Brake bleeding question
Thread Starter
Drifting
Joined: Oct 2007
Posts: 1,317
Likes: 22
From: Marina CA
Brake bleeding question
Wrapped up the rebuilt trailing arm installation today (thanks GTR1999!) and bled the brakes using the MityVac which has worked well on other vehicles in the past.
Went through 2 quarts of fluid and still getting air out of the system. Bled inside rr, outside rr, inside lr, outside lr, rf and then lf.
Had a great pedal before all of this. Installed new ss calipers, rotors, pads and all new hoses. The m/cylinder was 6 months old so it wasn't replaced.
Pedal can be pumped up so it's definitely air.
Is an exorcism needed or am I missing something in the bleeding procedure?
Went through 2 quarts of fluid and still getting air out of the system. Bled inside rr, outside rr, inside lr, outside lr, rf and then lf.
Had a great pedal before all of this. Installed new ss calipers, rotors, pads and all new hoses. The m/cylinder was 6 months old so it wasn't replaced.
Pedal can be pumped up so it's definitely air.
Is an exorcism needed or am I missing something in the bleeding procedure?
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
Wrapped up the rebuilt trailing arm installation today (thanks GTR1999!) and bled the brakes using the MityVac which has worked well on other vehicles in the past.
Went through 2 quarts of fluid and still getting air out of the system. Bled inside rr, outside rr, inside lr, outside lr, rf and then lf.
Had a great pedal before all of this. Installed new ss calipers, rotors, pads and all new hoses. The m/cylinder was 6 months old so it wasn't replaced.
Pedal can be pumped up so it's definitely air.
Is an exorcism needed or am I missing something in the bleeding procedure?
Went through 2 quarts of fluid and still getting air out of the system. Bled inside rr, outside rr, inside lr, outside lr, rf and then lf.
Had a great pedal before all of this. Installed new ss calipers, rotors, pads and all new hoses. The m/cylinder was 6 months old so it wasn't replaced.
Pedal can be pumped up so it's definitely air.
Is an exorcism needed or am I missing something in the bleeding procedure?
Thread Starter
Drifting
Joined: Oct 2007
Posts: 1,317
Likes: 22
From: Marina CA
Intermediate
Joined: Nov 2005
Posts: 38
Likes: 0
Watching the Master cylinder lfuid level key. Another area to watch is the other end of the bleeding process, the bleeding tube.
Not sure how you are exaclty bleeding the brakes, but if you are using the pedal, I always make sure the tube running from the bleeder in brake fluid in your catch conatiner so that you don't suck air back in between pedal strokes. To be really sure, close the bleeder each time your assistant has the pedal on the floor, then release the pedal. I have a bleeder tube with a check ball at the end that goes into the container - a double check to make sure you don't suck air in.
Not sure how you are exaclty bleeding the brakes, but if you are using the pedal, I always make sure the tube running from the bleeder in brake fluid in your catch conatiner so that you don't suck air back in between pedal strokes. To be really sure, close the bleeder each time your assistant has the pedal on the floor, then release the pedal. I have a bleeder tube with a check ball at the end that goes into the container - a double check to make sure you don't suck air in.
Melting Slicks
Joined: Jan 2003
Posts: 2,877
Likes: 13
From: Doha
St. Jude Donor '08
Throw away that mity-vac thing, and get yourself a Motive power-bleeder, it will be the best $60 you have ever paid for your vette. I can bleed my brakes alone and get a rock hard pedal in less than 10 min.
Pro
Joined: Jun 2008
Posts: 673
Likes: 2
From: Melbourne Victoria
I made a "power bleeder " from a piece of alloy, some rubber &
air fitting(you could use an old M/C cover and drill 2 holes).
I use a G clamp to hold it in place.
Attach air line(Don't crank the pressure too high),
crack open bleeder valves.
Did my whole system in 1/2 an hour.
Sure it's crude, BUT it works.
Hope this helps,
CHEERS
Gav
air fitting(you could use an old M/C cover and drill 2 holes).
I use a G clamp to hold it in place.
Attach air line(Don't crank the pressure too high),
crack open bleeder valves.
Did my whole system in 1/2 an hour.
