New Master cyl

Tiny
ANONYMOUS
  • MEMBER
  • 1995 NISSAN HARDBODY
  • 200,000 MILES
New master cyl. Calipers, and rear cyl. Bench bled master cyl. And all 4 wheels; no air. Now, must pump brakes to build pressure then once released wait 2 seconds and the pedal goes back to the floor. If I pump the brakes up, the pedal will hold pressure and not sink to the floor unless released, once released it goes straight back to the floor and you have to pump again. Any ideas?
Thursday, December 20th, 2012 AT 12:15 AM

6 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Sounds like you still have air somewhere. In some condition, you have to have it pressure bled to rid of air.

Try opening the bleeders and see if they gravity out the air. Let them open for about 15 minutes and watch fluid level

roy
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Thursday, December 20th, 2012 AT 12:29 AM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
TRY BLEEDING "MY WAY"---THE "TRADITIONAL" WAY

https://www.2carpros.com/questions/1999-ford-f-150-brakes--3

RETURN WITH A GRIN!

THE MEDIC
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Thursday, December 20th, 2012 AT 12:32 AM
Tiny
ASEMASTER6371
  • MECHANIC
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LOL. Nice CJ

Happy holidays to you

Roy
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Thursday, December 20th, 2012 AT 12:35 AM
Tiny
RYANROY
  • MEMBER
  • 1 POST
We have opened all bleeders and applied quick pressure to pedal and get a good solid stream out of all wheels. We have run 3 qts of fluid thru it bleeding the system. There is some sort of abs module on the frame rail passenger side as well as the load proportion cyl. Above the rear diff. Bled both of these as well and no change. As I said the pedal will hold pressure if held down after pumping but loses pressure almost instantly once you let it up. Don't think there could be any air in the lines. Anything else?
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Thursday, December 20th, 2012 AT 12:40 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Try blocking off each wheel with plastic pliers on the brake hoses. Do all of them and see how the pedal is. If it is good, then release one at a time and when the pedal falls, thats where the problem is.

If the pedal is still bad with all blocked off, bad master cylinder

Roy
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Thursday, December 20th, 2012 AT 12:47 AM
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
IF THAT AIN'T A WORKIN'---WHAT ASEMaster6371 JUST SAID

BEFORE YOU RUN OUT A BUY A MASTER CYLINDER

PLEASE EXPLAIN "EXACTLY" HOW Y'ALL ARE DOIN' THE BLEEDING PROCEDURE

THE MEDIC
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Thursday, December 20th, 2012 AT 1:00 AM

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