Disc Brake Conversion

[kittylitter]

Looking for comments and feedback about converting the rear brakes on my Tiger over to disc. Would like to hear from others who have done this and what everyone recommends on the best set-up and any issues that have to be dealt with. My car has a stock rear-end.

[Tom and Joanne Ehrhart]

I can’t tell you what works but I an tell you what does not. Dales Restoration has sold rear disk kit that bolted on with no modifications.

The problem is that they do not provide enough braking power to provide balanced braking on the car. I’m guessing it is close to 90% front and 10% rear when it should be something like 60/40. What ever the ratio is, it is a serious problem in that standing on the brake pedal as hard as one can fails to lock rear wheels up, even on gravel.

I have tried a variety of pads with some noted improvement. I eventually put a proportioning valve on the front calipers, of all places, to reduce front braking. This provided a more balanced system. Of course the pedal effort has increased. The problem with Dale’s set-up is that the caliper piston is too small. Fiat makes the same size calipre with a larger piston that will about double the effective force on the pad. The only problem is that there is no emergency brake. I’ve tried them and they work great.

[John & Gwen Logan Sr.]

Kitty Litter

I installed 1985 Mazda RX7 12A disk brakes on my Tiger. They fit on with a simple bracket and some easy machining to the disk. They have much more braking power than the original drum brakes and eliminate adjustment. When I put them on about 10 years ago it was very easy to find good calipers and emergency cables in junk yards. Since they are hard to find now I have not written a tech article on the conversion. If you can find the parts I will send you directions on how to install them.

[James & Susan Ellis]

Not sure how well my rear disc conversion is going to work but here is what I did and some thoughts on why.

For rotors I used rears off an Alfa Spider, the bolt pattern is the same they are fairly cheap to buy and have a pretty deep hat. I turned the diameter down a bit because of the caliper and for a smaller package to fit my 13 inch minilites.

For calipers I used rear Merkur Scorpion because they are a very close match to the stock cylinders in piston size and have a E brake that can be used with the stock handle and a set of after market cables.

For a bracket I made up a template out of plywood and once I got it right cut it out of flat stock. This is a weld on bracket, and with the deep hat of the rotor it is located far enough away from the bearing that I think warpage from the heat will not be a problem.

Were I to do it over think I would look at a different caliper of the same style like some of the Ford Mustang units. The Merkur caliper is just too pricey if you can find them to make it a good choice.

This conversion is on my SV Alpine with a V6 that I have a Tiger rear end under. For front brakes I just bought the Outlaw M16 calipers which are a bolt on. The car is not finished yet so have not got to try the brakes.

[Bob Hokanson]

To put rear discs on the car and get rid of the cheesy rear hub assembly at the same time I had big-bearing Ford 9 in axles cut and resplined to fit the Dana housing, then used Granada rear discs and calipers on fabbed brackets. Did it nearly 20 yrs ago so details aren’t too fresh in my mind.

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