rebuilt master and caliper, squishy lever still.


13 replies to this topic
  • Hakkalugi

Posted April 04, 2016 - 07:14 AM

#1

Hey guys I recently rebuild my master & caliper. Everything went together smoothly & I tried bleeding it for a while till finally I got no bubbles. The lever is still squishy and nearly to the bars before the thing will stop. Took it for a little ride the other day hoping maybe I could work some bubbles loose but it didnt seem to help any. Ive bled all kinds of brakes before but I just cant get this one right. Should I try a vacuum bleeder or just suck it up and buy a new master? 



  • grayracer513

Posted April 04, 2016 - 09:14 AM

#2

Probably a bubble in the banjo fitting at the master.  You mentioned pulling the lever to the bars, so I'm assuming this is the front.  Start by opening the reservoir and filling it, then open the bleeder and let it gravity bleed until you don't have anymore air running out the bleeder.  Be sure to keep the reservoir filled above bottom during the process.  Once satisfied with that, close the bleeder and turn the bars left so that the fluid path at the master runs uphill from the line to the reservoir.  Now move the lever through only the first 2-3 mm of travel.  You should get one bubble pop up and out, maybe two.  After that, it should be fine.



  • Hakkalugi

Posted April 06, 2016 - 12:23 PM

#3

Probably a bubble in the banjo fitting at the master.  You mentioned pulling the lever to the bars, so I'm assuming this is the front.  Start by opening the reservoir and filling it, then open the bleeder and let it gravity bleed until you don't have anymore air running out the bleeder.  Be sure to keep the reservoir filled above bottom during the process.  Once satisfied with that, close the bleeder and turn the bars left so that the fluid path at the master runs uphill from the line to the reservoir.  Now move the lever through only the first 2-3 mm of travel.  You should get one bubble pop up and out, maybe two.  After that, it should be fine.

 

awesome I will give this a try thank you 



  • Hakkalugi

Posted April 06, 2016 - 01:07 PM

#4

I gave it a go and it was a little better but still  not the solid lever i was looking for. Not sure whats going on here. 



  • OldMechanik

Posted April 06, 2016 - 01:12 PM

#5

Try pushing the caliper piston in to reverse bleed the system, lightly pump the lever and repeat a couple times.

 

 

Or you messed up the rebuild. :jawdrop:


Edited by OldMechanik, April 06, 2016 - 01:13 PM.


  • Hakkalugi

Posted April 06, 2016 - 07:09 PM

#6

ill try that out, the rebuild is pretty simple ill feel dumb if i messed up somehow. 



  • damnbiker94

Posted April 07, 2016 - 03:02 AM

#7

Most common mistake ive seen folks make with this repair is accidentally installing one of the brake piston seals backwards. Easy fix though.

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  • yz250f 78

Posted April 07, 2016 - 03:55 AM

#8

Bleed the banjo bolts like you would the bleeder

  • Hakkalugi

Posted April 07, 2016 - 08:14 PM

#9

Most common mistake ive seen folks make with this repair is accidentally installing one of the brake piston seals backwards. Easy fix though.

They are different sizes I made sure I put the right ones in the right spots. unless it matter which way they are facing? 

 

Ill try bleeding the banjo's tomorrow after I do the clutch I appreciate the help guys. 



  • damnbiker94

Posted April 08, 2016 - 04:41 AM

#10

Yes it matters which way they are facing. The open end (which is slightly wider than the closed end) of each piston must face inward as you press the assembly into the master cylinder bore.

  • grayracer513

Posted April 08, 2016 - 07:00 AM

#11

Yes it matters which way they are facing. The open end (which is slightly wider than the closed end) of each piston must face inward ....

 

...toward the brake hose.  Not toward the lever.



  • Arctic Pride

Posted April 08, 2016 - 07:35 AM

#12

if you zip tie the lever pulled in to the bar overnight it should force any air bubbles up to the master...



  • Hakkalugi

Posted April 08, 2016 - 02:00 PM

#13

Okay well I feel sorta dumb.. I had replaced my front brake lever because it was broken at the same time I rebuilt the master & caliper... Little did I know the new one had and adjustment to make it stick out further or come in closer. I bled the system for about 45 mins before discovering this. I moved it out about an inch and its a whole new brake now. I got alot of air out of the system while bleeding to using some (actually i tried them all) of the methods you guys mentioned. Its beautiful now. I also got a new clutch & clutch lever. Its like a whole new bike now. Pulls much harder without the clutch slipping and I can actually stop! Thanks for all the reply's. 



  • damnbiker94

Posted April 08, 2016 - 03:49 PM

#14

Lol we have all had moments of discovery like that. Glad the fix was simple.





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