Holy shit it did. 8-7/8" ring, 12-bolt cover. 30 spline axles. Unless that was for the limo chassis only...kevm14 wrote: I am wondering if the 77-81 got something like a 12-bolt. That really would be one hell of a solid powertrain, between the 425, TH400 and big axle. More research!
Caprice engine swap?
Re: Caprice engine swap?
Re: Caprice engine swap?
Hmm. I think that makes this technically stronger than what's in my Caprice anyway.All '71-'76 Caddies have a unique, off-set rear diff. with 12 bolt cover and heavy-duty innards. Not seen on any other GM full-size! It is an extremely robust rear axle. 1977-1981 RWD Cadillacs have the interesting 10-bolt cover with 12 bolt, 8.875 carrier and heavy duty axles. Not sure on the spline count for either, though.
Re: Caprice engine swap?
Ah, apparently it is a Pontiac axle, not a Chevy. Back when that actually was a thing. Also, it is said the cover has a drain plug in it. Take that, all Chevy axles.
Re: Caprice engine swap?
The factory rear disc in the 70's/early 80's was ok, but the calipers sucked and often froze up. The e-brake was part of the caliper, not at all like the 90's Impala SS/9C1 cop car rear disc.
Hilarious. GM traded parking brake problems for slide pin problems. I guess I will ask if he knows if it works and try it once the car is in my driveway, and not before.Watch those old calipers, they are often jam up the ebrake cable adjuster and the rear caliper won't adjust. So you tend to get bad brakes often. That bolt is rather fragile, so don't manhandle it when you put on new brakes.
Oh, an use the EBrake everytime you park the car, it is the only way the rear brakes get adjusted at all.
Re: Caprice engine swap?
More info.
http://www.cadillacforums.com/forums/rw ... -rear.html
http://www.cadillacforums.com/forums/rw ... -rear.html
This doesn't make sense to me.Found some more info:
GM had six different rear disc-brake caliper setups from the late 1970s to early 1980s. Most were for Cadillacs, but some were also used by Buick, Pontiac and Olds.
1977-1978 Seville rotors were 5 x 5 inches on an 11 3/16-inch rotor. Axles were 1.4-inch C-clip type.
The 1977 and 1978 De Ville, Riviera and Fleetwood used different calipers and mounting brackets, but the axles and rotors were the same as the above.
The 1979 Seville and the 1979-1981 Firebird with the WS-6 performance package used a similar configuration to the assemblies listed above, although they used a slightly different caliper. The Seville rotors had the 5 X 5-inch pattern and 11 1/2-inch diameter, whereas the Firebird rotors were a 5 x 4 3/4-inch pattern, but had the same outside diameter. Camaros did not offer the WS-6 package on any of their models, although it will bolt on directly to 1970-1981 Camaros. This is the most popular of the GM disc brake swaps, as it fits all 10-bolt and 12-bolt rear ends, as well as the S-10 trucks and Blazers. All of these rears used the four-bolt axle flange measuring 3 1/8 inches across the top and 2 5/8 inches across the bottom. Pay special attention when performing this exchange on the GM 12-bolt axles, because the Seville rotors will not fit without having to machine the center hub of the rotor to fit the axle. The Pontiac WS-6 rotors will not have to be machined to fit the axle.
All 1979 Fleetwood, De Ville and full-size Buicks also used the same axles and rotors as the 1979 Seville; however, the calipers are again different (as well as the caliper mounting bracket) from the above three.
1976-1978 Eldorado rotors were 5 x 5 inches on an 11-1/8-inch rotor. Axle used tapered inner and outer bearings and cups, and 1 3/8-inch and 3/4-inch tapered axle shaft similar in design to a front spindle.
1979-1985 Eldorado, Toronado, and Riviera; and 1980-1985 Seville rotors were 5 x 4 3/4-inch on a 10 1/2-inch rotor. Rear axles were plain steel beam, using a bearing hub assembly bolted onto the end in front-wheel-drive applications.
Because the GM corporate axles are held in by C-clips, it is not necessary to swap these out. However, the axles will have to be removed, both from the donor car and your vehicle, to both remove and install the brackets and backing plates.
One thing you may discover when searching for these parts on GM vehicles is that the left caliper is mounted to the front of the axle, and the passenger-side caliper is mounted to the rear of the axle. This was common on the earliest GM configurations, and does not mean someone has already done a changeover on that vehicle.
As far as I know, all disc brake caliper pistons are not designed to retract when you let off the brake pedal. By design, they are self adjusting in that the piston keeps the pad right at the rotor. It should not need a mechanical system to make that happen (in this case, the parking brake).Parking brake will bolt up (may need mods, of course...), and must be used.
