1966 Eldo disc brake conversion questions

[johnnyo53]

will the spindles and disc assemblies from 1969-1971 Cadillacs fit on a '66 Eldo? Looking for a cheaper conversion than aftermarket kits if possible.  Do the standard wheels still fit?  Thanks for your consideration on this.
John Olenchalk

[66 Eldo]

I can't answer your question but what is wrong with your drum brakes? Mine work great on my 66.

["Cadillac Kid" Greg Surfas 15364]

Fully agree with 66 Eldo.  The only problem with the original drum brakes is that it takes someone who knows what they are doing to make them work correctly.  Once the drums are trued and the shoes adjusted correctly they work great. I used my 66 (with the drums) for over 20 years as a daily driver and never ran into anything the brakes did not handle without certainty.  Agreed, they take a bit of time to dry out after going through deep water but other than that they stopped my 4800 pound Coupe every time they were called on.
Going back to your original question, if you are set on discs there have been several folks on this forum and others. 
Greg Surfas

["Cadillac Kid" Greg Surfas 15364]

I see you got your answer from "Andy" on another forum. It sounds like just about what I had found which helped convince me to keep my drums.
Greg Surfas

[Scot Minesinger]

Drums really stop the car well compared to disk brakes of the same era, and the change to disks were made for heat dissipation primarily.  After several hard stops within minutes of each other it takes longer for the drums to cool then disks.  Given our type of hobby driving it is unlikely drums would not be fine.  Even with a disk brake conversion on these Cadillacs (my 1970 Cadillac has disk brakes) assuring a safe distance is always recommended, and essential.  The Honda Civic driver does not think of you driving behind in a 45 year old car when they jam on the brakes routinely. 

I could reason that if you had a 1968 RWD Cadillac with drum brakes where disk brakes were optional (that year only), maybe an upgrade to disks if it was not a lot of trouble might be OK.  Even then it requires a master cylinder change.

Unless you intend to rally race the car or are going to drive routinely in modern rush hour traffic and not assure safe distances ahead, then convert to disk brakes.  The drums should work fine, after all many presidents and kings in 1966 (Lincoln and Ford came out with disks in 65, so 64 and earlier they all did) traveled in drum brake equipped cars all the time. 

If you are not satisfied with the drum brakes now, as others may have suggested, check that the brakes are in proper repair and adjustment.

[johnnyo53]

While I appreciate the answers and advise on the merits of staying with stock equipment, I was hoping someone could answer my specific question about using later model spindles etc..., or somebody who has made the conversion could weigh in. Car is a semi daily driver in some of the worst commute traffic in the country, and would benefit from some additional stopping power.

[John Abend]

Your 66 spindles can be used.  You just need the caliper brackets, dust shields, rotors, brake hoses, proportioning valve, brake booster/master cylinder off a '69.  You'll also need rims from a '69+ car to clear disc brakes up front.

[cadillacmike68]

While I appreciate the answers and advise on the merits of staying with stock equipment, I was hoping someone could answer my specific question about using later model spindles etc..., or somebody who has made the conversion could weigh in. Car is a semi daily driver in some of the worst commute traffic in the country, and would benefit from some additional stopping power.

The steering knuckle is the same on a 1966 and 1968. I think it want back to 1965 (possibly earlier).

Therefore, if you get a 1968 or 1969 steering knuckle with the brake caliper bracket instead of the drum mounting plate you can fit the Delco Moraine calipers on it. You can then use calipers up to 1971 or so. The books say they are different - yeah the piston is bigger on the later year(s), no difference in mounting and operation. !970 used a new steering knuckle - one piece assembly, but the lower ball joint and outer tie rod end are different. It can can still work, but more parts to change. I did it.

You really should get a proper disc master cylinder and proportioning valve. easy to find.


I have a set of steering knuckles, with the steering arm and the disc caliper bracket for 1968-69 both sides, complete. PM me if you are interested. This is also known as the spindle or axle assembly.


Rotors are pricey, but there is a procedure to make the 1972-76 rotors work. I have One 1968-70 rotor, new in the box. Again PM if interested.

Disc pads are IDENTICAL from 1968-1996.

[cadillacmike68]

Your 66 spindles can be used.  You just need the caliper brackets, dust shields, rotors, brake hoses, proportioning valve, brake booster/master cylinder off a '69.  You'll also need rims from a '69+ car to clear disc brakes up front.

1968 wheels will fit properly.

[blugg]

Have a 75 series 66 model year and once thought discs was the hotness to convert until i realized the factory drums operate so well there hasn't been one need in 25 years to change

[Vinny6t6]

I converted my 66DVC from drum to disc.  It was easy, just a lot of work and parts.  I used the rotors, calipers, dust shield and caliper brackets from a 69.  It bolted right up to my 66 spindles with no problems.  I used a brake booster and master cylinder from a 69-70.  Had to make the holes larger in the firewall to accomadate the booster.  I bought an aftermarket proportioning valve to hook up and changed the front brake hard lines to the correct 69-70 size.  Also changed the rubber brake hoses too.  bled the brakes and all worked fine.  Don't forget you have to change the rims to a 69-76 steel rim and hubcaps too because they wont fit the new rims.

