The Stovebolt Site Forums The Shop Area Driveline Help with new brake system!

Hello all
Looking for your expertise; I did a search before posting this
I have a 1950 1/2 ton that I just installed a completely new brake system
New stainless steel pre-bent lines, new master cylinder, new wheel cylinders, new soft lines, new shoes, resurfaced drums

After dealing with leaks at every joint with the stainless lines, that problem has finally been resolved
So now I've bleed the brakes 4 times (cycles) already at each wheel cylinder the pedal has little pressure. I turn the bleeder screw 1/4 turn and have good fluid flow with little to no bubbles by now. What am I missing?? The brake pedal lever is adjusted to 13/16 as the manual says

Was the master cylinder bench bled before installation?

Master cylinder on firewall or under floor? Did you adjust drums brakes for slight drag? If all drums and under floor mount, did you install 10# residual valves?

Sorry no bench bleed
The brakes are adjusted with very little drag

Try this, press the pedal very quickly in short strokes, maybe 1/2" or so. It should bleed out the master cylinder, 10 or 15 strokes, quick and short.

Joe

Very early in my working career an old timer asked me, "If you don't have time to do it right the first time, where are you going to find time to do it over?"

Lou,

Do you have the original brake configuration?

Did you bleed each wheel cylinder until there were no bubbles (slowly pump the master cylinder multiple times until there were no bubbles in the bleeder hose at the wheel cylinder)?

Did you bleed in the following sequence?
1. rear passenger
2. rear driver
3. front passenger
4. front driver

Did you top off/check the fluid level in the master cylinder after bleeding each wheel?

You might need to go through the 4-wheel-cylinder bleeding-sequence two times.

Is the fluid level going down in the MC as you pump?

Ed

go thru steps as mentioned above,it takes time and 2 people.
take your time and go through it again, somewhere in the circuit it will clear up.

More than likely air in line that needs to get out,with a lot of pumping. (keep checking reservoir)

hopefully that is all that is going on

Just a thought, if you don't have good pressure than you can't be sure all the leaks are sealed. From my experience the smallest leaks show up when the pressure is the greatest. If you pump the pedal twice quickly and you get some pedal, you have an adjustment problem. Also you should have zero bubbles when bleeding is finished.

I do my brake bleeding all by myself. Just like in the manual I use a small clear tube going into a bottle.

Lots of great tips here.
One more to add.
You have Huck brakes. They are a pain to adjust if the conture of the shoes do not match the conture of the drums. They never seem to. This gives you a false "slight drag" feel. This makes bleeding the brakes nearly impossible.
This phenomenon is easy to overcome by adjusting the brakes tighter than specs until you finish the bleeding job. I tighten them up until I can barely turn the wheel by hand. Make sure you adjust both adjuster wheels on each cylinder.
After you are done bleeding your brakes, back off the stars until you have more than a slight drag, and then plan on readjusting after 100 or so miles, as the shoes become naturally worn to fit the conture of the drums. After that you should have really good brakes.
Carl

Thanks carl
That's actually my plan for tonight

Thanks to all that helped
Still having some issues and so close
The PO really had some crazy stuff on the truck like a wood block on the top of brake lever to engage the switch because the pedal was adjusted so far out

Anyhow, what the status and remaining issues
Over adjusted all the wheel cylinders to hold the drums firm. Got some firm pedal after that. Checked all lines no leaks; after bleeding the brakes, had the rear lines with a little leak dribble, driver side tightened up no leaks; passenger rear a little leak that takes a bit to drip, but the nut is starting to get stripped. Also the passenger front and rear drum not tight anymore and spin
I do not get any big bubbles, just small ones; I am only turning the bleeder a 1/4 turn otherwise bubbles come from the outside
since I did not bench bleed the master am I just spinning my wheels? Should I crack the main line from the master?

This is the only thing other than installing new shackles and shocks from ever driving this in the 14 years I've owned it

I am not aligned with the thinking that you needed to bench bleed the master then or now. Probably the reason your two drums are turning is that getting that pressure and moving the shoes probably centered them. So you could probably adjust them again. I have no advice for your lines as I have not used stainless steel.

Try a power bleeder.

My thoughts as well. Nothing beats a power bleeder, especially when dealing with a dry system. In addition, the proper bleeding sequence per the shop manual is Left Rear, Left Front, Right Rear, Right Front.

Correct sequence
I just bought a mighty vac