1972 Front Disc Brake Conversion

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spadeturbo

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I have a 1972 Duster, 318 motor. It runs and drives, is pretty much all stock and overall in really good shape. This winter I would like to put disc brakes on the front of it. I've been looking at a lot of kits and had some general questions I was hoping someone could help me with.
1) Do you have to replace the upper control arms when doing a disc conversion? There are various kits out there and some seem to come with them, others don't.
2) Do you have to replace the lower ball joints?
3) Do you have to replace the booster and master cylinder?
3) Any recommendations on what kit to buy? I'm not looking for anything fancy. More about effectiveness and reliability. Are there any kits that are "easier" to install than others or are they all the same.
Any advice is much appreciated.
Thank you,
 
Gonna have to know more information about your car. What size drum brakes are on it now? Do you want to keep the 5x4” bolt pattern it has now? Do you want to keep your current wheels, and what are they?

As for the rest of it
1- No, not necessarily
2- Not necessarily
3- No, not at all
4- really depends on the bolt pattern and what wheels you have/want
 
I will have to measure the drums when I get a chance. Whatever is on it now is stock. It has stock front wheels and I would like to keep those.
 
Personally I would get the one that copies the factory 73 and up disks.. that way you can get parts most anywhere. As mentioned the bigger question is are you staying with the small bolt pattern and will your rims take disks. That will dictate what you can do.
 
step one: do you want to keep you current wheels and tires?

there are two flavors of brakes: small bolt pattern which is 5X4 inch lug pattern (aka SBP) and the large bolt pattern 5X4.5 inch lug pattern (BBP).

there is factory flavors of each, and aftermarket set ups of both. there are adapters and work arounds on the controls ams, but if you change out the spindle (aka steering knuckle) you'll be swapping the lower ball joint.

you should not need to replace your booster, but you will need to update the master.

no one kit is easier to fit than another, but factory backed kits that use stock components enjoy a lot of parts availability and a wide base of knowledge due to them being around so long. they're also more robust than a lot of aftermarket stuff.

so, the question is: how do you use your car? what level of braking do you need? how much do you want to spend and do you want keep your wheels?
 
spadeturbo said:
I will have to measure the drums when I get a chance. Whatever is on it now is stock. It has stock front wheels and I would like to keep those.
Click to expand...
To clarify I wouldn't necessarily be opposed to going to different wheels up front as long as I can still use the stock hub caps.
 
spadeturbo said:
To clarify I wouldn't necessarily be opposed to going to different wheels up front as long as I can still use the stock hub caps.
Click to expand...

Need to know if they are 13" or 14" then. If they are 13" you are stuck. Can't do disks with 13" wheels. You can do 14" if you can find the right wheel that will clear the Kelsey Hayes reproductions that SSBC makes. You need 10" drum spindles for that conversion (I have a set that I saved from the scrap heap to help someone out who wants to use the kit that SSBC makes, I have them on my Dart with a way to powerful aftermarket booster in a way they work too good ;) ).
 
junkyardhero said:
step one: do you want to keep you current wheels and tires?

there are two flavors of brakes: small bolt pattern which is 5X4 inch lug pattern (aka SBP) and the large bolt pattern 5X4.5 inch lug pattern (BBP).

there is factory flavors of each, and aftermarket set ups of both. there are adapters and work arounds on the controls ams, but if you change out the spindle (aka steering knuckle) you'll be swapping the lower ball joint.

you should not need to replace your booster, but you will need to update the master.

no one kit is easier to fit than another, but factory backed kits that use stock components enjoy a lot of parts availability and a wide base of knowledge due to them being around so long. they're also more robust than a lot of aftermarket stuff.

so, the question is: how do you use your car? what level of braking do you need? how much do you want to spend and do you want keep your wheels?
Click to expand...
I'm not necessarily opposed to changing the front wheels and tires. I'd like to keep the same ones if possible but that is purely out of convenience. I would really like to keep the stock hub caps if possible though.
Use of the car will basically be 20 minute drives, twice a day, 3 - 4 days a week. With the occasional 2-3 hour drive during summer. Mostly I want it to be a comfortable and enjoyable car to drive. Oh and safe ;)
 
Jim Kueneman said:
Need to know if they are 13" or 14" then. If they are 13" you are stuck. Can't do disks with 13" wheels. You can do 14" if you can find the right wheel that will clear the Kelsey Hayes reproductions that SSBC makes. You need 10" drum spindles for that conversion (I have a set that I saved from the scrap heap to help someone out who wants to use the kit that SSBC makes, I have them on my Dart with a way to powerful aftermarket booster in a way they work too good ;) ).
Click to expand...
Really appreciate all the help. Already learning stuff about the car. When I get a chance I will measure the current drums and check the current wheel size.
 
