those single pot kawasaki rear callipers is an abortion, always was.

It'll be corrosion inside the tube one of the slider pins runs through. If you look at it you'll see one of the pins goes into a blind hole, the other one appears to have a rubber cap on the end. This is actually a rubber boot that goes all the way through the calliper with the pin on the inside of it. Water can get in between the boot and the body of the calliper. The alloy corrodes and swells causing the pin to stick.

You need to pull the calliper off the pins and remove that rubber boot. It'll probably be knackered. Scrape all the powdery white corroded alloy out of the tube and fit a new boot (or reuse the old one if you didn't rip it getting it out). Use red high temperature grease on both the inside and outside of the boot when you reassemble it. Latterly, I started putting a bead of clear bathroom silicone round the end where the boot sticks out through the calliper to stop water getting in.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[upanddown22]

Gents thanks for the help so far! I'm so glad I asked this question as I took a look at my front caliper and it turned out that the little rubber boot that goes through the caliper wasn't all the way through and was stopping the caliper moving.

I took the slider bit off the caliper and greased it all up and the lever felt much much better, however when I spin the wheel round a bit it still stops fairly quickly, maybe after half a spin. Is this normal? you can definitely hear them rubbing.

Rear pads will be going on tonight.
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Kawasaki GPZ500S 1995

[DrDonnyBrago]

[upanddown22]

Yep I cleared out both the sliding pins, but I think the main problem was the rubber dust seal not being in the caliper completely. The pistons were a bit dirty, I should have cleaned them up more to be honest.

Think a rebuild sounds like a plan, the dust seals looked like they'd had better days. I think I'll get hold of everything to do it and do it in the next couple of weeks.

It'll be nice to feel the brakes are in tip top condition!
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Kawasaki GPZ500S 1995

[upanddown22]

Put the rear pads in last night, they went in fine apart from requiring a bit of metal being taken off from the backing plate on the pad. Guess thats what happens when you buy cheapo ones.

Strangely the sliding pins we in good condition and still had a liberal covering of grease, so not sure why the caliper would have been sticking?!
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Kawasaki GPZ500S 1995

[DrDonnyBrago]

A sticky piston that doesn't retract properly will also cause the brakes to bind. Usual cause is crud or corrosion behind the seals causing them to grab hold of the piston too tight, stops the piston retracting hence the pads are pushed into contact with the disc.

[upanddown22]