[jortega7451]

I have a 79 bronco I replaced front calipers, hoses and the master cyl. i bled the brakes all the way around till i had clean fluid coming out. The brake pedal has alot of travel in it and the brakes dont seem like they are grabbing the way they should be. Does any one have any ideas? Proportioning valve, rear wheel cyl. etc?

 

[Ranger429]

Did you bleed the brakes till all the air was out? Just because you got clean fluid does not mean there is no more air in the system. Re bleed the brakes starting with passenger rear 1st, driver rear 2nd, passenger front 3rd and then the driver front. Do not let the fluid chamber run empty while beelding other wise you start all over again.

 

[jr78f150]

ranger is right,especially if you didnt bench bleed the master cylinder.also,did you make sure you had the correct clearance between the rod comeing out of the booster and the new MC? it is adjustable

 

[Ranger429]

ooops, didn't see the new M/C. Was that bench bled?

 

[jortega7451]

I bleed everything properly and bench bled it 2. when i said i got clean fluid i ment i it till no air bubbles and until the fluid was nice and clean.

 

[Runnin'OnEmpty]

.....also,did you make sure you had the correct clearance between the rod comeing out of the booster and the new MC? it is adjustable

The Ford spec on that rod length is .9875", just a cat's whisker short of 1 inch.
It's measured from the pushrod tip to the base of the booster flange where the master cylinder sits.

If the rod's adjusted too long, the brakes will drag; if it's too short, then the brake pedal 'play' will be too much.

If the brake pedal just feels mushy, then bleeding's the problem.

 

[BigWheelz]

Don't forget that 78-79 bronco brakes just plain suck in stock trim! That being said, the brakes should at least operate the way they did before you replaced said parts.

Lots of people on this board (myself included) have cautioned of defective master cylinders & boosters from parts store remanufacturer A1 Cardone. A defective master cylinder could cause the problem you describe.

 

[CrazyBRONCOguy]

Mine was doing the same thing, bench bled it twice also. Adjusted the rod witch helped a little.
I ended up haveing to bleed the brakes with the truck running, to finally get them where they should be.
It was wierd it would get great pedal when the truck was off, but put the booster to it and it had nothing, before i bleed them with the truck on.
Then I let it sit a couple days and now they are great. I was tinking maybe something in the porportioning valve was stuck on mine and free'ed up.
The PO ran it with no rear brakes for who know's how long (that could of been some of my problem also, no fluid in the back cylinders).

You could also have a loose connection somewhere, I'd double check all of them.

 

[jigmister]

are you bleeding properly? if you do not have a tube from the bleeder submereged in a container of brake fluid it will suck air back in when you release the pedal.
unless of course you have someone hold the brake pedal in while you tighten the bleeder.

not trying to be a wise guy but I am not sure what method your using to bleed.

 

[jr78f150]

try reseting the proportioning valve.bleed the brakes as stated above,the farthest wheel from the master cylinder and work your way to the closest then use a pair of needlenose pliers and pull out on the pin on the prop. valve to reset it

 

[1978custom]

when you push the brake pedal, and hold it. does it go down? if so it could be a leak, or your master cylander.

 

[M.L.S.C.]

Question about brakes, I seem to have an issue with my rears - they seem to be doing nothing whatsoever! How I determine that - when I hit the pedal on snow all four tires should be locking, yet I can see in my rearview mirrors that my rear tires are still turning. Worse, if I try to hold the truck in place with front brakes on snow and rears on pavement the rear wheels will keep pushing the truck forward till either the rear hits snow, or the front hits pavement. There is pressure going to the wheel cylinders, system is properly bled. The pedal feels weird too, tis a bit soft but stops the truck just fine, then all of sudden halfway down the pedal travel it's as if I just lost vacuum assist and I run all manual brakes... Truck stops fine with obviously just the front brakes, however I'm trying to figure out what's the deal with the rears. I tried readjusting the rear brake shoes but only the driver-side star-thingie turns, and I'm not even sure which way to turn it? I'll be taking the propane torch to the passenger side tomorrow, hopefully a bit of heat and some tanking can get that one unstuck too. I believe what happens is I'm having too much fluid bleed off towards the rear so I can't build up proper pressure? Assuming I get the darn adjuster of the passenger side unstuck, which direction do I turn both adjusters to tighten up the brakes? Clockwise or CCW? Thanks!

 

[rkymtnbrnc]

My advice would be to pull the rear drums off. Soak the adjusters in PB Blaster or WD-40 till they are free. Reinstall the drums. Tighten them up till they rub & then back off a little.

 

[M.L.S.C.]

I tried pulling the drums already, that was the first thing I did, but they are like rusted solid to the axles and will not come off without some serious beating and likely heat, and I can't do that cause I live at an apartment complex.

 

[colobronco]

Got to do that first. Any muffler shop can help you.

 

[M.L.S.C.]

Still tho, which way do I turn the adjusters to tighten them, most adjusters I've seen have been regular right-hand thread so CCW tightens them up, but those have all been newer vehicles...

 

[Ranger429]

There is a left and a right star wheel. I cannot recall which way the DS turned to tighten the shoes but the passenger side will be the opposite. IIRC if you push down on the star wheel that will tighten the shoes up. Going up will loosen. You also have to hold the self adjuster lever out of the way to turn the star wheel.

 

[M.L.S.C.]

Figured it out - the driver-side star-wheel needs to be turned clockwise, and the passenger-side one, like Ranger 429 said, is just the opposite, and wants CCW rotation. Got the driver-side taken care of, passenger-side tho is still stuck, even heat wouldn't make it let go. A buddy just told me a trick about getting drums unstuck from the axles, will see how it works tomorrow.

 

[rocknbronco]

Apartments suck for workin on rigs.

 

[M.L.S.C.]

Tell me about it man, I'm lucky to have a nice manager that lets me slide as long as I don't get carried away and make much noise at night... That, and I know my neighbors, being nice to folks can go a long way.