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

 

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.

 

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.

 

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.

 

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

 

Thank you gentlemen.

 

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

 

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.

 

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.

 

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.

 

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.

 

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

 

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..

 

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

 

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.

 

Back to the orig topic of the thread and the stuff involved with the 98-02 swap. Anybody want to venture a guess of whether I'll see a SAE double flare hard line brake pipe on the end of my '84 made orig rear end?? Heard these were common in earlier models. Slim to no chance to see the matching 4.5 mm brake pipe with an ISO end to match the 98-02 lines???

 

I'll say, 50-50. Either you will or you won't.

​​​​​​​Why do you ask? Why don't you just LOOOOOOOOOOOOKKKKK?

 

But how often do the parking brake shoes need replacing? I've only replaced them when a axle seal failed on my 2500, and I probably could have just brake cleaned them off really well and called it good. it's not like it should be regularly stopping the car, just applied and released with the car already stopped.

 

Not that often, since its just holding the car in place like you said. My rear pads lasted almost 18 years. I replaced them just a year and a half back. The fronts do most of the work.

 

If you have an auto car why would you even use the parking brake?? I've never used mine ever. I've got 2000 Camaro rear brakes and they work great but I've never used the parking brake

 

Yeah, I deserve that. I like the little build nuances our cars have throughout the decade span and seeing if anybody with a 82-84 build car remembered what they had. I will find out eventually. Just wanting to keep it all intact a a month longer before putting it up and doing the swap.

My shoes looked almost new, though only 100k driven. That's some seriously low braking help back there

 

My understanding was that 98-02 axle lines have a totally different thread at the T block on the axle than 3rd gens.


So you would need to get a 4th gen T block if you plan to use the 4th gen axle hard lines..... probably a good idea to replace the old one anyway? Thats what I did with mine. its not in the car yet though.



Getting the parking brake to hook up seems to be more of an issue than anything that people seem to have.