Disc brake question

[70DartMike]

I'm getting a set of disc brakes from a 74 Dart, which are big bolt pattern. My 70 Dart still has small bolt pattern with front drums. My question is, what parts do I need to pull in order to bolt them into my car? I realize spindles and whatnot, but do I need control arms too? Ball joints? What?

 

[C130 Chief]

Upper control arms off the same car you got the brakes from. Lower ball joints (if you had 9" drums). An appropriate master cylinder and you should be set.

 

[70aarcuda]

Not any more. I'm in the process of making a bunch of 4130 cr-mo tapered adapters, so you can re-use your original upper control arms with the common 5 x 4 1/2" disc knuckles.

The batch may even be done this week,,,

i copied that from moparts....DoctorDiff is the one making the adapters...

[email protected]

 

[72bluNblu]

If you can get the UCA's I'd just grab them, they aren't that hard to get if you're already pulling the spindles. Probably easier, since you don't have to break the taper on the upper ball joint.

You may also need a new proportioning valve, I'd be sure to check and make sure.

 

[RedFish]

Not any more. I'm in the process of making a bunch of 4130 cr-mo tapered adapters, so you can re-use your original upper control arms with the common 5 x 4 1/2" disc knuckles.

The batch may even be done this week,,,

i copied that from moparts....DoctorDiff is the one making the adapters...

[email protected]

A little tapered bushing for the spindle hole is an idea that has been hashed over many times over many years. There has got to be something unsafe about it or it would have been done before. Chryslers engineers saw the need for a larger ball joint in disc brake applications. Such a bushing would allow someone to use the very largest C-body disc brakes under that small ball joint.

 

[crackedback]

A little tapered bushing for the spindle hole is an idea that has been hashed over many times over many years. There has got to be something unsafe about it or it would have been done before. Chryslers engineers saw the need for a larger ball joint in disc brake applications. Such a bushing would allow someone to use the very largest C-body disc brakes under that small ball joint.

Beancounters.

The change to the BBJ in A body cars in 73 was likely because it uses the same BJ as most of the other cars in the line. One stocking number is easier to maintain than two.

They used the SBJ in all the earlier A body disc brake apps (72 & down), so the pin size/strength isn't the answer.