No brakes

Tiny
JOHNATHAN ADAMS
  • MEMBER
  • 2003 CHEVROLET SILVERADO
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 170,000 MILES
My dads truck had a brake line blow. We changed the line, bled all four corners, and another blew. Got it changed, had to change master cylinder as well because it was leaking internally. Got everything changed out, had pressure without the truck on, but as soon as the key was turned they went to the floor. It has ABS brakes. What else could cause it to have no pressure when running? The truck is the 1500 model.
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Thursday, September 28th, 2017 AT 3:05 AM

3 Replies

Tiny
KEN
  • ADMIN
It sounds like you have air still trapped int he system. When you replaced the master cylinder did you bench bleed it?

Here is a guide to help you get the job done and back on the road:

https://www.2carpros.com/articles/how-to-replace-a-brake-master-cylinder

and

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

Please let us know what happens and upload pictures or videos of the problem.

Cheers, Ken
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Thursday, September 28th, 2017 AT 2:58 PM
Tiny
JOHNATHAN ADAMS
  • MEMBER
Thanks for the information Ken.

Yeah we bench bled the cylinder. I am thinking that when we did that, I accidentally shoved the piston to far into the cylinder and blew a seal in it. Or it was just a defective cylinder to begin with. Or a combination of the two. Could that have caused it? The last time we changed it, we did not bench bleed it, but we bled it on the truck and never had this problem. So a new cylinder is probably in order, but we are going to change out the rear calipers first because the driver side is froze. I will post pictures when we get up to the garage to work on it. I have none at the moment. I am also wondering if an air pocket in the frozen caliper could cause the problem? I know enough about working on cars to get me into trouble, but not enough to consider myself a mechanic.

Thanks again,
Johnathan
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Thursday, September 28th, 2017 AT 3:42 PM
Tiny
KEN
  • ADMIN
That is what you have us for, we can help you with anything. :) The air in the system should be able to be bled out even with a frozen caliper. Let me know what happens after the new master cylinder.

Best, Ken
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Friday, September 29th, 2017 AT 9:22 AM

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