Originally Posted by robinball

Hi,

Just wondering if anyone has any ideas. I have a Sierra which had ABS, I've removed the ABS unit, wheel speed sensors and replaced all the metal and rubber lines for braided lines through the whole car (see photos below)

Attachment 183406
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Obviously being an ABS model originally it's got the ATE accumulator type master cylinder (see offending unit below)

Attachment 183410

Since I've done this the front brake work fin, the rears however literally don't do anything. Even bleeding them way a pain, they gravity bleed but when the pedal is depressed the fluid doesn't move any quicker. Initally I though it was the OE bias valve so I bypassed this last night and it's still the same. Before I go condemning brake master and trying to fit a normal non-ABS Sierra traditional master and servo setup, does anyone have any ideas why there would be no pressure to the rear brakes and but the front work fine? In addition the pedal does feel a bit funny, but it was several years since I last drove the car standard so I'm not 100% if it's not right.

Anyway thanks in advance Robin