- This topic has 15 replies, 9 voices, and was last updated 15 years ago by dickie.
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2008 XT Brake set-up advice
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FarticusFull MemberPosted 15 years ago
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?
Thanks
zokesFree MemberPosted 15 years agoI gave up setting these up too, and gave them to the LBS, and it took them most of a disgruntled day. Now they are set up on the DH bike however, I reckon they could stop a tank! A pain to set up, but VERY powerful once done, and good modulation too. Stick with them….
FarticusFull MemberPosted 15 years agoFair 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.
FarticusFull MemberPosted 15 years agoAnyone got these set up properly? HEEEELLLLLLLLLLLPPPPPPPPPPPPPPPPPPPPP!!
davidtaylforthFree MemberPosted 15 years agoOn my older XT’s it seemed to be a case of getting the right amount of fluid in the system.
Try letting a very small amount out of the bleed nipple. Then push the pistons right back into the caliper, refit and try again.
bigyinnFree MemberPosted 15 years agoI 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.
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).
HTH
PS A re-bleed after a couple of bedding in rides will prob help too!dave_aberFree MemberPosted 15 years agoAs 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.
bigyinnFree MemberPosted 15 years agoTake your time and be patient.
They’re a lot more fussy to setup than my old M555s, but im VERY happy with my XTs now.
The brake held on works as it allows any trapped air bubbles to rise in the hose and return to the fluid reservor in the lever.DezBFree MemberPosted 15 years agoWeird, I did a rush job fitting the rear brake Saturday before a ride on Sunday and it worked perfectly.
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 docsFarticusFull MemberPosted 15 years agoCheers all.
I bled them originally from caliper up to lever using the pukka Shimano kit. I have had a sticky piston problem, so maybe I need to sort them out & re-do them from scratch.
The more I have to do, the better BB7s seem to be.
imp999Free MemberPosted 15 years agoYou 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.
FarticusFull MemberPosted 15 years agoRotors 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.
stFull MemberPosted 15 years agoI 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.
imp999Free MemberPosted 15 years agoFarticus
Have you actually ridden the things yet? I wonder if the pads are not parralel and need bedding in before you even start all the setting malarky.FarticusFull MemberPosted 15 years agoYes, 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.
dickieFree MemberPosted 15 years agoI’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.
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