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Discussion Starter #1
I am changing the rear brake pads on my bike and have question. The Clymer manual says to open the master cylinder cap when you push the pistons back. However the caliper has two bleed nipples for each piston so wouldn't it be easier and cleaner just open the nipples when I push them back and relieve the excess fluid that way?
 

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It really depends on how full the reservoir already is.

If pushing back the pistons isn't going to make the fluid to overflow then it isn't a problem, however, the issue is if the pads were worn and the reservoir was topped off at some point then fluid will spill over.

You could do the bleeder route, but usually it isn't recommended. Not much of a chance to have air enter the system, but it can happen doing it that way.

Josh
 

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Air can get in the system if you are not careful. One trick is to attach a short hose to the nipple and submerge the other end in a container with clean brake fluid. when you push the fluid out the hose fills up and will keep it from drawing air. (think of a drinking straw)
 

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Discussion Starter #5 (Edited)
Air can get in the system if you are not careful. One trick is to attach a short hose to the nipple and submerge the other end in a container with clean brake fluid. when you push the fluid out the hose fills up and will keep it from drawing air. (think of a drinking straw)
That's a good idea, did not think of that. When I will do my front pads I'll be sure to do that. I got it done then realized I had an air pocket because the brake was really weak so I bled it with a helper holding the pedal down and it seems to be good now. It brakes as strong as before.

BTW the Clymer manual was wrong. The only way to push the pistons back is with the nipples cracked open. Opening the master cylinder cap does nothing in this regard.
 

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i wouldn't open the system just to replace pads, but ^^^^^these guys are right you have to take the cap off the resevoir and make sure your brake fluid doesn't overflow back threw the resevoir. you could open the system, but then you will have to bleed. that being said this would be a great time to go ahead and flush out the system if you know what i mean.
 

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That's a good idea, did not think of that. When I will do my front pads I'll be sure to do that. I got it done then realized I had an air pocket because the brake was really weak so I bled it with a helper holding the pedal down and it seems to be good now. It brakes as strong as before.

BTW the Clymer manual was wrong. The only way to push the pistons back is with the nipples cracked open. Opening the master cylinder cap does nothing in this regard.
You can always push the pistons back when changing pads. Very few calipers require opening the system and a few actually require turning the piston in to reclock a parking brake.

But the ZX7 isn't like that. Just push them back in, and keep an eye on he fluid level so it doesn't spill out everywhere.

Josh
 

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Discussion Starter #8
You can always push the pistons back when changing pads. Very few calipers require opening the system and a few actually require turning the piston in to reclock a parking brake.

But the ZX7 isn't like that. Just push them back in, and keep an eye on he fluid level so it doesn't spill out everywhere.

Josh

You mean just push them back without opening the nipples? If so I tried that and they would not budge. Cracked the nipples and they slid back fairly easily while the nipples were pissing fluid.
 

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And the rear brake works ok?

Josh
 

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That's interesting. I can't imagine there is a check valve preventing the pistons from backing in unless the bleeder is cracked. Otherwise the pads would drag constantly...


Josh
 

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Discussion Starter #12 (Edited)
I'm doing the front now and ran into a snag. The pots are frozen solid and won't move back. They are the Tokico 4 piston ones anyone have any ideas? If not does anyone rebuild these for a fee?
 

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Discussion Starter #13 (Edited)
Ok so I had to remove the calipers from the bike, take them apart and then was able to push the pistons back with a pipe and lots of force. They had alot of brown goo inside of them.:thumbdown

Cleaned them the best I could and put them back on the bike with the brand new pads. Now I have another problem. The brake lever has no resistance and goes all the way to the bar. I tried pumping it and bleeding the calipers for a few minutes to no avail. I can't get it to pressurize. Master cylinder is full of fluid. Need help here big time guys and gals!:dunno:dunno
 

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It may be airlocked. Sort of like having to bench bleed a car master cylinder if it gets air trapped in the cylinder piston it won't pump fluid. Try loosing the banjo fitting at the lever to see if it is moving fluid. You only have to crack it open a little. Squeeze the lever slowly and use a rag to keep the fluid from spraying every where because it will damage paint. If you don't have fluid then pump it slowly a couple of times to see if you can prime it. If you have fluid there and it still won't pump up then you either have a leak and will lose fluid or you need to rebuild the cylinder. Of course once you open it you will need to bleed the system the rest of the way out but at least you will know.
 

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If you need help with it let me know I am in the south suburb of Chicago so I could help ya out if needed.

My Guess is that Brown Goo is still inside and has locked up the pistons up. only way is to take them apart again and remove the pistions and really clean them up. clean the walls of the Caliper up and reinstall them.

Enjoy:)
 

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Pull calipers off, put a C-clamp on it and compress the cylinder.

Use the old pad so you don't fuck anything up, and if you are worried about the paint on the caliper you use a small piece of plastic or wood.

This is like, basic brake procedures people. They even sell sweet little tools called caliper presses. Some of them are basically clamps, while others are like this and expand inside the caliper so you never touch the outer paint.

http://www.samicspecialtools.com/heavy-duty-disc-brake-pad-piston-changer-caliper-repair-press-tool/


But a c-clamp works fine and costs less to buy enough different ones to do any size caliper than buying one of those things.

You don't even need to open any nipples or caps or anything unless the system has a check valve inline - and if it did, your brakes would lock up every time you used them.

(what I am saying is that none of them have check valves)


Best way to bleed brakes is to totally flush the line using a vacuum pump. You can buy a "cheap" one for about 20 bucks, and having a friend keep the master topped off makes this VERY VERY fast because you don't have to rely on the tiny amount of fluid being moved by the lever.

Doing it using a one man bleeder setup with a jar/hose is "ok" but nowhere near as fast, and still kind of sucks because you can still suck crappy fluid back into the system.
 
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