sevill rear disc conversion how to

[dmec]

just finished rear disc conversion and thought i would post how i did it in case anyone is interested. first off the 76/79 seville came in various configurations. ill just cover the basics. it gets too involved. basically small and large frame calipers. im using a combination of small frame backing plates from 76/79 seville and small frame caliper from 82 up seville. they will be on the left side of the picture. the picture shows both small and large frame set ups for comparison.

[dmec]

the first step was to enlarge the hole in the backing plate so it would go over the housing. i used a die grinder in a circular motion around the opening. only .085 needs to be removed so it goes pretty fast.

[dmec]

next i marked the outline of the housing flange on the backside ot the caliper bracket. this part will be cut out so it will slip over the housing.

[dmec]

i then cut out flange area of stock backing plate leaving 3/16 margin to weld a piece of 3/16 rod to.

[dmec]

then i bolted the flange to the housing and tacked the 3/16 rod to it while heating and bending the rod to fit around the housing flange. this will act as a spacer to move the caliper bracket to the rear.

[dmec]

i then welded the caliper bracket to the spacer

[dmec]

bolt the caliper to the housing and you are ready for the axles.

[dmec]

the flanges on the axles had to be turned down to fit inside the rotors. i also removed the wheel studs and turned down a small ridge that prevents the rotor from making full contact with the flange. i did this on a lathe. .435 needed to be removed. final diminsion was 6.140

[dmec]

bolted everything together. the flange with the arrows on it has to be centered in the rotor that is the reason for the spacer

[dmec]

WALA both calipers are on the rear. that is why i used the later model caliper. WHADYA THINK

[Zkast]

Would it be easier to just cut a 2.5 inch space from the front side of the caliper mounting flange and slip it over the housing? Didnt know if the spacing would be right then or not.

[ebfabman]

I've done the same thing but I found it was way easier just to use the weld on brackets, makes a much cleaner install. I also used the knob type adjustable P-valve.

[dmec]

would have been easier to notch out bracket and weld to flange but i wanted something removable in case threads on mounting bolts ever stripped.

[Zkast]

ok ok, I see now.. The backing plate bolts on from the outside and you did that to space it inwards a bit.

[dmec]

correct. the backing plate has to be on the backside of the housing flange

[Fast68Chevy]

i was looking through caddy book the other day and saw that in 80 the sevilles and eldorados used rear mounted disc brakes too

does seem a bit more complicated than assumed, once you see what it takes to install it all

i have also seen that dana 44 calipers can be made to work for this conversion too.

[Rod]

Very good post.

[Shane]

i was looking through caddy book the other day and saw that in 80 the sevilles and eldorados used rear mounted disc brakes too

First year for the rear disc on Seville's was '76 or '77....can't remember which exactly....i used parts off a '78 (backing plates, calipers, proportioning valve).

[dmec]

in 80 the brakes went to 10 1/2 in rotors with 5 on 4 3/4 centers. small chevy bolt pattern. holes in backing plates changed pattern. calipers mounted on the rear. not staggered as previous years.

[Jeff M.]

Thank's for the explanation. I've had the setup for a year or so and just tinkering I discovered the backing plate would need that modificatin. Looks like a good winter project. Did you run the emergency brake cables? Thanks, Jeff

[Johngear67]

thanks for the time & effort it took to include us in your project
good luck

[mt Al]

Thanks for taking the time to show us your work, very cool of you. Speaking for those of use who could NEVER take on something like that: very impressive. Thanks again.

[dmec]

thanks for the thanks. its always nice to hear. ive put these brakes on chevelle, camaro and nova rears and have been wanting to do a truck. seems to be a lot of post looking for info so i thought i would share. i havent connected e brake cables yet but when i do ill post results.

[Beyond]

DMEC - Couple extra questions for you on the Caddy calipers. I'm in the process of doing this swap right now on a Ford 9" for my Nova.

Those calipers have a ratchet mechanism that adjusts with the Parking brake. How do you move the caliper piston back in once it has been ratcheted out - like when you replace the brake pads? I haven't figured that part out yet.

What parking brake cable did you use for your Nova & Truck?

Thanks

[dmec]

there is a special tool to rotate the piston. ive seen them in automotive parts stores. you can also remove the brake lever and you can push the piston in like any other caliper. thats the way i do it. the 76/79 seville had 1 long and 1 short e brake cable because of the stagger. i use whichever 1 that fits the application. i also use the rotors from 79/80 pontiac trans am. they are the same rotor with the smaller 4 3/4 bolt pattern and smaller pilot hole. in 79/80 pontiac offered rear disc option on firebird. they used seville parts. i would be interested in what you are doing to adapt to ford rear.