Sure it's crude, BUT it works.
Hope this helps,
CHEERS
Gav
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Drifting
Joined: Apr 2008
Posts: 1,992
Likes: 56
From: Antioch IL
i have tried the mity vac but have noticed that even though it creates a good vacuum it also lets air get past the bleeders. the threads of the bleeders are not air tight when they are open. I prefer the two person method. i usually ask my son to step on the pedal and bleed the brakes. However we DO NOT PUMP THE PEDAL. as this aerates the brake fluid. We just simply open the bleeder and push the pedal down close the bleeder and repeat until all air is gone. and you do have the right sequence. rr lr, rf, lf
Melting Slicks
Joined: Dec 2006
Posts: 2,669
Likes: 3
From: Kingston Ontario
It doesn't take much air to make the pedal spongy. Sometimes air bubbles get hung up on internals at calipers, distribution blocks, etc... Rapid pumping of the pedal at times throughout the bleed process during the two man operation is intended to release the little buggers! Gentle tapping of the brake components with a rubber mallet is supposed to do the same. Don't give up! 
Burning Brakes
Joined: Jun 2008
Posts: 1,086
Likes: 1
From: Michigan
Also be sure to leave the pedal depressed as you close the bleeder then have your helper let up on the pedal. If the helper takes his foot off the pedal when the bleeder is open air will enter.
Race Director
Joined: Feb 1999
Posts: 16,978
Likes: 7
From: In Dreams There Is Truth Ohio
Do a gravity bleed....submerge the tube in the catch can and let the fluid trickle out by itself...and watch for air bubbles...on the rear calipers, two bleed screws, do both...when no air, move to the next wheel...gravity bleeding takes a longer time. When done, system is free of air.
Thread Starter
Drifting
Joined: Oct 2007
Posts: 1,317
Likes: 22
From: Marina CA
Thanks to all of you for the good advice and tips. I think I'll try the gravity method and if that fizzles, buy the Motive bleeder.
The old MityVac has worked great on other vehicles but everything has it's match. It looks like the MityVac met it's match in the blue beast!
The old MityVac has worked great on other vehicles but everything has it's match. It looks like the MityVac met it's match in the blue beast!
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
I have the mighty vac also and read several times on this forum that other guys have said the mighty vac is so powerful it pulls air past the rubbers in the caliper so it actually does more harm than good.
I did mine by gravity in my 68 and I have perfect rock hard brakes with Dot 3 fluid
Kurt
I did mine by gravity in my 68 and I have perfect rock hard brakes with Dot 3 fluid
Kurt
Thread Starter
Drifting
Joined: Oct 2007
Posts: 1,317
Likes: 22
From: Marina CA
Received a few PM's and Motive seems to be the way to go. So now it's off to Amazon and ebay to see who has the best deal. Or if anyone has a good recommendation on who to purchase from, let me know.
Thanks again guys for all the good info received. Will use the MityVac as a vacuum tester only from now on!
Thanks again guys for all the good info received. Will use the MityVac as a vacuum tester only from now on!
Race Director
Joined: Feb 1999
Posts: 19,659
Likes: 34
From: Lenoir City Tennessee
Ci 6, 8 & 10 Veteran
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Seems like I have read on here where someone took the bleeder screws out and greased the threads so the air could not be pulled by. I have not tried it but thought it seemed believable. Anyone else try this?
Thread Starter
Drifting
Joined: Oct 2007
Posts: 1,317
Likes: 22
From: Marina CA
Motive brake bleeder
Ordered the Motive Magnum 0350 model, 4 quart capacity and 3 adapters for 99.00 delivered.
Thanks again for the advice and those that PM'ed with the Motive recommendatrion.
Thanks again for the advice and those that PM'ed with the Motive recommendatrion.
Melting Slicks
Joined: Mar 2007
Posts: 2,520
Likes: 11
From: Hinckley OH
I put grease on the bleeder screw threads as the last step in bleeding the system. I do this because I have broken many a bleeder screw after they have rusted into the calipers. The few times I have had to bleed calipers where I have used the grease I have never broken a bleeder screw. By the way, anti seize didn't work for me.