I know what keeps the caliper pistons from retracting on my bike..

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It's this mean grit that gets under the first seal, seems to cultivate, and squeezes the piston hard enough to disallow the brake pad to come away from the rotor, as if if your still squeezing the brake lever.
What I want to know is, does it happen to others?
Do you find time to disassemble calipers every couple of years to clean pistons and under the first seal in order for the brakes to work properly.
I ride year round in the Midwest, so it's not a mystery as to why and it's about the 3rd time in 6 years. Let me know
 
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have a 97 for 4 years now and put 2 sets of rear pads on. Put about 25k on since I owned the bike and have not had any caliper issues. The only reason I put rear pads on twice was that I used Kevlar pads that are real soft, wear out quickly but seemed to stop very well. The first seal or boot is a dust seal and should keep all the grime out. The lip on the piston should be clean and should the caliper lip. Nothing should be able to get in there.
 
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What I want to know is, does it happen to others?
Do you find time to disassemble calipers every couple of years to clean pistons and under the first seal in order for the brakes to work properly.
No, in 20 years on my '97 I've cleaned the pistons once that I can remember, that was last year. But I don't ride in the midwest, and very rarely ride in the rain because it doesn't rain much here.
 
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Is it environmental grit or the sand-like crud that forms when moisture and brake fluid mix?
It looks like I'm cleaning material off the entire first seal and groove like a coral reef. Guess what though, super exciting, I am cleaning the left side caliper and will take pictures ( why on this earth I didn't do all three on the same day, at least the left front caliper as well, now I have to bleed the system again, duh) It was the offending caliper, I'm sure the left one is close to it. I will see if the pistons retract ok before I disassemble unnecessarily.

My pistons may not be perfectly smooth, and it's the answer I was looking for. Though brake fluid does not leak, there are imperfections I believe are allowing grit to get where it shouldn't. Obviously I have been avoided buying 6 new pistons. Lowest price source 23.00 per.
 
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My pistons may not be perfectly smooth, and it's the answer I was looking for. Though brake fluid does not leak, there are imperfections I believe are allowing grit to get where it shouldn't. Obviously I have been avoided buying 6 new pistons. Lowest price source 23.00 per.
I did the same with my 1100. $23 or so is a LOT better than the $100+ range for pistons for some of the 1970/80's bikes I have rebuilt.
 
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My 98 needed the rear caliper cleaned in spring 2015 and the left front ( did them both ) in spring 2016.
Replaced the seals.
Thankfully this year they seem to be behaving themselves.
Don't ride in the winter but it's been known to get wet. Through the winter I use David's Technique and work them with my knee once or twice.
Good luck.
Upt'North.
 
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Even better, while working the right caliper off I noticed fluid that doesn't belong on the outside. While squeezing the brake to extend the piston, bubble bubble. Not a problem really, if I could find my extra caliper gasket set on hand when I needed it. Will have to postpone this repair, order the gasket set and am really compelled to order new pistons off the bat. Having done this, will be able to compare the condition and behavior of each side for sticking pistons over time. Full disclosure, in my haste years ago, I padded channel lock pliers with a towel to manipulate a stuck piston. The tiny amount of scoring was buffed out and it never leaked. What I think happened to the condition of my dust seal and the need to clean out the groove is because the piston isn't perfectly smooth.
 
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Brake fluid leak past one of the pistons in the left caliper. It's enough, I'm surprised I didn't run out of fluid on a 2600 mile ride. Best I can figure, the piston position with remaining brake pad, the leak wasn't that bad, but a leak none the less.
Here is a before and after of the dust seal.
IMG_20170704_142133.jpgIMG_20170704_142410.jpg

Next up, a rotation of my piston. Shame. I've been using these since I bought it 5 1/2 years ago. There may have been blemishes on it, but don't remember the grooves being there until I put them there. New ones on the way, hopefully before the next big trip.
IMG_20170704_142625.jpgIMG_20170704_142652.jpgIMG_20170704_142713.jpg
 
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clean the groves and a light coat of some silicone brake grease on the groves to help prevent any further corrosion.
 
