[bizkit075]

Well i just rebuilt my suspention and added power disc brakes from the old manual drums. I got it all in and aligned. When i bleed the lines and took it for a test drive, it felt really bad, i almost drifted into an interestion. My question is do i have to bleed the brake with the motor running for vacumn reasons. Or is there a certain way i need to bleed the brakes, or does anyone know of anything that could be bad. Please help, thanx

[fat50]

Do you have a single reservoir master cylinder? I'd upgrade to a dual reservoir. For bleeding them i have a drinkin' buddy pump the brakes 5 times and hold the pedal while i crack the bleeder open (they gotta earn that beer somehow!!) repete it a couple of time for each caliper.




C

[bizkit075]

its a dual, but i though i got all the air out, im just wonderin if the vacum has somethin to do with it, or is there a certain way im suppossed to bleed the brakes.

[gt2betubbed]

Did you bench bleed the master?

[bizkit075]

what does bench bleed mean? because i dont think i did it.

[gt2betubbed]

You have to bleed the master cylinder. You fill up the bowls, and there's a tube that you can buy at Kragen's for a couple bucks that sends the brake fluid out the master and back in the bowl when you pump it. You keep pumping it until there's no more bubbles going through the clear tubes. I don't know if this is the cause of your problem, but are your brakes acting like they have air in the system? If so, that could be it. Also, to answer your question, you don't need the car running to bleed the brakes.

[tm454]

If you pump bleed the brakes don't worry about bench bleeding the mastercylinder, you bench bleed the mastercylinder to remove all the air from it before you install it. The instructions should have been in the box the new mastercylinder came in alone with two plastic hose's and fittings.

Is the pedal hard, so hard the pedal dosn't move even with the car running means insufficient vacume or bad vacume assist unit?

Can you pump up the brakes, two or more pumps and the pedal comes up and you have better brakes, this means air in the lines?

Did you bleed off all the old brake fluid and start with new all around, you might have two different fluids in your system, use dot3 unless otherwise asked to do so?

Did you put on new brake shoes when you did the mastercylinder vacume assist change, new shoes makes a lot of difference on drum brakes?


With a vacume assist brake you must have the car running to pump the pedal to bleed the brakes. Use the suction pump offered at the parts store to pull fluid from the reservoir to each wheel cylinder in turn as you bleed the brakes.



Todd

[Robinson Robin]

Dot 3 and dot 4 are compatable so don't worry about that. Also don't worry about not bench bleading the master cylinder all it does is speed up the bleeding process but its no nessicary. It could be a situation where you have insufficent boost which would be my guess here. How low does the petal go? if it is at normal high when you stomp on it then it probably is the insufficent boast situation. Did you use a donar car? Oh one other thing no the car does not have to be running to bleed the brakes with vac assist

[bizkit075]

well i think we narrowed it down, we have bled the lines so much the liquid comming out is clean like just poured in the master cylinder. But we noticed the brake pedal pressure doesnt change if the vacumn line is hooked up, or not hooked up to the booster. So i thing the booster is bad. The funny thing is we bought it brand new. Damn *******s, lol. If anything else could be causeing this problem please let me know but for right now were gonna exchange the booster and see if another one will work.

[Robinson Robin]

keep us posted on how it goes good luck

[Hyper7]

to bizkit075
did you fix your brakes???