OK..so I read thru some previous threads (mind you, I didn't read ALL the pages) and I didn't really see a possible solution.
I had over $1000 worth of brake work done on my 1998 F150 (5.4, auto, trlr pkg., yaddayadda). New shoes, drums, rotors, calipers, parts, etc.
At 3 different shops (I have traveled and moved a lot).
I've had assorted problems ever since the initial install.
The brakes work fine but when stopping at highway speed, the shudder is incredible. It seems like it only does this when there is no load and the basic stopping is more on the rears rather than the front disc. Pulling a trailer or with a load in the bed, the shudder doesn't seem to be so bad (wishful thinking?).
And I have occasional lockup. Mostly, but not limited to, during hot weather. And this can occur at slower speeds, i.e., just moving along in traffic.
Took a rear wheel off to see about possible shoe reversal or some such. The shoes are the same length and the installation looks fine.
I looked up the specs on the recommended shoes and it says "11.03 in.". The shoes on the truck are 11".
Could this be a problem?
As far as the lockup, it almost feels like the thing hasn't been properly bled. Or am I having a problem with the ABS unit? One would think that at least one of these shops would have bled the entire system at some point but?
Appreciate thoughts and suggestions before I tear into this.
Thanks.

 

Sounds like the drums need to be turned and the shoes readjusted IMO. Had a similar experience on an ex g/f's Pontiac. Good luck finding a shop to turn em. A lot are getting away from it, but some still do.

 

I am thinking that the brakes might have some air in them and need to be bled as you mentioned. Bleed all four wheels and see it that solves your problem before you do anything else. Sometimes a shop will just bleed the fronts when they worked on the fronts and that is a problem.

 

The shutter could be warped front rotors. Just curious as to what brand brakes were used?

 

Not sure of brand and, unfortunately, the story is actually more involved.

After the initial install, the brakes were WAY too tight. High pedal, brake smell..returned to shop where they readjusted, supposedly turned rear drums.
Moved to FL, began to have lockup, mostly on fronts causing LF caliper to freeze up. Repair shop on corner installed new caliper.
Shortly after, RF locked up. Unstuck, went to another shop and they replaced THAT caliper.
Current lockup seems to be entire system. And the friggin shudder....
I would normally have done all this myself but was busy moving.
Original shop was usually ok. Reckon they were smokin' the good stuff the last trip in.
Gonna get drums turned, bleed system, see what happens.
Thanks.

 

Has anyone looked into the condition of the brake lines and hoses?

 

I was thinking a bad master cylinder or booster. Too much rear brake could also be a defective prop valve. Using pressure as the logic, then either could be the culprit. If the prop is bad, then it will hold pressure on what side is faulty. Just a thought to throw out there. It's not always in the wheel areas.

 

AK, i agree, one other thing i ran into also, the little hole in the bottom of the m/c can get plugged up and act like a check valve, it wont let the fluid come back into the m/c. I had an old ranchero that give me fits as a young man!

 

The OP did state that his BF was really black, and that is a possible cause. If there is a bunch of junk in the lines, a blockage could be the reason for the weak braking.

I had numerous older Fords do what you describe. The newer systems are better in the internal materials, but with the OPs description, made think the system, more than the individual wheels themselves.

 

Ak, yes, i think the o/p should look more towards the m/c end. Been fortunate enough not to have an abs unit apart, is there any small ports there that could cause his issues?