Brake Bleeding Question

[smn69]

I am getting ready to install my new master cylinder and I just want to confirm the proper bleeding procedures:
1. Bench bleed the master to make sure ther is no air in it.
Question 1: Should I use the same process to bleed the proportioning valve after it is hooked up to the master and before it is hooked to the brake lines by running a hose from the outlets back into the master until there is no more air coming out? Or will the proportioning just bleed with the rest of the system?
2. Bleed the lines starting at the furthest from the master.
Question 2: I have read the you should start at the passenger rear, but if you look at the length of the brake lines, the one going to the drives rear is the longest because the brake line runs down the passenger side and then back across the diff. Does it matter where you start in the back?
3. After bleeding all lines there should be a nice firm pedal. Any other things to look out for?
Thanks for all your help.

[cdowns]

you need to clamp the pin on the combination valve to keep it centered while bleeding the brakes

yes start at drivers rear

[smn69]

How far will the pin pop out? I am assuming just enough clamp pressure to hold it in place.

[mr48chev]

Usually you try to bleed the wheel cylinder that is the longest distance brake line wise away from the mastercylinder.

I never clamped the combination valve when I did brake jobs daily but I can see that it might help keep the valve centered and not let it stick to one side. I'd say just enough pressure to keep the clamp on and keep the pin from moving.

The main things are
Keep the mastercylinder full of fluid.
Have your helper pump very slowly.
Tell them to "hold it" open the bleeder, close the bleeder and then "ok, Pump it again".

[Longhorn Man]

in all reality, there is no need to do that furthest away thing.
I'll catch crap for this... but what ever.
Look at the rear brake line for example. You have one single line going from the master cylinder, to the proportioning valve (or combination valve if drum/drum) and then again, one single line going clear to the rear axle, then a hose, and a T fitting.
Now, what the heck does it matter which side you start with? The fluid and air doesn't know left from right, and it doesn't know an inch from a foot... air and fluid are kinda stupid like that.
For that matter... the front brakes and the rear brakes are 2 seperate systems... so why not start up front? Air and fluid doesn't know front from back either.
It will take the path of least resistance, be it left or right, front or back.

This stems from way back in the day (pre 67 trucks) where the front and rear were tied into one bowl. And in all reality, it shouldn't have mattered back then either.

This "rule" is as outdated as the old "don't put a battery on the ground", or "use hot water in the ice cube tray for clear ice", or "Don't feed a Moqui after midnight".

[LONGHAIR]

I am not a believer in the clamping thing either. Just don't push the pedal far enough to "pop" it. You can feel it stop, but there is more travel beyond that point...just don't do it. You will feel the click and the "Brake" light will come on.
If it does happen, all you have to do is close the bleeder that was open when it happened and open one on the opposite end of the truck, push the pedal to the floor and it should pop back.

If not, close all bleeders and "snap" the pedal hard/quick. This will jolt the pressure and balance it back out.

Personally I am more of a fan of gravity bleeding. Open all of the bleederes at one time, never touch the pedal. Let them all run/flow for a while. This "flushes" out some of the old fluid, wheich is a good thing anyway. Just be aware of the master cylinder while this is happening. You cannot let it run dry, just keep toppoin it up as it flows. After you have run some new fluid in for a while, go back and close the bleeders.....never touching the pedal until they are all closed.

[El Jay]

Originally Posted by LONGHAIR

I am not a believer in the clamping thing either. Just don't push the pedal far enough to "pop" it. You can feel it stop, but there is more travel beyond that point...just don't do it. You will feel the click and the "Brake" light will come on.
If it does happen, all you have to do is close the bleeder that was open when it happened and open one on the opposite end of the truck, push the pedal to the floor and it should pop back.

If not, close all bleeders and "snap" the pedal hard/quick. This will jolt the pressure and balance it back out.

Personally I am more of a fan of gravity bleeding. Open all of the bleederes at one time, never touch the pedal. Let them all run/flow for a while. This "flushes" out some of the old fluid, wheich is a good thing anyway. Just be aware of the master cylinder while this is happening. You cannot let it run dry, just keep toppoin it up as it flows. After you have run some new fluid in for a while, go back and close the bleeders.....never touching the pedal until they are all closed.

Hmmmm.
A man after my own heart......Except you forgot the "relax & have a beer" part.

[Longhorn Man]

that's actually how I normally do it too honestly.

[lytemup454]

does gravity bleeding take care of the bench bleeding of the master cylinder or does that need to happen as well?

[Sinister]

I have a new driveway so can't gravity bleed them. I bought a 1 man brake bleeding kit. Little bottle with a magnet and hose fitting. Hook it to the bleeder stick the bottle to the frame or backing plate above the bleeder and pump away.

[LONGHAIR]

Originally Posted by lytemup454

does gravity bleeding take care of the bench bleeding of the master cylinder or does that need to happen as well?

It probably wouldn't. The bubbles would be trapped in the bore by the piston. I always bench bleed first.