Senior Tech Team
Join Date: Dec 2006
Location: portland oregon
Re: '68 El Disc Brake Conversion Question
Yes, using oem donor brakes is similar to buying a Muncie at a swap meet....well not that risky.
You can easily mic the rotors to see if they're usable. If the backing plates are straight, you can have them replated or just spray bomb them, your preference. The booster probably needs rebuilt, but non-pitted cores are worth good money. The master is worth money but it'll likely be just a core. Like you said, the spindles are most likely good and the caliper brackets are also, but will likely need plating, or.... Now the calipers are easily rebuildable for cheap, unless they've seen setting moisture for long periods. Cheap, meaning less than $10 for the pair. If you're not caring about originality, a '71-'72 prop valve is the chit, and then buy all new lines for that year from your choice of vendors.
That's the advise if you're starting fresh. I say this because the kits run at least $800 and you're stuck with china metal, that is a whole lot riskier than rebuilding oem.
Done it myself but I was in a hurry, my bad. I've got less into my oem '69 setup and that includes rebuilding the master, calilpers, hold-off valve and booster and also the cost of replating the backers, brackets and booster....just took more time.
As for your master, that drum brake master isn't up to the task to pressurize the calipers. Not sure which one to use, but I'll bet it should have a 1" bore. You could call Wilwood and see what they offer for your app.