Brake question

[Kenneth Cole]

Hi
I replaced my master cylinder with a dual reservoir unit and added proportion valves in order to retain line pressure. The problem is I still have to pump up the brake in order to get about half a pedal and if I wait a moment I lose it and have to pump again. What do you think?
Ken

[Kaiser2boy]

You did something wrong.
I know that sounds like a stupid answer but with what you have done there are many variables and things that could be wrong the list is very long.
Did the brakes work prior to your experiment? What condition are the wheel cylinders in? Is there any sign of leaks ?

[W_A_Watson_II]

The most likely problem is air in the lines/etc... I'd suggest re-bleeding.

[Gordon Maney]

What is the state of adjustment on your brakes?

Is this a drum brake truck? If so, use your adjusters to move all shoes out against the drums. Try it then to see if you still have trouble getting a pedal.

[Kenneth Cole]

Thanks for the help. I will try adjusting the shoes and then rebleed the lines.
This isn't really an experiment it's more of an upgrade. Changing over to a dual reservoir master cylinder is for safety more then anything. I just got the truck on the road with a different engine( 318 Poly)and it hadn't been driven for many years. I had replaced the wheel cylinders and all of the lines.
Thanks again
Ken

[W_A_Watson_II]

Ah, yep if it wasn't driven for many years before Charles has it right on the adjustment first. Good luck and keep us posted.