I just got what I think was a great deal on a rear end. It's out of a 2002 F-150, 9.75 inch, Limited Slip, with the same gears I'm currently running (3.55), and has discs. It'll be replacing the 8.8 inch open rear with drums currently in my '97.

I've heard that I need to replace the Master Cylinder, and have found a great price on one meant for the '02 with 4 wheel discs--Raybestos mc390337. I'm having trouble finding out if this one will work on my truck, or if I have to do a number of other little games to get it to work. There may be issues with the ABS, or cruise, or anything else I don't know about.

Anybody with any ideas?

HELP!!

 

You better look at the drive shaft before you even start wasting money on parts. Ford never made two the same so to speak, and i would think that the drive shaft will need to be shorter and will probably have different end flanges.

 

The brake booster on the 97-98's is small in the late 98- 99 model year + up the brake booster was made larger most likely because thats when the rear disc brakes were started

 

The flange bolt pattern matches up--hadn't thought about the driveshaft length. I'll do what I can to check for length. I'm used to the OLDER "slide-in" self adjusting set-up that would take care of minor differences. Everything else, when I measured up the rear-end, matched up.

OK, I'm going to need to get a brake booster from another one. I'll see if they still have the booster from that '02.

Any other needs anyone can see? Anybody know about the ABS? Am I going to have any issues there?


I'm just so sick of the drums that light duty 8.8 has freezing up on me, and the noises I've been getting out of that rear end are NOT confidence inspiring. I was thrilled to find that 9.75. I'll keep everyone up-to-date as I go through the project, but as I said, anyone with knowledge giving forth input is needed.

Thanks.

 

WHAT is the proportioning valve, and WHERE is it? I'm assuming that the one currently in my '97 won't work, or if adjustable, will need to be adjusted. The '02 rear-end WILL bolt in, and the driveshaft WILL bolt up, and I now have the '02 brake booster to go in and mount the new '02 master cylinder to, but now my concern is this proportioning valve.

Is it the thing mounted to the bracket directly beneath the master cylinder?

Am I going to have to replace it, or is it adjustable, and if it's adjustable, is ti worth messing with, or am I better off just getting one for an '02?

 

I too have a 97 with a 8.8 drum system. I thought I could swap over everything I needed from an aquired 98 Expedition's 8.8 which had disc. I don't mean that I would be swaping the rear, eveyone knows it has coil springs and not leafs.But,WRONG,cant swap the brakes either, backing plate bolt pattern that is different!!
Now I can't think of how a booster would effect the brake swap, and I know of NO proportion valve on the ABS system. I have the ABS box which the lines run thru from the Expedition, so it's not a problem anyway.
It seems that I would be either stuck getting a newer complete rear. Unless something happens to the current drums, Then I was thinking about machining adapting plates to make the Expy's disk setup fit!! I think 3/8" thick plate would do the job?

Lowflyingbird

 

I, too had thought about just getting the discs, or maybe an expy rear, but was thrilled to get this '02 F-150 set up. So far, in measurements, the only difference I've found is that the 9.75", being a larger pumpkin, sticks forward about an extra 3/8 inch. The sliding input shaft on the front of the driveshaft should take care of that minor discrepency. The driveshaft mounting flange matches up, the suspension mounts match, the bolt pattern on the discs to the wheels matches up, the leaf mounting saddles match up, etc. I found this one at a local salvage yard with the 3.55 gears, limited slip, discs, etc, complete for $650. Like I said, I was thrilled.

As for the proportioning valve, what's that metal block directly underneath the master cylinder? Is that the ABS unit you were talking about? I'm still learning about this stuff, and discovering there are a lot of questions that I need to have answered before I can call it road worthy.

Thanks