Hey all,

Just recently I've been working on a '69 Mustang. This thing has seen better days and needs help.

So, the previous owner's son put disc brakes on it but kept the manual 4-wheel drum master cylinder, so some effort was required to brake.

I just installed the disc/disc power brake conversion from CJ Pony Parts and took it out for a drive. Still needs quite some effort to come to a stop, like the pads aren't gripping at all. Since the car's not mine and I've driven it a grand total of 500 feet, I can't tell if there is any improvement, except I know the booster is doing something.

Before I go down the rabbit hole, I was wondering if anyone here has any suggestions on where to look for the problem first. Next time I get around to it, I'm going to take a look at the pads, but I'm wondering if the proportioning valve is to blame, or even if the booster might be a problem. I haven't ordered much from CJ Pony parts, and I'm not familiar with the quality of their brake parts.

The car is a 4-wheel disc setup, the booster is getting 18in of vacuum, the pedal is solid (no air in the lines), and that's about it.

Any help is greatly appreciated.

I had someone tell me before to look at adding an adjustable proportioning valve to the rear line, but shouldn't the valve that comes in the kit be correct?