Diplomat disc brakes to 72 dart?

[Frank]

My buddy is thinking of buying an 85 Diplomat with 80K miles on it for the engine. I was wondering about the front end.

Does anyone know if I can adapt the front Disc brakes for an 85 Diplomat to fit a 72 Dart with front drums?

How much of the front end would I need to take from the Diplomat to make the set up work?

Also, what was the stock rearend in a diplomat?, will it fir under an A body? I have not been able to locate the measurements of the Diplomat rear end.


Thanks for any help you can give.

[joe2kool]

I think the A-body rear ends are 55". Don't know about the Dippy, but I'm pretty sure it is an 8.25. I'm looking for a late 70's or 80's rear end for the brake setup.

Regarding the front end, I have a 65 Barracuda, and most upgrades to disc brakes recommend the '74 and earlier A-body setup, with some larger B-body components. Get a hold of the Mopar Action Brake Swap-n-Stop article from a few years ago. if you can't find it, I could scan and e-mail it to you.

[5thAve]

Stock rear in a diplomat is a 2.2ish 7 1/4.

[joe2kool]

Oh well. I thought the 7 1/4 was replaced by the 8 1/4 before then.

Later...

[ajmopar]

Yes, you need the older spindles, but most of the other parts will work as far as the front brakes go.

Here is a link to the Mopar action article in question. It is pretty much the last word in that swap"

http://www.moparaction.com/Tech/archive/disc-main.html

[dave571]

Not much from the brakes would be any good. Like the article above say, you need spindles from a 73-76 a body or a disc brake e body.

Also the master cylinder and proportioning valve are not direct bolt ins. The 73 to 76 a body stuff is.

The calipers will work ,and probably the rotors, but that's about it.

[Bill55AZ]

http://www.moparguide.com/rearends.htm

Here is a link for rear axle info. This will tell you what mods you will have to do to make it fit. On the diplomats, the 7 1/4 is the most common, but 4BBL V8 cars should have the 8 1/4. Any F, M, or J can have either, so go for the latest year and best ratio that you can find.

[AndyF]

Well actually the Dippy front brakes will bolt right in there once you upgrade to a '73 or later upper control arm. For that matter, maybe the upper control arm from the Dippy will work but I'm not positive on that.

The master cylinder from the Dippy should be the good aluminum one. It will work just fine in your A body but you'll need an adapter plate to go from 4 bolts to 2. Check them out on our webpage at www.ARengineering.com if you're interested.

One thing about the Dippy front brakes is that they use a knuckle which is slightly taller than the factory engineers speced on the A body. Autocross and roadrace guys like to use the taller knuckles since it improves handling by raising the roll center. But there is also a reason to be cautious about altering the front suspension geometry on a car unless you have a good reason to do it. So read up some more and make a decision based on facts.

Andy

[ajmopar]

I would never use that Knuckle on an earlier car, things get nasty when an overstressed ball joint lets go. An inch or better in front end geometry is not a "slight" amount. No way that upper control arm will work either, totally different design (F M J bodies use a tie bar arrangement that bolts to a bracket on the k frame, while A bodies use a pair of cam bolts to a mount in the inner fender. The calipers, caliper brackets, rotors will work though. Go with the article, it's the real deal.

[Frank]

Thanks, everyone! I'm going to get the calipers and rotors from the diplomat, they're in great shape! I also just found a 76 Dart around Atlanta that might donate some other parts, including an 8 3/4!!!

again, thanks for al your help.

[dave571]

Like I said, only the calipers and rotors are of any use. The diplomat's I've seen, have an extra line on the master and proportioning valve, making them useless.

Don't even think of using the spindle, it's too tall. In a lot of cases there isn't enough adjustment left to align it properly when your done(I've seen it first hand)

And in worse case scenario's they can even cause the upper ball joint to break because the angle is completely out to lunch. The upper joint is out of it's normal operating area, not in a good way.

The 73-76 a body, and 73-74 e body stuff is the only direct bolt in(like the 76 dart stuff you're looking at). The stuff is easy to get so why fool around with crap that is known to be wrong.

As said, base your decision on fact's. Also base it on experienced advice.