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How To: Brake Caliper Rebuild

39K views 113 replies 44 participants last post by  siq75 
#1 · (Edited)
Rebuilding brake calipers should be done every year, whether you ride track or street. Track bikes go through pads quicker, so they accumulate more brake dust. Street bikes get dirt, water, salt and all kinds of other grime in the brakes. Thoroughly cleaning will not only make your brakes work better, but your pads and discs will wear more evenly when the pistons aren't obstructed by a bunch of shit.

It's only slightly less messy than a fork rebuild, and brake fluid is bad stuff so this is probably the nastiest job you can do. Make sure you have plenty of rags and good nitrile gloves.

This was done on my SV650 with Tokico calipers, but the procedure is the same for 06-08 Daytonas and similar to 09+ (I'll get to that). Here we go!

Drain the brake fluid, preferably with a Mity-vac or similar to get as much out as possible.


Disconnect the banjo bolt, but make sure you have rags and/or a bottle handy to catch fluid because it's almost impossible to get it all out. No matter how much you shake and dance, etc etc...


The brake lines are free; I like to wrap them and hold them high so they don't drip on my garage anymore.


Loosen but don't remove the pad pin (Daytona only has 1 bolt in the middle). It's important to use a good, quality allen as these bolts seize easily and they can be torqued tightly considering how small they are.

Next, remove the big caliper bolts that hold it to the fork leg, again using a good allen. The caliper will now come back off the disc. Be careful not to tilt the calipers upside-down or you'll spill a bunch of fluid.


Pull out the pad pins and you'll have 2 pads per caliper (I have 4) and the anti-rattle clip (the silver thing in the middle). The clips aren't necessary & I've never used them on my track bikes, but you can do whatever you like.


Tilt each caliper into a bottle and drain as much of the fluid as you can.


For 06-08 2-piece calipers, it's a lot easier if you split them, so loosen the bolts that hold them together. My brakes have 3 bolts each. They're torqued down pretty good so I put them back on the fork leg to get more leverage. You could also use a vise with soft jaws if you're careful.


Now you'll have 2 halves:


The pistons need to come out now. My preferred method is blowing compressed air into the fluid passageway, but make sure you have a rag held tightly over the pistons so they don't go flying into your face. Make sure you're wearing goggles too because you'll probably get a little spray. Plug all the holes except one and blow away. You'll hear a pop when each piston comes out.

For 09+ monoblocs, you'll have to do this as one piece. I suggest putting a block of wood between 2 of the pistons and just working on 2 at a time.




You'll notice 2 rubber seals in each cylinder. Those need to come out, but be careful if you're going to reuse them. I pulled the old ones out with an X-acto since I'm replacing them anyway. A dental pick would work well too.


Now you can go about actually cleaning everything. If you're spoiled rotten, you have a sonic cleaner and you can just stick them in for a while. If you're like me, you need to just scrub away. I used a rag and some WD-40, but you can also use Simple Green, brake cleaner, or pretty much any other de-greaser. Once I got the top layer of grime off, I polished everything with a Dremel's brass brush attachment to make it all shiny again. Make sure you get in the seal grooves too because they can leave behind black stuff. Also clean the pistons so they slide easily. Before & after:


All ready for reassembly. Put a light coating of new brake fluid or red rubber grease on the seals & pistons to lube them. Put them back in just with your fingers.


Put the halves back together, then the pads, mount it back on the fork legs & reconnect the brake lines. The banjo bolt's washers should be replaced whenever you take the bolt out. Torque everything to spec, bleed the brake system and ride! (don't forget the wheel if you've removed it...)
 

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#75 ·
1. If I want to do more of a quickie clean (not removing seals or pistons), in between total rebuilds, how would you suggest doing that:
What can I use to scrub everything down good that will make the job as easy as possible but not harm the caliper/seals if some of it remains behind the pistons or on the seals themselves. I would more than likely be blowing out any excess with a compressor but I want to make sure I don't do more harm than good trying to clean them.

2. I read that some of you knew where the bubbles were in your system. How did you know where?

3. Is there a particular brake bleeder you recommend?

4. Where can I find a good tutorial on the "Back Filling" brake bleeding method?

THANKS!
 
#79 ·
The OEM M/C isn't really rebuildable. You can get a new piston from Triumph, but I don't see anywhere you can buy all the seals separately.

