Performance online disc brake conversion kit

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ultimatejay

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Did a search and couldn't find much information on this kit. I have a 70 duster and I'm looking for a good disc brake conversion kit for the front. I really like the looks of the Performance online kit with the tubular upper control arms as they give 4 degrees of positive caster to boot. Has anyone used their kits and can you tell me how you like them? Also, any other recommendations of conversion kits that work really well? I think cpp makes a similar kit.
 
It’s just a 73+ disk brake conversion with cheap, no brand UCA’s and parts.

Go to DoctorDiff, spend a little more money for better quality parts and actual customer support and buy a decent set of tubular UCA’s if that’s what you want. QA1 makes nice UCA’s.
 
I have them, wish I had gone with something else, but they’re better than the drums I used to have.
I’ll eventually be going with the DoctorDiff Viper kit.
 
Did a search and couldn't find much information on this kit. I have a 70 duster and I'm looking for a good disc brake conversion kit for the front. I really like the looks of the Performance online kit with the tubular upper control arms as they give 4 degrees of positive caster to boot. Has anyone used their kits and can you tell me how you like them? Also, any other recommendations of conversion kits that work really well? I think cpp makes a similar kit.

A lot of these kits are junk. In my opinion, stay with the more well known suppliers that are road proven and have availibility of spare parts and support. Wilwood, SSBC, Dr.Diff, etc.. are reputable suppliers. A little more expensive perhaps, but, you get what you paid for.
 
It’s just a 73+ disk brake conversion with cheap, no brand UCA’s and parts.

Go to DoctorDiff, spend a little more money for better quality parts and actual customer support and buy a decent set of tubular UCA’s if that’s what you want. QA1 makes nice UCA’s.

Dr Diff, one of the nicest guys this hobby has.Very helpful.

You will not get better advice than this.

I have Dr Diffs 13/12.6 Disc kit and its great. Cass is a great guy and has came through every time I had questions. My dad too, he bough all the stuff to rebuild his 8-3/4 from Dr. Diff.
 
Thanks guys, I will look into Dr Diff. It appears that Performance online and cpp are out of stock until March!
 
Also opted for the Wilwood kit on my 72 Duster. Installation was easy peasy. Huge improvement over the old front drum set up. Had to replace master cylinder for the proper front disc- rear drum configuration.
 
Also opted for the Wilwood kit on my 72 Duster. Installation was easy peasy. Huge improvement over the old front drum set up. Had to replace master cylinder for the proper front disc- rear drum configuration.
My 70 Duster is bone stock with front and rear drum brakes. What are all the parts i need to use the willwood brake disc kit? Looks like I'm going to need the upper control arm and lower ball joint kit. I was thinking of just getting the Dr. diff rebuild kit which comes with the upper control arms and lower ball joints. So if i want to keep it manual front discs do I still need to buy a different master cylinder and proportioning valve. And if yes, then that means i have to re do all my brake hard lines as well correct?
 
My 70 Duster is bone stock with front and rear drum brakes. What are all the parts i need to use the willwood brake disc kit? Looks like I'm going to need the upper control arm and lower ball joint kit. I was thinking of just getting the Dr. diff rebuild kit which comes with the upper control arms and lower ball joints. So if i want to keep it manual front discs do I still need to buy a different master cylinder and proportioning valve. And if yes, then that means i have to re do all my brake hard lines as well correct?

Wilwood has kits that re-use the original drum spindles, so, you could leave your upper control arms and ball joints alone. That said, I wouldn't re-use a set of 9" drum spindles, the lower ball joint design was less than great and makes that part pretty weak. I wouldn't spend money on anything that re-used an original 9" drum spindle, but that's just my opinion.

The 10" drum spindles are better, so, if you have those you could use a wilwood kit and leave that other stuff alone.

Now, keep in mind a few things. The Wilwood hub is VERY large in diameter, as in, over 3". Factory wheels will not work with the current Wilwood hub. So go to Wilwood and look at their specs for the kit you plan to buy. You may need to dramatically change your plan for wheels, because even many aftermarket wheels do not have a hub register large enough.

The Wilwood stuff is all only available from Wilwood (or retailers that sell wilwood stuff). Unlike a conversion that uses 73+ mopar parts, you will not be able to just walk into any local parts store and buy replacements. Now, not that many parts stores carry 73+ stuff in stock anymore anyway so it's less of difference than before since most folks order all their replacement parts anyway. But it is still a consideration.

The 11" Wilwood set up actually has less clamp force at the rotor than a plain old set of single piston, 73+ mopar calipers.

As for the master cylinder, you should install a disk brake master cylinder. The reservoir for the front disks is larger than on a drum/drum master cylinder. I'm not saying it absolutely won't work, but the disk master cylinder is different for a reason. Same for the proportioning valve. Your drum/drum car has a distribution block, not a proportioning valve. There are different ways to handle that, you can leave your distribution block and install an adjustable prop valve, which doesn't necessarily require all new lines. Just a section cut out of the rear line with 2 flares added. But doing that assumes your brake lines are in good enough condition that they can be removed without damage and re-flared, which isn't always the case with original lines. If you switch to a factory style proportioning valve you'll need new lines from the proportioning valve to the master cylinder at the least. You might be able to keep the rear line and use a thread adaptor on the end of the rear line, but again that requires your rear line to be in good shape. The adaptor is needed because the factory prop valve uses different size threaded ends for most of the ports so you don't plug stuff into the wrong places. The original distribution block used all the same size threaded ends. The master cylinder is similar, the later ones used different sized fittings on the front and rear chambers to keep them from being swapped. Again, depending on the condition of your lines and the master cylinder you use you can sometimes use threaded adaptors and the original lines. But that assumes you can re-bend the original lines some without damage, and in most cases with factory lines that's not a given.

All of that is just a really long explanation saying that unless you have decently new lines already installed, it's probably better, easier and faster to replace the original lines when you change out the master cylinder and prop valve.
 
Wilwood has kits that re-use the original drum spindles, so, you could leave your upper control arms and ball joints alone. That said, I wouldn't re-use a set of 9" drum spindles, the lower ball joint design was less than great and makes that part pretty weak. I wouldn't spend money on anything that re-used an original 9" drum spindle, but that's just my opinion.

The 10" drum spindles are better, so, if you have those you could use a wilwood kit and leave that other stuff alone.

Now, keep in mind a few things. The Wilwood hub is VERY large in diameter, as in, over 3". Factory wheels will not work with the current Wilwood hub. So go to Wilwood and look at their specs for the kit you plan to buy. You may need to dramatically change your plan for wheels, because even many aftermarket wheels do not have a hub register large enough.

The Wilwood stuff is all only available from Wilwood (or retailers that sell wilwood stuff). Unlike a conversion that uses 73+ mopar parts, you will not be able to just walk into any local parts store and buy replacements. Now, not that many parts stores carry 73+ stuff in stock anymore anyway so it's less of difference than before since most folks order all their replacement parts anyway. But it is still a consideration.

The 11" Wilwood set up actually has less clamp force at the rotor than a plain old set of single piston, 73+ mopar calipers.

As for the master cylinder, you should install a disk brake master cylinder. The reservoir for the front disks is larger than on a drum/drum master cylinder. I'm not saying it absolutely won't work, but the disk master cylinder is different for a reason. Same for the proportioning valve. Your drum/drum car has a distribution block, not a proportioning valve. There are different ways to handle that, you can leave your distribution block and install an adjustable prop valve, which doesn't necessarily require all new lines. Just a section cut out of the rear line with 2 flares added. But doing that assumes your brake lines are in good enough condition that they can be removed without damage and re-flared, which isn't always the case with original lines. If you switch to a factory style proportioning valve you'll need new lines from the proportioning valve to the master cylinder at the least. You might be able to keep the rear line and use a thread adaptor on the end of the rear line, but again that requires your rear line to be in good shape. The adaptor is needed because the factory prop valve uses different size threaded ends for most of the ports so you don't plug stuff into the wrong places. The original distribution block used all the same size threaded ends. The master cylinder is similar, the later ones used different sized fittings on the front and rear chambers to keep them from being swapped. Again, depending on the condition of your lines and the master cylinder you use you can sometimes use threaded adaptors and the original lines. But that assumes you can re-bend the original lines some without damage, and in most cases with factory lines that's not a given.

All of that is just a really long explanation saying that unless you have decently new lines already installed, it's probably better, easier and faster to replace the original lines when you change out the master cylinder and prop valve.

Sounds like a lot of things that can go wrong. lol
 
My 70 Duster is bone stock with front and rear drum brakes. What are all the parts i need to use the willwood brake disc kit? Looks like I'm going to need the upper control arm and lower ball joint kit. I was thinking of just getting the Dr. diff rebuild kit which comes with the upper control arms and lower ball joints. So if i want to keep it manual front discs do I still need to buy a different master cylinder and proportioning valve. And if yes, then that means i have to re do all my brake hard lines as well correct?

The kit was very complete. The only thing I had to change was the master cylinder and the 2 flexible hoses to connect hard line to the new calipers. I also chose to replace all the original brake lines and components front to rear because the old stuff was pretty trashed and brittle. And I added and adjustable proportioning valve as well to allow me to dial in the f-r braking bias to my liking. I have 15" Centerlines, so the issue others have with stock rims wasn't an issue. No complaints what so ever.
 
