Projects Couple problems with the '51 F1 brakes

So we cant get the brakes to work at the moment. One of the brake lines had a leak in it, we relaced that line... Then we Replaced 1 wheel cylinder that looked pretty bad. But the peddle just goes to the floor. So we replced the master cylinder. Still no peddle.... Pressure seems to be escaping somewhere, but there's no fluid leaking anywhere.

Suggestions?

By the way, do these trucks have a positive or negative ground?

 

Positive ground I believe on the 6V system.

Did you bench bleed the new master? Have you been able to eyeball each of the old wheel cylinders to see if they are leaking?

 

Sounds like air is the system to me. Try re bleeding them.

 

Did you bench bleed the master? I take it you have bled the whole system. Was it a metal line or a rubber one? If one of the lines had a leak in it I might suggest changing them all just to be safe, depending on the others condition.

Stock, a F1 is 6v positive ground, who knows what it is now. The voltage regulator or generator might be best clues to see if its been converted to 12v.

 

On a truck of that vintage, you're best off replacing all the wheel cylindrers and soft hoses. Take a real good look at the steel lines as well. Those can be the weakest link when you have to make a sudden short stop.

Bench bleed the master, make sure all the shoes are well-adjusted (helps the pedal height), give it a good bleed all around.

Bob

 

Ok, thanks for the quick responses.

We did bench bleed the new master.

The metal line had the leak in it. All the other lines look really good.

Everything looks really good for that matter...

We're going to keep adding fluid and re-bleed and see what happens.

But keep the suggestions coming!!











6 year old gas + Muradic acid = new flavor wing sauce

 

6 year old gas, thats nothin.....you wouldn't believe how bad 25 year old gas is, and if you get some on your hands it will stink for days

Try gravity bleeding or vacuum bleeding if the standard pump the pedal method fails. Did you buy a new master or get a rebuild? I rebuilt the one in my F-3 and it would not create any pressure as the bore was too rusted out. Try putting a plug in the outlet for the master and see if that solves the problem.