A Bleeding Question?
Thread Starter
Drifting
Joined: Oct 2001
Posts: 1,290
Likes: 186
From: Naples FL
A Bleeding Question?
..and dying for help.
Just replaced my front (rubber) brake lines to the calipers. Replace one of the calipers. I am using a hand-held vacuum bleeder. For some reason, after repeated attempts (30 or so) I continue to get alot of air and only some fluid. Initially for quite some time, it was only air (did not fill the calipers beforehand). Now its mostly air with some fluid.
I know that I am sealed at junction of the caliper valve and bleeder tip. The vacuum pump itself seems good since when I use it on the rear calipers it draws fluid just fine (couple of ounces per draw).
When I push the brake pedal (all valves closed) the fluid squirts up from both front and back master cylinder reservoirs.
Is this typical of a brake bleeding job? Any ideas or troubleshooting would greatly be appreciated.
Thanks.
Just replaced my front (rubber) brake lines to the calipers. Replace one of the calipers. I am using a hand-held vacuum bleeder. For some reason, after repeated attempts (30 or so) I continue to get alot of air and only some fluid. Initially for quite some time, it was only air (did not fill the calipers beforehand). Now its mostly air with some fluid.
I know that I am sealed at junction of the caliper valve and bleeder tip. The vacuum pump itself seems good since when I use it on the rear calipers it draws fluid just fine (couple of ounces per draw).
When I push the brake pedal (all valves closed) the fluid squirts up from both front and back master cylinder reservoirs.
Is this typical of a brake bleeding job? Any ideas or troubleshooting would greatly be appreciated.
Thanks.
Racer
Joined: May 1999
Posts: 382
Likes: 0
From: Long Beach CA
Re: A Bleeding Question? (Midyrman)
Been there! The vacuum brings air in, either through the threads of the bleeder screw or the actual caliper seal. This is normal.
The MC will squirt up. This is also normal. Do not push the brake pedal with the MC lid off! It does make a really cool noise, but cleaning up brake fluid is no fun :mad
There are many people who have tried all kinds of bleeding methods. Most people swear by the two person method.
What I ended up doing was using the vacuum to get the fluid going. Then I disconnected the pump and let gravity do the work. Gravity is slow :lol:
There are also tubes with check valves. Have yet to try one.
Some people have some way to attach a compressor to the MC, using pressure instead of vacuum.
The MC will squirt up. This is also normal. Do not push the brake pedal with the MC lid off! It does make a really cool noise, but cleaning up brake fluid is no fun :mad
There are many people who have tried all kinds of bleeding methods. Most people swear by the two person method.
What I ended up doing was using the vacuum to get the fluid going. Then I disconnected the pump and let gravity do the work. Gravity is slow :lol:
There are also tubes with check valves. Have yet to try one.
Some people have some way to attach a compressor to the MC, using pressure instead of vacuum.
Le Mans Master
Joined: Aug 2000
Posts: 9,662
Likes: 7
From: Semper ubi, sub ubi
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: A Bleeding Question? (Midyrman)
If you use a vacuum bleeder on a 'vette, chances are excellent that you'll never get the air out. The best method for bleeding 'vette brakes is the "gravity method."
Check out this link, it works! http://community-2.webtv.net/MATTGRU/BRAKES/index.html
There are more brake tips available at, http://www.corvettefaq.com
Check out this link, it works! http://community-2.webtv.net/MATTGRU/BRAKES/index.html
There are more brake tips available at, http://www.corvettefaq.com
Instructor
Joined: Jun 2001
Posts: 131
Likes: 0
Re: A Bleeding Question? (Midyrman)
I just got finished with a 4-wheel caliper rebuilt while switching to DOT 5. Gravity bleeding gets you most of the way. Getting the car tilted with the front lower than the rear helps too.
Try the 2 person method and see if you can pick up those "speed-bleeder's" work. They don't leak air from leaking around the threads like conventional bleeders.
Just remember to put the brake pads soft side in! :bb Otherwise you'll trash the rotor (like I did. :U :cry )
-Rexx
Try the 2 person method and see if you can pick up those "speed-bleeder's" work. They don't leak air from leaking around the threads like conventional bleeders.
Just remember to put the brake pads soft side in! :bb Otherwise you'll trash the rotor (like I did. :U :cry )
-Rexx
Melting Slicks
Joined: Mar 2001
Posts: 3,365
Likes: 5
From: Lake Villa IL
Cruise-In IV Veteran
Cruise-In V Veteran
St. Jude Contributor
Re: A Bleeding Question? (Midyrman)
When you pressure bleed your system, do you have to have a special cap fitted to the top of the master cylinder resevoir?
Racer
Joined: Dec 1999
Posts: 485
Likes: 0
From: MESA, AZ, USA
Re: A Bleeding Question? (joeveto)
I used an old cap, new gasket, sealed the "breather" holes along the edges of the cap, drilled a hole in the cap and screwed in an air fitting, then used low pressure (about 5 -10 psi) air to pressure bleed. (Strap the cap on the master cylinder using large dryer vent straps, cause it'll blow off and make a real mess) Goes so fast you'll have to watch your master cylinder fluid level very closely. You'll empty the resevoirs faster than you think, but the air rushes out of the system in no time. No helper, just pressurize, walk around the car opening bleeder screws, (clear tube in a bottle filled with fluid to see the air bubbles), fill the master and move on to the next wheel. 30 minute job. Wait a day, tap on the wheel cylinders to get the smaller bubbles off the walls, bleed one more time the same way as before, and take the car for a fun drive. Oh, yes, no pre-filling, no master cylinder primeing, just add fluid and go. Hard to believe given all the posts about never getting all the air out, but its true.
Andy
Andy
Melting Slicks
Joined: Oct 2001
Posts: 2,065
Likes: 1,395
From: Halifax, Nova Scotia, Canada
Re: A Bleeding Question? (Midyrman)
A couple tips on bleeding.
1/ If using the gravity method, use a rubber hammer or a block of wood to tap the caliper and lines while bleeding. This dislodges any attached air bubbles.
2/ If using the two person method, the 'in car' person should NOT rapidly pump the brake pedal. Slowly depress the brake pedal until firm. Open the bleeder until pedal is on the floor.
'Important', SLOWLY release the pedal. Sometimes if the pedal is released quickly, the master cylinder will pick up air around the seals, before the fluid can refill.
Just some things I discovered over the years.
Barry
1/ If using the gravity method, use a rubber hammer or a block of wood to tap the caliper and lines while bleeding. This dislodges any attached air bubbles.
2/ If using the two person method, the 'in car' person should NOT rapidly pump the brake pedal. Slowly depress the brake pedal until firm. Open the bleeder until pedal is on the floor.
'Important', SLOWLY release the pedal. Sometimes if the pedal is released quickly, the master cylinder will pick up air around the seals, before the fluid can refill.
Just some things I discovered over the years.
Barry
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