GPX 600 Caliper help

[R1stu]

Ok Ive spent the weekend sorting bike, I had to replace fork oil, put in new bulb, wire in a 12v socket and fit a scotoiler.

All of this went well, but now I cant sort the front caliper. upon trying to get the right one open enough to fit over the disc, the pad popped out.

I cant get the pad back in and cant see a way of taking the caliper apart to replace the pads. also trying to get the pistons all the way down is proving to be an issue.

Any one with one of these bikes now how to sort the calipers?

Cheers
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Carbon closet tart! https://www.bikepics.com/members/r6stuk/02r6/
Stolen bike. 2000 R1: https://www.bikepics.com/members/r6stuk/00r1/
Current bike 1991 Honda ST1100 Pan European, 1986 Honda cb350sg (Finished)

[Fizzer Thou]

I worked on my brothers Kwack GTR1000 a few years ago and he had a problem with one of the severely worn pads falling out of the caliper mounting.I seem to remember that the pad locates onto a pin that the pad slides on.When the pad is new it locates much better onto said pin but all too easily can become easily misplaced when worn.

A photo of your caliper would help to sort your problem.Is it a twin piston floating caliper?
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Just talk bikes.What else is there?

Always have a 'Plan B'

[R1stu]

this is what it looks like, and B is the one thats fallen out.

https://img.auctiva.com/imgdata/1/4/2/7/1/5/7/webimg/601774745_tp.jpg

https://www.motorcycle-road-and-race.co.uk/images/FA129.jpg
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Carbon closet tart! https://www.bikepics.com/members/r6stuk/02r6/
Stolen bike. 2000 R1: https://www.bikepics.com/members/r6stuk/00r1/
Current bike 1991 Honda ST1100 Pan European, 1986 Honda cb350sg (Finished)

[Islander]

That's the same caliper as my OH's Zephyr. The lugs on the smaller pad locate behind the mounting plate lugs with the clip on springs. It's probable that the mounting plate isn't sliding freely and isn't moving forward enough to hold the pad in place. If this is the case then the hole that the longer of the two boots fits into will have corrosion build up inside it stopping the caliper moving freely on the pins. Remove the boot, and clean it out thoroughly before reassembling. I've just rebuilt three of these.

That caliper is in dire need of a good servicing BTW.

[Fizzer Thou]

That is the same pad that fell out of my brother's caliper.You can see how it locates onto a shoulder of the caliper bracket.

From what I remember the mounting bracket needs to be withdrawn from the caliper body on the floating pins.Push the fixed pad against the pistons and that should give you the clearance to disengage it.Once the two are seperated then slide the fixed pad off the fore and aft mounting pins.

When my brother rang me and said that the braking on his GTR was really not working very well and could I have a look for him,one quick look at the caliper told me that the piston inserts rubbing against the disc does not make for very good friction
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[Islander]

For the avoidance of doubt see the attached pics:

[R1stu]

Thats not my caliper, I googled it I relise where the pad clips into but with the piston up they don't sit under. I will get some pics later when home if go home and stick up

How do I get the boots and pins out? I pulled the rubber and it snapped off and there is a rod behind there but cant see a way of removing it.
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Carbon closet tart! https://www.bikepics.com/members/r6stuk/02r6/
Stolen bike. 2000 R1: https://www.bikepics.com/members/r6stuk/00r1/
Current bike 1991 Honda ST1100 Pan European, 1986 Honda cb350sg (Finished)

[Fizzer Thou]

If you have a look at this fiche (I know that it is not your model of Kwack but I could not find the relevant one-but the caliper/bracket is the same)

https://www.cmsnl.com/kawasaki-1989-b2-zx1000_model12743/partslist/G5.html#results

you will see that the caliper mounting bracket locates into the caliper body.So you need to push the fixed pad against the caliper pistons so that you can part the bracket from the caliper.
____________________
Just talk bikes.What else is there?

Always have a 'Plan B'

[Islander]

It won't sit behind the lugs because the caliper isn't free to move on the mounting plate pins. The mounting plate just pulls out of the caliper body - it'll be jammed by the corrosion and may need some gentle - and I do mean gentle - persuasion to come out.

Wemoto sell the rubber boots for these. Replace them both and lubricate with grease suitable for rubber. Then check the other calipers - I'll bet they have the same problem.

