914/6 alternate rear calipers Options

[Racer]

The rear factory calipers on my 914/6 are giving me some annoyance. In this case, the passenger side rear caliper has developed a slight weap. Its been an issue for the past two years. I've addressed the hard line, soft line and had the caliper re-built, but still, there is a slight leak.

Since 914/6 rear calipers are somewhat difficult to find in working order, I am wondering about an alternative use rear caliper while I sort the issue.

Knowing I would forgo the handbrake/e-brake, would then period (early 911 - 69 911T/912) "m" rear calipers work? I imagine the 912 or early 911T had solid rear rotors vs later vented (wider) rotors and calipers?) What are the piston size differences? How different is the mounting? Would I need a portioning valve installed or modified? Do they work with the stock rear rotor?

The car is otherwise very original, so I am not looking to upgrade everything brakes, just the rear calipers

I know the other answer is "reach out to PMB, they can help you"... and I will.. Just thought I'd ask here too.

TIA

[messick]

Talking to Eric at PMB about the, at least on paper, insane brake setup my car came with (48mm BMW calipers on the front, 48mm Jag/MG front calipers on the rear), he recommended replacing my rears with 911 M rear calipers and 914/6 rotors since getting 914/6 real calipers would be significantly more money.

My car already doesn't have an emergency brake, so that part isn't getting any worse.

You could always call up PMB and confirm the rotors would fit with the Ms, but seems like best thing would be getting them to fix your current calipers.