78 Seville Rear Disc Brakes on 69 Eldorado????

[AZCadillac]

I am trying to put some rear brakes on my 69 Eldo and I was thinking if I can just take all the parts off of the 77-78 Seville and use them on my 69 Eldo...
Any suggestions?? I have been doing some research and it shows that the stud bolt pattern is the same.
Please help me out, thank you.

Keep on Cruisin 

[TJ Hopland]

Wheels were the same but have you looked into the rest of the 'rear end'?   I know the 66/67-70 Eldo had a completely different rear suspension setup than the 71-78 Eldo's so I doubt you could swap the entire axle.  It was leaf springs with the horizontal shocks vs coil springs on the later model. 

I never looked that close at the actual spindle / backing plate area so I suppose maybe that was the same and was just bolted to the axle so then could be easily swapped.    From what I remember the 71-78 Eldo was like a typical trailer where the axle stubs stuck out the main axle.   

As for how any of that may translate into the first gen Seville I don't know.    Seems like I read that all the GM cars except for the Corvette used the same rear disc brakes in that late 70's.    That was Eldo, Seville, Fleetwood,  98, Park Ave, Firebird, Camaro.    I am also not sure what was meant by 'same'  Guessing that was calipers and maybe rotors?   Seems like the F body was the smaller bolt circle.   Rest of the cars on that list would have been the 'big' 5 on 5.     Seems unlikely that the caliper mounting bracket would have been the same on all those but who knows. 

[bcroe]

If your 69 has rear drums, I would recommend keeping it that way.  All my cars have
front disc/rear drum which is simple and works fine.  The early rear disc setups had
great issues because of the emergency brake cable.  A 79 all disc Toro was so troublesome,
I considered converting it to the rear drum option.  Bruce Roe

[Scot Minesinger]

Agree with Bruce and stay with the factory set up of rear drums/front disks, as in proper working order they should work well.  Trouble is the 77-78 Seville is rear drive and 69 Eldorado is front drive-the rear suspensions and axels will be quite different.

[AZCadillac]

Thanks for the feedback, I talked to a guy at a junkyard and he says that the 81-85 Seville's have the rear disc brake assembly.
I would really like to have rear disc brakes, I'm really tired of drums, and as far as the parking cable.....I rather not have it to be honest. If its going to be between having a parking cable that works or rear disc brakes....I'm gonna go with the disc brakes.
Yes there is no rear axle on the 69 Eldorado.
Any other opinions please feel free to share.

[Glen]

If you lived in this state you would not be able to drive the car without a parking brake. 

What is you find so bad about drums that you want to go to all this trouble? 

[The Tassie Devil(le)]

I think that everywhere in the World you have to have a working Parking Brake, and it has to be mechanical in operation as well.

Bruce.

[TJ Hopland]

First thing you need to figure out is / was the 'backing plate' bolt pattern they used on your car the same as other GM stuff.   Typical design which I assume this car used was that there was a flange on the end of the axle with 4 bolt holes in it.  For drums the backing plate bolted there, for disc the caliper bracket goes there.    If that flange is a common pattern you may be in luck and can find an aftermarket kit.  Who knows you may find out its the same as say the 10 bolt truck rear end and there are several kits for those.    Once you find a caliper bracket to fit the next trick will be to find a rotor to fit but I don't think that will be too hard because there are likely a lot of options there with the correct bolt pattern so all you have to do is find the correct offset. 

The 80-85 Seville was FWD with an independent rear suspension.  The rear hubs were kinda FWD style where the bearing was in the knuckle with the hub sticking out of them.   The rotor or drum then just slid on.  These used the slightly smaller bolt circle so won't do you any good.   Its been a while since had mine apart but I sort of recall that the caliper bracket is part of the 'knuckle' so its not something that would be of any use for a conversion.

The 71-78 Eldo rear axle was a solid beam with stub axles sticking out.  Bearings were in the hubs.  Drums or rotors slid on. 

I never took apart the rear in a 67-70.   


My understanding of RWD era rear disc brakes 63-85ish:

Corvette starting in 63?  I believe these were multi piston fixed calipers.  It was its own animal and didn't share parts with any other GM and was never popular for any swaps, guessing because of the independent suspension.

There was then the 'big' single piston caliper setup that was standard on the 76-78 Eldo (FWD) and 76-79 Seville (RWD).   Also optional on F bodies (Firebird Camaro), Fleetwood, 98,  Park Ave (All RWD).   I'm not sure if those all used the same rotor or not.   I believe these calipers will physically interchange with the front ones used on the Eldos and possibly other cars its just the front ones are lacking the parking brake stuff.   Rebuilt calipers have never included parking brake brackets and external hardware so that was always the valuable part.  I know those calipers were what many of the early DIY conversions for full size cars and light trucks used so they were difficult to find in salvage yards.   Not sure what the current production status is of these. 

There was then the 'medium' caliper.  These were standard on the 79-85 Eldo, 80-85 Seville, and Optional on Toronado and Riviera (All FWD w/independent rear).  I think they were also optional on the 82-85ish F bodies.   These area apparently used for many of the conversion kits and are currently being made new.  I got a new 'fully loaded' pair complete with the parking brake hardware for less than a naked rebuilt one from a parts store.

I think by 85 ish when 90% of the line went to FWD they came up with some new options and I have not really paid attention to the details. 

   

[Scot Minesinger]

Yes, operational e-brakes are a requirement most everywhere, and for good reason - safety -especially on an older car.

The 81 -85 Sevilles are rear drive and again, you will suffer trying to use(retrofit) them on a front drive car.  Go for a front drive car with rear disc brakes if you want that set up.  I think, but am not positive rear discs were an option on Eldorado at some point up thru 78, which will resemble your car the most.  Rear disc brakes were available on early 70's Riverias, so Cadillac is unlikely to be bested here.  Alternatively the 79-85 Olds Toranado, Buick Riv and Cadillac Eldo rear disk brake option from salvage yard may work.  However in this post they were reported to be troublesome on the Olds.

No one I know has complained that the brakes on a late 60's early 70's Cadillac with front disc/rear drum set-up.  Are you 100% positive that the brakes are working correctly?  If they are not and you make the switch, you may remain unhappy.

[TJ Hopland]

The 81 -85 Sevilles are rear drive

81-85 Seville was definitely not rear wheel drive.

76-79 Seville was rear drive, I believe they were called a K body.  Those are the ones that for the most part looked like other (not Cadillac) full size sedans of the era.

80-85 Seville was the 'bustle back' sedan built on the E body platform.   The 79-85 E body was the 3rd gen of the longitudinal front wheel drive system that debuted in the 66 Toronado.   Gen 1 was 66-70, Gen 2 was 71-78, Gen 3 was 79-85,  and I quit paying attention after that but I believe the E body made it till at least the later 90's.   The big oddity in the E body line was up to 1979 the Riviera was rear wheel drive but still an E body.

As I stated earlier the rear disc was standard equipment on both the Eldorado and Seville starting in 76 and I believe remained standard equipment till the end of the Eldorado name, or ETC ELC at the end.   IF they still make the Seville (sts) I'm sure it still has rear disc standard.   Starting in 79 it was a different / smaller caliper than the earlier models.   I would bet the caliper again changed in 85/86 with the next gen of cars.

[Scot Minesinger]

right, sorry my error, the Sevilles of the 1981 thru 1985 mentioned were FWD, so maybe those brakes would work