Disc Brake / Upper Ball Joint Identifcation

[dustymopar]

Hi Everyone,

I have a 71 Duster (originally a /6 car) fitted with disc brakes. I am trying to identify parts so I can order the right Willwood kit and replace the Upper ball joints.

The rotors are Unicast (1 piece) and are a fraction under 11" so these are 10.87"? The calipers are the slider type. So it is likely that the Upper Control Arms and stuff have been changed and have possibly been sourced from a post 73 A or E body - right?

Would anyone know the size of pre 73 and post 73 upper ball joints so I can confirm. Help in identifying the spindle would also be appreciated.

Thanks:thumrigh:

 

[crackedback]

Castle nut size would tell you for sure.

5/8 is small ball joint
13/16 IIRC is BBJ

If they are stock mopar rotors and BBP, you 99% BBJ uppers installed already.

 

[71DartGuy]

Go to mancini racing's web site. I think they tell you the two different sizes. I bought the socket to install the big ball joints when making the conversion and it measures 1 13/16".

Mike

 

[jaxle]

you should have the bigger ball joint upper arm. you can't run 73-76 disk on early model a-arms. my book says that if you have the later unicast it measures 10.87; the 2 piece rotor measures 11.04 also your lug pattern will
be 4 1/2" not 4" the sucky part for you is that you cant run a sway bar with the old k-frame and new brakes. they hit. so if your /6 aint a /6 anymore than some one probably swapped your k-frame at the same time and you can run sway bar through the k-frame. if thats the case than everything in your front suspension is 73 or later.

 

[dustymopar]

Just checked my upper ball joint 7/8" nut on a 9/16" thread - the larger size I guess. The brake proportioning valve is A Body, so this is all likely to have come from a post 73 car.

I'm sure the K frame is /6 - BB mounted on schumacher mounts

Lug pat is 4 1/2"

Thanks for your help guys:thumrigh:

 

[2 Darts]

If your calipers are sliders, you do not have a 1971 factory installed disk brake system. It's possible that the previous owner also swapped out the K-frame. If it has "spool" type motor mounts it also is a 73 or later unit.