As I said in my other post I have a 1968 f100 2wd that I am doing a ground up rebuild on. I pulled the front clip from a 1978 f150 for a full disc conversion and I purchased large Chevy Brackets as well as 78 El-dorado Calipers. I have a true Big ford 9" rear and have rebuilt the differential with a 21 ring and pinion set for better fuel economy and brute strength. The problem I ran into is the axel ends have the large 5” lug bolt spacing and all the rotors I have looked at have a smaller pattern.

I owe the kids, excuse me guys, over at the chain parts store I’m always goofing on for there lack of knowledge and in ability to cross reference stuff. They let me open a lot of boxes and searched for about three hours with me for something that would fit.

I wound up drilling a set of 98 f150 front discs to match the axel. The center needs a spacer to take up the gap between the center of the shaft end and the disc. I paid 45 bucks for the pair I just drilled. The speed shop down the road will order a custom made set for $145 each disc I just have to give him the specs, but there has to be something out there that is off the shelf that will fit ford or otherwise.

Has anyone run into this problem and found a disc that will fit correctly?

Additionally I need to locate the E-brake hardware for the El-Dorado Calipers as the place who supplies the parts store doesn’t include the brackets, piston stud arms, or the springs. Any help here would be appreciated.

Thanks

John

 

I just did a homemade rear disc conversion on a 9inch rear for my truck. Here's the thread on how I did it.https://www.ford-trucks.com/forums/s...d.php?t=483499 I'm not sure if this helps but I used rotors from a 79 F150 4x4.

 

Nice job.
"I wanted to be able to go into any auto parts store and get replacement parts easy so that meant using factory parts."

I totaly agree with the concept and this was exactly what I was going for. Maximum reliability with minimal modification. Custom made parts could be a problem to replace years down the road and make it hard to fix in a hurry.
My older 9 inch axel's bolt pattern is actualy 5x5 1/2 inch. Your 94 F150 has the smaller 5x5" bolt spacing which is the problem I ran into with finding off the shelf parts. All the ford discs I looked at use the smaller pattern.
Great job though.
Thanks
John

 

Actually I forgot to mention I swapped in an older 9 inch rear. I indeed have 5 on 5 1/2 axle. The 4x4 rotor is the same..
Thanks

 

Well I went and measured my suff again and I have a 5x5 1/2 bolt patern. The shaft-end faceplate is 7 inches in diameter and 1/4 thick. As I still hadn't final assembeled the rear yet I put the shaft into the trunk of my honda civic and drove to the part store with my kids in tow to return the 94 lincoln towncar discs. They fit right over the face of the shaft very tightly as the inside diameter is just a hair over 7 inces but have a there were two problems. first the bolt pattern was to small and the second was the Disc Diameter was only 10 inch. I'd picked up the set of 98 discs originaly but they had the wrong bolt pattern. As I was searching for something off the shelf I didn't want to drill anything. The guy at the Part store was cool and pulled out the 79 F150 4x4 discs for me. when we opened them up the platic bag was torn and turned out to be a set I returned a week ago. yes the bolt pattern matches but the inside diameter is 6 1/2 inches and Im not cutting a full 1/4 inch off the face plate. I wrote a letter to Baer Brakes and one to Bendix and included the specs I am looking at. I asked if they could locate a vented 11inch disc like the front ones that would fit the endshaft and be an off the shelf Item. I'll let you know what kind of response I get. I suspect the shafts on your rear were either remachined or are from an 8.8 axel which used the same housing as the regular 9 but is just a little smaller. Still a good axel and a bit more comon which makes it easier for repair.
John

 

That turned out great, I'm impressed and very interested. I totally agree with using factory parts - more reliable and easy replacement in the future. How do the brakes work with the rear discs, does it stop good? Did you do anything with the porportioning valve? Did that all fit in a 15" rim? Any progress on the parking brake?

Marty

 

Thanks. They work great. I didn't have to use an adjustable proportioning valve. Maybe because of the large tires, I'm not sure. Everthing fit inside the 15" rim, partially because it was origionally designed for a 1/2 ton front end with 15" rims. As Johnny mentioned, I did have to grind a little off the axle to get the disc to slide over it. It was only about 1/8 inch. As far as the parking brake goes, I know how I'm going to build it and I have all the parts. The only problem is I set my motivation down somewhere and forgot where I left it.
I plan on getting on it this weekend. I'll throw some pictures of it up when I'm done.

 

That would be great if they can set you up with an off the shelf rotor. I would love to get that info. On my axle I did have to grind 1/8 in. off all the way around. Thanks for the update.
Tony