For everyone using the Caddy ebrake caliper for 3/4 ton: Unless you can find a GM or Ford rotor 24mm (Just under 1") thick w/eight lugs, you're up the creek. The chevy rotors everyone says to use--75-87 K20 4wd-- are ... 1.28" thick, more than 1/4" too thick to fit between your pads!!!

The oem caddy rotors are 24mm thick. So either you shave the pads, throw the wonderful Caddy cals down and beat them with a hammer and get the chevy ones, or, you buy a kit. $$

 

I took one apart to check. I pulled these of two different Sevilles, not el dorados. Although the parts books claim both models used the same rotor, I wonder if maybe the dorado was the upper end model, and maybe used a thicker rotor.

To allow for that, GM must of used a shallower piston that allowed the pads to spread more. With my piston against the back of the housing, it still juts out 3/8". Even with the same years, same models, my pistons are slightly different from each other.

 

I need to hear from someone who has done the disc swap with the Caddy calipers. Are you using a 12.5" (chevy) chevy rotor, or an 11"?

 

I thought I would get one or two helpful replies.

 

are you looking for someone that did the 1/2 ton or 3/4 ton

 

I dont think this swap is that common. I know its been around in the hotrod world for just about as long as those calipers have been in the yards. I read all about this a couple of years ago, and bought some calipers. I started mocking stuff up and did not like the calipers at all. I eventually decided against them. I was putting them on a 9 inch.

 

I'm looking for anyone who put the 76--78 El dorado calipers on the 75--87 chevy K20 4X4 front rotors. I find they don't fit.

The bracket to the Dana 60 fits. The calipers bolt right to the brackets. But when I put on the pads and try to drop the caliper over the rotor, the rotor is too wide...by 1/4"! I even spoke to one guy, miotimouse, who used the same set up on his dana 60. I can't figure where I went wrong.

 

I have done three of these swaps. Eldorado calipers with GM rotors. It has been several years since, with miles of trouble free use. I purchased a complete conversion on Ebay, and collected the parts from Napa on the other 2. The set that came from Ebay went together with no problems. The other two were a little tight. I sanded some material from the pads, but no where near 1/4 of an inch. Is there a possibility that different makers of the brake pads would have different thickness of brake pad material? I will check tomorrow to see if I used 11 or 12.5 inch rotors

 

Thanks for checking. I am wondering if possibly GM used a different piston in these calipers from the El dorado models to the Seville models. The parts house sites say they used the same thickness rotors, but I've learned that as corporations streamline, the parts that don't sell much get dropped from the computers, and hey, if it's not on the computer, 'it never existed.'

I will check the bone yards again. I don't mind shaving a bit, but whoa, 1/4" is half the pad life. I checked several manufactures pads, and they all measured about 1/2" thick with backing plate.

 

[SIZE=4]I wanted to post all this info in case someone else was having this problem.

[U]I did some research and found the answer on another forum, I am posting it here. (I'm happy to learn that I'm not whacko.)

ok all, please tell me im not crazy and Napa is rebuilding stuff wrong

attached is a pic of the driver side brake pistons: silver one is from my '76 eldo junkyard caliper, the black one is from Napa's "76 eldo caliper" After not being able to compress the piston enough (I was around 0.12" too thin) I said f-it and popped the pistons out to see if there was a difference, and sure enough, there is. The original piston measures 1.950" tall, while the reman piston measures 2.160"! WTF is Napa using the wrong piston or something? the caliper itself matchs, and the casting numbers match, so WTH?!?!

BTW: the P/N i got from Napa is 242-2106, which the website confirms as 1976 Cadillac Eldorado Left Rear Caliper - "Semi Loaded"

Also, this is the 2nd caliper I have gotten from them like this --- the first had FUBARed banjo bolt threads so I returned it and picked up this one instead


btw, i am very temped to just use the old piston in the new caliper, but the problem with the old one was that the piston itself was leaking fluid (which ruined a brake pad before i found out - yay!) so im not very trusting of it
Yep, the rebuilt caliper has the wrong piston in it. The fleetwood and seville calipers use the black piston on the right while the eldorado uses the silver piston on the left.

