disk brake options (factory) 73 Scamp

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moffetkustoms

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Hello. I'm new to the forum but not to cars...... lol. old guy here. I sure this has been answered in some of the threads on here, but I haven't actually found the answer that I seek. So, I'm gonna kick the proverbial "dead horse" again. Have a 73 Scamp that I just purchased. From the Build sheet it is a 73 built in Dec of 72, therefor it has the 4" bolt pattern on 10 front drum brakes. Have searched a lot of the threads on here about aftermarket kits, bolt this, bolt that. All valid and good answers, however, I need to know if I can bolt on factory disk brake rotors, caliper brackets and calipers to my drum brake spindles. According to my research, the wheel bearings (inner and outer) are the same size between the disk rotor and the drum mount. If this is the case then would the rotors not bolt to my spindles and work for a daily driver? I know hoses will have to be changed and caliper brackets sourced, but the other parts can be purchased at local parts store. Please help me understand if I am correct or not.. Thank you all for your posts. I learn something every time I read them.
 
You need factory stock 73/later "stuff." --for disk brakes. You need upper a arms with the large balls, the disk specific spindles, and of course calipers and rotors also 73/ later. The drum spindles will not work. I'm thinking you also might have to change the lower ball joints

Disk were optional, don't remember if/ when they became "standard equipment." I have a 74 Scamp also drum, also small pattern

Also drum cars do not have a proportioning valve, only a drum type distribution block. You'll need to either replace the distro block with the 73/ later style valve, or do a bit of line re-routing and add an aftermarket prop valve of some sort
 
There is nothing factory that you can bolt onto your current drum spindles.

Either of the factory options will require a spindle swap. Your December '72 built '73 should have the later, 73+ large ball joint upper control arms, the swap over to the large upper ball joint UCA's was finished by November '72 according to the factory TSB. That means that the earlier Kelsey Hayes disk spindles (that use a 5x4" bolt pattern rotor) will not fit your current UCA's. The later 73+ disk spindles will fit, but the 73+ disks use a 5x4.5" bolt pattern.

DoctorDiff now sells a 73+ disk brake kit that uses the 73+ spindles (which will fit your UCA's), but has an option for the 5x4" bolt pattern available for the rotor. That's probably your best solution unless you want to convert the whole car to 5x4.5". @DoctorDiff is very knowledgeable about these swaps and should be able to answer any questions you have.

10.95" Front Disc Brake Kit (Stage 1)
 
72bluNblu said:
There is nothing factory that you can bolt onto your current drum spindles.

Either of the factory options will require a spindle swap. Your December '72 built '73 should have the later, 73+ large ball joint upper control arms, the swap over to the large upper ball joint UCA's was finished by November '72 according to the factory TSB. That means that the earlier Kelsey Hayes disk spindles (that use a 5x4" bolt pattern rotor) will not fit your current UCA's. The later 73+ disk spindles will fit, but the 73+ disks use a 5x4.5" bolt pattern.

DoctorDiff now sells a 73+ disk brake kit that uses the 73+ spindles (which will fit your UCA's), but has an option for the 5x4" bolt pattern available for the rotor. That's probably your best solution unless you want to convert the whole car to 5x4.5". @DoctorDiff is very knowledgeable about these swaps and should be able to answer any questions you have.

10.95" Front Disc Brake Kit (Stage 1)
Click to expand...
 
Thank you for the info. I at least have an angle to take now. I've been out of the mopar scene for quite a few years now. I do have a 79 Volare front end under a 50 that I have been tinkering with for a few years. I don't suppose that these parts will fit either?
 
I believe a Volare is an F/M/J body and many of the front end parts do swap. Tom Condran's "Performance Handling for Classic Mopars" book covers the options.

If you have small bolt pattern on your 73, it must be a slant six car. In that case, you could swap the 67-72 Kelsey-Hayes disc brakes and retain the small bolt pattern to match the rear. But it sounds like you want to convert all around.
 
There was a kit to use Viper Calipers with your spindles. Assuming they are the large upper ball joint control arms. AR Engineering?
 
moffetkustoms said:
Thank you for the info. I at least have an angle to take now. I've been out of the mopar scene for quite a few years now. I do have a 79 Volare front end under a 50 that I have been tinkering with for a few years. I don't suppose that these parts will fit either?
Click to expand...

The '79 Volare parts will fit. The FMJ spindles can be swapped over, and everything from there out will work. That would also give you the 5x4.5" pattern.
 
thank you everyone for the help. I will look for the Book you mentioned. Sounds like it will be a lot of help.
 
If all your doing is the disk brake swap to the 73+ stuff you definitely don't need the book, this article covers the FMJ swap.

Swapping Disc-Brake Spindles - Mopar Muscle Magazine

Condran's book is useful, but it goes back to when you could easily find all of this stuff in a wrecking yard. That time has pretty much passed, and everything you need is reproduced new now.
 
First: Thanks to all for the input on the original post.
Second: Since original post, Have purchased and restored a complete front UCA/ spindle set up from a later model that I purchased. Has all new bearings, ball joints, etc. Ready to install when I get time from customers projects. Also bought a narrowed 8.8 disk brake rearend for the car and changed to a 3.08 from the 3.73 to be better behind the /6. So Limited slip, disc brake, etc. Also purchased an aluminum master cylinder kit. Hope to get time this summer to get the 4 wheel disc brake setup installed and run all new brake lines to get much better stopping power.
 
That was the old AR011 kit! It bolted on to the big bearing drum knuckles and held an early Viper caliper. Then you slide on a 11.75 cop car rotor and you're good to go. You'll need a big bolt pattern 15 inch rim to clear the bigger brakes of course.
Doctor Diff has everything you need for a brake conversion. You can keep the drum knuckles if you want, or he can sell you disc brake knuckles that will bolt in. There are lots of options and lots of ways to go. Good luck with the project.

AR011a (Large).jpg


AR011b (Large).jpg
 
andy, two questions: is that a swaybar off the strutrod?!? and how do you like those eddy shocks?
 
^^^^ My question also. Is that a sway bar mounted to the strut rod? Never noticed that before on any suspension. I guess as long as the part moves with the travel of the spindle, you could mount a strut to it..........
 
Sway bars were mounted to the struts on early B body cars so I copied that design when I built my own parts. This design didn't work so well for the street because it was too noisy so I eventually changed it to include a rubber mount.

The strut rods are not factory. I machined a set from chrome moly and had them heat treated so they would be strong enough to handle the load from the anti-sway bar. The anti-sway bar was also custom built from chrome moly tubing and then heat treated. I made those parts back in the 90's so they are all 30 years old. They have held up fine over the years.

As for the Edelbrock shocks I never used them. I took them off and sold them before I used them and put a set of Koni shocks on there. The Koni shocks are fantastic. The picture with the Viper brakes is really old. I took the early Viper brakes off the car about 20 years ago and switched to Porsche twin turbo calipers. I've had the Porsche calipers on the car since then.

DSC_2416 (Large).JPG
 
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