F-Superduty Antilock Brakes

[Special K]

I bought a 1989 F-Superduty rollback and have been going through every system on it. The truck was a total mess with nearly everything rigged or broken on it. I replaced the entire wiring harness from a 1991 donor F-250. Every thing works as it should now, but am wondering now if it is possible to add rear antilock to the truck given that it has rear disc brakes. There’s even a speed sensor in the rear end which to me would serve no purpose other than rear antilock. The only thing I don’t have installed yet is the antilock valve assembly that mounts on the frame rail. The truck even has the two lines capped off there from the factory. Does anyone have any info on this?

 

[Nero]

Fords of this era were built to be modular, to mix and match features, I'd imagine you could just drop everything in and it'll work, however I'm unsure if the braking distance would be the same with discs versus drums in the rear. But I don't see why it wouldn't work.

 

[hacked89]

The point of the vss is to sense when the rear wheels locked up and tell the rabs so it can pump the brakes for you. Questions:
I can tell you for sure that the fsuper duty non rollback didnt have rabs. I think the f350 dually that year did have rabs. I would assume it's the same rear end but on the superduty they plugged the vss port. So did somebody put a disc brake conversion on a bricknose DRW axle or is this a newer factory disc DRW that was swapped in? If it's the former, you would just replace the f superduty bypass with a rabs and plug the vss in.

 

[chillman88]

I think the f350 dually that year did have rabs. I would assume it's the same rear end but on the superduty they plugged the vss port.

Yes the 350 dually did. Completely different rear axle though. F-supers used a Dana 80 rear with discs factory if I recall correctly.

The f-super is what everyone pulls the bypass fitting off of so I'd imagine ABS from a 350 should bolt right up as long as it has the correct signal for everything.

 

[Jesus Freak]

I don't know anything about it, but the idea of rear disk brakes really excites me! Thanks for bringing this up, I had no idea there was rear disc brakes in any of these trucks. Now I got something else to look out for.

Congrats on the roll back, I got a wrecker I just got running. Fun, fun, and they're powered by mechanically injected diesels!

 

[chillman88]

I don't know anything about it, but the idea of rear disk brakes really excites me! Thanks for bringing this up, I had no idea there was rear disc brakes in any of these trucks. Now I got something else to look out for.

I thought about swapping one in but I'd lose my parking brake and that's a deal breaker because local inspection laws require an emergency/parking brake here. The F-Superduty trucks used a 4x4 version of the transmission with a parking brake bolted on the back of the transmission where a transfer case would go. There are no provisions for a parking brake on the Dana 80 except for possibly a Dodge version but that's beyond the scope of this thread lol.

 

[hacked89]

Yes the 350 dually did. Completely different rear axle though. F-supers used a Dana 80 rear with discs factory if I recall correctly.

The f-super is what everyone pulls the bypass fitting off of so I'd imagine ABS from a 350 should bolt right up as long as it has the correct signal for everything.

Last comment, myself included ha.

Thanks, I didn’t realize the d80 had disc brakes in that gen. What’s the deal with its vss?

 

[Jesus Freak]

I thought about swapping one in but I'd lose my parking brake and that's a deal breaker because local inspection laws require an emergency/parking brake here.

Keep a couple rocks in your bed.

 

[IDIBRONCO]

There’s even a speed sensor in the rear end which to me would serve no purpose other than rear antilock.

What’s the deal with its vss?

Wasn't that for the speedometer? It was also for the few F Superdutys that had an E4OD.

 

[IDIBRONCO]

Yes the 350 dually did. Completely different rear axle though. F-supers used a Dana 80 rear with discs factory if I recall correctly.

Yes. You're right. I may not remember correctly, but I thought that all of the F Superdutys had rear disc brakes. That's why they had the driveline parking brake on them.

 

[Jesus Freak]

Yes. You're right. I may not remember correctly, but I thought that all of the F Superdutys had rear disc brakes. That's why they had the driveline parking brake on them.

Dang! That's sweet!

 

[Jesus Freak]

There’s even a speed sensor in the rear end which to me would serve no purpose other than rear antilock.

I didn't register this until I saw @IDIBRONCO had it in quotes, but my zf5 doesn't have a hole for a speedometer. My assumption has been that it came off a more modern electronic engine (ie powerstroke) and a computer figured how fast you were going by some esoteric means, but maybe it's out of one of these type of trucks with a speed sensor in the differential?

 

[IDIBRONCO]

If you have one from a 4X4, the speedometer cable came out of the transfer case, from what I've seen on these trucks. Some of the earlier transmissions that came from slightly older (Ford) vehicles had the hole for the speedometer cable with a stainless plug in it. I've seen that before too. Maybe it wasn't factory, but it did happen.

 

[Jesus Freak]

It had a regular cone on the back set up for 2wd, and there's no access anywhere for a anything. And there's no evidence of it having a parking brake on the back. When I start messing with the dually it's one of the things I plan on pumping y'all for information about.

 

[IDIBRONCO]

Yours is from a newer vehicle that used the VSS for the speedometer.