- 2008 XT Brake set-up advice
I’m having one last go with these infuriating things, otherwise it’s back to the BB7s & XTs up on Classifieds.
One of the supposed advantages is the ability to adjust the throw, allegedly, by means of that little “free stroke” screw at the base of the reservoir. I thought this would retract the pads into the caliper a bit, and so increase the gap between them and the rotor. As far as I can tell, it does nowt.
As far as I know I bled them with the screw in the full in position and using the yellow spacer block.
Anyway, the pads seem very close to the rotor, and it’s almost impossible to set them up without the rotors rubbing the pads.
So how do you get it so that you have maximum pad clearance? And any tips on how to get these things running troublefree?
ThanksPosted 9 years ago
Fair dos, but I don’t want to get my LBS to do them (largely because what was my LBS is now 200 miles away!).
The BB7s stop me well enough – I just want to see if I can get the XTs to work so that I can find one single advantage over the BB7s, and good pad clearance would be a start.Posted 9 years agobigyinnMember
I had a set of 2nd hand M770s off the classfieds, so about a year old max. Replaced the hoses with the goodridge braided ones i already had.Posted 9 years ago
Took a while to get them bled properly. Best way seems to be from the caliper to the lever.
Another trick is bleed then as best you can and then zip tie the lever as close to the bars as you can, then leave overnight, this helps get the remaining bubbles out of the hoses. Also helps if you have the hoses as vertical as possible so the air can rise easily. I did make sure the caliper was supported so it didnt bend the hose too much.
Pistons have been a “little” sticky, but a bit of time working the pistons in and out and lubing with brake fluid has helped.
The free stroke doesnt change the pad clearance, it just changes the relationship between the master cylinder and the lever. So you can “tune” where you have the brakes starting to bite.
Im pleased with them and yes the power is plenty to slow a 17st lump like me with no issues.
Looking forward to putting so new pads in, as originals havent worn evenly (suspect due to aforementioned sticky pistons).
PS A re-bleed after a couple of bedding in rides will prob help too!dave_aberMember
As BigYin says. Always bleed by injecting fluid at the caliper, preferably with the brake off the bike, hose as near vertical as possible.
Can’t work out why the “brake held ‘on’ with a tywrap overnight” thing works, but it does.
Done this way I’ve never had any real headaches with XTs.Posted 9 years agoDezBSubscriber
Weird, I did a rush job fitting the rear brake Saturday before a ride on Sunday and it worked perfectly.Posted 9 years ago
Just the usual – follow the Shimano instructions – open bleed valve, fill reservoir, squeeze lever, pump. Used the yellow block.
The only tricky part I’ve found is getting the bleed valve opened the right amount, so experiment with that, and tap the caliper and hose occasionally to remove air bubbles.
here for Shimano docsimp999Member
You don’t need a huge rotor clearance if the rotor is true and the caliper centred on it.
Is the pad touching the rotor all the way round? no= rotor needs tweeking.
yes, one pad contact,=caliper needs centring. Undo mounting bolts, squeeze lever, tighten bolts alternatly small amount at a time to prevent caliper twisting.
Sometimes one piston can move more than the other and this means that the other hits the rotor first and deflects the rotor. Try to free off any stickyness or compensate for the piston that is not retracting fully by biasing the caliper as you tighten(3 hands needed)
Good luck.Posted 9 years ago
Rotors are totally true (fairly new RT97s) – I’ve checked using a zip tie attached to the fork leg and there’s as close to zero warping as makes no difference.
I set them up as you say, imp999, but still get either constant or partial rotor/pad rubbing – which one I get is one of the delightful surprises involved. Zero rubbing doesn’t seem to be an option.
Sticky pistons I’ve also had to have a go at & a leaking one too (including returning one caliper & getting a replacement).
I can see this needs a few hours put aside, and lots of sweet tea to calm the nerves / relieve stress.Posted 9 years agostMember
I never needed to use a spacer block when bleeding any brakes including current model XTs.
I’d always suggest pushing the pistons right back into the caliper so that they are flush and bleed from there. Unless you’re pulling on the lever with the bleed nipple closed there should be no movement in the pads during the bleeding process.
This then ensures that the pistons are set up with the right amount of fluid to allow the pistons to fully (or very nearly fully) retract.Posted 9 years ago
Yes, ridden. Fine initially, then started to rub. Rebled & checked no stickiness, but thereafter they were very hard to set up with no rubbing, as if the pads were closer to the rotor than initially.
Then got a leaky piston which trashed a set of pads so got a replacement caliper. Now about to re-install them.
Having found them lovely when first set up I bought a second set for another bike. They’re now behaving the same – sticky pistons, rubbing etc. Thanksfully I’ve kept my BB7s which have been troublefree for years.Posted 9 years agodickieMember
I’ve got 3 pairs of these & on 3 brakes had the sticking piston problem.
Take out pads, push pistons in, hold one piston in & pumpp out other other with lever, put some brake fluid round piston & push back in – repeat 10x.
Then do other piston – re assemble.
Best brakes I had. Stick with them.Posted 9 years ago
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