Front brake problems

[chefman1]

Hello All, Need major help with this last problem. I have restored entire bottom part of this z. Suspension, brakes, brake lines, bushings, rotors, calipers, rear conversion. I can not get brake peddle to rise. New brake lines including new booster and master. no leeks, but peddle will not rise? I'm getting bubbles in both reservoirs for front and rear? I have a peddle but it sucks? Please help me, this car is too perfect to let sit in garage.

[Zed Head]

There's a spring that brings the pedal up. Can you pull the pedal up by hand?

[chefman1]

There's a spring that brings the pedal up. Can you pull the pedal up by hand?

Hey Zed Head, Spring is there and pedal comes back up but pedal is still soft. This is even after a two man bleed? Master is after market and getting a bubble affect during bleeding but no excess air at the front or back calipers? I did replace the booster and believe that there might be too much free play between the master and booster but not sure at this time? Please help? I have two portioning valves on this car, do i really need two? I have been told by datsun z that upgrading to wilwood 1in and new p-valve that issue would be solved? but i really do not think so? you advise please? Thanks

[Zed Head]

So what you mean is that you can't get a firm high pedal. The pedal drops too low before you get any braking action, or you have to pump the pedal to get any brakes. ???

One pretty common error that people make is to put the calipers on the wrong sides. They will fit either way. The bleed screw needs to be at the top of the caliper, not the bottom.

[chefman1]

soft pedal, but no air in lines during car on or car off. pump pedal the same. bleeder screws on top always.

[chefman1]

I'm thinking new booster stem has too much play between the master and booster? there are no leeks and bubbles are coming up form each reservoirs while pumping brakes? whats your thought?

[grannyknot]

Have you bled the master cylinder? There are 2 bleed screws on the side of the m/c

[chefman1]

Yep, bled the master. Bled the lines back to front. Every thing a z needs. I have come to the last two problems, which is p-valves, master or brake booster adjustment. Please advise?

[chefman1]

That's three problems

[Zed Head]

rear conversion.

Many, many people have problems bleeding the brakes after installing calipers on the rear. Many. Quite often they have to remove the caliper, install a block of wood between the pistons and hold the caliper so that the bleed screw is at the top. There are people on this forum who have spent weeks. maybe even months, trying to get their rear caliper conversions bled.

[chefman1]

rears are great, just having problem with the fronts

[Zed Head]

I'm getting bubbles in both reservoirs for front and rear?

Hard to tell what's really going on then. How do you know the rears are great? They lock up but the fronts don't? That's typical of air in the front calipers. Can you pump the pedal to get it high and the brakes working? If you can pump them up then you have air in the system. If they just start braking with the pedal low and there's no change with pumping, then you have an adjustment problem.

But you should not have bubbles in the reservoirs.

Did you install a different master cylinder also? The stock system shouldn't have any problems bleeding the brakes.