Jim Kueneman said:
Need to know if they are 13" or 14" then. If they are 13" you are stuck. Can't do disks with 13" wheels. You can do 14" if you can find the right wheel that will clear the Kelsey Hayes reproductions that SSBC makes. You need 10" drum spindles for that conversion (I have a set that I saved from the scrap heap to help someone out who wants to use the kit that SSBC makes, I have them on my Dart with a way to powerful aftermarket booster in a way they work too good ;) ).
Click to expand...

Given the current status of customer service at SSBC I wouldn't recommend them to my worst enemy...

SSBC Returned Items (No Refund and Now Being Ghosted)
 
Jim Kueneman said:
Bummer.... They got me mine fast 4 years ago and I had no issues.
Click to expand...

I think they went out of business and started again since then. And based on their current business practices they may be looking to go out of business again.

Regardless, several of the wearing parts in those kits are custom machined, which means if they do go out of business again you'll have to source and machine your own parts to keep the kit.
 
72bluNblu said:
I think they went out of business and started again since then. And based on their current business practices they may be looking to go out of business again.

Regardless, several of the wearing parts in those kits are custom machined, which means if they do go out of business again you'll have to source and machine your own parts to keep the kit.
Click to expand...

They will last long after I am gone as much as I drive it.
 
I went with Kelsey Hayes disc brakes that I grabbed from a junkyard. I replaced everything from rotors to calipers and in the end it was pretty pricey. If I were to do it again, I would probably go with the Scarebird Conversion.
 
72bluNblu said:
I think they went out of business and started again since then. And based on their current business practices they may be looking to go out of business again.

Regardless, several of the wearing parts in those kits are custom machined, which means if they do go out of business again you'll have to source and machine your own parts to keep the kit.
Click to expand...

SSBC 1.0 after going belly up about five years ago. The building was still empty as of August when I took this picture.
They were once quite a business, but declined when the founder and owner died in the early 2000s.
The current company is considerably scaled down from the original, which was founded on improving OEM brakes. Specifically, sleeving corrosion prone Corvette calipers with stainless. Since K-H calipers can have the same issue, I asked today's SSBC if they would sleeve them. They said they will only service products they manufactured.
At least they're continuing the tradition of stealing from their customers.

Screenshot_20240803-154447.png
 
If you go with large bolt pattern wheels up front you will also want to change to large bolt pattern on the rear. If not, you gotta ask yourself “is my spare in the trunk gonna be a large bolt pattern or small bolt pattern rim?”
 
You could check with Aerospace Components. I bought a 4 wheel set for my AMX and even though I haven't installed them yet, they were very easy to deal with and the parts look fantastic. I believe they have a sale in December.
 
just to note, and it probably won't be useful


with a set of disk brake spindles that match you upper balljoint
you can have any combination of
big or small bolt pattern hubs or big or small top balljoint
with a caliper pads and rotor that fits a 14 inch wheel

its just hard work and you would need to import the parts

as far as i can tell the US had a s swap over to 4.5 inch PCD with big upper balljoint
the australians and south africans did not, the change to 4.5 PCD was in isolation for 1971 and they stuck with the small upper joint

means you can add to the mix of US parts

small balljoint non vented rotor 4 inch PCD 14inch wheels 2 pot caliper Australian Valiant VC and VE models
small balljoint none vented rotor KH pin sliders 4 inch PCD 1 pot slider VF and early VG models
small balljoint vented rotor KH pin sliders 4.5 inch PCD 1 pot slider VG
Small balljoint vented rotor Girling Lockheed Girlock claw slider, the short bracket, 1 pot slider VH VJ VK models from 1971 until 1976

all working on the type of spindle that takes the small upper joint with the small inner hub bearing

and all working with 14 inch wheels

all spindles take a caliper with a 3.5 inch centres mounting so you can mix and match
so you can fit either US hub/rotor and caliper
or Australian Hub/Rotor and caliper and the small inner bearing hub came in 4 and 4.5 inch PCD

you can not fit a US caliper to an australian bracket, the brackets are matched to the calipers
but a set of the other countries complete calipers. not a problem

apologies apart from saying what's possible its a post of useless info... :)

Dave
 
spadeturbo said:
I have a 1972 Duster, 318 motor. It runs and drives, is pretty much all stock and overall in really good shape. This winter I would like to put disc brakes on the front of it. I've been looking at a lot of kits and had some general questions I was hoping someone could help me with.
1) Do you have to replace the upper control arms when doing a disc conversion? There are various kits out there and some seem to come with them, others don't.
2) Do you have to replace the lower ball joints?
3) Do you have to replace the booster and master cylinder?
3) Any recommendations on what kit to buy? I'm not looking for anything fancy. More about effectiveness and reliability. Are there any kits that are "easier" to install than others or are they all the same.
Any advice is much appreciated.
Thank you,
Click to expand...
I used a Pirate jack kit but manual.... and honestly i wish i had kept the stock drums... the discs don't stop as well and it was money wasted.. i wish i had my drums back at this point (trash it all of course) But with power i'm sure it will be fine. The pirate jack parts worked fine.
 
