Bleeding brakes
Thread Starter
Heel & Toe
Joined: Jan 2016
Posts: 15
Likes: 1
Bleeding brakes
I'm power bleeding the brakes on my 69 vette. When the fluid first starts draining, it's more solid but the longer I let the power bleeder go, it just starts suckin air. Could there be that much air in the line or am I missing some air leak somewhere? Help please, thanks.
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
I'm power bleeding the brakes on my 69 vette. When the fluid first starts draining, it's more solid but the longer I let the power bleeder go, it just starts suckin air. Could there be that much air in the line or am I missing some air leak somewhere? Help please, thanks.
and dimension in size and quantity, over time.
which could be a caliper piston seal,
especially if you still have the older style caliper piston seals.
Thread Starter
Heel & Toe
Joined: Jan 2016
Posts: 15
Likes: 1
Is the answer to replace calipers? I just replaced the rear calipers, haven't gotten to front calipers yet. But front and rear brakes have separate reservoirs in the master cylinder so an air leak in the front wouldn't have an affect, right?
Burning Brakes
Joined: Sep 2009
Posts: 1,124
Likes: 140
From: Western New York
I guess it all depends on the type of power bleeder you're using. If it's a Motive bleeder that pressurizes the system through the master cylinder and adds fluid to the master as you open up a bleeder, then keep bleeding until all the bubbles are gone. Motive is the best!
On the other hand, if you're using a bleeder like the Mighty Vac that attaches to the bleeder via a hose that sucks the fluid from the caliper, you are more than likely sucking air around the bleeder itself. Most guys put a glob of grease around the bleeder threads to try to prevent this. Also don't forget to add fluid to the master if you're using a Mity Vac type bleeder. If it gets too low you'll suck air into the system and have to start all over again.
I've used both types and find the Motive to be the easiest and most efficient, but for a really firm pedal, my wife does the pedal pumping while I open and close the bleeder. It's the easiest. Get a buddy to help. Good luck.
Duane
On the other hand, if you're using a bleeder like the Mighty Vac that attaches to the bleeder via a hose that sucks the fluid from the caliper, you are more than likely sucking air around the bleeder itself. Most guys put a glob of grease around the bleeder threads to try to prevent this. Also don't forget to add fluid to the master if you're using a Mity Vac type bleeder. If it gets too low you'll suck air into the system and have to start all over again.
I've used both types and find the Motive to be the easiest and most efficient, but for a really firm pedal, my wife does the pedal pumping while I open and close the bleeder. It's the easiest. Get a buddy to help. Good luck.
Duane
Last edited by Duane4238; May 27, 2016 at 11:06 PM. Reason: misspelled word
Intermediate
Joined: Sep 2012
Posts: 27
Likes: 1
I use the Phoenix brake bleeder system that pushes from the bleeder into the m/c. Been working great for many projects. Mine, with manual brakes always seemed a little soft regardless of the draw through tool I used under $150 dollars. Bought the Phoenix system, and I have a nice firm pedal.
Lifelong Vette Lover
Joined: Feb 2016
Posts: 177
Likes: 35
From: Naples FL
Pressure Bleeding Leaks
Hi, guys. I'm new to the Forum but have really learned a lot from numerous threads. Some very knowledgeable folks!
Brake question on my 69: I'm using a Motive pressure bleeder to bleed new lines, calipers, etc. and have had some leaks. Looks like for most of them, I didn't have the fittings tight enough but I'm still getting a good leak from the proportioning valve/block to the hard line for the right front. It's very tight now and I'm concerned about over torqueing it. Any suggestions on how to stop it? Dare I use Teflon tape? Other?
Thanks much.
Brake question on my 69: I'm using a Motive pressure bleeder to bleed new lines, calipers, etc. and have had some leaks. Looks like for most of them, I didn't have the fittings tight enough but I'm still getting a good leak from the proportioning valve/block to the hard line for the right front. It's very tight now and I'm concerned about over torqueing it. Any suggestions on how to stop it? Dare I use Teflon tape? Other?
Thanks much.
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Burning Brakes
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
Hi, guys. I'm new to the Forum but have really learned a lot from numerous threads. Some very knowledgeable folks!
Brake question on my 69: I'm using a Motive pressure bleeder to bleed new lines, calipers, etc. and have had some leaks. Looks like for most of them, I didn't have the fittings tight enough but I'm still getting a good leak from the proportioning valve/block to the hard line for the right front. It's very tight now and I'm concerned about over torqueing it. Any suggestions on how to stop it? Dare I use Teflon tape? Other?
Thanks much.
Brake question on my 69: I'm using a Motive pressure bleeder to bleed new lines, calipers, etc. and have had some leaks. Looks like for most of them, I didn't have the fittings tight enough but I'm still getting a good leak from the proportioning valve/block to the hard line for the right front. It's very tight now and I'm concerned about over torqueing it. Any suggestions on how to stop it? Dare I use Teflon tape? Other?
Thanks much.
big NO on Teflon tape.
Lifelong Vette Lover
Joined: Feb 2016
Posts: 177
Likes: 35
From: Naples FL
Melting Slicks
Joined: Jun 2000
Posts: 3,431
Likes: 298
From: MN-C3, AZ-C7
Grease the bleeder.....good tip. I did mine last week. I started with my mini-vac, but as usual...too much air getting around the nipple causing bubbles. I then tried my one person bleeder with the one way valve.....better but even with a circle clip over the hose at the bleeder I was drawing in some air. Okay out came the Motive pressure bleeder. A tip on here about using "C"clamps to hold the bleeder top on the master cylinder worked like a charm! I should of just grabbed the Motive to begin with.