Most nice aftermarket M/C's like Brembo have rebuild kits available, and it is recommended to service them every once in a while.
 
#81 ·
See the previous posts, doesn't look like anyone was able to buy seals cheaply since they come with pistons too. If you want to do this often and cheaply, I suggest switching to R6 calipers. You may not be able to run stock race classes though, check your rulebook.
 
#87 ·
I've rebuilt the calipers and now installing them. All I've go to do is fill them with DOT 4.
I've a jar on the floor with fresh fluid and a hose running up to a loosened bleeder. I filled the res with fresh fluid, squeeze the brake and nothing happens. As I release the brake fluid is sucked up into the hose from the jar but nothing will flow out of the res into the system. What is wrong here?
 
#88 ·
Sounds like you're just sucking more air into the system. Read a how to procedure on here for brake fluid, and it'll be way easier if you spend $40 on a Mityvac at an auto parts store. It gets the fluid flowing from the master to the calipers in about 30 seconds, and you can just bleed it manually from there to get the small air bubbles out. Make sure all the other bleeders are tight except the one you have the Mityvac on.
 
#90 ·
Believe it or not, your Brembos get dirty too ;)

Yes, it's a good idea to clean & rebuild them every year if you're riding street, more often if you're going to the track. It's the same procedure as 09+ monobloc Nissins, i.e., pop out the pistons a pair at a time while keeping the other pair together with a wooden block. I don't know about availability of seals but you can ask your Triumph dealer or Brembo directly.
 
#93 ·
Anti Seize

Also, something to note that no one has gone over in this thread - threadlock/lube.

The service manual calls for a drop of Loctite Hydraulic Sealant 569 specifically on the bolts that hold the two halves of the calipers together.

Also a 'minimal' amount of copper based anti seize on the retaining pin (I'm assuming on the threads).

The '13/14 FSM calls for copper based anti seize on the first four threads of the caliper mounting bolts (onto the fork mount), but the older FSM for my 2009 doesn't call for any.
 
#94 ·
My last reply here. I've rebuilt these things now three times, once reusing same seals, once with new ones, and now troubleshooting. The reason I make this post is to save you all some headache when reinstalling old or new seals. In my experience it was worth purchasing new, for the record.

The oil seals are DIRECTIONAL. They have a slight taper to them - this is not mentioned in the How to, nor the FSM, nor the Haynes manual. If you look closely, the taper faces outward, not inward, but if installed backwards, they will put undue pressure on the caliper piston and prevent it from retracting.

You must install with the tapered (wider) end facing the PADS. Then a very slight smearing (half a fingernail's worth) with hydraulic grease as assembly lube if you wish, and push in the pistons square.

For clarification, the dust seals are not directional.

See here for a good picture on the layout - these are for tokico calipers but the design is the same for us.

http://www.tlzone.net/forums/perfor...76-how-overhaul-tokico-six-pot-callipers.html

I noticed with the Powerhouse (aftermarket set I used above) the taper is a bit more aggressive than the OEM ones - not sure if this is due to age or design. This makes it even more important, as I've painfully found out.
 
#95 ·
OK, very last post lol. Some major screwing around with this (way, way more than I wanted to) and I found that the caliper seals from Powerhouse are garbage. Could not push pistons back into caliper housing at all. Like impossible. This was because they were deformed, which gave the APPEARANCE of them being tapered when removed from the caliper.

Here is an image of the aftermarket (left) and oem (right)

https://i.imgur.com/Fr5OabY.jpg

After two weeks. Garbage. They were dragging all over the place. I reinstalled the original OEM ones, and now they work great (still some more bleeding to do... grrr) but they work evenly and don't drag.

I'm putting in a claim with ebay to get my money back, but either reuse OEM or buy new OEMs, don't go aftermarket on these guys.
 
#96 ·
For those still looking for seals

For those jumping to the end (on my saga of searching for seals for this bike...) to get where to find cheap seals, you can buy them from these guys

http://www.triumphparts.gbr.cc/product.php/5734779/

for about 63 british pounds for both calipers. They claim they are genuine Nissin kit. That's about $60 cheaper than going through triumph, though you could just get the piston and seal kit from triumph for about $155, and then you get pistons too (if they are really bad).
 
#100 ·
Neanderthal, we linked to the same site lol. Great minds think alike!