Jim Kueneman said:
They will last long after I am gone as much as I drive it.
Click to expand...

Well that’s a shame.

At the rate I drive mine I’ll probably need at least a couple of rotor replacements, which is why I prefer kits that use off the shelf wearable parts.

Icetech said:
I used a Pirate jack kit but manual.... and honestly i wish i had kept the stock drums... the discs don't stop as well and it was money wasted.. i wish i had my drums back at this point (trash it all of course) But with power i'm sure it will be fine. The pirate jack parts worked fine.
Click to expand...

Well, I don't know how to say this but there is absolutely something wrong with your disk brakes then.

The Pirate Jack kit is based on '73+ Mopar disks, and in the physical world we inhabit there is no test where OE 73+ disks lose to OE 10" drums.

Not sure if you have some kind of mismatch of components, or if the cheap Chinese parts that come with the PirateJack kit are not the same quality as the OE parts, but the 73+ disks outperform the 10" drums in every way, shape and form. If yours do not, there is a problem.
 
72bluNblu said:
Well that’s a shame.

At the rate I drive mine I’ll probably need at least a couple of rotor replacements, which is why I prefer kits that use off the shelf wearable parts.



Well, I don't know how to say this but there is absolutely something wrong with your disk brakes then.

The Pirate Jack kit is based on '73+ Mopar disks, and in the physical world we inhabit there is no test where OE 73+ disks lose to OE 10" drums.

Not sure if you have some kind of mismatch of components, or if the cheap Chinese parts that come with the PirateJack kit are not the same quality as the OE parts, but the 73+ disks outperform the 10" drums in every way, shape and form. If yours do not, there is a problem.
Click to expand...


Don't feel sorry for me.... I have too many cars to drive one all that much :p

Jim
 
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72bluNblu said:
Well, I don't know how to say this but there is absolutely something wrong with your disk brakes then.

The Pirate Jack kit is based on '73+ Mopar disks, and in the physical world we inhabit there is no test where OE 73+ disks lose to OE 10" drums.

Not sure if you have some kind of mismatch of components, or if the cheap Chinese parts that come with the PirateJack kit are not the same quality as the OE parts, but the 73+ disks outperform the 10" drums in every way, shape and form. If yours do not, there is a problem.
Click to expand...
No idea, all new stuff.. even put on EBC pads to help.. BUT they have almost no miles on them so far, they "Work" but i wouldn't trust them to panic stop.. going to get them broke in all the way first.. Thing is.. Drums take much less pressure to run (being manual that matters) and discs don't self energize which once again for manual matters.. but i will figure it out. Not sure if the OP is going power or manual is all.
 
Icetech said:
No idea, all new stuff.. even put on EBC pads to help.. BUT they have almost no miles on them so far, they "Work" but i wouldn't trust them to panic stop.. going to get them broke in all the way first.. Thing is.. Drums take much less pressure to run (being manual that matters) and discs don't self energize which once again for manual matters.. but i will figure it out. Not sure if the OP is going power or manual is all.
Click to expand...

It's possible you haven't bedded in the pads yet, which means you won't be getting the best braking yet. What EBC pads are you running? Because some of their pads are basically race pads and they need to be at temperature to work at the best. And regardless they do have a break in procedure to bed them in.

All of my Mopars have been converted to manual disks, either by upgrading to disks from drums or by removing the power booster from a car that already had power disks. The amount of pedal force you need doesn't tell you how good your brakes actually are. If you lack the leg power to fully apply the manual disks then I suggest you upgrade to power brakes. You may also look into a different sized master cylinder, depending on what you have, to better match the pedal force to the line pressure needed. Personally I don't think that the pedal effort needed to stop an A-body mopar with manual disks is all that high, and for me I find that the brake modulation is better with manual brakes than power, at least with the OE power booster.

Drums self energize, but that makes them very easy to lock up. And locking up your brakes is the slowest way to actually stop.
 
Icetech said:
I used a Pirate jack kit but manual.... and honestly i wish i had kept the stock drums... the discs don't stop as well and it was money wasted.. i wish i had my drums back at this point (trash it all of course) But with power i'm sure it will be fine. The pirate jack parts worked fine.
Click to expand...
as 72blu noted upthread you've got something amiss.

the difference between 73+ discs and stock drums is night and day.

the issue of pedal effort can be mitigated with a combination of MC piston size and to an extent caliper pistons size, if you can source the specific 74 dart big piston calipers. failing that, a power set up is always an option.

i'd try massaging what you have currently and see if there's better results.
 
I opted fo the often maligned Wildwood kit that retains the stock spindles etc. Stupid easy installation, stops great and I couldn't be happier.
 
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