First let me say whoever figures this out, I will legit mail you a gift card to your favorite restaurant.

I did post in the f150 online group ...lot of good suggestions, tried all, no fix.

Helping my friend with a Craigslist purchase, 2002 f150 screw 4x4. Brake pedal feels firm, a little firmer than the 00 f150 I own. Problem is the Craigslist truck won't stop easily. Standing on the pedal won't lock up or get a buzz from the abs even on loose surfaces. We did have some snow recently and I did confirm the abs worked lol. At slow speeds stopping feels....ok... But if I had to slow down from 60 quickly....scary thought.

so...it brakes straight and even. No pull no pulsation ...just long

I swapped front rotors and calipers and pads from my truck no change.
I swapped the booster and master cylinder from my truck no change

In both cases the "bad' parts when put onto my truck work fine and my good parts don't work well on the 02.

Booster vacuum problem you say? Checked w a gauge stable 18" at idle on both trucks.

Literally what is left? If I had a blockage that should cause a pull or lockup on a wheel or two only right?

Help!!!!

 

Brake lines. Run new to both rear cylinders and go from there. Semi plugged and therefore act on off.

 

What kind of pads? Ceramic stops better. And how are the hoses?

 

Pads not sure came with it.... But I have cheapo AutoZone pads on my truck which stop fine, but not on the Craigslist truck. Hoses aren't swollen...admittedly they're original but they look ok.

 

Replace the rubber portion of the brake lines. Had both a GMC and a Dodge that the rubber portion deteriorated internally, and were swelling/expanding when the brake pedal is depressed. It would stop fine at 30 mph or below, but would not lock up the brakes when stood on. Above 50 mph was an adventure. I had the EXACT same issue with both trucks, and replacing both front rubber lines cured it. Putting my money on this if you have done all the other things you mentioned correctly.

Right before I sold the GMC, it developed a pin hole leak on a metal portion of the line going over to the passenger side. Would leak all the fluid over several weeks, but no wet spots on the ground underneath. Took me forever to diagnose.

 

I would agree with F150DAD. I would even take it a step further, and replace the rear flex line as well. You are obviously building pressure to stop, but not enough to stop quickly enough. Rubber hoses that have failed internally and expand with the pressure would make the most sense.

 

Ok well go after the hoses this weekend and report back. Thanks for the suggestions ...fingers crossed!

 

this blocked/plugged rubber hoses has been a problem since the late 1970's ... GM then Ford (even the SHO had it. )...,,, Chrysler...
and on an on....

I learned of this on a 1977 Caprice.. in 1981....

the crud is formed into a ball.. making a one way check valve.. depending on what end the ball is sitting...

 

Not to be snarky but, save your money and frustration, find a new truck.
Mickey.

 

I have a 98' F150 myself but I seemed to have this similar issue on a 66' Mustang. It experienced had long stops, felt like the rear brakes weren't working strong enough.

My problem ended up being this:
Old brake fluid, Dot 5 (24yrs old)-car sat during a extended restoration.
semi frozen Rear brake cylinders, Only the front calipers were working.
Car would stop but had a hard pedal anyways due to (manual disc brakes) would go 2-4 car lengths past where I wanted to stop.

If the rear brakes were manually adjusted, had good brakes for a while, then they'd fade to like only the fronts were working.

Flushed entire system of the dot 5- replaced with dot 3.
replaced M/C with a dual res type
disassembled the rear brake cylinders, they were clean but stuck/sticking.
replaced all rubber hoses and front disc calipers.

In my case I think it was the rear cylinders being semi frozen.

You mention replacing the front calipers but I didn't see anything on the rear brakes. (unless I missed it). From what I've read it sounds like your rear brakes are the culprit.

Hey, hope that helps!

I've had this happen on a few vehicles (over the years) that the fronts were doing all the work and the rears were either frozen, dragging or not working at all.
My worst experience was with a 86' Bronco, both rears were rusted stuck from being in salt water, I slid it thru a blind T intersection at 60mph, missed a telephone pole by "that much" and almost when thru a fertilizer plant building! (pinched a hole in the seat on that one LOL).

The front brakes do most of the stopping anyway but once you've experienced this you can kinda tell when the system is working right or "half right" that is.

T

 

When you have the hoses OFF, pump the pedal up and down 10 times and FLUSH the steel lines and replace with new fluid.. Check the VOLUME coming out each line to appear adequate.

 

18" of vacuum at the booster doesn't necessarily mean it's working.

 

Inspect the brake lines carefully to see if any portion is crushed.

 

I second the opinion of old brake fluid. Brake fluid is hydroscopic which is a fancy way of saying it absorbs moisture/water. This will impede your braking capabilities. Cheap enough to just bleed the brakes and keep adding fluid till you get fresh fluid coming out on all four corners. As a matter of fact, I'll be doing this to my truck this weekend.

 

Thanks for all the suggestions. In reply to the rear brake question. I didn't swap the rear calipers but I did pull everything apart and re lubed the slides made sure everything was moving freely. Swapping the front was desperation after taking everything apart and putting it back together with no change. So was swapping the booster / MC. You keep expecting something to change but nothing did.

I did manage to swap the driver's side brake hose yesterday as the local parts store had one and it didn't take very long to do. I am getting a slight pull to the left now when braking so that is a positive result. Whether it is due to the new hose, fresh fluid since it drained quite a bit out when I was changing it - who knows. The fluid that drained out had a yellow / greenish color, kind of like pee...but with a drop of green food coloring. It was light, not dark or dirty - again making me think someone has already attempted unsuccessfully to solve this problem. I've bled brakes before and seen black fluid come out. I'm hopeful that changing the rest of the hoses will get us where we need to be, the hoses look original to the truck. I didn't check every metal line, but the metal lines from the MC to the ABS unit and from the ABS unit to the front brakes look fine. Even if I had NO rear brakes, I should still be able to get some skid/ABS activation on loose road surfaces from the front - considering I have good pedal pressure building somewhere....just the question of where lol.

I'm picking up the passenger's side today and replacing that one, and I have ordered the hoses for the right, left and center rear lines so will attack those next. Will keep everyone posted. Again, truly thanks for the suggestions. Usually can figure this stuff out but this time it felt like I hit a wall. Oddly enough, I've never had to replace brake hoses, and I've had my share of clunkers and sub $1000 dollar cars as daily drivers in my life. Maybe I got lucky