Rear disc conversion kits

I have a 1973 sport looking to convert to rear disc which conversion kit is the best bang for the bucks, and do I need a rear proportioning valve.

I like the rear disc kit offered by BC because I could buy it in stages. That made it a lot less expensive for me not having to buy it all at once. The other kit that I really like is the wild horses kit that uses Explorer rear calipers and pads. It does require specific axles and rotors but Wild Horses sell them as part of the kit. And it's an upgraded better than stock axle so you're killing two birds with one stone but it still cost a little bit of coin.

My rear disc kit from BC uses Cadillac calipers and Jeep rotors.

My parking brake is never going to be that great since it uses the factory caliper to do that work. The Explorer system uses a far better drum parking brake with in the Hat of the rotor like many Corvettes do today as well. And while that system is a far better parking brake I am told it's still not perfect. Which is why a lot of guys are looking into this additional parking brake caliper whether it be driven mechanically or electrically it is the hot thing on many sportscars today.

Still love my BC rear disc kit. I have been running it for almost 20 years.

I am using the vendor marketed stock replacement Bronco proportioning valve. You have probably seen them a number of times in the catalogs you simply take this little spring out of one end of it and replace it with a plug and it's good for 4 wheel disc. I have since learned that I could have just left my stock h block for the drums in place. I did not need an adjustable proportioning valve for the rear brakes as so many do. But I also did not go to Power yet. My brakes are still manual but no rear proportioning valve was needed for me.

If you have a medium duty (Torino) axle housing, take a look at the Explorer rear disc. Brackets bolt right up to housing but you will have to do machine work to rotors or buy the conversion ones. I used a Wilwood adjustable prop valve.

I believe a lot of the "kits" sold through the vendors are from a company called the street rod manufacturing company. I just did the rear conversion on mine. I'm not sure what your MC set up is but I had previously boosted my drum brakes with a vac assit booster. I had to change my prop valve to a disc/disc, two new lines from my MC to my prop valve, braided stainless flex lines, I had to shorten and reflare my rear hard lines on the axel, you'll want to pull your axels and replace the bearings while your down there if you don't know the history on them along with the seals. I went with a parking brake delete set up and used front calipers for an 83 monte carlo. I have stock steelies that were from a later year bronco because they were argent gray before I blasted and powder coated them but I ran into clearance issues with the rim and caliper. I had to shave my calipers about 3/16" on the edges to get them to clear. If your running bigger rims w/ more backspace you should be fine. Here's my thread I had on the caliper issue... http://classicbroncos.com/forums/showthread.php?t=291975

The big question, do you need (or want) a parking brake?
If "no", it gets pretty easy and cheap.
The "yes" answer adds complexity and costs more.

Unlike the front where there things stayed the same and one kit will work on anything the rear is a lot different. Different backing plate bolt patterns, and axle offsets. Most years there are at least 2 different axle options, and even then they changed over the years, multiple times. Sometimes if you have the right axle, something like the Explorer with the rotors redrilled is a great choice. But if you have the wrong offset and/or the wrong bearing end that rear disk is a lot of work and there are other options.

The cheapest rear disk I ever did to a 9" was on an F150. Got the front brakes off a 90's Geo Tracker and made my own brackets out of scrap metal.

As for needing a rear prop valve, too many unknowns. Much like front disk conversions, maybe or maybe not. Everything from ride height to brake pad material can change the brake bias. A good ratio of front to rear braking should not need a prop valve, But you don't always get that. There are a lot of things that can be tuned in the brake system. A prop valve should not be a first stop at fixing them. Caliper bore and pad material are a much better starting point. Then adding things like a prop valve or a hold back valve can further be used to fine tune. But not a gross tune of mismatched parts.

Love my Wild Horses kit. Went with axles too which you may not need.

https://www.cj-8.com/threads/1983-frame-off-refresh-finally.43498/page-6

Start at post 106 for my rear disc on my AMC 20 rear full floater on my scrambler. My "holding" brake to follow

Broncobowsher said:

The big question, do you need (or want) a parking brake?
If "no", it gets pretty easy and cheap.
The "yes" answer adds complexity and costs more.

Unlike the front where there things stayed the same and one kit will work on anything the rear is a lot different. Different backing plate bolt patterns, and axle offsets. Most years there are at least 2 different axle options, and even then they changed over the years, multiple times. Sometimes if you have the right axle, something like the Explorer with the rotors redrilled is a great choice. But if you have the wrong offset and/or the wrong bearing end that rear disk is a lot of work and there are other options.

The cheapest rear disk I ever did to a 9" was on an F150. Got the front brakes off a 90's Geo Tracker and made my own brackets out of scrap metal.

As for needing a rear prop valve, too many unknowns. Much like front disk conversions, maybe or maybe not. Everything from ride height to brake pad material can change the brake bias. A good ratio of front to rear braking should not need a prop valve, But you don't always get that. There are a lot of things that can be tuned in the brake system. A prop valve should not be a first stop at fixing them. Caliper bore and pad material are a much better starting point. Then adding things like a prop valve or a hold back valve can further be used to fine tune. But not a gross tune of mismatched parts.

Click to expand...

Excellent advice, Sir. The TSM kits have been around forever and are still an excellent choice. Just check the backing plates for 3/8 or 1/2" bolts. You slide off the drum...no need to remove other compnents...and see which size socket you have to use on your backing plate bolts. For example, if it takes a 3/4" socket, you have the 1/2" backing plates bolts. It does make a difference, as the brackets and the hardware are different.

BTW...TSM actually casts their own calipers...all new parts. They also build the rotor with the correct BP. No re-drills.