In the past I've seen several posts concerning upgrading rear drum brakes to disc but nothing ever concrete. A lot of opinion and uncertainty but nothing exact. I just wanted to provide you with my experience changing my F150 differential. My truck is a 1997 F150 4wd with 8.8, 3.55 gear. I had a bad bearing or ring and pinion causing a loud roar and leaving me not feeling comfortable driving any distance at all. I took it to a local shop and they stated depending on what was wrong could cost up to $1800. A local Ford dealer gave me the same response. I didn't want to pay that much or even half seemed like a lot to me. I started calling salvage yards for a replacement and for the exact same differential was around $600.00 with most warranties about 3 months. I just kept looking and found a 2003 8.8, 3.55 with disc brakes. I saw the truck it came out of and it had a little over 10,000 miles. I took measurements and everything was verbatim. The anti lock rear brakes just plugged in as mine did. I was told by a couple of mechanics the master cylinder and control valve would need changing and was discouraged from replacing with anything except what was in mine. Well, I didn't listen and bought the 2003 disc rear for $350.00, it is also a locker. I started the change out on Friday about 9:00am and had completed and driving it by 12:00 noon. There were no modifications. I had to study and reroute the emergency brake cables but that was simple once I figured it out. I just bleed the brakes with no other changes and it works perfect. Best part is the roar is gone. The only thing that wasn't the same are the lugs. I'm guessing that my original are 7/16 and these are 1/2. I went to ford and bought 10 lug nuts and the wheel actually fits the larger lugs better. To make the hubcap fit I just bent the prongs to fit over the larger lug nuts. The brakes actually work much better than they did with drum. Not sure if a different master cylinder is used with different pressure to the rear but based on my experience thus far and over 400 miles of use with many stop and starts, I'm not planning on changing anything in the breaking system. I'll be glad to answer any questions that I can.

Thanks,
Dan Benson

 

I've been thinking about looking into kits to change out my back brakes.
I don't have any problems but the brakes are "soft" which I hear are a common problem with that year truck.
You've convinced me to keep my eye out for a new rear end.
If I can find one for that price it would deffinetly be worth the upgrade to disks.
I'll keep you inform and incase I have any questons.
This one's for you

 

Geez, what a great idea! I've got a 98 with the 308 gears and our local shop wants 1200 bucks to put a 355 limited slip in. I called the local junk yards and they want 650 for a disk brake 355 rear end. You got an extremely great deal. How's the brakes holding up?