Well after the wife deciding that we were not going to spend the summer holidays with her parents, and that the camper had to go, and that we had to buy a fifth wheel, I finally get around to getting the truck ready.
It is a 77 F-250 supercab, 2wd auto, heavy duty brakes, 400CI
We only use it about six months a year, for holiday time and such, so it does sit outside on ashphalt and unfortunetly the driveway floods pretty good, so the water is hard on the truck, anyway I fire it up after putting the batteries in it, that I keep in the garage on charge.

And I drive it up and down the driveway, well the brake line to the back blows behind the fuel tank, okay so I get under there and see that the driveline is pushing right into the tranny, so now I have to do the steady bearing on the two piece driveshaft.
So I take it out and it has to be hammered to seperate both splines, then I take down the fuel tank and get at the brake line and fix it, now I have the line in and brakes bled, replace center bearing, all three u-joints, and the rear tranny seal just to be on the safe side and the splines are tight going together even though I lubriplated them and then I go to move the truck and it is sluggish, so I realise the brake lights are on, so I pull up the pedal and lights go off and truck moves quicker, so put brakes on again and sure enough truck doesn't really want to move till pedal is pulled up to make it move and take the rear lights off.
So my thought is that the master cylinder that is not that old must have buggered up from not getting used.
It has heavy duty drum breaks in back and dual piston calipers in the front, but the only way I can see the brakes hanging up is the master cylinder as lifting the pedal seems to release them.
Any other ideas? Or have I hit on the reason for the problem?

 

Behind the brake booster is a linkage that will bind up sometimes. You have to take the 4 bolts out and pull it ahead to get at it.

 

I'm with Mark A. Try lubricating all the pedal linkage first.

When you say the brake lights are on I assume you mean the tailights and not the idiot light?

 

Yes, the stoplights are staying on because the pedal is staying down.
I did try lubing just the brake pedal under the dash, and I tried pumping the brakes and holding them and then starting the truck and the pedal seemed to sink down like it should, so it must be either the master cylinder or the linkage in the booster.

 

Now I have had a place tell me the proportioning valve may be causing a problem.
What do you all think?

 

Doubt it's the prop valve.

What happens when a vehicle sits for a long time is that the brake fluid absorbs water and rusts things. Like lines, calipers, wheel cylinders, master cylinders, and prop valves. Flush the fluid out when you have a chance.

It sounds like the linkage binding up to me as well. Take it apart, clean it, lube it with a little white lithium grease, and put it back together.

Seems to me that if it were a blockage in the line, either at the prop valve or the MC, the pedal would return all the way up, but you'd still get dragging brakes. Because you're feeling it in the pedal says to me that it's the pedal itself.

 

Okay, thanks all.
I tried to get time tonight, but did not get too far.
Will try and do it tomorrow.

 

Well I pushed the brake pedal down, then went to the back of truck and the brake lights were on, so jacked up the back wheel just to see if they are the ones hanging up, and sure enough with the pedal not returning the back wheels are hanging up.

So obviously something in the system is holding back.

 

This is a picture of the linkage we are takling about. The pivits could be frozen up.

 

Great picture thanks, I just do not seem to get to have the time to look at these problems.
But am trying to get the wife to realise, she has to give me the free time to fix it.

 

Well I drove the truck around for two days and also tried spraying up around the linkage, and now the brakes appear to have freed up, I also tried a guys plastic brake bleeder and flushed all the fluid out of the system, so they do appear to be working, but will still pull the drums and also check the front discs to give it a once over.
Just a pain with the full floating axles I find, but it needs a look I am sure.
Thanks for the help.