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clean the groves and a light coat of some silicone brake grease on the groves to help prevent any further corrosion.
Roger. Will need to buy that, but well worth it with new pistons and seals on the way. Guess what, found a supplier on eBay for stainless steel 316 pistons for guess how much? 2 for about 35.00 after shipping. Seller redeye.tech
 
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I'm still having problems with edit on this site....should of been " break loose the banjo bolt". if it retracts, then the problem is on the bike's side
 
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I'm still having problems with edit on this site....should of been " break loose the banjo bolt". if it retracts, then the problem is on the bike's side
I rebuilt the master cylinder 2 years ago, so I know it was the piston. Hopefully, after I replace the pistons, it will work much more agreeably.
By the way, so far the only grease I can find is what you lube the caliper's moving parts, not the inner seals. Do you have a specific product recommendation?
 
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This will keep me from jacking up the surface of the piston. I know I did it, though an effort was taken with the channel lock jaws protected with a towel. It worked great until the channel locks went through the towel.
The grease used to keep the corrosion down, anyone. I'm betting with better condition pistons, less will get inside the dust seal and corrode it.
 
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Is the grease you recommend silicone grease. Anything to keep the corrosion suppressed. Any other year round riders find your pistons stick due to the dust seal getting junky?
 
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To put in my 2cents on this issue, my ZRX for years never had a full brake lever. Bled them til the cows came home. Rebuilt them several times. Issue, I never replaced the orings. Cleaned up the pots with used skotch brite and wiped up the orings. Lubed with fluid and reinstalled. Never leaked!! Problem was, the orings would get swollen and dry. The pots would come out when the lever was pulled in, but! the orings were holding the pots back ever so slightly as they stretched and pulled the pots back in. So it always took about a half pull just to get the pots to the rotor. Finally bought some new orings......which IMO are freaking expensive! But, I used some of this grease that I got from a fellow board member. Suppose to be high temp and brake fluid resistant. Brakes were cherry after that!! So you still might be able to use your same pots, just clean them up with the skotch brite and use the grease on the orings. I know if a pot gets cocked ever so slightly, they are a PITA to get out unless you get it just right as you work it out. I will be doing my rear in the near future. Good luck! :mrgreen:
 
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To put in my 2cents on this issue, my ZRX for years never had a full brake lever. Bled them til the cows came home. Rebuilt them several times. Issue, I never replaced the orings. Cleaned up the pots with used skotch brite and wiped up the orings. Lubed with fluid and reinstalled. Never leaked!! Problem was, the orings would get swollen and dry. The pots would come out when the lever was pulled in, but! the orings were holding the pots back ever so slightly as they stretched and pulled the pots back in. So it always took about a half pull just to get the pots to the rotor. Finally bought some new orings......which IMO are freaking expensive! But, I used some of this grease that I got from a fellow board member. Suppose to be high temp and brake fluid resistant. Brakes were cherry after that!! So you still might be able to use your same pots, just clean them up with the skotch brite and use the grease on the orings. I know if a pot gets cocked ever so slightly, they are a PITA to get out unless you get it just right as you work it out. I will be doing my rear in the near future. Good luck! :mrgreen:
Thanks for the input. Surprisingly, the grease is about 2 dollars less than a gasket kit, or o-ring as you call it. Interestingly too, I'd never seen a reference of "pots" to caliper pistons. I thought it was a misspelling at first but a recurring word spelled the same...anyway, it was a humorous time.
The amount of fluid getting past the pot when I squeezed the brake lever will be worth a careful exploration of the inner most seal. The pot's integrity might be ok, but it would be hard to explain what caused the injury to the inner seal. It has to be where the leak is coming from because the dust seal won't hold fluid back. Time will tell, parts are ordered. Not aligning the piston when it goes in the caliper properly is why I had to use an evil tool to free it.
 
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