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Discussion Starter #1
Brake caliper piston swap for ‘05+ Triumph Sprint

Disclaimer
I’m no lawyer, but I probably need to add some type of disclaimer.

I am not a trained mechanic. Nothing I write here has been evaluated or endorsed in any
way by Triumph motorcycles. If you use these instructions, use them at your own risk. This procedure worked for me, but I make no claims that it will work for anyone else.

Okay, now that’s out of the way………..

Materials

Parts
1. Triumph part # T2020465 (Piston kit). This kit comes with pistons and seals. It’s available from www.cycle-parts.com. The total, with shipping, was $135.59
<UL><LI>14mm Socket
<LI>14mm wrench
<LI>8mm wrench
<LI>6mm Allen wrench
<LI>5mm Allen wrench
<LI>Torque wrench
<LI>Phillips head screw driver
<LI>Needle Nose pliers
[/list]

Other Necessities
<UL><LI>At least 1 bottle of new DOT 4 brake fluid.
<LI>1 Roll of shop towels
<LI>Lots and lots of rags
<LI>Three cheap aluminum roasting pans (from the grocery store)
<LI>At least two, 2” (or longer) thin machine screws
<LI>At least two wing nuts for the machine screws
<LI>Four small metal washers
<LI>At least four small beveled rubber washers (available in the plumbing section of the hardware store)
<LI>Three feet of 3/16” inner diameter CLEAR vinyl tubing
<LI>A small, glass container, preferably with a top (I used an old canning jar with a screw on cap).
<LI>Tweezers
<LI>Latex gloves
<LI>Brake caliper cleaner
<LI>Beer
[/list]

Procedure
Read this procedure through completely BEFORE attempting the work.
Step one: crack a beer. You’re about to disassemble your brakes. You’re not going to ride anywhere, and it’s probably a good idea to calm your nerves anyway. Drink a beer. It will help.

This procedure describes the rebuilding of one front caliper. This process will have to be repeated for the other caliper.

Unless you want to have REALLY dirty hands, put on a pair of latex gloves.

Place one of the roasting pans underneath the brake caliper. Place another roasting pan behind the front wheel. Place some shop towels underneath the pans so that any open space between the pans is covered. This will help catch any dripping brake fluid. Brake fluid is nasty stuff, and WILL EAT THROUGH PAINT!!!!!!

Using the 6mm Allen wrench, break loose the four Allen bolts that hold the caliper together. DO NOT REMOVE THESE BOLTS YET. Simply break them loose. They’re tight! It’s a LOT easier to get these bolts loosened when the calipers are bolted to the bike. If you loosen them too much brake fluid will drip out.

Using the 5mm Allen wrench, loosen the gold colored brake pad retaining pin.

Using the 14mm socket, loosen the two bolts holding the caliper to the forks. These things are tight, so be prepared to grunt a little to get them loosened. Again, don’t pull these bolts out yet, just get them loosened.

Place several shop towels over your tank and fairing directly under the brake reservoir. Remove the reservoir retaining clamp. Remove the reservoir cap and diaphragm.

Get ready to get MESSY……

Make sure your machine screws, metal washers, beveled washers and wing nuts are ready. The idea here is to use the beveled washers to hold in the brake fluid while the calipers are removed from the bike. Slide one metal washer and one beveled washer onto the screw. Keep another beveled washer, metal washer and wing nut handy. Here we go. Using the 14mm wrench, remove the bolt that holds the banjo fittings onto the caliper. Brake fluid will seep out. As the bolt gets looser the brake fluid will flow faster. Don’t panic, but work quickly.

Remove the bolt and place it and the metal crush washers into the roasting pan directly beneath the caliper. Slide the machine screw with the metal washer and rubber beveled washer through the banjo fitting. Slide another rubber beveled washer and metal washer onto the screw on the other side of the banjo fitting. Screw together with the wing nut. This will seal off 98% of the dripping brake fluid. You might get some slow drips, but this will keep things pretty clean. If you’re doing the right caliper first, you’ll have to seal off two banjo fittings. The left caliper only has one banjo fitting.

