I thought these were hard to find

[makovai]

Because of the design of the piston due to the e-brake i highly doubt you'll be able to modify the pistons to work and it would be more time and trouble to try and make new pistons than to just buy the correct calipers. I checked into all of this about 5 years ago.

You are prolly right.
I know i can make them work, but the amount of effort its gonna take is all im gonna look into at this point. The other thing is i can buy the correct one for $150 a pair so it'll have to be an ez quick mod. And just going by what i've seen i dont beleive it will be quick and ez.

 

[CDA 455]

Man, this should a sticky post.

Excellent info . This is my next project after I deal with the crossover steering.

 

[makovai]

I haven't even tinkered with this at all, however i did learn something about the eldy calipers. I found this pic in the motors manaul, and it appears the Riviera also had the shorter piston for the fatter rotors. It's not alot of info but it does give another option for parts.

Unfortunatley the car domain logo is right over the top where it says:
Fig 96 Rear disc brakes caliper disassemblies. 1976-79 Eldorado & 1977-79 Riviera

update: i just looked up a 1978 Buick riviera and the calipers are once again a different part number. However motors manual had them list as the only 2 with the big opening for the larger rotors......more to come.