Bleeding XT Disk br...
 

[Closed] Bleeding XT Disk brake HELLLLLL - Help!?!

Posts: 0
Free Member
Topic starter
 

Hello,

Being somewhat of a **** I drove my car with the bikes on the roof under a barrier and ripped them off the car. Not too much damage but snapped the clamp on my rear brake lever (br-m785) and dented my forks:(

However after getting and fitting a new xt disk lever I just cannot get it to bleed preperly. I have bled lots of disk brake before but have never had an issue like these. The issue is, on first pull the lever feels o.k (ish) but on repeated pulls (even 2 or more) the lever pumps out and starts to feel like it should. This results in a big changing of the lever bite point. Its actually doing my nut in. I've even tried ordering a second slx lever and it does the exact same thing. I cant see any further bubbles coming out either.

Please someone say they've had the same issue!

HELP!

Thanks for any advice.


 
Posted : 26/11/2012 3:19 pm
Posts: 6480
Free Member
 

make sure the servo / bite adjust is adjusted to be in the middleish, doesnt like being fully in or out, cant remember which.


 
Posted : 26/11/2012 3:22 pm
Posts: 0
Free Member
 

Genuinely interested to see what anyone else says about this. I'm in a similar position - never once been able to get a satisfactory bleed on my 785s and when I bleed them, never seem to get many/ any bubbles out.
It's a shame, because when they are working properly, they are by far the best brakes I've used.
Got a new lever waiting to go on my rear brake after damaging the original in a crash. Hoping for better results...


 
Posted : 26/11/2012 3:26 pm
Posts: 0
Free Member
Topic starter
 

I agree, the brakes are amazing when you get them and I've never had any issues up till now. I've spent hours and hours trying to get these bled and it just aint happening. I've tried all the you tube vids and methods to try and get them going and nothing. sometomes with the bleed block in it feels good then once its set back up with the pads in etc just get the same old issue.

The brake is now off the bike and hanging from the shed roof to try and get the air to rise!!!!

For the servo thing do you mean the dial you twist to adjust the lever in or out or the (useless) free stroke screw?

cheers

chris


 
Posted : 26/11/2012 3:30 pm
Posts: 9021
Free Member
 

I had this a week ago. Bled my SLXs for the first time (long overdue!) since I was building a new bike and had a right mission to get them working.

In the end I read something about reverse bleeding them (so pumping oil via the syringe into the caliper and forcing bubbles upwards to the lever). Worked first time... Huge power ๐Ÿ˜€


 
Posted : 26/11/2012 3:31 pm
Posts: 2745
Full Member
 

You need something like [url= http://www.epicbleedsolutions.com/products/bleed-kits/shimano/complete-kit/ ]THIS [/url].

Video to help is also [url= http://www.epicbleedsolutions.com/resources/videos/ ] HERE[/url].


 
Posted : 26/11/2012 3:38 pm
Posts: 6480
Free Member
 

CG- free stroke but winding the reach in and out can dislodge bubbles aswell.


 
Posted : 26/11/2012 3:41 pm
Posts: 1428
Free Member
 

mine bled fine first time following the shimano instructions (push fluid up from the caliper into the funnel screwed into the lever)

I also thought that the bite point adjust screw did nothing, but bleeding this with the screw out, and then screwing it in as far as needed after bleeding seemed to make all the difference


 
Posted : 26/11/2012 3:41 pm
Posts: 0
Free Member
Topic starter
 

Has anyone had the bite point change after the lever pulls issue? Just curious so i know it isnt just me...


 
Posted : 26/11/2012 4:18 pm
Posts: 77
Free Member
 

I bled my rear 785 XT brake the other weekend and had major problems, so admitted defeat and took it into my supplying LBS, who after an hour or two also had problems and decided it was faulty. I am now awaiting a warranty swap out from Madison, who dont have any in stock until end of month....so I guess its not just mine that is faulty?


