Rear brakes no fluid after VT brake upgrade in VH

[gtrboyy]

When I put vt booster setup on vp ute went through 2 bottles of brake fluid was so much air in the system & forgot to bench bleed m/cyl was big mistake lol

 

[Immortality]

There is a difference in the brake systems between 4 wheel disk brake and rear wheel drum brake systems, exactly what it was escapes me but rear drum brakes work on much lower pressure and I also remember something about a residual pressure valve for drum brakes. I haven't worked on a rear drum brake system ...since forever.

 

[vc commodore]

Will add in, VB through to VR had the same master

 

[vc commodore]

Just looked at an exposed view of a brake master cylinder in a Haynes manual and no sign of a proportioning value

This is for VB to VK...However we have to consider the OP has a VT master cylinder

I also have a Max Ellery and Gregories manual if need be to check for this valve

 

[stick3]

wonder if the op will give us a update if it fixed or not and what brakes are fitted

 

[gtrboyy]

Think valve thing was in m/cyl rear brake line port & all you had to do do was stick a screw in it & pull it out....been very long time since worked on drum brakes.

Guessing without it would be too much pressure to rear wheel cylinders & they'd lock up way too easily......not a good thing lol

 

[vpower13]

Just an update. Drum brakes on rear. Further, I had since got fluid coming to the rears. It seems the rear passenger side isn’t bleeding as well as the others. It’s gets fluid, but doesn’t shoot it out through the tube as the other 3 do. I’ve bled it twice now, and the 2nd time feels better, but still no where where it should be in terms of brake feel. I am googling troubleshooting possibilities online, but can’t seem to find the answer. I know when I cut down the screw head in the booster I didn’t make it exactly flush, prob 2-3mm longer than flush, could this be the cause? Further, can anyone please clarify which lines on the master are for front and rear? Better double check they’re going to the right place.

Edit: there also seems to be a noticeable sound of air being pushed when the brake is pressed. I don’t recall the same sound prior to doing this work

 

[vpower13]

did you do the booster rod bolt head/thread mod on the VS plastic booster???
Did you connect the front/rear lines in the appropriate ports on VT master???

No fluid in the rear points to block in line/issues with master piston/seals and booster problems which will be felt when pressing brake pedal.

I put a reply down below but just further to this, yea did the modification to the bolt head. But I didn’t get it completely flush. Sticks out about 2-3mm, you think this could be a problem. I currently have fluid coming through, but the spongy brake pedal is the problem here currently.

 

[vc commodore]

The line out of the master closest to the booster is to the rears.

Why did you cut the valve?

Have you checked the brake line isn't clogged slightly?

The brake shoes...If they aren't adjusted correctly it will give you a low brake pedal feel....

If there is air in the line, pumping the brake pedal should cause it to come up higher...So another thing to consider

 

[vpower13]

The line out of the master closest to the booster is to the rears.

Why did you cut the valve?

Have you checked the brake line isn't clogged slightly?

The brake shoes...If they aren't adjusted correctly it will give you a low brake pedal feel....

If there is air in the line, pumping the brake pedal should cause it to come up higher...So another thing to consider

Would the shoes need to be adjusted if they haven’t been touched? I only replaced the Fronts and didn’t do anything in the rear.

What’s the best way to check for a clogged line?