Fix/Workaround: Shimano XT M785 Brake Lever

[BaGearA]

you did remove 8?

 

then bottom up, ie. turn the lever with the name SLX facing down, and pushing 5 out

just the little rubber cap and then the grub screw right ?

[Meezo]

just the little rubber cap and then the grub screw right ?

yes!

[BaGearA]

took some motivating but i got it 

[Meezo]

took some motivating but i got it 

 

[BaGearA]

okay how does that small spring go back in , any tips I can't find anything on the net

[spyghost]

okay how does that small spring go back in , any tips I can't find anything on the net

It will help if you clamp the lever on bars as it'll free up both hands.

 

Do not pinch the spring until you are able to insert the rod. If you pinch the spring it'll resist and make reassembly harder.

[milky4130]

probably not, however what i have found that in extreme heat the piston would swell and the "brakes" would lock up due to the piston not being able to return the lever completely. if the race is on Sunday you could easily do this fix, but if you not keen on risking it, ride as is

Meezo have you discovered the cause of this, after a strip & clean of both levers they worked like brand new for more than 3 months now, suddenly the last 2 weeks the levers would stiffen up & lock up the pistons\disc pads. We have hardly had extreme heat in the Western Cape yet so curious to know why this is happening? Gonna attempt a strip down, clean, sand & bleed again as a last resort.

[droo]

Meezo have you discovered the cause of this, after a strip & clean of both levers they worked like brand new for more than 3 months now, suddenly the last 2 weeks the levers would stiffen up & lock up the pistons\disc pads. We have hardly had extreme heat in the Western Cape yet so curious to know why this is happening? Gonna attempt a strip down, clean, sand & bleed again as a last resort.

 

There's most likely either damage to either the piston or the lever bore, or there's debris in the system from the first time it seized.

 

Aside from rebuilds, how often do you bleed your brakes?

[spyghost]

There's most likely either damage to either the piston or the lever bore, or there's debris in the system from the first time it seized.

 

Aside from rebuilds, how often do you bleed your brakes?

Based on my use, I do it annual.

[Meezo]

Meezo have you discovered the cause of this, after a strip & clean of both levers they worked like brand new for more than 3 months now, suddenly the last 2 weeks the levers would stiffen up & lock up the pistons\disc pads. We have hardly had extreme heat in the Western Cape yet so curious to know why this is happening? Gonna attempt a strip down, clean, sand & bleed again as a last resort.

As droo says, there is very little to no room for expansion.

 

So the debris or dirt that comes over time can too be the cause, i still think that bit we sanding off is not necessarily the actual plastic or rubber of the piston rather just the dirt of of old tired brake fluid.

 

I've taken the time to read Shimano manuals they actually recommend brake fluid gets changed every 3 months, clean refreshed brake fluid means little to no dirt and no build up on the pistons.

 

So yes, open them up give them a thorough scrub and clean, sand very little if you need to, rebleed and off you go...

[dev null]

I recently serviced the brakes on my wife's MTB, and it is amazing how quickly the oil gets dirty. I would suggest a complete oil change every 6 months. That is if you ride around 25km per week.

[Meezo]

I recently serviced the brakes on my wife's MTB, and it is amazing how quickly the oil gets dirty. I would suggest a complete oil change every 6 months. That is if you ride around 25km per week.

 

hijack, i haven't forgot about the damper, again 10000000000000000 thanks for the kind offer. instead i've bought a new fork that i plan replacing my existing fork! apologies too for not getting back to you.

[milky4130]

There's most likely either damage to either the piston or the lever bore, or there's debris in the system from the first time it seized.

 

Aside from rebuilds, how often do you bleed your brakes?

 

 

As droo says, there is very little to no room for expansion.

 

So the debris or dirt that comes over time can too be the cause, i still think that bit we sanding off is not necessarily the actual plastic or rubber of the piston rather just the dirt of of old tired brake fluid.

 

I've taken the time to read Shimano manuals they actually recommend brake fluid gets changed every 3 months, clean refreshed brake fluid means little to no dirt and no build up on the pistons.

 

So yes, open them up give them a thorough scrub and clean, sand very little if you need to, rebleed and off you go...

to be honest the 1st strip down I did not sand, just a clean out & re-assemble. I think the most recent cease up could be more debris from another very muddy ride post the strip down. I just didnt think it would cease up so soon again. The last time I bled was when i was stripping the levers which was about 3-4 months ago i think. 

 

 

So actions I'll take now, sand piston, clean out lever, fresh fluid with bleed, still contemplating new hoses.

[babse]

time for an oil change before the heat it seems, its been 12 or so months 

[dev null]

hijack, i haven't forgot about the damper, again 10000000000000000 thanks for the kind offer. instead i've bought a new fork that i plan replacing my existing fork! apologies too for not getting back to you.

 

Yes, you are in the dwang.

 

You better come deliver some curry chicken rotis to atone for the emotional damage caused. 

Edited September 19, 2017 by Moridin

[Meezo]

Yes, you are in the dwang.

 

You better come deliver some curry chicken rotis to atone for the emotional damage caused. 

this can be arragned :thumbup: