Performance online disc brake conversion kit
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.
