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^ ^ I think locking up the rear has a lot to do with the tyres as well as the brakes.
I used to lock the rear on mine with the original Metzler MEZ2, but since going to tyres with a slightly softer compound haven't had this issue
 

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^ ^ I think locking up the rear has a lot to do with the tyres as well as the brakes.
I used to lock the rear on mine with the original Metzler MEZ2, but since going to tyres with a slightly softer compound haven't had this issue
Probably has more to do with BIG EYEBALLS and the BIG PUCKER
 

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Yeah, I had some Michelin 80/20 tires that were hard as rocks and skidded anytime the pavement wasn't perfectly dry. Tires are a big factor.

I used to use a lot more rear brake than I do know. A thread about trail-breaking around here really changed how I think of the brakes. Used to be it made a bigger difference to me, but now not so much.

Probably the answer is to pick one, doesn't matter which, and get used to it. Once you have the feel, it's just up to your right foot to keep you from locking up the rear. It'll get used to whatever you have back there if you practice a bit.

My biggest problem locking up the rear a bit is downshifting coming to red lights. I get too aggressive about it, a habit I have from manual cars. I get a chirp sometimes, nothing too drastic.
 

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I have 25,000 miles on my 2013 Bonneville. Original front brakes still have about 50% left. Original rear brakes are due to be replaced now. I have no real complaints about the OEM brakes, although I've read lots of reports of improvement with EBC sintered pads and rotors.

After spending a few HOURS reading about all the "rear brake pad" stories, and since I am getting decent mileage out of the OEM pads, I decided to just go with OEM pads on the rear. At least this time around. (I read that some people blow through the "organics" pretty quickly, some go through good pads every 6,000 miles too.)

Maybe when the fronts are worn down, I'll switch to EBC sintered F&R. I've never locked the rear wheel, but have not encounter a situation where that could happen...yet. So I'm not sure about putting them on the rear based on many posts here. (I ride solo, but have side luggage.)
 

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I have 25,000 miles on my 2013 Bonneville. Original front brakes still have about 50% left. Original rear brakes are due to be replaced now. I have no real complaints about the OEM brakes, although I've read lots of reports of improvement with EBC sintered pads and rotors.

After spending a few HOURS reading about all the "rear brake pad" stories, and since I am getting decent mileage out of the OEM pads, I decided to just go with OEM pads on the rear. At least this time around. (I read that some people blow through the "organics" pretty quickly, some go through good pads every 6,000 miles too.)

Maybe when the fronts are worn down, I'll switch to EBC sintered F&R. I've never locked the rear wheel, but have not encounter a situation where that could happen...yet. So I'm not sure about putting them on the rear based on many posts here. (I ride solo, but have side luggage.)
They who respect history (and experience) usually benefit from it.
 

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I took of the rear caliper and took out the brake pads. Definintly time to replace! The pads have 25,000 miles on them and they are worn exactly even all the way around!! I had flushed the brake fluid 2 years ago and it still looks very good. Never ridden in harsh weather.

I operated the brake pedal to extend the pistons so I could clean the crud off of them. Only one piston moved. Once I cleaned that one, which wasn't too bad and you could see where the seal kept things clean behind it, I blocked off that one and the other one moved out so I could clean that one. Nothing major at all. Just some light surface crud.

In automotive disc brakes, pistons usually have a boot/dust seal that protects the pistons and seals from crud, so you can just push them back in, but not on these.

I was barely able to push the pistons in by had, but I do have arthritis. When I got to the point where both were close to being all the way in, I set in the old brake pad and used some pliers to bring them in together. Almost. The reservoir was full, so I just cracked open the bleeder enough to get them in. There was some slight resistance. Tightened the bleed screw and proceeded to assemble everything.

Bracket mounting pins are cleaned and lubricated. Caliper went on easily without the pads hanging up on the disc.

I operated the brake pedal a few times and then it was a "proper" hard pedal. No need to bleed this. There is an air gap above the fluid in the reservoir.

BUT, now the rear brakes are dragging. It's hard to rotate the wheel by hand. I can twist the caliper and all is free again. Wheel spins easily. Apply the brakes, and it drags again. There was always some slight drag on the brakes before, but nothing like this.

I have not ridden the bike yet. I think I'll take it on a short ride and see what happens.

Any ideas other than "rebuild the caliper?"
 

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^ ^ ^ I experienced what you are going thru with the rear brakes ages ago. kept them cleaned, lubed the pins but no matter what they would drag when spinning the wheel while the bike was on the centre stand.

eventually ordered a set of caliper seals from where I cant remember, and re-built the caliper with the new seals. used the old pistons but made sure everything was super clean and polished the pistons with the finest wet n dry I had and some steel wool including the pins. put it all back together and all good for the next 3 - 4 years. I do wash the rear caliper periodically using hot water, detergent and a parts brush to stop the crud from building up, but just recently it is beginning to drag again even after washing so maybe time for a rebuild again..

seals have a certain amount of tension on the seal lips that "grab" the piston.
talking to a brakes expert I was informed that when pressure is released off the pedal the seal tension should grab the pistons and withdraw a few microns off the pads and the pads should follow and ease back off the disc. a build up of crap will stop that and seals that are loosing their tension will too

I also use that anti brake squeal goo that sticks the under side of the pads to the pistons so 1/ they dont squeak and 2/ they follow the pistons and back off
 

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Discussion Starter #28
I would not be so bold as to give you advice, but Delboy's garage has a great video on it. Did you lubricate the pistons after cleaning them? He recommends red rubber grease on them so they lubricate the seals. I bought all his suggested lubricants in preparation for the job, the copper grease, the white lithium grease, and the red rubber grease.

