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Or is it just me?
Ive SLX on a Rock Lobster that lost all resistance in the lever after about six months, and had to bleed it to get it slightly better. I've just had a problem with an XT back brake that the same thing has happened. Resistance at the lever goes unless you pump it 6 or 7 times but after about 5 seconds its back to the bar again. Ive bled it today (and yes I do know how to bleed brakes, if I didn't I would have killed myself on my old CBR600!) its only slightly better but it still comes back to the bar.
Pads on both were half worn, surely the rubber diaphragm in the reservoir is designed to take up pad wear?
Brakes were brand new and fitted two new bikes from two different bike shops
Anyone help?
Its just you....
I had SLX's...rock solid lever feel and no problems...did u bleed them top down....or caliper up?!
I did mine top down!
i had this, it was air stuck in the calliper - and yes i also know how to bleed brakes 😉
for some reason it was rather stubborn!
rangerbill - Member
Ive bled it today (and yes I do know how to bleed brakes,
If it's bled properly, then the behaviour you describe will not happen. Go to the back of the class and try again.
As onion says, your doing something wrong. Try bleeding with two syringes and forcing mineral oil through the system from the bottom.
Well I've got this too. I decided I could see fluid coming out past the piston on the rear XT caliper. I've spent most of this afternoon fitting a new caliper and trying to bleed them (and actually I've never done this before but I do know what I'm doing!) but find masses of bubbles coming out with the fluid level remaining the same in the reservoir. I guess therefore that there's a leak somewhere (can't see where) or that the lever is knackered. When I opened the reservoir lid it was empty.
Any help welcome!
Have heard of this reverse bleed technique, I'm guessing its messy?
So How come I can bleed linked brakes on a car and van,similar single brakes on a motorbike but I have to do some random reverse bleed black magic shite for a MTB?
I had a similar issue which turned out to be a leaking seal at the caliper: would lose all power and too much lever throw, bleed would sort it, then quickly got worse again.
Take out the pads and 'burn' them over a gas hob: loads of white smoke = contamination (probably oil). Keep heating till the smoke disappears then put them back in the brake. Burn them again after a few days: more smoke indicates you've probably got a leaky seal. Unfortunatly cannot get new seals for shimanos, so new caliper time. This happened on very well used brakes though: less likely to be the isuue on a new set.
Paul4stones: sounds like one of the seals in the lever may have gone. i've had this too when just can't stop bubbles coming out into the reservoir. Solved for me with a new lever, maybe your caliper was fine?
DeeW,
Funny you should say that I did hear a whistling/sucking at the rear of the bike twice on todays ride, first time I thought it was the start of a puncture or my camelback!
Be interesting to see if I am a cack handed gimp (likely) or a knackered Shimano part.
As I have had two incidents on brand new bikes that I hadnt touched thought I would see if anyone else had suffered.
Paul4stones: sounds like one of the seals in the lever may have gone. i've had this too when just can't stop bubbles coming out into the reservoir. Solved for me with a new lever, maybe your caliper was fine?
Sorry if I'm hijacking here.
No the bubbles are out of the tube on the caliper not into the reservoir. I am wondering if the lever needs replacing. Wish I'd bought a whole set now having just looked at the price of levers . . .
Paul, keep bleeding and keep topping up the reservoir, the bubbles should eventually stop, then fit everything back together andthey should be tickety boo...or in my case, not!
If you suck air in through the reservoir you need to start all over again 😥
Yes indeed, I understand that. The problem is that the reservoir level does not drop particularly while the bubles persist.
i bleed mine from the bottom and remove excess oil from the reservoir as and when needed. if the bubbles keep persisting try tapping the caliper and the hose lightly to encourage the air to dislodge from wherever it's hiding. go and have a cup of tea and then come back to it.
i bled the front brake last night and had the same problem, but all is now good....
I'll hold off buying a new lever until morning then 🙂
Thanks
Similar issues with XT's here. A bleed and its sorted, for a bit anyway.
I'll see what it's like on the Sunday ride after tonight's bleed session.
This is a common problem on the XT brakes, I have stated before these are a pain in the ass to bleed. Every other brake system I have had have always been a doddle to bleed.
I had the same issue for the first few times, I would bleed from the caliper end till no more bubbles were seen. Everything would be ok then all of a sudden the lever would return to the bar and a few sudden pumps would harden it up again.
I found if you leave the res cap on and the lever pulled back (isolating the caliper) attach a syringe full of mineral oil to the caliper and crack the bleed nut, then create a vaccum by pulling on the syringe you should be able to remove the trapped air in the caliper.
I found if you leave the res cap on and the lever pulled back (isolating the caliper) attach a syringe full of mineral oil to the caliper and crack the bleed nut, then create a vaccum by pulling on the syringe you should be able to remove the trapped air in the caliper.
this is what i had to do, just doing a bottom-up bleed isn't enough