Brake bleeding help

[63longfleet]

Need some help. What is the best way to bleed the brake system after replacing all of the hard lines, master cylinder and prop. Valve?

[Bimus]

I bought this kit from Harbor Freight it hooks to a air compressor and needs at least 90 psi but it makes it a one person job .

[mongocanfly]

Filling reservoir with fluid and cracking your bleeder screws will gravity flow fluid to the wheel cylinders...be sure to keep master full while gravity works for you..do that till you get fluid at each bleeder...if you dont have the one man bleeder it's a simple process with a buddy on the peddle and you on the bleeders..start at the furthest bleeder from master...if you have a trip style prop valve you'll need the tool to hold it centered while you bleed...

[damnyankee36]

There's a lot to be aware of about bleeding brakes that's beyond the scope of a single answer to your question. Here's a couple of places to look at to get you started.

https://www.youtube.com/watch?v=qPLaPv8DITE
http://www.classicperform.com/TechBook/BrakeBleed.htm

[dracko]

Originally Posted by 63longfleet

Need some help. What is the best way to bleed the brake system after replacing all of the hard lines, master cylinder and prop. Valve?

Also bench bleed the MC prior to install. If your MC didn’t come with a kit to connect the hoses to the ports then Dorman makes one, available at any parts store. Also pay attention to your pushrod adjustment, if not adjusted properly, braking will suffer and fluid may be blocked from returning to the MC.

I just completely redid my braking system as well and my biggest bit of advice would be to tighten your fittings and unions more than just snug, they’re a double inverted flare fitting and need a good crank to keep leak free.

[mongocanfly]

brake line fitting shouldn't be a tapered thread...should be double inverted flare

[dracko]

Originally Posted by mongocanfly

brake line fitting shouldn't be a tapered thread...should be double inverted flare

Sorry you’re right I’ll fix that, I guess I was thinking more they need a good crank to set the double inverted flare which has a tapered shape to it.

[franken]

If the master's been upgraded to a dual res, there should be an annoying valve in the distribution block or prop valve that will close (and not want to reopen) if you try to bleed the system. There's a little button that needs to be kept in one spot while bleeding.

[dracko]

Yes there a special tool you can get called a prop valve bleeding tool that keeps the piston centered. I used a Cotter pin and held it in place with some electrical tape and it worked fine. You unscrew the brake light pressure differential switch and replace it with the tool or whatever you have on hand. The button on the end of the prop valve is to push the piston back to where it should be if pressure is lost on a front line and the piston slides forward. If it slides towards the rear you need to find some other means of sliding it back in place.

[demian5]

Bleed the master on the bench first.

Put rags under your master area to protect the paint and use a fender cover.

Install master in the truck then open the bleeders at the wheels (with the reservoir cap off) and let gravity bleed till fluid is dripping at the bleeder. Tap the wheel cylinders, calipers with your wrench to get the bubbles moving. When fluid drips, close that bleeder.

After all are closed, top off the master fluid level to the top and put the master cylinder cap on tight, pump up about 10 or more times and release. Find all the leaks from the new lines fittings that need to be re tightened down. Clean up those messes and pump up again. Tighten more fittings, cry about messed up paint on frame.

Top off the master fluid level again to the top and put the master cylinder cap back on tight, then bleed from RR/LR/RF/LF until all bubbles are gone. I have never needed a prop valve tool.

Use a clear hose if you can, or just vacuum line from the bleeder into a container of some kind.

With a helper in truck, open bleeder, have them slowly press to floor, when at the floor, they hold until you close bleeder, then the release. Do that till there is a good flow of fluid with no bubbles.

Check the fluid level after each couple of wheels, it goes fast.

When done the first time around, pump the brakes a few times.

Repeat RR/LR/RF/LF until there are no more leaks at fittings and all air is gone. its easy to go through half a large bottle of fluid.

Clean up the driveway and wash the brake fluid off of your arms before your test drive.