Don't be mad... my first "distance" non-test drive since getting the Excursion running was....

TO THE GROCERY STORE

Anyway, it was about 13 miles round trip. About 2 miles into it, it felt like it was having a hard time making power. Right before I got to the store, I smelled the brakes. Both fronts were pretty warm. On the way home, I drove a little, rested a little, repeat. They were both pretty hot once I got home.

While finishing up the build, I moved the rotors, calipers and pads over from the truck, because they didn't have much mileage on them. They worked fine on the truck. Also, the flexible lines are new. I haven't pulled everything back apart yet, but I'm not understanding why they worked fine on the truck, but not on the Ex.

Is it possible that the ABS unit could be malfunctioning and not letting the brake fluid back to the master cylinder? Or, could it be a parts mismatch, such as the master cylinder and brake booster came off of a Super Duty truck, and different parts are used on an Ex with 4-wheel ABS? I know nothing about the truck that the master cylinder and booster came from other than it was a SD truck (so, probably rear ABS like mine). Or even- were there different pushrod lengths between trucks and Excursions?

I'm just trying to gain as much insight as possible before I yank it all apart.

PS- in case anyone looks at the year of my truck, I had upgraded the brakes to the post-99 setup a few years back, so everything should be a match for the Excursion.

 

Well, looking at part numbers on Rock Auto, it looks like both the master cylinder and the brake booster are the same between Excursions and similar-year SD trucks- with no mention at all as to the type or absence of ABS. So I guess that rules THAT out...

 

You had an engine bay fire correct? How is the speedo behaving? Only reason I'm asking is the ABS module/computer receives and interprets the VSS signal before sending it to the speedometer.

How do the soft lines look for the brakes? I haven't kept up with your build/resto thread

If the whole pump was malfunctioning, you should have other indications that would point that direction.

 

Speedo is acting normal and rubber lines are new. Brake pedal even feels normal while driving.

 

I just now reread and saw where you already covered the soft lines, my bad Are the proportional long valves the same between the truck and Excursion? Just randomly thought of that, however that should impact pedal effort and travel to stopping, not releasing IIRC.

If the brakes are dragging it usually indicates the slide pins, however if they worked fine on the truck prior to swapping them then I'm not so sure about that this time around. It still wouldn't hurt, unless you're 100% on the pins being greased using the proper type and heat range grease.

If the MC bled dry during the brake swap it's possible an air pocket worked into the ABS module, those are a little bit of a biatch to get out of there without a program to command open the valves. With the pedal feeling normal however, again I am uncertain.

Basic and free stuff I can think of just to rule them out completely would be a full brake bleed and checking the slide pins. It's also just the front brakes that are getting hot?

 

I yanked everything apart and decided to re-grease everything just as a precaution. I found that one of the pistons in the driver side caliper is sticking pretty bad. So it looks like a caliper.

On the passenger side, it seems to release just fine after the re-grease. I've got it back together.

Then came the rain...

 

Got the LF caliper replaced and then took it out for some more miles and braking. Everything seems to be working correctly now.

Well, except for the ABS code for the LF speed sensor, but that'll have to wait for another day. I'm broke now.

 

Glad it sorted out easily enough bud

 

Thanks for all the help and advice. My entire Excursion is built on it!

 

That's what we're here for!

Well, that and shenanigans. Everybody loves shenanigans.