Wednesday, September 28, 2011

Rear Disc Brakes Install

After a long summer of projects around the house and vacation, I finally found time to take another step forward on this Mustang project.  I had ordered a complete rear disc brake conversion kit for Ford 9".  This kit included (and this may frighten the purists) GM calipers with brake levers and GM universal rotors, brackets, hydraulic hoses, parking brake cables, and some necessary hardware. Why do they use GM parts?  Probably due to low cost and high availability and readily adaptable design.   

The first step is to remove the bolts that hold axle retaining plate and pull the axle.  The axles need to be removed so that the old drum brake backing plate can be removed.  The kit provides a new spacer plate that is the same thickness as the drum plate so that the caliper bracket can sit flush to the rear housing and not against the bearing. It just slips over the bearings like the drum backing plate so no pressing is needed.  If they just machined a recess into the mounting plates, a spacer would not be needed. Probably costs less this way.
The next step is to replace the wheel studs.  This is not required by the kit but is needed for my application since I'm not using the stock steel wheels.  This should be required since you need larger diameter wheels to clear the calipers anyway and they tend to be thicker alloy wheels - YMMV.  I used Moser Engineering 8250 Torino/Lincoln wheel studs.  Stock is 1.5", these are about 2" and thats just enough for my application.

Next step is to reinstall the axles and mount the caliper bracket adapter plates to the housing.  The plates are held in place by the axle retainer bolts and I used slightly longer grade 8 bolts since the brackets add thickness.  The stock ones are supposedly long enough but in my case they were replaced long ago with grade 5. Since brakes are involved, I'm not willing to compromise.   Then the caliper bracket plates are bolted to the adapters.   

After that, the rotors are mounted.   The instructions say that some axle flanges may have a larger diameter and need to be machined down for the rotor to fit correctly.  Luckily mine were ok.   Finally, the calipers were installed using the supplied bolts.    
Once I find the stock parking brake parts, I can begin that install along with the brake lines.
Stay tuned....