You’re now ready to remove the caliper. Unscrew the bolts holding the caliper onto forks. Carefully remove the caliper from the bike. You may have to slide the caliper down to the bottom of the brake rotor to make removal easier. Keep in mind that the caliper is full of brake fluid, so as you slide the caliper down it WILL drain brake fluid. Make sure to wipe any brake fluid that spills on the bike.

Take the removed caliper and place it in the remaining roasting pan.

Using the 5mm Allen wrench, remove the gold colored brake pad retaining pin. The pin will slide out and the brake pad retaining clip will probably fall off. Slide the brake pads out of the caliper. I wrap them in a rag and set them aside. This makes sure you don’t get brake fluid on the pads.

Now, using the 6mm Allen wrench, remove the four Allen bolts that hold the caliper together. The caliper should split into two pieces, and drain a bunch of brake fluid out. Look at the inside of each caliper half. You will see very small rubber washers in each caliper half. Don’t lose these. One of these small rubber washers fell out when I did this work, and my caliper leaked brake fluid until I replaced the washer.

You’ll also see two pistons in each caliper half. If you have an air compressor you can use this compressed air to blow the pistons out. I don’t have an air compressor. I removed the pistons with needle nose pliers. Grab as much piston as you can and pull. Pull HARD. If your pistons were like mine, they’re stuck. You may have to put the caliper half under your foot and PULL.

Yet again, more brake fluid will drain out.

Depending on mileage, your calipers might be REALLY MESSY. Spray the caliper down with brake caliper cleaner and watch all the gunk and nastiness drain down into the roasting pan. Aren’t you glad you’re wearing latex gloves?

Once the pistons are removed and the caliper is clean, you’re ready to start the caliper rebuild.

Using the tweezers remove the two dust seals (the top most rubber seal) and the two fluid seals (the lower seal inside the piston cylinder) in EACH caliper half. There’s a big piston and small piston in each caliper half.

Now, open the piston kit with the 675 pistons and seals. Notice that the 675 pistons are a flat grey while the stock pistons are a very shiny (when clean) copper color. Remove the seals. Rub a little brake fluid over all of the new seals. Install the new dust seals and fluid seals into each caliper half. This will be a total of four dust seals and four piston seals per caliper (8 total seals per caliper). Again, note that there is a big piston and a small piston. Make sure to fit the appropriate seal into the appropriate cylinder.

Now, rub brake fluid on the outside and bottom of each piston, and CAREFULLY slide the pistons into the cylinders. It may take a little bit of effort to slide them in all the way. You’ll probably feel a bit of resistance, and then the piston will quickly slide into place. Make sure the piston stays square to the cylinder and try to use steady and even pressure to seat the pistons. Again, each caliper contains four pistons, and each caliper half contains a big piston and a small piston.

Congratulations, you’ve just rebuilt a brake caliper. It’s ready for reassembly.

Make sure all of the caliper half seals are still in place. Place the two caliper halves together and finger tighten each of the four Allen bolts that hold the caliper together. Now, tighten these bolts with the Allen wrench. Just make sure to tighten them in an appropriate fashion. Tighten the right outside bolt, then the left outside bolt, then the right inside bolt then the left inside bolt.

Slide the brake pads back into the caliper. Put the pad retaining clip on top of the pads and slide the pad retaining pin through the pads and over the clip. You’ll wish you have three hands to do this, but you’ll eventually get it. Tighten the pad retaining clip. The Triumph spec is to tighten this pin to 19 Nm.

Carefully slide the caliper over the rotor and fit to the forks. Finger tighten the bolts that hold the caliper to the forks.

Check the amount of brake fluid in your reservoir. If it’s low (and it probably is), fill it to the max line with fresh brake fluid. You want to make sure that the reservoir never goes dry.

Get ready to get messy again.

Remove your banjo plugs by spinning off the wings nuts from the screws holding the rubber beveled washers to the banjo fittings. Place the banjo bolt and crush washers back through the banjo fittings. Make sure you have crush washers on either side of each banjo fitting. Now, screw this bolt back into the caliper. Again, your third hand will come in handy here. The brake fluid is slippery and makes getting this bolt threaded into the caliper tricky. Don’t panic or swear too much. You’ll get it. Make sure to tighten it enough that no brake fluid is leaking out. You may need a wrench, but don’t torque it down quite yet.

