This is a very straightforward modification that can give better brakes with less fade than the stock front drum brakes. 1975 to 1980 Ford Grenada spindles, rotors master cylinder and proportioning valve are used for the conversion. The Ford Grenada disc brake spindle is are almost identical in dimensions to the stock 1958 to 1960 Thunderbird drum spindle. The Grenada spindle is only 3/8-inch lower than the stock Thunderbird spindle, so ride height is not significantly affected.
Parts List for conversion:
two 1975 to 1980 Ford Grenada spindles
two 1975 to 1980 Ford Grenada backing plates
two 1975 to 1980 Ford Grenada wheel bearings
two 1975 to 1980 Ford Grenada calipers Wagner part 890 and 891
two 1975 to 1980 Ford Grenada rotors Wagner part 522
one 1975 to 1980 Ford Grenada proportioning valve
one 1975 to 1980 Ford Grenada master cylinder
two Banjo Bolts 7/16 inch - 24 thread, one-inch long
four copper washers 7/16 inch
two brake hoses NAPA part 36959
two anti-rattle clips NAPA part 82304
two sets disc brake pads Wagner part PD91 PD7027R
Good quality rotors will not need to be machine true, since they are true out of the factory. Some cheaper ones may be slightly warped and you may have to have the rotors machined true. The lower ball joint hole on the Grenada spindle will have to be machined out to accept the larger 1958 to 1960 Thunderbird ball joint. Rick Nolen, who has done this modification on his Thunderbird, recommends Fat Man Fabrication of North Carolina, because they are very familiar with this procedure. The spindles, proportioning valve, and backing plates can be found at the bone yards for about $150. You will also have to get new wheel bearings. All the new parts you need can be found at the local NAPA or other automotive parts store. Stock 1958 to 1960 Thunderbird wheels can not be used because the center hole is too small. 14-inch wheels with the larger center hole will have to be used and they can found at any bone yard or custom wheels can be used. Rick Nolen used nice 14-inch chrome smoothie wheels with baby moons on his 1960 Thunderbird. He says total parts cost outlay for this conversion is about $300.
Remember to bleed the air out of the hydraulic brake system before driving the car. The bleed screws on the calipers must face up to get all the air out. Clamp the caliper piston if you remove it while bleeding.
The brake hose will need to have the stock 3/8 inch hole drilled out to 7/16 inch to accept the Banjo bolt.
The bracket from the brake hose should be removed since it is not needed.
This shows the installation of the brake hose into the new disc brake caliper.
On the brake caliper there is a lip about 1/8-inch high half way around the hole that has to be ground down a little so the copper seal and hose end can fit snug onto the caliper. You are not touching the seating surface, just the lip around it. This will be obvious when you try to attach the hose to the caliper. A simple hand grinder will take care of this and you are not compromising the strength or operation the caliper in any way. The shiny areas on the caliper above is where material was ground away.
The brake hose attached to the Grenada brake caliper. Make sure that there is a copper washer above and below the Banjo connection of the brake hose.
Pictures of the completed conversion:
Make sure the bleed screw on the caliper is facing up.
Pictures and information courtesy of Rick Nolen.