Good luck with your issue. Here is Delboy's video. He starts on the caliper at 2:20, and he goes into quite a bit of detail, maybe this will help.

 

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I took of the rear caliper and took out the brake pads. Definintly time to replace! The pads have 25,000 miles on them and they are worn exactly even all the way around!! I had flushed the brake fluid 2 years ago and it still looks very good. Never ridden in harsh weather.

I operated the brake pedal to extend the pistons so I could clean the crud off of them. Only one piston moved. Once I cleaned that one, which wasn't too bad and you could see where the seal kept things clean behind it, I blocked off that one and the other one moved out so I could clean that one. Nothing major at all. Just some light surface crud.

In automotive disc brakes, pistons usually have a boot/dust seal that protects the pistons and seals from crud, so you can just push them back in, but not on these.

I was barely able to push the pistons in by had, but I do have arthritis. When I got to the point where both were close to being all the way in, I set in the old brake pad and used some pliers to bring them in together. Almost. The reservoir was full, so I just cracked open the bleeder enough to get them in. There was some slight resistance. Tightened the bleed screw and proceeded to assemble everything.

Bracket mounting pins are cleaned and lubricated. Caliper went on easily without the pads hanging up on the disc.

I operated the brake pedal a few times and then it was a "proper" hard pedal. No need to bleed this. There is an air gap above the fluid in the reservoir.

BUT, now the rear brakes are dragging. It's hard to rotate the wheel by hand. I can twist the caliper and all is free again. Wheel spins easily. Apply the brakes, and it drags again. There was always some slight drag on the brakes before, but nothing like this.

I have not ridden the bike yet. I think I'll take it on a short ride and see what happens.

Any ideas other than "rebuild the caliper?"
I second everything from Bonza there. When you replace the seals you will see the difference between the old and new, and you'll see a new rear brake afterwards.
I also highly recommend to change the brake fluid - 2 years is longer than I will let it go. At that age it's already absorbed its share of water and will deteriorate your hoses anyway if you leave it. I've had that caliper apart a few times and new seals make such a difference, especially if you have 25,000kms from the current ones. There's probably crud behind the seals at this stage, on the inside of the caliper housing and this, if left there with worn seals, will lead to only one thing and you'll be looking at new pads sooner than you want and probably forced to do this job anyway, ask me how I know :).
Polishing the pistons, cleaning the caliper and new seals should get you another 25k.
Remembering the first time I took that caliper apart I was horrified at the condition of it, couldn't believe how bad it was compared to the front but it had taken such a bashing from the elements and in hindsight it was totally neglected, out of sight below the swingarm and behind the silencer.
 

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Thanks for the suggestions. The factory manual and the Haynes manual only state to lube the pistons with brake fluid when installing new seals. No mention of any lube when pushing the pistons back in when replacing the pads. Only to clean the crud off of the pistons.

I am satisfied that I got 25,000 miles out of the pads, but now disappointed that the caliper needs servicing. As noted above, perhaps they are only good for a few years before needing new seals. The bike is 6 1/2 years old, but only ridden in sunny SoCal.

I had a V-Strom 1000 for 10 years/25,000 miles and it needed no brake work in all that time.

Getting seals.
 

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...or so I thought. I don't see that Triumph supplies just the seals. Their kits comes with pistons for over $90. Being Nissin, does someone have a crossreference part number for seals, or something from Honda, etc?
 

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Discussion Starter #32
Here is just the seals kit if your pistons are OK.


Edit: The kit comes with a little packet of red rubber grease, so Delboy is right. You do use red rubber grease on the pistons, apparently.
 

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Thanks! Pistons should be fine, but won't know for sure until I get them out. The part you can see when the pistons are extended look fine.

In "other parts that fit our bikes" it is mentioned that the Honda ST1100 uses the same rear caliper. I have not seen that confirmed. Bike Bandit has a seal kit for it at just over $6. Has anyone done that, or better to stick with the link above??
 

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Here is just the seals kit if your pistons are OK.


Edit: The kit comes with a little packet of red rubber grease, so Delboy is right. You do use red rubber grease on the pistons, apparently.
Brembo caliper kits have come with that tiny tube of red grease for decades and decades and decades.

It's for the pistons specifically.
 

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I just bought some silicone lube for the bracket pins. Is this not good to use on the pistons? I thought maybe I could try that to at least see if it helps.
 

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Discussion Starter #36
Well, there you go! Delboy does say lubricate the pistons with brake fluid when reinstalling them in the caliper in his video. He advises the red rubber grease during his cleaning videos. Presumably, he uses brake fluid only to reinstall them in the caliper cylinders, but lubricates the part that extends a bit when operated with the red rubber grease after they are back in the cylinders.
 

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Discussion Starter #37
Watch this video. All the lubes are covered, Columbo. This is different from the rebuild video, this is normal service. But the two videos combined will answer all your questions, I think.

He discusses all the lubricants at 18:30

 

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Brake Crafters is a good vendor. You'll have your rebuild kit within a week. I find the grease they supply to be very stiff and sticky, no problem to lube the seals with it for installation, but I'm not sure about putting it on the pistons, seems like a dirt magnet, so I use brake fluid and a Q-Tip for that job.

The hardest part of the rebuild is filling and bleeding the brake fluid. The rest is easy, if tedious.

I should probably clean the rear more often, as mentioned. The rebuild was two years ago. Last year I had to rebuild the front as well, it had a seized piston after sitting all winter.
 
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