Help: 71Duster Drums to 68 Barracuda Disc

Hello all,

I am swapping my stock 71 Duster 6cyl front k-member and front end with one from a 68 barracuda 8cyl that had disc brakes/sway bar etc. ( I am not changing out the rear drums, just front)

I do have the proportional valve, but do I also need to swap the brake booster and master cylinder as well? or can I use the existing one from the Duster? any other red flags that I should be aware of?

I've done some research, but most pertains to upgrading to later 73+.

FYI - The car is older than me. Take it easy on me. ;) thanks!

You can use your existing booster, but you will need to change the master to a disc brake unit! They are easy to find, as close as your nearest auto parts, or online through Rock Auto

cosgig said:

You can use your existing booster, but you will need to change the master to a disc brake unit! They are easy to find, as close as your nearest auto parts, or online through Rock Auto

Click to expand...

Thanks! Another question, do I need to use a proportional valve on my 71 Duster with the KH brake swap? I have the stock distribution valve and the separate proportional valve from the 68barracuda donor, but they've seen better days.

You need to use the valve which came with the K-H setup from the donor car, or an aftermarket adjustable prop valve!

I dont think the Drum booster will work with the Disc Brakes. I did it one time and had a "weird" brake peddle. I left it but it was wrong.

I didn't think the boosters were application specific that way. I think I have had a drum booster on my KHers. Might even still, not sure. I have awesome brakes.

If you're gonna run the 9 inchers out back, I (That's me personally) I wouldn't bother with a P-valve, especially if you run bigger-than-stock tires back there.
I have a Dual M/C with a 15/16 bore. I highly recommend it with the KHers. Excellent feel and very nice pedal travel.I run 10 x 2.5 brakes out back with 7/8 W/Cs and my P-valve is gutted; so no proportioning going on back there. This has worked very well for me,with 235s in front and 275s or bigger out back.

IMO you can,as in, it's possible, to run the Duster drum/drum M/C on your KHers. These pistons do not require a whole bunch of fluid like a big single piston job.Nor do they NORMALLY retract as far. It's a little tricky, with the small reservoir, to get the system bled without sucking air, and once everything is up and running, you just need to keep an eye on the fluid level a little more often until you get a sense of how fast your pads are wearing. Then, at pad replacement time, (5 years from now with street pads), you will have to suck most of the fluid out that you have been adding over the months and years, so that it doesn't all gush out when you push all 8 of those little pistons back in. So because of those reasons, it is usually way less hassle to just run the larger Disc reservoir. So while it's possible, it's not recommended.

If you are putting an SBM in there, you'll probably also want to upgrade the T-bars. Mine are 1.03s and they are not too big.And forget the factory alignment specs. If your UCA bushings need replacement, get the Problem-Solver offset ones and put them in to maximize Caster with about .5* neg. Camber. Toe can be stock.Set both sides the same. With soft bars, put your bodyweight worth of weight in your front seat, unless you run double most of the time, then put the same weight on the passenger side
After the alignment, do not mess with the ride height, cuz that will mess with the alignment angles.

From what I have read here, and from looking up parts online, the dics brkae MC, like used in the 73-76 cars, is not used with the earlier Kelsey-Hayes disc brakes. IIRC, it looks like a drum-drum one, but may have had taller sides than the original drum-drum MC's.