[mrtonegto]

I was wondering if anyone else has this issue: I installed Caddy rear disks on my 12-bolt rear and the passenger side shock rubs the e-brake spring when the suspension is not supported.
These have been installed 6+ years ago and this has never been an issue when driving but the brake locks up when the rear end is not supported.
This was a fairly popular mod and I wondered if anyone has this issue and has come up with a fix.

[pro-tour79]

Even though something may be popular it does not mean it's perfect, that brake system was engineered for a different application and long after the gto was gone.
The solution is to re-engineer it to fit your application.
I'll apologize now if my statement comes across a little harsh but.... :-)

[mrtonegto]

Agreed, and it's exactly that re-engineering that I am seeking................

[Scarebird]

Can you post a few pics of the interference?

['ol Pinion head]

Its been quite some time since I performed this rear disc addition, but in using the late 2nd Gen caliper mount brackets (same as '79 Seville) on an A-body rear, we always used 2 of the lh side caliper mtg brackets. Had to do this to get the clearance for the passenger side shock. Now that I'm waaaay ahead on pass side caliper brackets, am going to have to re-drill the bolt pattern on the drill press in at least two of these brackets.

[mrtonegto]

Scarebird: Just saw your post, would have taken pics today since I was just over there. I'll get a couple and post them asap. Further to my issue, the Caddy calipers have a E-brake lever on the back side and that lever has about a 2" return spring on it. On the passenger side that spring rubs hard against the outside bottom of the shock when the suspension is somewhat extended. Pics to follow.................

OPH: I used rear discs from a '75 Caddy Seville and I'm guessing that these brackets/backing plates are different then the brackets you're referencing. These are fairly thick backing plates and match the 12-bolt pattern.

[mrtonegto]

Here's a pic of the issue. Actually the shock is not all the way seated since I was working on the rear coils at the time, but the picture is a good representation of what's happening.

[Scarebird]

Strange - usually the 75-76 Sevilles had rear drum, and the 77-78's had the big pattern body, unlike the metric sized 79.

[mrtonegto]

Year may be wrong. What e-braked rear discs could I install in lieu of these?
It's a 12-bolt pattern. I understand some have the internal drum e-brake - like F-body, etc. Prefer something I could convert from a salvage yard.

[mrtonegto]

Saw the fix on an El Camino site:

http://i149.photobucket.com/albums/s...s/DSCN1816.jpg

Some guy sells these to move the shocks inward. Requires that a hole be drilled for a small bolt that prevents the angled bracket from turning.

['ol Pinion head]

That looks like a rig. The cleanest solution is to either use two driver's side's caliper brackets, OR re-drill 4 holes in the RH caliper bracket in the same spot as the LH bracket, basically making a another lh bracket. I'm doing this, as have buuilt numerous 8.5 a-body rears with brackets from rear disc T/A's & am now short have two rear disc T/A rears to go theough & put back in cars. As Scarebird alluded, there were no disc brake Sevilles till '77 model. I've pulled over two dozen '75 & 76 Seville rears for cores & all were drums. The '77 & 78 Seville used one style of caliper brackets (& calipers), while the '79's used the late 2nd Gen T/A style. Wondering what you have, there are part numbers stamped into the caliper bracket. Or, if you can get good clear pics of either caliper bracket, I can pull out both styles of caliper brackets & compare & ID.

[mrtonegto]

These are the same brackets I used but I cut off the angled sections opposite the axle flanges.

['ol Pinion head]

Ck'ed the pile of brackets today & the style you have are the '77-78 Seville version. While I have not used the '77-78 style for disc brake conversion on A-bodys, the premise is the same, due to the way the parking brake levers attach.

[mrtonegto]

So it looks like the fix would be to weld up the axle bolt pattern on the pass. side bracket; turn the bracket up-side-down; and then drill the corrected axle pattern into the bracket.
Problem then would be that the pass caliper would be upside-down. I would need to find one with the same spec's as the DS one and with a bleeder now at the top. Is one available?

['ol Pinion head]

When I've used the '79 Seville style, all using a left bracket on the passenger side did was cock the caliper bracket at a slightly different angle & allow the passenger side caliper to fit. The '77-78 Sevile calipers are a little wider where they pop down into the "mouth" of the caliper bracket. I can go through & see if I have anymore of the 77-78 calipers or not & see what is going on.

What I'd try is take the driver side caliper bracket off, mount it on the passenger side, in the same direction as the passenger side was originally mounted. Then bolt on the pass side caliper & see if the interference problem with the parking brake lever has disappeared. If it does, then just re-drill the rh caliper bracket. Can't remember how I came up with this using the'79-81 rear disc pieces when started adding disc parts to rearends. Just had so many '79-81 posi rear disc rears, nearly every one of them, I ended up completely parting out, & the lh caliper brackets are what I used not only on 12 bolt Chevelle rears, but on bolt-in axle 8.5 A-body rears that I also had to make spacers so the axles would be properly retained

[mrtonegto]

PS and DS calipers are the same - interchangeable, therefore the PS caliper (like the DS caliper) would then be upside-down if mounted in front of the axle on the PS.
I appreciate your help on this OPH, but I don't think there's a way to get there from here, as they say............LOL
Unless there are other calipers that match the bolt pattern of these brackets AND are opposites whereby they sit in front of the axles with their bleeders on top - it's not going to happen.

[mrtonegto]

Now that I look closer at the bracket shown in #7, it's not geometrically correct.
Meaning that the bottom of the shock was originally designed to rotate on an axis that ran front-to-back on the car. It would now has an axis that is side-to-side.

This would not be correct IMO since it would not allow the shocks to move freely as the rear end traveled up and down.

FWIW

[HWYSTR455]

I had a similar problem on the clone when I installed a SSBC rear kit based off the same calipers. Odd thing was that it worked on the LeMans without issue, I had saved the kit when I upgraded the LeMans. After a bunch of head scratching and phone calls, it came down to the bracket on the housing tube was welded on in the same position. (Guess it doesn't matter on a drum setup that much).

I say get brackets, or better yet, a kit. The one I went with on the clone was a Right Stuff kit, and it was $400. Pretty hard to justify piecing one together when the replacement parts you will most likely need will amount to that, or more.

KORE3 sells just brackets, can go that route, or look at the S-10 or late camaro setups.

.

[mrtonegto]

Probably should have gone the kit route although the Seville conversion was very inexpensive and only required re-drilling the rotors to 4 3/4.
The issue at hand only occurs when the rear end is fully extended (when rear is hanging from shocks). It has never caused an issue when driving. It is however denting up the bottom of my PS shock.

[HWYSTR455]

I meant to say the bracket 'wasn't' welded in the same position, but seems you understood anyway.

Dips and hills, you might get it extended the whole way, enough to make contact, and in time, will damage the shock body, maybe enough to make it leak.

I say leave it and just keep in mind you should correct it. Maybe once you need rotors or pads, get a kit and swap it out.

.