Replaced Master Cylinder

[Jim Roach]

I havn't had brakes on my 52 B3B for the past two years. They worked when I parked it in the winter of 2005. In the spring of 2006 I went to start the truck, stepped on the brake pedal and it went right to the floor. Rebuilt the entire front brake system and went over the rear brakes. Bled the entire system rear to front. First I rebuilt my current MC and re-bled the system, again with no luck. Went out and purchased a new one from NAPA. Attempted to install it this week with not luck. Tried adjusting the push rod at five different positions from all the way out to all the way in and three places in between. Totally disgusted again. That is why it's been two years. All four brakes are adjusted up to a slight drag on the drum. Any ideas? I am at a loss. Any help would be appreciated. Thanks, Jim Roach

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[Merle Coggins]

Jim,

Your truck is too nice to be sitting in the garage. I can certainly understand your frustration. Will the pedal still go to the floor without any brakes, or is it just soft? It sounds like you may still have a slug of air in the system. When I was bleeding mine I found it benefitial to bleed the lines at a high point besides bleeding the cylinders. At the rear, where the line down the frame connects to the hose going to the axle, is one high point that I'm refering to. Even when I thought I had the air out, I found some at that point. It is sometimes hard to push air bubbles down to get them to the bleeder screws.

Good luck,

Merle

[Aaron]

I have spent the last couple months pulling my hair out re-building my entire brake system.

When you are bleeding the brakes, is the fluid level dropping in the master cylindar every time a cylindar is bled?

Next I would probably check the guts of the MC. After a rebuilt you don't want to push the pedal all the way to the floor right away or it could mess the guts of the MC up.

Sounds like it could be a Master Cylindar related issue.

[Jim Roach]

Merle,

I knew you would reply. Anyway, I wouldn't feel so bad if I had a pedal that faded, but there is no pedal at all. It almost feels as though the MC is missing. I thought about the problem being the MC, but it's new. What are the odds it could be bad?

Thanks for your help, Jim

[Merle Coggins]

How did you bleed the brakes? Did you bleed the master cylinder? It just sounds like a lot of air in the system. The only other way that the MC could fully stroke without building pressure would be to have a blown line, severely leaking wheel cylinder, or unconnected line. But if that were the case you'd have found it from the big puddle on the floor.

I suppose it's possible that your new MC is bad, but it's unlikely. Especially since you stated that you rebuilt the original with the same results. Try bleeding with a pressure bleeder or vacuum bleeder and see what happens.

Merle

[tctrkca1]

Maybe silly question,but Drums are on when being bled?The push rod from brake pedal has some play{The piston hasn't any pressure on it when pedal is up}.I assume cyl are empty and clean.Take a clean pump can and put brake fluid into each w/l cyl thru the bleeder screw hole.This will rapidly complete the filling.If all equal rapidly pump pedal and stop holding it to the floor.Open right rear bleeder,close and release pedal.Complete couple of times and be sure to check m/cyl.The picture in the article does not look to have had a master brake adj.Jim

[JoelOkie]

A compressed air brake bleeder is easily done on the B1B I bought recently. The old vent plug was 1/2 " pipe thread, so I just got a 1/2 " to 1/4 inch reducer and screwed the quick connect right in. When I bought my new master cylinder the vent plug in it has a finer thread, so a 1/2 " copper fine nipple to 1/2" pipe thread is needed. Works nice. I am new to Dodge trucks, but am assuming the old one (1/2 " pipe thread) that was already on it was "original". Either way, it makes it very easy. One person asked about re-filling the master Cylinder during bleeding. You are taking fluid out, so have to keep re-filling constantly, unless you have auto-fill equipment.

[JoelOkie]

new mc setup

[JoelOkie]

Another variation. Don't know if any pickup or trucks have this type vent plug, but is what I made for my 46 club coupe, and what my 48 deluxe seden had, so I think it is standard on P-15s. You need an old cap for this. Drill and tap a 1/2" thread for the quick coupling.

[Jim Roach]

Hi everyone! Haven't been around for a while because of some family issues and as a result I haven't had time to even look at my truck. I want to thank everyone for their help. Merle has suggested that I have a problem with air in the lines and I think he is 100% correct. It just so happens that Grey Beard has made a great offer. He has offered to come to my house and bring along his pressure bleeder to fix my brake problems. I'll keep everyone informed on how we make out.

Thanks again, Jim Roach