Now that everything is fit together, you can tighten things down to spec. The torque spec for the bolts holding the caliper to the forks is 40Nm.

The torque spec for the banjo bolt is 25Nm.

Once everything is torqued to spec, check the tightness of the Allen bolts that hold the caliper together. There is no spec published in the Sprint manual for these bolts. Make sure they’re tight.

Now, do the whole thing again on the other side. Drink a beer first, it will help.

Okay, the calipers have been rebuilt with 675 pistons and seals. It’s time to bleed the brakes.

Get your small glass container and fill it about half full with fresh brake fluid. Place one end of the clear 3/16” inner diameter tubing over the brake caliper bleed nipple, and the other half into the glass container with brake fluid. Make sure the end of the tub in the glass container stays completely covered by brake fluid.

Now, place your 8mm wrench on the caliper bleed screw. Loosen the screw about ¼ turn and then slowly squeeze the brake lever all the way back to the handle and hold it there. Tighten the bleed screw, then release the brake handle. You may see fluid with bubbles, or just bubbles (or maybe even nothing) come out of the bleed nipple into the clear tubing.

Now, do it again….. Loosen the bleed screw, squeeze the brake lever handle, see the bubbles come out into the tube. Tighten the bleed screw and then release the brake lever. Eventually bubble free brake fluid will be pumped into the clear tubing. I like to see at least three pumps of the brake lever with NO bubbles before I’m satisfied that the line has been bled.

Now, you get to do the same process on the other caliper. You MUST bleed both sides.

Fill the reservoir to the max line, and replace the diaphragm, reservoir cover and cap retaining pin.

Okay, you’re finished……..

Let’s check the work. Pump up the brake lever until the pads contact the rotor. The brakes should feel pretty good, but may not feel great. No worry.

Shine a flashlight onto each caliper and pull the brake lever back as far as you can. Check and make sure that there is no brake fluid leaking out of the caliper. If everything looks good, you’re really finished.

The last step is to tie the brake lever back as far as you can (to the handle if possible) and leave it over night. Drink another beer. You’re not riding anywhere.

The next day, release the brake lever and test things out. Look for leaky brake fluid. Hopefully you won’t see any. Roll the bike forward and grab the brake. It should work. If the bike passes this test, go for a LOW SPEED ride through the neighborhood. Test the brakes. If that works out, find an empty (or nearly empty) parking lot. Progressively test the brakes until you are panic stopping. If your bike has ABS, work until you get the ABS to kick in. How does it feel? If your bike is like mine it will feel MUCH, MUCH better.

Keep an eye on the calipers over the next few days to make sure nothing is leaking. Everything should be fine, but you want to make sure everything has seated.

Good luck. This sounds harder than it really is.

If you get stuck, give me a call at 925 551-8058.
 

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Great work David :gpst: Do you ever sleep?
 

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So all in all, it's only a three-beer job. That's disappointing. Clearly you need to do two motorcycles at once to turn it into a more worthwhile six-beer procedure!

Great post.
 

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Discussion Starter #6
The amount of beer consumed is completely up to the person doing the work.

I checked the service manual, and the Triumph spec is anywhere from 3 to 24 beers for this procedure. Just make sure you drink AT LEAST three beers. :-D
 

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3 beers is probably the "official book" spec.
But since we RAT.NET riders are much more careful than the dealer, add one beer, care more about a complete job than the time it takes to do the job, add one more beer, and are using all the wrong tools, add one more...
And, we need to take care of the buddy helping out, so add a few more... Of course the test ride is done the next day!
:-D

...sorry, couldn't resist...

C
 

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Excellent post! You should write service manuals. I especially liked your design for plugging the banjo fittings to limit brake fluid loss while the brake lines are detached from the calipers. I don't have any brake problems YET but your instructions will be helpful when I need to replace pads.

Thank you for taking the time to help others in need.
 