[R1stu]

Hopefull can get pad back in tonight or tomorrow, otherwise slow ride into work wed. Lucky I have a bike garage below my office.
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Carbon closet tart! https://www.bikepics.com/members/r6stuk/02r6/
Stolen bike. 2000 R1: https://www.bikepics.com/members/r6stuk/00r1/
Current bike 1991 Honda ST1100 Pan European, 1986 Honda cb350sg (Finished)

[Casper]

[R1stu]

Yep in place. Will take pics when get home. may get my G Clamps and use them to get both pistons flush.
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Carbon closet tart! https://www.bikepics.com/members/r6stuk/02r6/
Stolen bike. 2000 R1: https://www.bikepics.com/members/r6stuk/00r1/
Current bike 1991 Honda ST1100 Pan European, 1986 Honda cb350sg (Finished)

[Casper]

When I renew pads I push the pistons out first almost to the point where they fall out. Give a wee wipe and lube and push back with a plumbers wrench

https://us.123rf.com/400wm/400/400/ajt/ajt0711/ajt071100035/2142971-adjustable-pipe-wrench-isolated-on-white-background.jpg

[R1stu]

here some pics my caliper.

https://i145.photobucket.com/albums/r232/stuartkeith/100_4048_zpsc4c4eb7b.jpg

https://i145.photobucket.com/albums/r232/stuartkeith/100_4050_zps3327cc21.jpg

https://i145.photobucket.com/albums/r232/stuartkeith/100_4051_zpsaa9948de.jpg

https://i145.photobucket.com/albums/r232/stuartkeith/100_4052_zpsf5227d66.jpg

https://i145.photobucket.com/albums/r232/stuartkeith/100_4053_zps917ab8a8.jpg
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Carbon closet tart! https://www.bikepics.com/members/r6stuk/02r6/
Stolen bike. 2000 R1: https://www.bikepics.com/members/r6stuk/00r1/
Current bike 1991 Honda ST1100 Pan European, 1986 Honda cb350sg (Finished)

[Casper]

The pistons are out to far so you cant hook the other pad in. Pump them out another cm and clean them a bit. Give a little lube and push back in then hook the pad back in. You need to push down first as it sits on a spring. Well I say spring its that silver bit of metal you see at the bottom.

[Casper]

BTW. Pull out the hanger and lube up under the rubbers as they dry out quite quick. If sticking they wont help trying to get the pads in.

[R1stu]

[Islander]

I told you the reason the mounting bracket won't move - there's corrosion build up in the side that had the long rubber boot through it. You need to gently tap the bracket down as far as it will go, remove the other pad, then tap the bracket up until it comes out. Remove the remains of the boot and carefully use a round file or similar to remove the corrosion - don't remove any metal!.

Then install a new boot, lube it with a suitable rubber friendly grease and put it back together.

To be honest, I'd be looking at removing those pistons and replacing the main and dust seals. If the pistons are badly pitted then you may have to replace them. Wemoto do the rebuild kits and stainless pistons if they're needed - unfortunately they ain't cheap.

You'll need to check your other calipers because I'll guarantee they're in the same state.

[Casper]

[R1stu]

ill bodge it together for this week. am off all next week so will do a full rebuild then. brakes have been working well since had the bike, only took the forks off to replace oil as they were bottoming out.
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Carbon closet tart! https://www.bikepics.com/members/r6stuk/02r6/
Stolen bike. 2000 R1: https://www.bikepics.com/members/r6stuk/00r1/
Current bike 1991 Honda ST1100 Pan European, 1986 Honda cb350sg (Finished)

[R1stu]

All sorted now. Dremeled with a light brush and then sprayed with lots of brake cleaner and a toothbrush. Wiped some fluid around and then un done the banjo and used a g-clamp to compress the pistons.

The bracket came of nice and easy, no corrosion, but i wiped it down and greased, Topped the fluid and bleed, and the brakes are far better then before, and the added advantage of the forks no longer bottom out!


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Carbon closet tart! https://www.bikepics.com/members/r6stuk/02r6/
Stolen bike. 2000 R1: https://www.bikepics.com/members/r6stuk/00r1/
Current bike 1991 Honda ST1100 Pan European, 1986 Honda cb350sg (Finished)

[mentalboy]

You'd best hope that by pushing those scabby pistons back into the caliper you haven't wrecked the oil seals! (Even if you managed to dremel them all the way round the pits may give grief to your seals)
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Make mine a Corona.

[R1stu]

[Casper]

[mentalboy]

I'm all for making do with what you've got ( take a gander at the thread on my zed's journey back to road life to see some of my bodges!)
BUT I know the consequences that can result from my bodges whilst some people out there seem genuinely surprised when they bodge something and it backfires on them - jivebunny springs to mind - I'm not saying the OP doesn't know but sometimes we do these things without further thought and the braking system is one of those areas that I personally like to function at it's best.
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Make mine a Corona.