# Bleed proportioning valve mk2



## Vwhall (Dec 12, 2008)

I've done the brake disc conversion and i replaced my proportioning valve beacause mine was jammed in rust.
So now i've bleed my brake but my pedal goes very very low.
I think it's my proportioning valve???
So is there a procedure to correctly bleed it?
My master is new, my rears calipers are new and all my brake line are new.


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## greyhare (Dec 24, 2003)

*Re: Bleed proportioning valve mk2 (Vwhall)*

The rear suspension must be loaded to bleed the rear brakes. With the back of the car in the air the proportioning valve is shut and will allow very little, if any, flow to the rear brakes.
I have never seen a procedure to bleed just the valve.


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## germancarnut51 (Mar 23, 2008)

*Re: Bleed proportioning valve mk2 (Vwhall)*

Bleed the rear brakes with the tires on the ground, or place the jackstands in the rear on the axle beam to hold in the same position it's in with the rear wheels on the ground.
When bleeding the brakes I vacuum bleed with a MityVac 8oz past the last bubbles I see or crud particles I see in the clear bleed tubing,


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## dkashbmx (Apr 17, 2009)

*Re: Bleed proportioning valve mk2 (germancarnut51)*

im in the same situation! except my right front and my left rear have no pressure behind it when i try to bleed it. it just gravity bleeds and i push the pedal and nothing happens. it just oozes out


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## germancarnut51 (Mar 23, 2008)

*Re: Bleed proportioning valve mk2 (dkashbmx)*

This car has diagonal braking, meaning the left rear and the right front are on the same fluid circuit.
Are the rear brakes fully adjusted? Did you replace them recently? Are the parking brakes working? If the rear brakes are not properly adjusted you are not going to have good braking, because pedal travel is going to be wasted moving the brake pads or shoes to contact, instead of clamping force. The brake pads and shoes must be in good condition, with working calipers or wheel cylinders, and adjusted properly for the brakes to work.
Did you replace the master cylinder with a new one (not rebuilt), or have you let the master cylinder run dry? If so, then you probably still have air in the master cylinder.
Otherwise, the master cylinder is defective, and in need of replacement.


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