I did a post on this subject back in July.If you do a search for "self adjusting brakes" one of the 4 topics that come up is "self adjusting brakes for 55-56 Ford".That is my post from when I did mine last summer. I did ad a second adjuster hole as Paul did.If anyone knows how to bring that post "connection"(so others can click on and read it) to this topic go ahead.The parts are readily available from Napa and it cost me about $40.00 here in Canada.Cheaper in the States.These kits should fit 57 also if they used 11 inch brakes as the 55-56 Ford cars and T-Birds do.I believe the first year Ford had self-adjusters standard was 58 or 59.This is one retrofit that I feel is worthwhile especially if you have disc brakes but would also benefit any car with 4 wheel drum brakes.I just added pics.The blue spring at bottom right is the lever return spring.It hooks onto the lever to return it to "rest" position.As the shoes move outwards under applied pressure the rear shoes moves outward.If it moves past a certain point because of wear on the shoes the,the cable will pull on the lever.As the brake is released the lever turns the star wheel adjuster moving the shoes closer to the drum." Äutomatic brake adjuster".
In the bottom picture I had already removed the 2 return springs before thinking to take a pic.Notice in the installed picture that the diamond shaped retainer at the top is NOT reinstalled.Not enough room with the cable installed.In my 65 Mustang manual the adjuster cable is all that is used as a retainer.I suppose you could use a really thin washer if you did want to replace the original piece but I dont think it is necessary with the cable end replacing it.