That is the only major difference between the Eldo, fleetwood, and seville calipers. The caliper core itself is the same.
Put the caliper back together and take it down and show them what the problem is and have them order another caliper and check to see if it has the correct piston in it.

If they don't believe you about the piston being the incorrect one for the application then have them look up a piston for a fleetwood or seville (same piston) then have them look one up for the eldo (different piston) and they should understand what has happened. The book does give a spec on the pistons.


I also wanted to throw in this parts number for anyone looking in the future: RAYBESTOS Part # DPS85066 More Information About this Part Professional Grade; 1.96" Overall Length / 2.497" Piston Diameter / Steel
Rear; Left

Part Image
$77.79
Add to Cart
RAYBESTOS Part # DPS85065 More Information About this Part Professional Grade; 1.96" Overall Length / 2.497" Piston Diameter / Steel
Rear; Right

Does't that **** ya off? You pull a caliper from the boneyard and end up having to pay $78 for the f... piston assembly.

And of course I have to say that I knew I was right!!! Yeah!!! ha ha!!!!

 

The fleetwood and seville calipers use the black piston on the right while the eldorado uses the silver piston on the left.

The above is from the other forum dialogue I pasted above, and this part is not correct. Not all the 'silver' pistons belong to eldorados. I currently have one, and it measures 2 5/16" long or tall. You need one that is about 1 7/8" long or tall, or else the chevy rotor will not fit between the pads.

 

An Eldorado was a much higher end car than the cheapo SeVille, to answer that question.

 

The only way to get replacement pistons is to buy rebuilts from Azone.

I don't know how many j.yards I've searched to find these things!

 

After searching and searching for a shorter piston for my Caddy calipers, that would allow me to use the 1.28" thick Chevy rotors, this is what I have found:

1. You can pull and use the 'big GM' caliper from the Seville, but you have to swap the piston/ebrake assembly for a shorter one. If you pull the caliper, and can see the p. sticking out about 3/8", then you know it is the long piston.

2. Raybestos makes the short 2" piston/ebrake assembly brand new, and it is available at Rock Auto for about $80 ea, plus shipping. Yep. Bend over.

3. GM used that same short piston in the 79--83 Caddy Brougham (sp), which is a 5 1/2" bolt c. to bolt c. caliper. Just remove the piston and put in in your large GM caliper.

4. Most rebuilts DON'T change the ebrake seal--and they are NEARLY IMPOSSIBLE TO FIND. The only place I could find who has them is ABS Power Brake, Inc. $5 ea. Telephone 714-771-6549

5. Once you install that seal and assemble the piston/ebrake, if you pull the ebrake out, you have to replace that seal. Pulling it out flips the seal lip backward and tears it. It will leak on your new pads.

6. BEFORE you connect brake lines, YOU HAVE TO RATCHET THE EBRAKE LEVER, PUTTING THE NUT BACK ON EACH TIME YOU PUSH LEVER BACK, so shaft doesn't disappear into housing. If you don't do this FIRST, BEFORE connecting brake lines, you may damage the workings, or risk ever getting good pedal.

<a href="http://s659.photobucket.com/albums/uu316/bobbyrogue/?action=view&current=P1010395.jpg" target="_blank"><img src="http://i659.photobucket.com/albums/uu316/bobbyrogue/P1010395.jpg" border="0" alt="Photobucket"></a>

7. If you need the ebrake cable brackets and/or springs, call Shawn at Great Lakes Off Road.

8. The tube type adapter in the photo below, allows you to use oem ebrake cable with the 'large GM' calipers like mine. Either TSM, or Virginia 4X4 has them for sale.

<a href="http://s659.photobucket.com/albums/uu316/bobbyrogue/?action=view&current=ebrakebracket.jpg" target="_blank"><img src="http://i659.photobucket.com/albums/uu316/bobbyrogue/ebrakebracket.jpg" border="0" alt="Photobucket"></a>

 

Interesting and good info! Happen to have a pic of the E-brake arm-unassembled, and how it keys in?