I am still having trouble finding a way to put disc brakes on the rear of my 1972 Cutlass. Wilwood says they can't help me and gave me a company to call. TCE told me it would be around $3000 to $4000 to do the change. Wilwood has kits that range from $2000 to $2500 on the high side. I have put Wilwood calipers on the front of the car and I would like to keep it the same. They show on there page on the internet diagram they have kits for 1964 thru 1972. Something about mine is different and I don't know what. The housing is for a Oldsmobile the casting number shows it. Any ideas anyone has sure can help. Thank you JIM

 

You probably don't want to do this.

 

 

Jim, we had a big argument on another thread about disc brake conversions. While we were able to conclude that a quality FDB conversion using factory parts is almost always beneficial, nearly everybody agreed that with a rear disc conversion, you rapidly run into the law of diminishing returns.

 

I came into what at the time was considered a great deal on an aftermarket (SSB if I recall) rear disc brake kit for a prior '72 Skylark ragtop that I had for awhile - total mistake to have bothered with. Maybe for the most part a kit quality issue, albeit they all seemed to be essentially the same in terms of quality, with only the degree of kit completedness and rotor options having driven the costs differences between kits.

But ultimately it made no noticeable improvement to the braking system and in fact, felt more like it diminished it some. Forget the fact 1 of the calipers seized up after only about 500 miles, leaving me to replace both on the chance the other one wasn't far behind.

I'd never install another aftermarket RDB kit on any classic car after that experience.

 

Unless you are going w/ a full-on track suspension for autocrossing or road racing (and actually planning on tracking the car), rear disks are a complete waste of money on pre '72 A-bodies. Rear brales add only about 10% of the total stopping power on stockish suspension (the ~60/40 weight distribution quickly becomes ~90/10 under hard braking) and their primary function is to NOT lock-up before the fronts to prevent the rear coming around. The drums on the rear have nearly as much friction area as front drums so they are already over-designed for their application. Ultimately, tires are the limiting factor on stopping distance. Front disks powerfuly address brake fade issues of front drums, but the rears carrying only a ~10% load won't generate nearly as much heat to cause fading concerns.

 

Its been a while but I put rear discs on the 12 bolt Chevy in my old GTO using 78 or 79 Cadillac rear discs. They had parking brakes integral with the caliper and i used 79 Trans Am WS6 rear discs to fit the bolt pattern. You can get all the parts except the mounts at any NAPA and there was a noticeable improvement in stopping power. I got the idea out of an old issue of Hot Rod Magazine.