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Discussion Starter · #1 ·
I've bled my XTR m9020 trail brake both ways..gravity and traditional.with a syringe. The brake doesnt have bubbles anymore, but is soft and the lever pulls to the grip.

This is only one side, other brake feel fine.

Is a new brake housing/lever assembly needed?

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I've bled my XTR m9020 trail brake both ways..gravity and traditional.with a syringe. The brake doesnt have bubbles anymore, but is soft and the lever pulls to the grip.

This is only one side, other brake feel fine.

Is a new brake housing/lever assembly needed?

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I had very similar issue, but I was using Shimano XTR m9000 race brakes.

I noticed one piston was sticking. Take a look at this video.


Unfortunately, I cleaned/lubed the pistons and changed out the pads at the same time, belt & suspenders approach. But the brake feel is greatly improved. I just can't say what was the determining factor.

Let me know how you get on...

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Discussion Starter · #3 ·
I had very similar issue, but I was using Shimano XTR m9000 race brakes.

I noticed one piston was sticking. Take a look at this video.


Unfortunately, I cleaned/lubed the pistons and changed out the pads at the same time, belt & suspenders approach. But the brake feel is greatly improved. I just can't say what was the determining factor.

Let me know how you get on...

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Thx

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Have you checked that the connections from the bolts going into the lever and caliper are properly torqued up? If they're not the problem, have you looked to see if you see a leak anywhere in the caliper, checked the pads for contamination to indicate a leak? How worn are your pads? Does the lever pull and return freely? If you're down to 1/3 or less, try new pads.

Never had any issues with Shimano brakes once they're properly bled and don't have a fault/leak, check your bleed and try the gravity one again and don't forget when you close of the bleed nipple at the caliper to then give the lever a further bleed.
 

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I've bled my XTR m9020 trail brake both ways..gravity and traditional.with a syringe. The brake doesnt have bubbles anymore, but is soft and the lever pulls to the grip.

This is only one side, other brake feel fine.

Is a new brake housing/lever assembly needed?

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Newer Shimano brakes are meant to be bled in one direction, caliper to lever. Make sure you're using the right bleed block. Also check to make sure your banjo bolt is tight. Third, make sure your pistons have not inadvertently pushed out from squeezing the lever without any pads or block in the caliper. I doubt it is your cable or lever.
 

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Well, once you've pushed fluid through the system, there's still the chance that there's air bubbles still stuck in the system, you need to go about taping the caliper and reservoir and move it about while pumping to try and help and force any air bubbles into the system (could be trapped in the corner somewhere) and get them out of the system.
One thing that can help is the pump the lever and then lock/tie it in the closed position for a decent period of time, which will pressurize the system and help to move any air bubbles to the top of the system.

Can you further clarify what you mean here?
 

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Discussion Starter · #9 · (Edited)
These are the older 1pots. I've bled both ways and this is a new issue with them. I didnt have this issue with them before. So not first time bleeding nor am I nee to it.



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These are the older 2pots. I've bled both ways and this is a new issue with them. I didnt have this issue with them before. So not first time bleeding nor am I nee to it.

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Is one piston sticking when you pull the brake lever? By chance, Is it the rear brake?

I noticed on my XTR, the rear pistons are black and the front piston is more like a ceramic white material.

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Discussion Starter · #11 ·
Is one piston sticking when you pull the brake lever? By chance, Is it the rear brake?

I noticed on my XTR, the rear pistons are black and the front piston is more like a ceramic white material.

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Yes. Rear. I'll have to check piston range of motion.

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Discussion Starter · #13 ·

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Discussion Starter · #14 ·
Thanks everyone for your help..

It was a.combination of cleaning the pistons as described in video above, zip tie the lever down for a bit and then attaching the funnel and pumping the lever to get the air out...btw my pistons were both white versions..


Thanks again


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Thanks everyone for your help..

It was a.combination of cleaning the pistons as described in video above, zip tie the lever down for a bit and then attaching the funnel and pumping the lever to get the air out...btw my pistons were both white versions..

Thanks again

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Nice!

Glad we could help...

Did you notice if one piston was sticking prior to cleaning?

And any more air bubbles come though while using the zip tie trick?

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Discussion Starter · #16 ·
Didnt look like one piston was slower than the other, but definately dirty. Ues bubbles came up after the zip tie.

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Another thing you can do is push/pause your syringe when bleeding. To do this, push just a few milliliters hard then pause, then repeat (all while keeping the line open). This creates turbulence in the line and will help move bubbles. I don't zip tie my lever but I do pump/release rapidly the lever with the funnel attached and at various lever angles, as the last step before I put the lever bleed port screw back in. I've also found that cotton pipe cleaners (gun supplies) work great to scrub around the pistons.
 
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