 
Posted : 26/11/2012 4:45 pm
Posts: 0
Free Member
 

Buy Hope

Arrrrrrrrrrrrrrrhahahaharrrrrrrrrr


 
Posted : 26/11/2012 4:47 pm
Posts: 0
Free Member
Topic starter
 

Variflex - was yours working ok until you had to bleed it?

Mine was working fine up til I banjod the lever and had to swap. But then the two replacement levers I had on, an xt one and a slx have had the same issue.I even bought the slx in case the xt was from a faulty batch.


 
Posted : 26/11/2012 5:14 pm
Posts: 0
Full Member
 

As others have said, reverse bleed with the Shimano kit works a treat. I got fed up of doing mine, then the seals went, cant buy new ones. ๐Ÿ™
So I bought HOPE. Happy now ๐Ÿ˜€


 
Posted : 26/11/2012 5:35 pm
Posts: 8892
Free Member
 

Always screw the free stroke screw out completely when bleeding 785 brakes. This increases the size of the reservoir slightly and makes getting all the bubbles out really easy. If you bleed them with the screw right in then there isn't enough fluid in the master cylinder to make a difference if you then screw it out.

There is a much smaller amount of fluid in the newer systems compared to older ones so even a tiny bubble can make a difference to the brake performance.


 
Posted : 26/11/2012 5:37 pm
Posts: 66087
Full Member
 

DaveyBoyWonder - Member

In the end I read something about reverse bleeding them (so pumping oil via the syringe into the caliper and forcing bubbles upwards to the lever)

Is that not what the instructions tell you what to do? Old M775 originally recommended messing about with hoses and bags and was generally a total fiasco but I think pretty much everone knew to reverse bleed them. But now the funnel thing only really lends itself to reverse bleeding, which ought to mean less people doing it wrong.


 
Posted : 26/11/2012 5:39 pm
Posts: 0
Free Member
 

This video is also good


 
Posted : 26/11/2012 6:02 pm
Posts: 77
Free Member
 


Variflex - was yours working ok until you had to bleed it?

Mine was working fine up til I banjod the lever and had to swap. But then the two replacement levers I had on, an xt one and a slx have had the same issue.I even bought the slx in case the xt was from a faulty batch.

Yes it was to a point, although after changing pads the lever went slightly spongy and couple of pumps on the lever got it back up to a solid feel again, hence why I thought it had air in.


 
Posted : 26/11/2012 8:49 pm
Posts: 0
Free Member
 

DaveyBoyWonder - Member

In the end I read something about reverse bleeding them (so pumping oil via the syringe into the caliper and forcing bubbles upwards to the lever)

Is that not what the instructions tell you what to do? Old M775 originally recommended messing about with hoses and bags and was generally a total fiasco but I think pretty much everone knew to reverse bleed them. But now the funnel thing only really lends itself to reverse bleeding, which ought to mean less people doing it wrong.

Shimano calls it One Way Bleed, you're meant to bleed their new brakes from the caliper up!


 
Posted : 26/11/2012 11:02 pm
Posts: 0
Free Member
 

Mister P - Member
Always screw the free stroke screw out completely when bleeding 785 brakes. This increases the size of the reservoir slightly and makes getting all the bubbles out really easy. If you bleed them with the screw right in then there isn't enough fluid in the master cylinder to make a difference if you then screw it out.

There is a much smaller amount of fluid in the newer systems compared to older ones so even a tiny bubble can make a difference to the brake performance.

I think that's the tiny bit of advice I need to get mine working perfectly again. Cheers.

Oh, and thanks for the pads I bought off you at the Dyfi GE, earlier this year. I think I would have killed myself with the rubbish Superstar pads in.


 
Posted : 26/11/2012 11:08 pm
Posts: 0
Free Member
Posts: 0
Free Member
 

It's definitely not just you who has this problem. I persevered with my SLXs for a year before giving up an buying an XT for the rear. Same pumping up problem. And that's with a lot of bleeding.

Now all three are hanging up in the shed and I'm back on my Formula Oros. Nowhere near as good a brake, but at least the lever feel is consistent!


 
Posted : 27/11/2012 12:02 pm