Loving life! 2 years since my 67 Imperial GM full-size Disc Brake upgrade!

[regr]

Good morning C body people. Well its been 2 years to the day since I fixed the brakes on my beautiful 1967 Imperial Crown 4dr Hardtop. After many expensive attempts to get the BUDDS calipers to not leak by buying SS modified ones for big money and Yada yada yada I threw in the towel on the Budds and built a slick simple conversion using full size GM , Cadillac, Ambulance, Police, commercial large single piston calipers available in any auto store around the country. Conveient that the full size GM's use also the 5" x 5" bolt spacing. I never posted about this upgrade I did to my Imperial back then as I thought I would do it later after I knew how it was working. Well the car stops amazing the last 2 years, no leaks no vibrations, when you put your foot on the brakes at highway speed the nose of the car comes right down and stops this be heave beautiful car like a dream. Anwyay a few pics for you below and if any of you have questions post here or PM me. All the best guys and galls. Reg Riemer.

 

[regr]

Photos contiuned

 

[regr]

Photos Continued 2

 

[Mr C]

Does the Mopar Imperial rim clear? Or are you using GM rims...very interested in the shim and caliper bracket specs so that I can duplicate for my 68.

 

[67ImpCrown]

Excellent work! Double points for a creative solution to the Budd brake issue. For now, I'll go the OE route since I've spent way too many dollars on acquiring parts, but it's nice to have a backup plan should (or maybe when?) things go wrong. Thank you

 

[regr]

Yes factory Imperial wheels and all fits stock !

 

[regr]

Does the Mopar Imperial rim clear? Or are you using GM rims...very interested in the shim and caliper bracket specs so that I can duplicate for my 68.

Yes all original wheels and tires

 

[regr]

Excellent work! Double points for a creative solution to the Budd brake issue. For now, I'll go the OE route since I've spent way too many dollars on acquiring parts, but it's nice to have a backup plan should (or maybe when?) things go wrong. Thank you

Yes, I hear ya. I spent a fortune on Bud's calipers and everything. I could never get it to work properly. Real frustrating waste of time and money. My new set up works very nice OEM look as well, and the car stops like a dream now. If you want to get a kit from me later, I'll do that for you.

 

[crv]

How much difference in price are we talking about here?, does this type of conversion work on later Imperials?

 

[regr]

Does the Mopar Imperial rim clear? Or are you using GM rims...very interested in the shim and caliper bracket specs so that I can duplicate for my 68.

you can pm me anytime.

 

[regr]

How much difference in price are we talking about here?, does this type of conversion work on later Imperials?

This upgrade will work on 1967 to 1973 Imperials only.

 

[live4theking]

This is interesting. How did you determine this would work or did you see it somewhere else?

Did you change the spindle too?

 

[3175375]

Great job! Do you have a complete parts list of what you used?

 

[fury fan]

Not to steal @regr 's thunder, but some thing's I've learned:

Those are the GM D52 calipers (D52 is the industry # for the brake pad).
D52's are in use in lots of aftermarket brake kits, there are even new/aftermarket castings available (Jegs, Summit, etc).
Wilwood even makes a drop-in 2-piston version (but they are pricey).
The reman market is full of them, too.
There are some vendors that sell special-compound pads for them, too.

D52s were in use from around 1969 thru 2002.
One must watch the application, these calipers are made for 1.03" and 1.28" rotors.
You really must verify all the details on the donor vehicle to ensure getting the right caliper part#s for the rotor you have.

The piston dia on the GM units is 3.1", C-body is single-piston is 2.75".
So they should give better braking (although there are other variables involved with that which must be reviewed).

The design of the caliper allows it to mount to a simple flat adapter plate. No 3D geometry required there.

 

[regr]

Hello guys , I have the 1.28’” rotors and matched callipers off the shelf at local O'Reilly auto parts store in Bullhead City , Az. Car uses stock Imperial spindle with custom bearings and spacers, d52 rotors 5x5 “ bolt pattern , stock wheels etc.
I had these D52’s on fleet vehicles I worked on for years and just thought that it would be a great upgrade to the 67-73 imperial which so badly needed better brakes . I love my 67 but not having brakes made it scary to drive.
I have not been on the internet as I have closed my home in Arizona and am now arriving at my lake cabin in northern Saskatchewan Canada. Pm if you have questions but I’m only randomly in cell and internet service all summer, back to Arizona in October 2024.
Reg

 

[fury fan]

@regr
I'm keenly interested in all of this as it relates to something I'm evaluating for a D52 caliper on a C-body drum spindle.
Maybe you'll see this now, if not -- we'll see you in October...

I presume you are using this spacer because the bearings are closer together on the GM rotor than on the Imperial hub?
I see the Imp uses an A5 inner while the Cadillac is an A6. The Caddy rotor's inner bearing bore is smaller (1.25" vs Imp's 1.375") and apparently closer to the outer bearing?
I only see the Set 3 bearing box in the photos, but regardless, the 1.25" ID Caddy bearing would not fit the spindle.

While both A5 and A6 bearings use different cone/race part #s, both have the same outer radius of 1.168".
The A5 Imp bearing+race could go into the Caddy rotor (not to use the Caddy race).
That would be the swap of bearing/race as matched geometry, so should be OK for long bearing life.
(I had an email discussion years ago, with a Timken engineer, who told me to NOT mix-n-match with cups and cones simply by diameters, as the angle on the rollers might not match.)

The seal then becomes a question.
The OD and shaft dia of the Imp and Caddy seals is different.
Imp seal is 2.44" OD, for 1.0893" shaft, Caddy is 2.568 for a 2.00" shaft.

So the Imp seal would be loose in the Caddy rotor, and the Caddy seal would need to seal on that bearing spacer.
Or another seal could be used if it had the right ID/OD.
What seal part# did you use?
Is the bearing spacer machined to the same OD as the Caddy spindle or the Imp spindle? Or some other diameter?
Below, the red line is the witness mark of the original Imp seal.
The spacer moved the bearing outboard by x, so presumably the seal did also, and seals on the spacer?

.

 

[bnz84]

With that plate and spindle spacer reminds me of scarebird kit I have in use.

 

[fury fan]

I'm thinking I found the/another reason for bearing spacers.

On the setup I'm mocking up, there is only about 1/8" clearance between the back surface of the rotor and the outboard mounting surface of the spindle. Not enough thickness for a bracket. Without the resources to do any FEA on this, 1/4-3/8" seems a suitable thickness for an adapter plate. The threads on the caliper pins are in that ballpark, so that's a good clue. So a bearing spacer could move the rotor outward, and it looks like both bearings would roughly stay on their journal surfaces. But it brings up all the seal-related questions I mentioned.

It looks like @regr's bracket might be mounted on a different plane than the 4 bolts of a C-body drumbrake spindle, which hold the backing plate. So a different situation.

I'm thinking that using the original 65-72 drumbrake hub, with a shallower hat-type rotor that moves the braking surfaces outboard, is what I will review next. Ironically, I have looked at a bunch of rotors and nixxed many of them for not being as deep as ours. Requirements have now changed.

Maybe I should stop hijacking this thread though...