1970 AMX Brake Upgrade

Rebuilt K-H calipers are cheap, AMC specific ROTORS are expensive! Almost all manufacturers who used K-H disc brakes use the same caliper. The mounts and rotors are different for each manufacturer though. Same goes with Bendix and Delco calipers. Any AMC rotor made before 1979 is going to be $100 or more.

Unless you luck up and find a 79-83 Concord/Spirit/Pacer in a local pick-n-pull and get all the parts cheap (from the caliper bracket out, including spindles) I'd stay away from converting with an AMC setup -- unless you're restoring a car and want to use factory year correct parts to reflect an option.

Cheapest way out is a Scarebird conversion. The Scarebird AMC kit will fit all 52+ drum brake AMC cars. If you have disc brakes now and want to convert you may have to do some spacing to get the calipers centered over the rotors using disc brake spindles. Other options are Aerospace Components and Wilwood. Both of those are about the same price -- I think the Aerospace kit is just a little cheaper than the Wilwood, but not by much. Either of these options use readily available parts instead of obsolete, hard to find and expensive parts.

Most all AMC front disc brake setups will fit your 69 Javelin as long as you have the correct spindle and caliper mounting brakets for the setup you are using. The only caveat is that the 4 cylinder setups used smaller rotors and thus different caliper and mounting hardware.

The cost of the 4 piston setup is cheap only if you get bad calipers and rotors that are not cheap at all to replace, if you can find new ones at all.  The calipers can be rebuilt but often need to be sleeved at $650/set.  New rotors for the 4 piston calipers are getting very hard to find and ridiculously expensive if you do find them and old ones cannot be turned once they get to the minimum thickness.  

Edited by amx39068 - Jan/01/2014 at 10:30pm

That's a great price (although the later ones are $40).  Thanks for the lead....will use them in the future for 4 piston setups.

Stock brakes are fine for a driver -- even the drums if in good working order.
ANY AMC brakes can be swapped from one car to another. AMC used the same spindle bolt pattern from 1952 (1950 on the Nash Rambler) until the last rear drive only car made in 1983. As long as you swap everything from the steering knuckle out (backing plate or dust shield/caliper bracket, spindle, drum or rotor, and caliper for disc brakes) you can interchange all of them. I've put 64 Classic 6 drum brakes on a 61 American (brakes were 1/2" wider and had a slightly larger wheel cylinder, stopped like disc brakes!), and put 79-83 Concord/Spirit/Pacer brakes on several 60s cars, -- Marlin, Classic, Javelin, AMX, American, etc. You do need to understand braking systems and how to check if you need a balancing device. But physically they will all interchange.

If you're properly restoring a car you need to use what it came with, or at least what was optional for that car. If you're building a driver the 79-83 setup or a Scarebird setup is your best bet for price and performance. Wilwood and Aerospace Components make nice four piston setups in the $900-1100 range.

There is a big difference between the 66-70 Bendix four piston and modern four piston calipers. The Bendix brakes had the seal on the piston, so the body wears and eventually leaks. That's why they need sleeving to be properly rebuilt (assuming they were leaking). The modern ones moved the seal to the body, so the piston wears instead. Pistons are cheap and easy to replace when rebuilding. A simple change made a world of difference!

Go to one of the vendor websites (Kennedy or APD) and price rotors for all the pre 79 disc brake systems. All are over $100 each. They are hard to find through regular parts stores, if they can source them at all, and even more expensive. Calipers are cheap (except for the Bendix four piston) as they were used by other manufacturers as well -- brackets and rotors were unique to each manufacturer.

The Bendix four pistons brakes can likely be replaced with components from Wilwood. The original rotors can be removed from the hub. At that point you need a hat that has the same offset and a rotor with the same diameter (or close so it can be turned down). It should be hard to adapt a Wilwood caliper to the bracket either, as they are similar. Wilwood may make a caliper that bolts on, as all manufacturers used the Bendix four piston calipers in the late 60s.