First of all I apologize to the person who responded with the e-mail following. After I posted the first one, I lost the author of this response and then for the life of me I couldn't remember who wrote this !!! Gosh I love my senior moments. Anyway, I haven't been able to find any PBR around here because well frankly there may be as many as two British cars in my city. My hometown is full of Tuners. And to top all of this off I found out I'm in pretty deep with this conversion and rapidly running out of answers. I found a rebuilt power booster for disc brakes and got it here now but then discovered the brackets are different on the drum power booster versus the disc power booster. I am looking for the brackets now. Russ H from Oregon please look for a e-mail coming to you regarding this problem. I do have the proportioning valve from the disc brake donor car but if it's in the same condition as the one originally in my 70 Javelin I'm gonna be a hurtin unit. It also requires a brake line change from the original configuration. (not really a problem just takes more time) The easy route might be to locate a proportioning unit or equivalent to what was factory on 70 Javelin/AMX. Apparently this part is found under the chassis near the rear axle, and is unique to power disc brake equipped AMCs. Maybe the summit unit mentioned in the e-mail message below is the answer. I guess I need to put my thinkin cap on and figure this one out. I'm open for advice/suggestions......... Thanks, Armand A: Since it's not a real prop valve, I would switch it for one from a disc brake system, or get an aftermarket adjustable one from Summit ($35 average on Evilbay) The common Jeep fix is to take the o ringins off and lube the piston lightly with PBR rubber grease (available mostly in Brit car enthusiasts shops) as it is the ONLY assembly lube I know of that is compatible with brake components. If there is another, I'd like to hear about it. I'm about to dive into modifying the brake system in my Comanche because the load level sensor makes it brake erratically since my 6" lift and 33" tires.