# Brake Bleeding on my 1979 gmc



## illday (Oct 12, 2003)

The new starter did the trick (thanks to ya'll for helping me troubleshoot that problem. Here's the latest issue my truck.

Throughout the day I could feel air in my brakelines. By
the end of the day I had no brakes. Checked my fluid and it
was low, so I filled it. Figured the next step would be to bleed my
brakes. I'll spray the bleeder with wd40 tonight and bleed them
in the morning. I got confused when the rear tires each had
bleeders. Does this sound rite? I'll admit it, I'm a rookie when
it comes to brakes. This is the first time I bled the brakes.
This old truck has paid for itself a thousand times over and I
want to keep it on the road for another 25 years.
Any tips on this would be helpful.


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## wfd44 (Jan 31, 2004)

Each wheel cylinder will have a bleeder screw. Start at the wheel furthest from the master cylinder (right rear) and progressively closer to the master until you finish with the left front.


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## illday (Oct 12, 2003)

Bled the brakes and still no brakes. Is it possible that old fluid
could cause a complete Brakes loss.
Here's what is happening...
My brakes pump up when the
truck isn't running and go straight to the floor as soon as I start
the engine and won't pump at all with the engine running.
Any suggestions would be helpful.


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## towman (Aug 19, 2003)

sounds like you need a master cylinder


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## ratplow408 (Apr 7, 2004)

Look for fluid in cab or fire wall.


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## jrm123180 (Aug 23, 2004)

Master cylinders are cheap...I think I paid like $15-20 at autozone for one for my 79 chevy K10 and I believe that has a lifetime warranty. If yours is original, i would just replace it, regardless, for that price.


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## POWERBAND (Jan 18, 2001)

*Brakes broke*

Chevys of that era can be a bear to bleed, especially for a novice. The proportioning/safety valve will shut off the rear circuit if you crack the rear bleeders to respond to a "fault" lack of pressure. Also if the MC has been pumped dry it will take a "bench bleed" or close to it on the truck before you can start with the wheel cylinders.

I don't want to discourage anyone trying to learn but please try to get someone who's _been there done that_ to show you instead of a frustrating exercise. You could also try a FSM or decent aftermarket book to learn the procedure. YOu can do it and it is easier after the first dozen times or so.

PB


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