Triumphrat

ohiorider · 10-11-2008, 01:10 PM

I do replace brake fluid periodically. Obviously, I replace brake pads when they're down to the minimum specification or even before. What I have never done is to remove the caliper pistons, clean them, and replace them. I can understand what a few of you who do so have said about cleaning 'gunk' off the pistons that might cause them to stick in their bores, causing the brake pads to ride too heavily on the rotor.

Here's my questions. Can the Triumph caliper pistons (a) be removed without disturbing the seals, (b) do the seals stay in place in the caliper when the pistons are removed, and (c) can this be done without losing brake fluid, or having to go through the brake fluid bleeding process? In short, any gotchas?

Bob

greyplague · 10-11-2008, 03:56 PM

Bob,

when I replaced the seals (dust and oil seals) on my former bike (TT Legend) with similar (Nissin) brakes to solve a leak problem I found out that:
-I had to bleed the brakes afterwards.
-needed a fair amount of brake fluid.
-only 1 seal was leaking- had to replace all of them (I scare easily).
-they're a PITA to get them in. My wife has smaller fingers-she did it
-you can leave 'em into place if you like to gamble.However:save
lots of $$ if you keep'em- see below...
-I found the Haynes manual very useful.
Exploded view found on internet, comment added:

Click pics to enlarge

I also renewed the pad pins (corroded) and the anti rattle springs,also the cover screws on the pad pins.
That's when the bad news came: See bottom pic -price in Euro's, in real money something like 148 US$...as sold by my T dealer.
A helpful link: http://www.dansmc.com/hydraulics.htm

Good luck,Thieu.
PS: I was lucky: only the front brake needed this overhaul.

Anchorbend · 10-11-2008, 07:37 PM

These are the front brakes which are used on several of the Honda cruisers like the 750 and I think the 1300. You will get the parts cheaper and also quicker from a Honda dealer.

http://www.bikebandit.com/houseofmot...o-2005/o/m2882

ohiorider · 10-11-2008, 08:23 PM

Thanks ................ good information. based on the cost, I may not do a rebuild at this time, IF the pistons slide relatively easy (as the one attachment stated ...thumb pressure). I'm punctual on valve adjustments, oil and filter changes, chain lube ...but for some reason, I do the brakes only when the mood strikes, and that isn't often!

Bob

Baltobonneville · 10-11-2008, 08:27 PM

Good information. Is there a rebuild kit available for these calipers, so the parts don't have to be purchased separately?

propforward · 10-11-2008, 08:46 PM

I don't know if there's a rebuild kit - that would certainly be convenient.

What I do with bike brakes like these is to make sure I wipe the pistons clean before pushing them back in. If you do that you shouldn't have to replace the seals very often. It has worked for me anyway.

Typically when installing new pads, I will clean all the parts on the brake assembly, wipe the pistons clean using a cloth with WD40. Wipe the pistons completely dry, and then I use a simple tool I made, which consists of two steel bars, with holes at each end. The two bars are joined by threaded studs at each end. This is placed over the caliper assembly, so that by gradually tightening the nuts on each stud, you push the pistons in.

Now - please note that you do not need the natural force this provides to push the pistons in - they should move very freely - but this way you can push both pistons (or more than 2) in at the same time, without trying to hold one while pushing the other......

Of course, a small G clamp will hold one piston while you push the other in.

Regualr changing of the brake fluid should stop gunge building up insode the caliper assembly.

That's what I do anyway - seems to work. The only time I have had problems with bike brakes is when they get left for extended amounts of time (5 years plus) with no use or attention.

fullplat1 · 10-12-2008, 02:46 PM

Hi Guys
just replace front and rear brke pads on my Bonnie. Most of what has been said previously is good advice except for the bit about wiping the pistons with WD40 on a rag, DONT, any mineral oil contamination has the potential to damage the caliper seals

Also keep the brake cleaner away from the piston/seal interface

I had the rear caliper off the bike, I carefully plugged the fluid port and took the caliper in to the kitchen , filled the sink with hot water and plenty of detergent, using a tooth brush I scrubbed away at the pistons until they were spotless, this took sometime and 2 changes of water. Once spotless and hot, the pistons were easy to ease back into the caliper. I then let the caliper dry befor hitting it with bike strength brake cleaner toremove the last of the road film. Refited to bike with EBC HH pads and new braided brake line, the ezibleeders did thier thing and the brake bled up in a few moments. Same procedure for the front
Phil

propforward · 10-12-2008, 06:58 PM

In 16 years of repairing and maintaining bike brakes, I've never seen WD40 affect a brake seal. A cloth dampened with the stuff gets those pistons clean without having to take the caliper off the bike. A separate dry cloth to dry the pistons removes / reduces the risk of getting some on the seals. So - given that brake fluid is a lot more corrosive than mineral oil, I'll stick with my method.

I'm intrigued now. Might have to get some old brake seals and soak them in WD40 and see if there's any effect.

Some good overall advice in this thread though.