Installed a booster off a 73-79 in my 67 F250. The body is a donor and is installed on a 78 F250 4x4 chassis. I kept the original brake pedal and hanger system.

Stupid question of the day... but now that it's all together with new pads and bled.....when the brakes are depressed, they do not force the pedal up ( in other words the front brakes stay on ) you have to pull the pedal up the last 1/3 of the way by hand to get them to come off. Now the rotors are crap and the calipers are so so..not sure if that would have any adverse effects on the system. I thought maybe proportioning valve also a possibility as I was getting kinda crappy flow to the rears when bleeding ( and well it's only the fronts holding on when the pedal is "stuck"..but I also still need to adjust the rears so I think that point is moot)

Anyone ever encounter this? I've never seen / there should be no reason a brake pedal needing a "return spring" ( trying to imagine how wrong that would be...lol)

Give me some opinions for my situation

 

When bleeding the front ,did you move the pin on the Proportioning valve?

Were the rear shoes adjusted properly before bleeding ?

Was the booster rod adjusted correctly on installation ?

 

Move the pin on the proportioning valve? I didn't think you could do anything to it( factory non adjustable). When I re installed it after I cleaned the frame up and line-x coated it... ( the frame not the valve)... I just primed the oustide * (plugged the line holes) and stuck her back in...never touched anything. Didn't notice anything I could adjust on it persay.

No, to be honest I have not even pulled the rear drums. Brakes worked ok 1 1/2 years ago when the project started. Just got the bleeders all loose and bled em. Was going to adjust the rear and have a look/clean things out later.
I suspect it would be a good idea to do so now.

The rod bolted up to the pedal with little modification( ground the end down that the 67-73 style stoplight switch goes on) other then that..the stock bolt when in the pedal and seems to line up ok. Should I be doing something else there? Another fellow I spoke with the other day mentioned improper rod length..but the travle is not impeeded by anything at this point..as you can pull it back to the stop and the brakes release.

 

Old calipers & Old wheel cylinders corrode & breakdown the system so bad that the return springs won't pull the shoes or calipers back to normal position.

I'll post you some links.

EDIT:

Here are some illustrations from my gallery.

See pics number: 4,13,& 14

https://www.ford-trucks.com/user_gal...542&albumid=44

 

Bad booster had the same problem and got a new booster problem fixed!!

 

Update time: Took the booster off today.. think that's it. Looks like the master has been leaking into the booster...and when push the rod from the back ( pedal side) it doesn't want to return all the way ( till you pull it like I was doing)....

So... I had a spare one off another 78 3/4 (this one is off a 2wd) they look a little different, but not overly so. The master on the spare has the lines coming out the other side( pass), and the bore looks smaller. SO..I will just head off to the parts place tomorrow and get a reman correct one. Also took the time to vacuum bleed the brakes completely removing all old fluid. I had just bled them, but the crap that came out was amazing. Also just in case crap got from the master to the proportioning valve, I also vacuum bled the backwards ( bottle of fluid on the nipples- sucking from the lines at the master. That produced some crap too. All nice and clean now... will re bleed after I throw on the new master and see how it goes.

No doubt, the calipers and wheel cylinders are next... I am sure given the condition of the master/booster...the other stuff is crap too.

Oh and I found the adjustment for the booster..it's on the rod on the master side. I will try and turn it in 8 turns so I can move my pedal down some inside too.( it's sky high, would be higher if I take the stop out too.) Would have been a nice idea to use the pedal and hanger off a 73-79 , but then it doesn’t bolt up to the dash the same way... oh well.

What's a little more money right ? When I get her bled I'll let you know how it went.. Thanks for the advice so far.

 

Don't adjust it by turns,do it by measurement

My pic links contain the adjustment info.
Illustration #4
Just click image #2 to enlarge it.

https://www.ford-trucks.com/user_gal...d=1756&width=2



What is the FT number on the booster ?

 

No sure of the Ford# as I think it's been replaced. There was a date stamp that appeared to be from 1996..there was a month/date too but I didn't look too close. There was a Bendix Part # on the bottom if it... #12XYZ... I will look again tomorrow and see.

The "8" turns i mention..basically I turned that little nub all the way in.. it was maybe 1/4-3/8 inch out in the first place( the 8 turns). Is there a "proper way" to do what I am doing here? What I want to accomplish is that it is fully released before the pedal arm hits the stop. As it was before, when I was pulling back on the pedal to get the defective master/booster to release.. it hit the stop, but with the stop removed( on thing I checked today) the pedal still moved back another 1/2 inch or so. ( can you picture what I mean ? ) and no the stop wasn't holding the brakes on... as when I pulled the pedal up to the stop the brakes came off.

I installed this spare booster this afternoon, made the brake light switch work this time. When you depress the pedal with no master on it ( maybe not a good thing) it pops right back up to the stop ( something the other booster didn't) so far a good sign.

 

Click my link I left in my last reply to see the illustration of the booster rod adjustment.
Don't do it the "turn so many turns" method.
This... after the rear brakes are adjusted properly, is to ensure the brakes & pedal work... the way Ford designed them to work

The FT# is located on the very end of the activation push rod linkage near the hole that goes Pedal side .

 

Well with new Rotors/Calipers and my spare used ( but good) booster.. I have perfectly functioning brakes !!! Whoo hoo... I am sure the booster was the big problem, calipers second. Still going to open the rears and see what's up there. Can't get a good bleed back there. ( the only parts I haven't changed yet- axle lines, hose and wheel cylinder.. which I guess will be next.

 

Be sure to pay attention to Mil1ion's posts. He usually does know what he is typing about. That is great that you have identified your problem!!!! But make sure that your brake adjustments are correct. Remember, these are your stoppers. If you haven't already done so, take a look at Mil1ion's links.

 

There is a booster test that is performed in the vehicle.

Sorry, I forgot to pass that on to you.

Ford Truck brakes have been a problem for quite some time.

They require almost perfect tolerances to be most efficient.

One major upgrade is to swap in F-350 brakes.

Something I intend to do in the future.

While you're under the truck, inspect every mm of the rubber brake hoses.
These are the weakest link in most brake systems.