Hokie, read my warning earlier in the post about Powerhouse aftermarket seals - I found they didn't fit properly and hung up the pistons quite badly.

These brakes are the only thing that's keep me from fully enjoying the bike, I really need to get them properly sorted.
 
#102 ·
Ok so I finally got around to rebuilding my brakes yesterday with the powerhouse seals. I had none of the problems you talked about.

And holy hell I should have done this years ago. Instead of maybe one revolution of spin I now get 3-4. Plus now the calipers are nice and clean.
 
#103 ·
I tried the rebuild and reused the seals paying close attention to the taper on the oil seal. No improvement in drag unfortunately. Ever since I replaced pads I cant get anymore than 3/4 revolution on the wheel. All I can think is to buy the piston and seal kit as a last ditch effort before swapping to R6 calipers. I'd like to stay stock though in case I start racing.
 
#105 ·
I did clean everything pretty well, but not with a brass brush. I even got the cotton swabs out and cleaned as best I could. Ive got 5600 miles on the bike. Maybe 1500-2000 or so track miles. The issue didnt occur until the pad swap.

The picture is before i started cleaning.
 

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#106 ·
I've been really bad maintaining my brakes and decided that needed to change. I pulled my calipers and cleaned them up with some dish soap and water and a toothbrush. While I was extending the pistons out to make sure they were all moving equally, one of the pistons popped out and brake fluid seeped out. I pushed it back in and continued cleaning.

Fast forward to installing new pads and flushing the fluid. I bled the calipers first (at least 2 or 3 separate sessions) and was unable to get a good firm brake lever. I bled the master cylinder and while it help, still suffer a soft brake lever.

At this point I am wondering if it is necessary to rebuild the calipers since I screwed up. Can anyone chime in?

Bike is a 2012 675R. Thanks!
 
#108 ·
Can anyone chime in?
Bike is a 2012 675R. Thanks!
To start, make sure your master has the lever extended to the farthest position out.. If you are bleeding at the bleeder on the caliper, also consider when pressure is built up, cracking the banjo itself, as air can get trapped there.
Personally have swapped to the reverse bleeding technique (forcing fluid from the bleeder up through the line into and thru the master.)

Something to consider is that air is caught in the space behind the caliper piston. push all the pistons in, use the reverse method and you should golden as long as nothing is leaking.
 
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#107 ·
You took the pads out to extend the pistons? When the piston popped out, it could've moved the seal, and pushing it back in without checking behind it may have pinched it. It's worth taking a look before you buy a whole seal kit.

You also could've gotten air into the caliper behind the piston. Try turning the caliper upside-down and bleeding, shake it around a bit, then bleed again upright.
 
#109 ·
The pistons were not all coming out the same distance when I pulled the lever so I wanted to get all the caked up brake dust off. I'll try turning the caliper upside-down for bleeding. Thank you!

To start, make sure your master has the lever extended to the farthest position out.. If you are bleeding at the bleeder on the caliper, also consider when pressure is built up, cracking the banjo itself, as air can get trapped there.
Personally have swapped to the reverse bleeding technique (forcing fluid from the bleeder up through the line into and thru the master.)

Something to consider is that air is caught in the space behind the caliper piston. push all the pistons in, use the reverse method and you should golden as long as nothing is leaking.
I'll double-check the lever next time but I believe I had the lever adjusted out because of how low my last set of pads were haha.

I'll follow your recommendation on pushing the pistons back in and will order syringes for reverse-bleeding. Looks to be a much more effective technique. Thanks!!!
 
#112 ·
i went to do my front pads & fluid flush today, and the bottom pistons on both calipers are frozen(wont go in or out).

my bike is a gen 2, how do i get the pistons out?
You've tried using compressed air? Heat it up with a propane torch. If that doesn't loosen it, you can soak them overnight in some WD40 or PB Blaster then try again with air in the morning.
 
#114 ·
i didnt see you guys reply. guess i was a little impatient, and didnt read the WHOLE thread before i asked for help!

i was able to block off the pistons by wedging a socket in between them, pumped the brakes, and it freed the frozen ones up. i cleaned them all off 1 by 1 with brake cleaner and a tooth brush, now they are working properly.

ill put new fluid next weekend and go for a ride to bed in my new sbs pads
 
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