Guy's.

After a hiatus, I'm back to the brake issues, but there has been some progress. The parking brake is now working. As suggested, a problem inside the drums and not the cables was the problem. And thanks to all for the advice so far!

I still have a brake dragging problem, along with a questionable pedal feel and return problem. The pedal seems firmer upon startup than after it warms up, but way above and beyond that, the pedal still does not come up all the way after depressing it. I can put my foot behind the pedal and pull it up, maybe a 1/4" or so until it stops, and you feel the truck speed up a little after doing that, or will roll slowly after doing that from a stop on anything other than level. That 1/4" of slightly "still depressed" pedal is the difference between dragging and rolling freely. And I should say at this point that the only things brake related that are not brand new are the front parking brake cable, proportioning valve and the two brake pedals!

How much travel does the booster pushrod adjuster have? This adjuster was mentioned in an earlier reply. I ask because my brake and clutch pedals are quite some distance apart and I can't help but wonder if this is contributing somehow. I measured- the brake pedal is 2 1/8" beyond/lower than the clutch pedal foot pad. I just don't remember that much difference with the other "80's era vehicles I've had. Are all the standard trans. pedals/hangers/linkage/mounting holes the same? Do I have something different in this somehow? Something changed incorrectly before my ownership? Multiple boosters/cylinders had to be tried in another earlier reply- do I have a one that is not allowing the pedal to return fully?

Any additional ideas and thoughts on this strange brake condition of mine will be greatly appreciated. I think this is exactly why Henry stuck with mechanical brakes for so long and resisted the juice brakes! Lol.

Steve

 

I have a ranger pickup that was basically given to me a few years ago. It had been passed from one person to another, it had a brake dragging problem. A bunch of parts had been swapped out and it hadn't fixed it yet. When I got it, it was awhile before I figured out what it was. It was the brake booster. The input shaft had rusted and was sticking inward like you describe.

When the brakes started dragging and I was able to re-create the problem, the first thing I did was loosen the master cylinder a little bit with one of the front tires jacked off the ground. When I first lifted the front tire, it had a lot of resistance to it and the rotor was hot. As soon as I loosened the master cylinder mount to the booster, the brakes released. So I knew it was up there somewhere, the rest of the brakes were good. That's when I started experimenting and found I too could pull the pedal up with my foot and make the problem go away.

I tried to wd40 the shaft and loosen it up, nothing would work. I ended up replacing the booster and the problem went away. You said you have replaced the booster so I don't know what you tell you next. I do know when you get a rebuilt booster from the store, they have a warning tag saying do not pull the output shaft that goes to the master cylinder out of the booster. Some little disc could fall out of place if you do, and mess it up. When you replaced the booster, did you get a rebuilt one or a used one? Was that shaft ever pulled out and then put back in place?

 

I would also check the pedal assy.
On another project they use a pivot between the firewall and booster.
You have the pedal / rod going to this pivot and pivot to the booster.

I found this pivot was rusted to the shaft and would not move.
Taking it apart, what a job, I found rust and plastic bushings that got ruined when taking it apart.
Not using the car I now have a hard pedal but I think its a bad booster and need to send it out for rebuild some day.

So I would check the booster like DaveF said but check any pivots in the pedal assy. that they move as they should.
BTW my brake pedal is lower that the clutch pedal but I dont worry about it much.
I also added power brakes, (pedal assy., booster & master) to my truck from my parts truck so I dont know if that has anything to do with it as it was all from a power brake truck?

I do have 1 front caliper that you can feel lock a little at the vary end of a stop. You can also feel it release when you let off the pedal.
The calipers were new rebuilts when the truck was put on the road as were all rubber hoses, master & booster.
Dave ----

 

Years back, I had my trusted mechanic replace the brake booster and MC after having to pull the pedal back up with my foot. He replaced a couple of boosters before he found one that worked kind of like the OEM one did. Since that time maybe 12 years ago, I have had another shop replace the booster. A few years back I replaced it and the MC again and finally have a brake pedal that is close to what the OEM brakes felt like.

These parts are cheap...you may need to replace them again...is there a warranty on them ?

 

I agree with you guy's, the trouble lies in the pedal/booster/ master cyl. area. I will have to ask about the rebuilt or used parts, and what warranty is on them. Some serious inspection is going to have to happen on the shaft condition and check any bushings, discs and pivots. Something is going on there.
Were there different boosters and M.C's offered for an '86 F-350? It's a 4x4- does that matter? Or could someone have swapped in an F-150 or 250 booster/cylinder because it might have bolted up the same but is not sized correctly for the 1 ton brakes? Just thinking out loud here, just in case nothing out of the ordinary is found with the shaft and pivots.

Steve