air in the ABS module ?
Brakes have no pressure
When I step on the brakes, the pedal goes all the way in. I replaced the booster, master brake cylinder, and put new brakes on the vehicle. I have bleed the brakes and the brake pedal doesnt seem to get hard when applied. I have unplugged the hose that goes to the Booster and covered the hose with my thumb then had someone apply the Brakes, this seems to get the brake pedal hard when applying pressure. Does anyone know what might be causing this?
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What do the brake hoses ( how old ?) look like?When I step on the brakes, the pedal goes all the way in.
Does anyone know what might be causing this?
When they get old they can go soft inside and will expand with the pressure so no pressure goes to the caliper so your foot goes to the floor
If they were that soft , they'd leak
What year? Was the master cylinder new or rebuilt? Did you bench bleed the master first?
Toby
Toby
Bleeding Brakes
Any time your brake pedal goes all the way down it means you have air trapped in the master cylinder, lines, or calipers. The only solution is to bleed the system to remove the air. You can easily gravity bleed it by simply removing the lid on the master cylinder, keep it full of fluid, and crack the bleeders open one at a time until only fluid leaks out. If the air is trapped in the master cylinder it can take up to 30 minutes to get the air out but if the air is trapped in your calipers it usually takes just several minutes at the most.
When I step on the brakes, the pedal goes all the way in. I replaced the booster, master brake cylinder, and put new brakes on the vehicle. I have bleed the brakes and the brake pedal doesnt seem to get hard when applied. I have unplugged the hose that goes to the Booster and covered the hose with my thumb then had someone apply the Brakes, this seems to get the brake pedal hard when applying pressure. Does anyone know what might be causing this?
Any time your brake pedal goes all the way down it means you have air trapped in the master cylinder, lines, or calipers. The only solution is to bleed the system to remove the air. You can easily gravity bleed it by simply removing the lid on the master cylinder, keep it full of fluid, and crack the bleeders open one at a time until only fluid leaks out. If the air is trapped in the master cylinder it can take up to 30 minutes to get the air out but if the air is trapped in your calipers it usually takes just several minutes at the most.
or the ABS module
you need a tech 2 ( or 1 , can't remember ) to cycle the module
you need a tech 2 ( or 1 , can't remember ) to cycle the module
Any time your brake pedal goes all the way down it means you have air trapped in the master cylinder, lines, or calipers. The only solution is to bleed the system to remove the air. You can easily gravity bleed it by simply removing the lid on the master cylinder, keep it full of fluid, and crack the bleeders open one at a time until only fluid leaks out. If the air is trapped in the master cylinder it can take up to 30 minutes to get the air out but if the air is trapped in your calipers it usually takes just several minutes at the most.
i will take a look at them and see the condition there inWhat do the brake hoses ( how old ?) look like?
When they get old they can go soft inside and will expand with the pressure so no pressure goes to the caliper so your foot goes to the floor
1990 corvette, master cylinder was rebuilt. I dont know what you mean by bench bleed.What year? Was the master cylinder new or rebuilt? Did you bench bleed the master first?
Toby
ok thanks for the tips i will try that outAny time your brake pedal goes all the way down it means you have air trapped in the master cylinder, lines, or calipers. The only solution is to bleed the system to remove the air. You can easily gravity bleed it by simply removing the lid on the master cylinder, keep it full of fluid, and crack the bleeders open one at a time until only fluid leaks out. If the air is trapped in the master cylinder it can take up to 30 minutes to get the air out but if the air is trapped in your calipers it usually takes just several minutes at the most.
uh , oh....hope you didn't push air into the ABS.......1990 corvette, master cylinder was rebuilt. I dont know what you mean by bench bleed.
http://www.superchevy.com/technical/chassis/brakes/0509sc_bench/
http://www.lsxtv.com/news/how-to-properly-bench-bleed-the-master-cylinder-with-wilwood/
Sounds like you have to bleed the master cylinder. Pretty easy procedure. I believe when I did mine it came with the hoses and instructions on how to bench bleed it
Oops. :stupid: J/K1990 corvette, master cylinder was rebuilt. I dont know what you mean by bench bleed.
First, there is a 50% chance that a rebuilt is any good. New is the way to go if they are available. Problem with rebuilt is if there was any (I mean any) corrosion (rust, oxidation, ect, ect) you can't get it out, it may look like it but it is still there & will only get bigger. Second, bench bleeding is getting the air out before you hook up the lines. It can also help identify if the rebuilt master is even any good before you install it. If air got into the ABS, it's not the end of the world, but can be a pain.You will need to get a manual to find the procedure for that vehicle & a power bleeder would make it easier.
Toby
Toby
First, there is a 50% chance that a rebuilt is any good. New is the way to go if they are available. Problem with rebuilt is if there was any (I mean any) corrosion (rust, oxidation, ect, ect) you can't get it out, it may look like it but it is still there & will only get bigger. Second, bench bleeding is getting the air out before you hook up the lines. It can also help identify if the rebuilt master is even any good before you install it. If air got into the ABS, it's not the end of the world, but can be a pain.You will need to get a manual to find the procedure for that vehicle & a power bleeder would make it easier.
Toby
I have found the rebuilders often rebuild cores that are way beyond rebuilding because they are pitted so bad. As a master cylinder lasts such a long time I always buy BRAND NEW ONES.
If you can find a shop that has a guage that get hooked in at the bleeder valves, check and see how much pressure you have at the calipers. You should have about 1300 or better.
it lasts if you change the fluid regularly :thumbsup:I have found the rebuilders often rebuild cores that are way beyond rebuilding because they are pitted so bad. As a master cylinder lasts such a long time I always buy BRAND NEW ONES.
thanks i just got my new Master Cylinder in today not a rebuilt one this time 
Thanks for the tip, I will be installing my new master cyinder this weekendIf you can find a shop that has a guage that get hooked in at the bleeder valves, check and see how much pressure you have at the calipers. You should have about 1300 or better.
So I Bought a brand new master cylinder installed and bleed the brakes that seemed to fixed the problems thanks for everyone's help and tips.
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