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Discussion Starter · #1 ·
Hi guys, I recently bought a set of used K1 front calipers to put on my D model. I disassembled, cleaned and rebuilt the calipers using an All-Balls seal kit. The pistons went in reasonably easily, using only thumb pressure and were not cocked to the side. I installed and bled both calipers until there were NO bubbles visible in the clear line which I attached to the bleeder screw. I went through about a half pint of fluid.
I was never able to get a firm lever feel, nor effect any acceptable braking ability. The lever went to the bar.
I repeated the bleeding process several times over two days with the same results. I tried tapping the calipers with a hard plastic mallet, I even tried tying the lever to the bar overnight with the same result.
There are no leaks at the seals, banjo fittings or bleeder screws, nor were there any air bubbles when re-bleeding.

After a couple of days of this, I reinstalled the original calipers and re-bled them in about 15 minutes without issue. They work as before.

It almost feels like the GSX-R caliper seals are not letting the pistons move out far enough with each stroke of the lever, and then retracting the pistons. I observed a small amount of pad movement, out and back which indicates that the square seals are doing their job.
From what I have read, everyone else that has done this conversion has used the original master cyl. and it has worked well.

Is there something I'm missing? Any suggestions? T.I.A. guys. :confused:
 

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‘83 Gpz750 Resto-mod, ‘78 Kz1000 Resto-mod, ‘18 Z900RS
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I don’t know about others on here but I’ve heard that AllBalls fork seals leak and don’t match OEM quality. I’m betting the same may apply to their caliper seals too. Maybe they don’t leak but something is wrong. If others have used the Gsxr calipers with the Zx11 M/C and the Zx11 calipers work with the Zx11 M/C then my thinking is that the seals are the only main difference between yours and others.

Just a thought…

Later, Doug
 

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AllBalls is junk IMO. I have worked on a few bikes that have used their stuff (bearings, seals, carb kits…) and have not seen any good with their quality.
Especially with brakes, buy quality and never worry about them again. I use Powerhouse seal kits and pistons on all brake jobs that I do now. Rebuilt both my P and N using these kits and 100% recommend them. You can find them on selling on eBay as well. Decent price and top notch quality.
 

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I'm on many ZX11/ZZR1100 facebook groups, and the All Balls brand seems well reputed. I don't remember the seals brand I've purchased, but after the change I could say that the brakes never worked better, with minimal lever travel (original master cylinder) the power is awesome. I helped to my mechanic friend to disassemble the calipers, but he did the bleading.
 

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Discussion Starter · #6 ·
Hmm, well now it makes me think twice about the All-Balls seals, although I'd like to hear a couple more opinions if anyone has experience with them.
I suppose it really has to come down to the seals. There's not much else in there, and I've done many caliper seals- both automotive and motorcycle and bleeding them isn't that hard.
I'll check out Powerhouse and see what they have...
 

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With dry calipers (no fluid inside), folks have taken the brake line banjo bolt and bleeder valve off, and poured brake fluid into the caliper. If you push a piston in, fluid should be forced out. I would also check your caliper banjo bolt and ensure fluid is getting through it. I also use a vacuum bleeder when installing new brakes or lines. If your OEM brakes were getting pressure before, then your master cylinder should be good (I use the OEM with GSXR brakes).

I used OEM Suzuki seals on my calipers, and I tend to ensure there is brake fluid on them prior to installation (just like an oil filet gasket). This will reduce initial friction and prevent ring-roll-over during movement.
 

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Discussion Starter · #10 ·
Hi guys, I haven't had time to do anything with the calipers yet. I did buy a genuine Suzuki parts kit with new pistons and seals, but have not had time to rebuild the calipers.

Jetfixer- I also always coat the seals and pistons liberally with brake fluid before assembly, so that I don't tear the new seals. I've never had good luck with vacuum bleeders, so I just use the master cylinder and lever. My original brakes are still working fine after I re-installed and bled them in the usual manner.

I'm not sure when I'll have time to dig back in to them, but when I do I will post the results.
 

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A question about the brakes: is normal that the pads touch the disks ?. I can move the pads with my fingers, they are not locked over the disks, but I can hear them skimming the rotors when I move the bike. I still don't understand how the system works, what cause the pads go back when the lever is released, but after the change of the seals I'm amazed at how powerful the brakes are now.
 

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Discussion Starter · #12 ·
If you look at the cross section of the lower seal, you will see that it is square section instead of round. This causes it to twist slightly when you apply pressure to the piston and the piston moves forward. When you release the pressure, the seal rolls back and pulls the piston away from the disc slightly. Exactly how much depends on the particular seal and caliper design parameters but it isn't much.
As the disc wears the piston advances through the seal bit by bit, after the seal has reached its maximum twist.
 
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