Brake bleeding issue

Tiny
OLSKWL
  • MEMBER
  • 1978 PONTIAC TRANS AM
  • 130,000 MILES
No fluid to back brakes when bleeding or very little, Brake pedal very spongy.
Wednesday, March 11th, 2020 AT 6:38 AM

4 Replies

Tiny
94 TRANSAM
  • MECHANIC
  • 680 POSTS
It sounds like either you have air in the master cylinder or the rear plunger has failed. It could also be a plugged proportioning valve.

If you have someone step on the brake and crack the rear line lose on the master what kind of flow do you have there? Note do not let the brake pedal up until you re-tighten the line or you will let air into the master.

Rich
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Wednesday, March 11th, 2020 AT 11:37 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Here is a brake bleeding guide to help also a low brake pedal troubleshooting guide as well:

https://www.2carpros.com/articles/how-to-bleed-or-flush-a-car-brake-system

and

https://www.2carpros.com/articles/brake-pedal-goes-to-the-floor

Please run down these guides and report back.
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Wednesday, March 11th, 2020 AT 2:45 PM
Tiny
OLSKWL
  • MEMBER
  • 2 POSTS
I put on a new master cylinder that seem to do the trick so far. Thank you for all the input.
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Wednesday, March 11th, 2020 AT 8:23 PM
Tiny
94 TRANSAM
  • MECHANIC
  • 680 POSTS
Sure, let us know if you need anything else.

Rich
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Wednesday, March 11th, 2020 AT 8:48 PM

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