What is the actual PSI?
01-27-2012, 09:46 AM
#1
Team Owner
Thread Starter
What is the actual PSI?
In our brake lines? (max)
In a modern H type clutch?
This question came up when I was doing the brakes on a car. I opened the bleeders and attached tubes to a vented catch bottle on the vacuum bleeder. Then I pulled the lines off the master and proceed to blow out the lines with regulated 80 psi air. My mechanic friend said that it could damage the caliper piston seals. I told him that for years I've been doing it without a problem. I then use the vacuum bleeder to draw new fluid in.
I also have done this on a Ford pickup H-clutch assembly.
I've never had a gauge showing actual Line PSI I just assumed that it had to be way over 80 PSI
In a modern H type clutch?
This question came up when I was doing the brakes on a car. I opened the bleeders and attached tubes to a vented catch bottle on the vacuum bleeder. Then I pulled the lines off the master and proceed to blow out the lines with regulated 80 psi air. My mechanic friend said that it could damage the caliper piston seals. I told him that for years I've been doing it without a problem. I then use the vacuum bleeder to draw new fluid in.
I also have done this on a Ford pickup H-clutch assembly.
I've never had a gauge showing actual Line PSI I just assumed that it had to be way over 80 PSI
01-27-2012, 10:35 AM
#2
In our brake lines? (max)
In a modern H type clutch?
This question came up when I was doing the brakes on a car. I opened the bleeders and attached tubes to a vented catch bottle on the vacuum bleeder. Then I pulled the lines off the master and proceed to blow out the lines with regulated 80 psi air. My mechanic friend said that it could damage the caliper piston seals. I told him that for years I've been doing it without a problem. I then use the vacuum bleeder to draw new fluid in.
I also have done this on a Ford pickup H-clutch assembly.
I've never had a gauge showing actual Line PSI I just assumed that it had to be way over 80 PSI
In a modern H type clutch?
This question came up when I was doing the brakes on a car. I opened the bleeders and attached tubes to a vented catch bottle on the vacuum bleeder. Then I pulled the lines off the master and proceed to blow out the lines with regulated 80 psi air. My mechanic friend said that it could damage the caliper piston seals. I told him that for years I've been doing it without a problem. I then use the vacuum bleeder to draw new fluid in.
I also have done this on a Ford pickup H-clutch assembly.
I've never had a gauge showing actual Line PSI I just assumed that it had to be way over 80 PSI
Test pressure for the braking system is 1500 psi. Don't know on the clutch, but it's way less.
You can't damage anything with an air hose.
Steve g
01-27-2012, 11:48 AM
#3
Race Director
In our brake lines? (max)
In a modern H type clutch?
This question came up when I was doing the brakes on a car. I opened the bleeders and attached tubes to a vented catch bottle on the vacuum bleeder. Then I pulled the lines off the master and proceed to blow out the lines with regulated 80 psi air. My mechanic friend said that it could damage the caliper piston seals. I told him that for years I've been doing it without a problem. I then use the vacuum bleeder to draw new fluid in.
I also have done this on a Ford pickup H-clutch assembly.
I've never had a gauge showing actual Line PSI I just assumed that it had to be way over 80 PSI
In a modern H type clutch?
This question came up when I was doing the brakes on a car. I opened the bleeders and attached tubes to a vented catch bottle on the vacuum bleeder. Then I pulled the lines off the master and proceed to blow out the lines with regulated 80 psi air. My mechanic friend said that it could damage the caliper piston seals. I told him that for years I've been doing it without a problem. I then use the vacuum bleeder to draw new fluid in.
I also have done this on a Ford pickup H-clutch assembly.
I've never had a gauge showing actual Line PSI I just assumed that it had to be way over 80 PSI
Agree with the comments above, I've heard "thousands" before, in casual conversation.
Seeing as how the bleed lines are open, I wouldn't worry about the caliper seals in either case. They're pretty robust though.
01-27-2012, 12:34 PM
#4
Team Owner
Thread Starter
Steve in years past i used to do the two man deal of one guy pumping the pedal and the other guy underneath opening and closing the bleeder until you see clear fluid.
Now I just hit the lines with dry air out of the compressor until nothing is left in the line. reconnect lines to the master cylinder. Fill the bowls with fluid. turn on the vacuum bleeder. Add fluid as required and monitor the clear vacuum line until I have free flowing fluid.
Button everything up and I'm done.
I left out step one............ empty the master cylinder before pulling the lines. with the lines removed, pump the pedal to clear the master cylinders
No water, no old fluid, done
Now I just hit the lines with dry air out of the compressor until nothing is left in the line. reconnect lines to the master cylinder. Fill the bowls with fluid. turn on the vacuum bleeder. Add fluid as required and monitor the clear vacuum line until I have free flowing fluid.
Button everything up and I'm done.
I left out step one............ empty the master cylinder before pulling the lines. with the lines removed, pump the pedal to clear the master cylinders
No water, no old fluid, done
01-27-2012, 06:11 PM
#5
Team Owner
The air pressure won't hurt anything....unless the caliper doesn't have the rotor/pads to clamp onto. If the caliper is 'free', the pressure could blow the pistons out of their bores.
