No Pedal on Manual Brake Swap

[Stroked383]

Just finished up with my manual brake conversion on a 86 Monte Ls. Master is out of a Manual brake Malibu. Front calipers are wilwood oversized GM calipers, new pads, and stainless lines. The rear brakes have new shoes, new wheel cylinders, and new stainless line. Master is from Napa, my second one, thinking the first one was bad. Master was bench bled then transfered to the car. Used my power bleeder (air compressor kind) to get the majority of the air out, then went and did all the sides by hand. The pushrod is adjusted so there is roughly 1/4 inch of play in the pedal. I cannot get any pedal on the car what so ever. I have heard Napa masters can be just from the store, but I'm on my second one. The back brakes are adjusted tight. I have another master comming from a different store, different brand. Anyone have suggestion where to go next? I'm starting to run out of options.

I also put the old power master on the car to check pedal. Again NO pedal. I have checked again and again for leaks but to no avail.
Thanks,
Cory

 

[malibudave1978]

Cory,

Like you I am having issues with my brand new, name brand master cylinder that I bought from rockauto.com.

It seems that the rear port for the front brakes is bleeding fine, but the front port for the rear brakes will not allow the brakes to bleed. It seems that the front port will suck air back into the master cylinder from the brake line and not push the fluid down to the wheel cylinders and the bleeder screw. I have almost no pedal at all from this scenario.

I know my brakes worked (with a spongy pedal) with the stock 24mm power brake master cylinder bolted to the firewall like a manual master cylinder after I switched over to all my new brake components. It stopped the car, but I couldn’t get it to lock up. That is why I stepped down to a 7/8” bore to get more pressure to the caliper. Now I am having issues with the rear brakes getting bled, because of what I believe is the master cylinder.

Was your old master cylinder a step bore design? If that master was working fine before you swapped over, there has to be air in the system. You should be getting some pressure with at least the old master cylinder.

 

[Stroked383]

Dave,


Do the brake lines from the power master cylinder hook up correctly to the new manual master cylinder? If my analysis is correct, the front port of the manual master is providing fluid to the front brakes. I know this is incorrect, but that's how it looks from my standpoint. The large port being in the front with the smaller in the back. I will try and use my power bleeder again on the system with my stock power master cylinder and go from there. Thanks for your help
Cory

 

[malibudave1978]

Smaller line goes to the front brakes on the back port of the master cylinder.

 

[LS6 Tommy]

Stupid question, but are you still using a power brake master cylinder?

Tommy

 

[Stroked383]

I am using a manual master off of a malibu that came with manual brakes. The master came from napa. I tried using the power master to see if I could get any pedal but no luck.

 

[LS6 Tommy]

Did you relocate the pushrod to the manual brake position on the pedal?

Tommy

 

[Stroked383]

Yes, the pushrod is now in the top hole of the pedal.

 

[LS6 Tommy]

Ok, I'm offically stumped...

 

[454RAT]

what about the proportioning valve. is it bad?