by farna » Thu Aug 03, 2006 12:39 pm
Gill, try 79-83 Concord or Spirit brakes. The 77-78 models have something different about the rotors -- they are expensive and hard to find. I haven't been able to determine the exact difference though. There were no two wheel drive AMCs after 1983. 84-88 Eagle calipers will work, but the brackets and rotors won't.
You DO NOT need the control arms. In fact, 79-83 control arms and steering knuckles WILL NOT FIT the 66. AMC used one design for the big cars (Classic, Ambassador, Marlin, Rebel) from 1962-1969, another slightly different one for the small cars (American, Javelin, AMX) from 64-69. Earlier models used different suspensions along the same lines (big and small cars). Beginning in 1970 the front suspension was redesigned and all cars used the same design.
To put late model (79-83 Concord/Spirit/Pacer) brakes on an early car, you need to unbolt the spindles and caliper adapter. You'll also need the caliper frame (the piece that bolts to the mount), as rebuilt calipers only have the piston body assembly. All AMCs use the same bolt pattern for the spindles back to at least 1950. Bolt the late model spindles and caliper mounts to the 66 steering knuckle. You may need longer bolts, but they will bolt up. I've done several of these conversions. The only thing you really need is a banjo bolt brake line and bolt. 79-81 calipers use a Ford Escort EXP (85?) bolt and hose. 82-83 calipers are a GM design and will need a 83-88 Eagle or Jeep Cherokee hose and bolt. Alternately, you can use a 90 degree brass fitting that will screw into the caliper and mount the standard brake hose. I've done it both ways. When you use the 90, you'll need some copper sealing washers. I had to use one washer under one 90, two washers under the other to get the 90 turned where I needed it and sealed.
The 90 or banjo hose is required to clear the steering knuckle of he older cars that weren't designed with disc brakes in mind, or had the old Bendix four piston brakes (66-70). Alternately, you can use 70-72(?) AMC brake hoses, but they are getting hard to find. These have a couple inches of hard line on the brake end that can be bent to clear the knuckle. This won't work on the 82 and later GM calipers as they use a different size fitting. The older calipers use the same fitting as the drum brakes.
You can use other years of AMC discs, and 74-79 Matador brakes, but the rotors for all the others are getting expensive and hard to find. That's why I only recommend 79-83 Concord/Spirit/Pacer brakes. These also have the advantage of being able to use you drum brake master cylinder. The residual pressure valve must be removed from the front brake reservoir outlet, but otherwise the master is the same. The other years and models use a larger caliper piston which requires a larger bore master cylinder.
There are a few other little things to consider, but I'll leave it at this for now. This appears to be an old thread anyway. Not much traffic on here, but that might be because there hasn't been many AMC people about!!
Frank Swygert
Publisher, American Motors Cars