[cadillacmike68]

^^ 1968 wheels will fit fine. The wheel covers for 68 and 69 were the same, so there are 3 years to choose from. In fact, If I remember correctly 66 and 67 (same wheel cover) will also fit on the 68-70 wheels, because I used to change out the wheel covers on my 1970 occasionally and I had from 66-73 to choose from.

[TJ Hopland]

Scarebird makes brackets for this app that use the early 70's calipers and rotors which are still reasonably priced and easy to find. 

Drum vs disc just depends on where you drive.   I have spent time in places where you could drive safely with no brakes at all but where I live traffic and roads such that you need all the help you can get and then some.

[cadillacmike68]

Scarebird makes brackets for this app that use the early 70's calipers and rotors which are still reasonably priced and easy to find. 

Drum vs disc just depends on where you drive.   I have spent time in places where you could drive safely with no brakes at all but where I live traffic and roads such that you need all the help you can get and then some.

That scarebird kit is strange. It uses ElDorado calipers!! Why didn't they just make a bracket that takes the regular RWD DeVille / Fleetwood calipers. Those are Much more numerous and therefore less expensive.

It also has this warning:

They will NOT fit inside the stock pre-1971 rims - you will need later 15" or larger rims.

No amount of caliper grinding or wheel spacers will fix this!

Here's the link for those adventurous enough to do this:

https://scarebird.com/index.php?route=product/product&path=60&product_id=114


The better alternative is to just find a 1968 - 69 caliper bracket and connect that to your existing steering knuckle & arm.  Then you can use proper 1968-75 calipers and (only change was internal piston size from 70mm to 75mm) either the 1968-71 rotors or grind off the back of the inner bearing seal and fit the less expensive 1972-76 rotors.

I went down this road. I have the 1968-68 complete steering knuckle, arm and bracket assemblies, plus the 1971-71 one piece replacement, and both the 1968-71 rotors and the 1972-76 rotors. I used the one piece knuckles and the later rotors.

The newer rotors WILL fit by just grinding away the lip of the end of the inner grease seal.

The one piece steering knuckle fits, but you need to get new (1970-76) Camber eccentrics, lower ball joints and outer tie-rod ends, because the angle of the dangle for these three items changed with the one piece steering knuckle.

GM did not need to do this, the differences are so small there seems to be no engineering reason for it, other than "we did it because we could".  What's really insidious is that even though the Camber eccentric was changed in 1970, the exact same upper ball joint fits both the 1969 & earlier And the 1970 & later steering knuckles.     

[TJ Hopland]

I did ask Mr Scarebird (that isn't his name, I just can't remember it) one time why the Eldo calipers are used on so many kits and I think he said it was basically the same caliper as the RWD's but its overall external shape was more controlled because of the closer clearances in the Eldo setup.   A RWD they left more rough spots in the casting since there were typically no clearance issues.   Being that space is often an issue with conversions they just figured more clearance was better.    At least that is how I remember the answer, it was many years ago.

I actually like the Scarebird stuff.  My area just does not have junkyards full of old cars.   I also like that they tell you what the parts are, you don't have to depend on them still being around years later when you need a replacement rotor like some other kits that are out there.

Interesting that the difference in rotors is just the seal area and you can 'fix' it with a hand grinder or do you have to get it on a lathe?

The wheel clearance issue is usually due to the fact that for whatever reason drum era rims tended to have an extra step in them that they got rid of in the disc era.   Sometimes that extra step was where the hubcap grabbed so going to a later wheel can cause issues with keeping original hubcaps.   Recently I have seen some kits using some Euro based rotors that are a bit smaller in diameter than what we normally had to choose from but I think the 'catch' with those is they don't use the same bolt patterns so its still not a perfect solution.   You would think one of the big aftermarket would or could make or adapt one of their super high performance rotor/caliper systems for something that say had 14" wheels that would fit drum era 15's and perform as well as the 15 inch wheel factory disc would have.   I suppose the issue is new/aftermarket wheels are so popular for just about everything now that its just us weirdos that want better brakes but stock look that have a problem.         

[cadillacmike68]

TJ,

I've not seen the ElDorado calipers up close. I'll have to look at a set.

But, the Eldorado had such a huge offset that the wheels were unique (includes Toronado, i guess), and the regular RWD calipers (with the factory 1968-1968 caliper brackets) fit just fine on 1976-70 wheels. To me it is less stiff to change.

The only shortcoming is getting a hold of the 1968-68 caliper brackets. If someone would make those, we'd be all for for this sort of conversion.

However, even with the fewer number of years available for the RWD disc brackets (2 years vs , there were so many more RWDs made than Eldorados in the time period, that it should be about the same availability.

I have the 1968-68 RWD disc caliper brackets in my garage. I suppose I could look at them and compare them with the ones from scarebird. They might be the same.

But that would beg the question: Why does his site insist on 1971 and later wheels??? And that brake line in one of the photos looks to be in a different spot than the RWD calipers.