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Discussion Starter #9
I especially liked your design for plugging the banjo fittings to limit brake fluid loss while the brake lines are detached from the calipers.
I wish it had been my idea. I belive Sport on this board is the one who suggested it.
 

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d_m

you keep posting like this.... Triumph are gonna have to put you on the payroll.... either that... or we need to shout you a beer or 3 for all your R&D work!

stay shiny side up!

G
 

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The question is not if it works immediately but how it works after a few months or 3-4k miles.
 

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Discussion Starter #12
Well, the Sprint has about 2,000 miles on it since the swap. The brakes are great!!

I'm convinced it's a permanent fix. Just make sure that ALL of the caliper half seals are present before reassembling.
 

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Pardon me for being such a cynic, but I think I'll wait just a little longer to see how your results are then. No offense to you at all...just being pessimistic. :wink:
 

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David...awesome work!!!
I'm looking at this real carefully.
...5 seconds after the brake is applied, the stock rubber seals pull the pistons back just enough to require extra lever pull for the next brake cycle.
You say the coating on the 675 pistons is more slick (which eliminates the pull back)...did you change the seals to the 675 type?
Do they look a little different than stock?
Steve
 

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Discussion Starter #15
Initially I used the stock seals and the 675 pistons. Braking performance was dramatically improved. However, when I reassembled my right caliper after this work, I accidentally left out one of the caliper half seals (has nothing to do with the piston seals). This made my right caliper slowly leak brake fluid when the lever was applied. D'oh!!

I had to open the calipers back up to diagnose my problem (this is when I ralized one of my caliper half seals was missing). When I opened my calipers back up , I went ahead and used the 675 seals since the brakes were already torn down.

The 675 seals and the stock seals look and feel identical. I'm not a material scientist and they could be made of completely different material, but they look and feel identical.

I'm not at all concerned if anyone is cynical of this fix. I've experieced the improvement first hand, and I know it works.

Changing to new calipers also works, and if you shop around on Ebay you can get used but clean calipers for about the same price as new pistons. The choice is yours.

On my particular bike the stock brakes rated about 2 on a scale of 1 to 10. After changing to the 675 pistons the brakes on my motorcycle rated about an 8 on a scale of 1 to 10.
 

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david,
Sorry to hear about selling your bike, but right now I wouldn't buy a Triumph either. On the 675 piston swap, did you notice that the shape of the rear of the piston is different too. The old one is indented while the new is flat. A suggestion to anyone else who is doing this, rather than mess with the various screws and stuff to clamp off the fluid, I recommend just draining it. I'm putting on new break lines and a MC so I had to anyway but it works really well. Also, I have an air compressor and that is good for two of the four pistons so I had to use some needle nosed pliers to get them all out anyhow.

Thanks david for doing the pioneer work on this. Good luck on your next bike whatever it is.
Rod
 

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Discussion Starter #18
I didn't notice that the pistons were a different shape.

I didn't want to drain all of the brake fluid because my bike had ABS and I didn't want to bleed the whole system. Whitout the Triumph service tool, bleeding the whole system from dry would take quite a while.

I would consider owning another Triumph. I'll just never buy a new one again. The factory seemed completely disinterested in supporting me as an owner of their product.

A new bike should come with a solid warranty, but Triumph's warranty is useless. I'd rather let someone else take the depreciation hit, and then I could use the cost savings to buy appropriate parts to fix the bike's flaws.
 

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I dont think I'm taking a hit on mine..

I just changed my mind and got the silver showroom bike (instead of the red demo) with 0 on the clock and not so much as a scratch..

$9,300 with hardbags...



Six pot one

Six Pot Two

$50... total..

Pads probably $50...
 

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On 2006-10-02 20:22, david_m wrote:
A new bike should come with a solid warranty, but Triumph's warranty is useless. I'd rather let someone else take the depreciation hit, and then I could use the cost savings to buy appropriate parts to fix the bike's flaws.
Totally agree with you on that one David. The factory warranty department have put me off buying a new Triumph. I wonder how many other customers they have put off with their mean and penny pinching attitude?
 
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