HELP! New brake system and no system pressure???

[atomicjoe23]

I installed a whole new brake system (front-to-rear. . .new lines, calipers, master cylinder, proportioning valve, everything) and I've pumped fluid through the system going through the bleeder valves to the M/C and I still don't have any pressure in the system when I pump the brake pedal???

I have no idea why this could be???

Could anybody PLEASE help me out? BTW, this is the first time I've done this, but it seems like to me if you've verified that the lines are full of fluid, there are no leaks and the fluid can make it from the calipers to the M/C that you should be able to get some pressure in the system. . .but that's just me.

Thanks for the help!

[KennyTJ]

did you bench bleed the MC and calipers?

[atomicjoe23]

I didn't bench bleed the M/C as I was told it wasn't absolutely necessary. . .this of course was after the fact that it was already installed and I had already put some fluid in it because I didn't know about bench bleeding a M/C. . .

. . .and I didn't know you should, or even could, bench bleed a caliper. Again something that I hadn't heard of.

Yes it will make a mess, but I'm willing to pull the calipers and the M/C if that is what necessary.

Care to clue me in on how to bench bleed the M/C and calipers or offer up a solution that doesn't require their removal (although it may be a longer and less desirable method of doing things).

At least I will know about this bench bleeding stuff the next time around!

Thanks!

[JunkCJ6]

You don't have to remove the master cylinder to bench bleed it. Just unhook the lines coming out, plug one outlet and loop a short piece of line from the other output back into the resivour. Pump the brakes till you see no more bubles then switch to the other output and repeat. Once you have the master bled then reconnect the lines. Crack the line at the caliper and pump til you have fluid at the end of the line. Repeat for all 4 wheels til you get fluid at the end of each line. Make sure while doing this that the master keeps atleast 1/2 full. Then bleed the calipers and wheel cylinders starting with the farthest away. You should then have good brakes. If not, you may have a bad master cylinder. Always buy new if possible. I have seen more bad remans than good.

[95rokrunner]

hopefully you didnt dry stroke the m/c alot, nothing will fawk up a new m/c quicker then dry stroking it! did you get in the rig after it was installed but before fluid was in it and push it at all??

[atomicjoe23]

Thanks JunkCJ6 hopefully that will fix my problem.

I don't know if this was a new M/C or a reman. . .a friend got it in a kit and he already had a new M/C and didn't need this one so I got it for FREE.

Thanks again!

[brewchief]

Calipers are on the correct side? Bleeder screws up? Many calipers can be switched side to side and if the bleeders are down you'll never get the air out.

[atomicjoe23]

Calipers are on the correct side with bleeder valves up. . .

I don't remember specifically, but I might have stroked it dry. . .if for no other reason to check it's location in the cab and make sure it was in the right place. . .would dry-stroking it only once (maybe twice) cause a problem?

[JunkCJ6]

Yeah, it may have rolled an o-ring/seal and won't push pressure.

[Bubba_Jeep]

You need to bench bleed the MC, unless it's mounted perfectly level in the truck, otherwise you'll never know for sure if all of the air in the MC has been removed. If you have air trapped in the MC, you'll never get a firm pedal, no matter how much brake fluid you pump through the system.
One way to test the MC, and isolate where the problem is, is to plug both MC outlets and see if you have a solid, NO MOVE, pedal. If yes, you can assume the MC is bled. Next, leave the plug in for the front system, and connect the rear. Bleed the rear untill you hav a firm pedal. Once you feel the rear's are properly bleed, attach the front system, and bleed.

[atomicjoe23]

Thanks for the help guys. . .I'll try those tips out.

I've bled brake systems in the past before, just not a completely dry system before.

No anti-lock, but it is a power brake sytem. . .I made all my own lines out of 3/16" MS tubing, braided SS flex lines, a Wilwood proportioning valve and '75 Chevy calipers.

[wtf over]

if it wont build pressure its probably air (given you dont have a m/c problem) did you use a vacum pump at the calipers when you bleed them? its a cheap tool that works wonders. 1 air bubble in the caliper is enough to cause no pressure build up. when you pump the brakes with the cap off the reservoir does it pump fluid up? this might help diagnose the m/c. does the peddle just bottom out or does it build and hold any pressure? brakes are over rated anyways, just throw it in reverse it will stop.