ericjon262

I'm looking at putting late 4th gen rear discs on my 87 'bird that came factory with drums, I don't want to swap the whole axle, but I assume I can swap the backing plates onto the 3rd gen axle and install the 4th gen style drum in hat parking brake and disc brakes after I adapt the lines and cables, is there a reason I can't? I didn't see it covered in the stickies either here, or in the drivetrain section.

Thanks-

Eric

sofakingdom

iTrader: (1)

The flange on the axle that the plate mounts to is completely different between drum and disc brakes. It's possible to do that swap but FAR FROM a bolt-up. A large section has to be cut off, holes drilled with some degree of precision, etc.

Firechicken82

I have seen a bolt on adaptor plate that mounts a stock disk backing plate onto drum axle 82-92 drum axle flanges. I forgot who made it but it's worth looking. I'm pretty sure the only way to get drum in hat setups on a drum axle is cutting and drilling like mentioned. There may be someone that machines plates that fit. I think the two lower flange bolts line up and you can use the backing plate as a template for both cutting and drilling. Drilling and tapping the upper two holes in the flange shouldn't be too difficult but, if not done properly you'll be swapping the axle or have a pretty sketchy braking situation.

//<86TA>\\

iTrader: (14)

On the homepage there is/was a tech section with a good writeup on how to do this swap. I've done it twice, it's actually pretty straightforward and simple if you have the tools. The drum brake flange needs to be cut down to a square, the existing 2 small threaded holes need to be drilled out larger, than place the 4th gen backing plate and drill the last 2. The rest bolts on.

Hawks sells the proper conversion parking brake cables, you will need the parking brake brackets from the 4th gen axle.

You can use the drum brake hardliners if they are in good shape, you need to bend them a bit. Or make new ones to match.

LAFireboyd

iTrader: (3)

BBC shares some pictures and details of his drum to LS1 swap in this thread. And in post #2 there are two links to similar drum to disc conversions.
LS brake swap - Third Generation F-Body Message Boards

ericjon262

Thank you gentlemen.

Speedy Mike

these are to bolt up PBR calipers to a drum rear is my understanding. Bought them a while back

ericjon262

one of the biggest reasons I want to do the swap, is the drum in hat parking brake, so an adapter like that isn't so helpful.

TTOP350

iTrader: (8)

Was never a fan of that parking brake setup on the ls rear setups.
especially when the shoe material falls off. Un needed extra weight and parts to fail.

ericjon262

I've never seen the shoes fail, but I have seen parking brake mechanisms in calipers lock up, fail, or otherwise be a service problem, which is why I prefer to divorce the parking brake from the caliper and make it it's own separate part.

84 1LE

iTrader: (9)

The early PBR e-brake is very reliable. Ive never had to adjust mine in 30yrs. Not so much on those cast iron moraine calipers though. I think EBmiller makes that bracket pictured.

thatsupnow

Lol extra weight😆 a few extra grams isn't gonna be a make it or brake it deal

TTOP350

iTrader: (8)

You're right for most, it won't matter, but for some It does. The 98-02 brakes got more parts, bigger, heavier rotors and the more complex parking brake setup. It was so simple from 89-97, then GM had to mess with it I guess, bigger and heavier is their way..

thatsupnow

Is it more complex tho?? There had to be some good reasons as to why they went to a parking brake setup like the 98-02. And that design isn't just limited to those cars my 05 F150 has the same parking brake setup

84 1LE

iTrader: (9)

I recall older rear disc brake GM (and non gm)cars using a similar e-brake, before the Delco moraine set up on 3rd gens. Maybe 70s era vettes, caddies. Then PBR came along. Maybe GM talked them into switching to the drum style e-brake. I like the clever design (on paper) and how they incorporated it into the rotor hat, but I prefer the early type since you only need one set of brake pads.