A lot of these kits are junk. In my opinion, stay with the more well known suppliers that are road proven and have availibility of spare parts and support. Wilwood, SSBC, Dr.Diff, etc.. are reputable suppliers. A little more expensive perhaps, but, you get what you paid for.

SSBC was considered reliable until they went belly up, stiffing customers, vendors, and employees out of millions in parts, money, and benefits owed.
They are now reopened in a new location couple of miles away from their previous buildings, having never made restitution.
The only way I would buy from them is if I needed their proprietary replacement parts for a kit I already had installed.

For any A-Body brake upgrade, there's no reason to make your first stop anywhere but at Dr. Diff's.
 
Sounds like a lot of things that can go wrong. lol

If you're trying to re-use the original lines, yeah. If you use a factory style prop valve and just order new lines it's a lot easier. More expensive, of course. But when you try to re-use stuff and start mixing and matching factory and aftermarket parts a lot of things can go sideways. And if you have original lines I'd just replace them. They make look ok, but as soon as you start taking stuff apart you'll find frozen fitting and brittle lines, even if they look decent.

DoctorDiff sells new lines too. For a disk brake conversion he can be a one stop shop, from factory 73+ stuff all the way to 13" rotors with Viper calipers. And you won't have to safety wire your hubs together, or be stuck with one of like 3 or 4 rim styles that have a hub bore larger than 3" like with the Wilwoods need. They work, but honestly they're not the best stuff out there anymore. They've been trading on their name for a long time, I think their advertising budget and sponsoring all the TV show stuff is the only reason why they're still popular. It isn't because they have a superior product.
 
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I donr have there front kit biut i do have there rear disk kit. Nice kit for the money.
 
The kit was very complete. The only thing I had to change was the master cylinder and the 2 flexible hoses to connect hard line to the new calipers. I also chose to replace all the original brake lines and components front to rear because the old stuff was pretty trashed and brittle. And I added and adjustable proportioning valve as well to allow me to dial in the f-r braking bias to my liking. I have 15" Centerlines, so the issue others have with stock rims wasn't an issue. No complaints what so ever.
Did you get everything from Dr. Diffs?
 
How do you like them and what did you have to replace to make them work?

What 72bluNblu said sums it up. I got lucky and bought complete set-up years ago from a member for $350 with UCA included. He was going with something else. Just changed the Flex brake lines and MC.
 
If you're trying to re-use the original lines, yeah. If you use a factory style prop valve and just order new lines it's a lot easier. More expensive, of course. But when you try to re-use stuff and start mixing and matching factory and aftermarket parts a lot of things can go sideways. And if you have original lines I'd just replace them. They make look ok, but as soon as you start taking stuff apart you'll find frozen fitting and brittle lines, even if they look decent.

DoctorDiff sells new lines too. For a disk brake conversion he can be a one stop shop, from factory 73+ stuff all the way to 13" rotors with Viper calipers. And you won't have to safety wire your hubs together, or be stuck with one of like 3 or 4 rim styles that have a hub bore larger than 3" like with the Wilwoods need. They work, but honestly they're not the best stuff out there anymore. They've been trading on their name for a long time, I think their advertising budget and sponsoring all the TV show stuff is the only reason why they're still popular. It isn't because they have a superior product.


I have to agree with the comments on brake lines. When I redid my car for the second time, the brakelines looked perfect on the outside, but when I was removing them to redo the car, the lines pretty much crumbled in my hands! I guess corrosion was occuring from the inside out as the car had sat for quite a long time. Wake up call for me for sure. Also, Wilwood has a lot of competetors now and there are certianly more options available. The one thing that kept me with them was their service which I found stellar. I am hearing a lot of good things about Dr Diff in my area so I wouldnt hesitate to use him either. Actually, Im using his services to redo my 489 differential.
 
If you're trying to re-use the original lines, yeah. If you use a factory style prop valve and just order new lines it's a lot easier. More expensive, of course. But when you try to re-use stuff and start mixing and matching factory and aftermarket parts a lot of things can go sideways. And if you have original lines I'd just replace them. They make look ok, but as soon as you start taking stuff apart you'll find frozen fitting and brittle lines, even if they look decent.

DoctorDiff sells new lines too. For a disk brake conversion he can be a one stop shop, from factory 73+ stuff all the way to 13" rotors with Viper calipers. And you won't have to safety wire your hubs together, or be stuck with one of like 3 or 4 rim styles that have a hub bore larger than 3" like with the Wilwoods need. They work, but honestly they're not the best stuff out there anymore. They've been trading on their name for a long time, I think their advertising budget and sponsoring all the TV show stuff is the only reason why they're still popular. It isn't because they have a superior product.
So i had time to look at my brakes and i took the front drums off and measured inside diameter and its 10". Correct me if I'm wrong but i thought 70 Dusters with 225 slant 6 are supposed to have 9"?
 
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