I have found out that the reason people used to have problems with the Cadillac rear discs is because they DIDN'T use the parking brake. These calipers require the use of the parking brake every time the car is stopped. This causes the piston to ratchet the pads down and maintain contact with the rotor, and when released, the piston stays extended. This keeps the piston out as the pads wear. If you don't use the parking brake, the brakes will be soft, and will require an extra pump to build pressure. I have also found all the info on how to rebuild them, so I will do that myself instead of trading them for rebuilds.
Re: Caprice engine swap?
It took going to some Ford site to find actual info about these calipers!! Because they often used them in conversions.
http://classicbroncos.com/reardiscs.shtml
Ok I guess this is confirmed. The parking brake return spring pulls the piston back and relies on the adjuster to keep the piston at the right place. That sucks. It means I will need a functioning parking brake.
http://classicbroncos.com/reardiscs.shtml
Ok I guess this is confirmed. The parking brake return spring pulls the piston back and relies on the adjuster to keep the piston at the right place. That sucks. It means I will need a functioning parking brake.
In a conventional disc brake caliper, the piston is advanced out of its bore as the pads wear. There is no mechanism that retracts the piston when the brakes are released, so it and the pads remain in light contact with the rotor at all times, ready to clamp when required. In the GM caliper, things are different. When the brakes are applied, the piston is forced out of its bore as always, but the parking brake mechanism inside the piston actually causes it to retract when the brakes are released. Instead, the GM caliper does indeed depend on the regular use of the emergency brake to advance the piston and remain in adjustment. When the emergency brake is applied, the lever is rotated, which causes the threaded shaft to drive the piston out of the bore and clamp the pads against the rotor. When the emergency brake is released a "one-way clutch" built into the piston slips, allowing the piston to remain extended while the clamping force is released.
The problem arises when that mechanism seizes.
Re: Caprice engine swap?
Sounds like a real PITA. However, two key maintenance items should keep them working properly:
1) Keep the parking brake functional and use it at some frequency
2) Don't let the brake fluid get too old, so flush maybe with pad changes. The adjuster hardware I guess is completely bathed in brake fluid and old brake fluid that has a lot of water in it will just seize the adjuster inside the piston.
I can see why these were an issue because most people would do neither of the above.
I will also say this: I still hate drums and I think now that I understand the weaknesses of this disc system, I would still prefer it.
The ideal system may have been the front-style calipers but with a 94-96 style parking brake shoe inside the rotor hat. Best of both worlds.
1) Keep the parking brake functional and use it at some frequency
2) Don't let the brake fluid get too old, so flush maybe with pad changes. The adjuster hardware I guess is completely bathed in brake fluid and old brake fluid that has a lot of water in it will just seize the adjuster inside the piston.
I can see why these were an issue because most people would do neither of the above.
I will also say this: I still hate drums and I think now that I understand the weaknesses of this disc system, I would still prefer it.
The ideal system may have been the front-style calipers but with a 94-96 style parking brake shoe inside the rotor hat. Best of both worlds.
Re: Caprice engine swap?
I don't see the big deal here. You know about the situation, so when you park the car, apply the parking brake. Most people who drive standard do this, so what is the problem?
Also, the parking brake is supposed to work to pass inspection so yo need this to work at some point anyway.
I get it is a minor inconvenience but who cares? If this is the worst thing about driving a car that is 40 years old, you are doing good...
Also, the parking brake is supposed to work to pass inspection so yo need this to work at some point anyway.
I get it is a minor inconvenience but who cares? If this is the worst thing about driving a car that is 40 years old, you are doing good...
Re: Caprice engine swap?
Couple things...
- Parking brake has an auto release when you put into gear. Because Cadillac. My 95 FWB did this, too. So one less step.
- I never use the brake on an automatic. I can't remember the last time I did.
- In my experience, they don't require the parking brake in an automatic. In fact I passed more than once without one and they never tested it. I found out later that it is pretty typical for a shop to ignore it.
All that said, I agree. And the fact is, drums bring their own annoyances and maintenance hassles so it's not like the alterative is awesome. I'd rather have discs because I think it is cool in a car of that era.
- Parking brake has an auto release when you put into gear. Because Cadillac. My 95 FWB did this, too. So one less step.
- I never use the brake on an automatic. I can't remember the last time I did.
- In my experience, they don't require the parking brake in an automatic. In fact I passed more than once without one and they never tested it. I found out later that it is pretty typical for a shop to ignore it.
All that said, I agree. And the fact is, drums bring their own annoyances and maintenance hassles so it's not like the alterative is awesome. I'd rather have discs because I think it is cool in a car of that era.
Re: Caprice engine swap?
Yeah, I don't ever "want" drums for brakes. I don't use the e-brake in an auto either, I was just saying manual people deal with it and don't seem to care. It seems like a small price to pay to drive a car you like.