Bleeding Brakes - Proportioning valve

[snomobeelr]

Was trying to bleed the brakes. Pedal is staying soft. I bench bled the Master . Brake fluid is coming out bet the pedal does not harden up. Is there also something I need to do with the Proportioning valve?  Is it possible the Master is bad? 

 

[monte70car]

You might have to reset the Proportioning valve.

[MCfan]

There's a push button valve on the back side of the proportioning valve that must be held in while bleeding the front brakes.  I used two door leveling shims between the vacuum booster and the valve to hold the button in.  Don't forget to remove it before you go for a drive.  I always bleed the rear brakes first, followed by the front.  Sometimes it goes smoothly, sometimes it's a bear - not sure why.

 

[snomobeelr]

This will be interesting , My Proportioning valve is located down on the frame. Its from inline-tube. So I have to keep the black button Depressed while bleeding the Fronts?  

 

 When bench bleeding the Master the air is out but the front Bowl - port of the Master seems to blow Fluid up when Bench bleeding. Is this Normal? Link below to a video of it.

 

[Sam (Bones)]

yes, as Dennis suggested, do the rears first, and if the rear brakes are not adjusted, that will give you a low pedal too

 

first I suggest to adjust the rear brakes

 

if you do not get fluid flow from the front bleeders, push the valve in

[lastss]

Gm factory manuall state bleed LF,RF,LR,RR always shortest distance from Master Cly to furriest. Are your rear shoes adjusted properly?.When yo push down on petal does it stop at some point & stay hard? You can adjust petal height if necessary under dash.

[lastss]

1. If there's air in the system doing rears first only makes it harder to remove & making air travel that much farther to get out. & could results in some not getting out.

 

[snomobeelr]

Thanks much guys, I

[snomobeelr]

Oops combination keys ........... I had bled the brakes.  I Started on the rear Passenger side. I do get fluid out of all for wheels.  I bleed them 3 times. Same condition. Pedal does not Harden up. All brake component lines metal and rubber are relatively new.. The rear brakes are adjusted. 

[snomobeelr]

One thing, I did add a hydro-boost unit but I don't think that shouldn't effect this as that is a brake asset unit and I am just bleeding the brake system.  I did adjust pedal out.

[snomobeelr]

Since the master is on the bench I was bleeding it again. My vise is by the window and the sun was coming through. I could see tiny miniscule bubbles in the hose to the front bowl. I bled the master until they cleared out. I saw online about the level of the car and the Master cylinder that air can get trapped. I have been changing the level/pitch of the master cylinder in the vise. The bubbles continue in the front bowl an go away. I reposition the master and bled  it again and they return. I even changed the bleeding fitting that goes into the master and the hose. I also put grease around the fitting to seal it up.. When I reposition the master I get the same tiny bubbles coming from the line into the hose. 

[snomobeelr]

So I opted  and got a new master. Its been bench bled. When I was bleeding the brakes with the old Master cylinder I kept the lid on. Should the lid be on or off the master when bleeding the brakes?

[Sam (Bones)]

I leave it on when I bleed them

[snomobeelr]

Thanks guys. It was the Master cylinder. Strange I thought when they went they leaked. My son  and wife are thrilled they don't have to assist me bleeding the brakes any longer.  I decided to go with the Wilwood Black master even though expensive as it looks a lot nicer. Hers some pictures with the Hydroboost and New master installed..

 

 

[7tonemonte]

Nice looking engine bay! The master cylinder looks great also

[stangeba]

Looks great!

[bigscaht]

looks great.....glad you got it figured out....your gonna love your brakes....