Disk brakes on straight axle

[coffee break]

My cat has a Austin Marina straight axle. I think the drums are at the max dia. and I have not found any new parts available. I am considering converting to rear disks. I see a few advantages; new parts, no adjusters (the existing ones are crude at best) but will I need to replace the master cylinder and/or install a line pressure adjuster and what does this do to the parking brake?

Am I asking for trouble or an adventure.

[dvl]

I'd call it an adventure. I believe James Whiting, in the UK, used to make a rear disc conversion for live axle Caterham Fireblades. A picture may be found in the archive section of his website. http://www.jameswhiting.com/page15.html

 

For my live axle (Ford Escort axle) Seven, I'm using the Milton English Ford caliper mounting kit, for a Ford Sierra caliper (standard Caterahm DeDion rear caliper). I turned down the axle flanges to clear bell of a Ford Fiesta rotor, as well (recommended by Milton). For the master cylinder and front brakes I'm using a late model Caterham .700 bore master and Triumph Spitfire calipers. I placed a Tilton proportion valve on the rear caliper circuit, in case reducing the rear braking is necessary. The car is not yet complete, so I have not tested the brake system. I will go through the math eventually and verify the piston ratios.

 

The parking brake is still in work. I have an under-dash handle, a Caterham cable to adapt an under-dash handle mechanism to a Sierra hand brake cable (found it on the Caterham website a few years ago), and a Sierra cable. The Milton kit included a parking brake cable mount, but I suspect I will have to fabricate some form of cable mount.

 

I hope this info is helpful or at least supports that your idea sounds reasonable (well, reasonable to someone who would build a Lotus Seven replica from scratch, starting with not much more than an Arch chassis and a few pieces of body work).

 

Dave