hard brake pedal
 

ok guys i have a question that i can't seem to figure out. i did the disc brake upgrade to my truck using ece dropped spindles and brakes. i used the original rebuilt power brake booster. and new master.brakes have a hard pedal and don't stop very well. i don't think it is the booster because it worked fine before. any suggestions?? thanks

Re: hard brake pedal
 

Did you change the brake hoses? Also did you clean the rotor after installation?

Re: hard brake pedal
 

new hoses , brakes bled good. it's not combo valve checked it with light --not on?

Re: hard brake pedal
 

It probably wouldn't hurt to tee in a vacuum guage to verify that you have vac at an idle.
Also look at your check valve to make sure that you are capturing the vac. that you develope.

Re: hard brake pedal
 

it has a steady 16hg at idle a little low but should be good?

Re: hard brake pedal
 

That should be plenty...
You might check the check valve...The plastic 90% thing that pushes into the rubber grommet and has the hose on the other end...If you pull it out of the hydro-vac ....you should be able to blow into it..(toward your intake manifold) and you should not be able to suck through it.
I hope it's that simple for ya...
By chance, when you bolted yer new master cyl. onto your H-Vac....was the plunger engaging the piston prior to the housing seating against the booster....so that as you tightened the nuts the MC began to stroke befor it was tight...?

Just shootin in the dark.

Good luck...

Re: hard brake pedal
 

the check valve works blows but doesn't suck. the pushrod was not engaging the plunger, when installed. i took it apart the other day and adjusted it some so ther is a little play in pedal before it engages plunger. thanks for your thoughts and ideas. i am going to pull wheels and maybe rebleed brakes tommorrow.

Re: hard brake pedal
 

Sounds like the master bore diameter might be wrong for the rear wheel cylinder bore diameter.. or the calipers. Too-small slave cylinders can give a hard pedal.

Do you feel the booster kick in if you start the engine with the brake pressed?

Re: hard brake pedal
 

yes forgot to add that .. pump brakes let vacume out start engine pedal drops maybe 1/4 in. but you can feel it.

Re: hard brake pedal
 

You might check the master cylinder specs and see if the drum side is for 1-inch wheel cylinders.