I am going to be working on the brakes on a 1972 1.7 that has not been driven in 25 years or so. I have rebuilt calipers front and back, and the rotors look good. May just need to be surfaced. My biggest question is the master cylinder. Do you think it will hold pressure after 25 years of sitting around. Can they be rebuilt? Or should I just replace it? If I do replace it, do you have recommendation on a model / manufacturer.

Any luck would be appreciated.
Steve

There is no MC rebuild kit available AFAIK.

Replace. Avoid URO parts--they're cheap, as well as inexpensive.

--DD

Get a new MC from Eric and PMB...

Eric and PMB is the only way to go. While your at it have them rebuild the brake balance cylinder as well. Cheap insurance for your braking system

You could rebuild it only if the bore of the cylinder is perfect ,you will be very lucky if this is the case since the car has been sitting a long time,@ the end of the day its really not worth the work or the risk.
Rebuilding master and slave cylinders is a thing of the past now,the brake specialist I deal with locally wouldn't do them anymore (safety again ),however they do offer a process which involves boring the them out and fitting a stainless steel sleeve,they offer a lifetime warranty on this work.
As mentioned Eric @ PMB is the place to go.

Just went through this with my '73.

A) If the car's been sitting for the last 25 years, especially if exposed to moisture over the years, plan on replacing the whole brake hydraulic system. Just not worth the risk in the long run.

B) Unless you want to rebuild the calipers yourself, go to PMB for rebuilds. However, rebuilding the calipers yourself isn't hard as long as you follow the directions.

C) There are currently no rebuild kits for 17mm master cylinders. Have been bugging Mark at 914Rubber about this, but no ETA at this point.

D) If you're going to stick with the 17mm MC, might as well get it from PMB. I bought an NOS one that turned out to have gone bad while sitting on the shelf, and ended up having to buy a new one from PMB anyway.

E) Some people "upgrade" from the 17mm MC to a 19 MC. It is slightly cheaper than the 17mm unit, but it will make your pedal pressure ~25% higher. However, there are rebuild kits available for the 19mm MC.

F) Avoid URO parts, especially their 19mm MC. It's a lot cheaper than the ATE unit, but there have been plenty of reports of them not even lasting 6 months.

G) AutoAtlanta sells replacement hard line kits. BUT, you need to bend them yourself and most of the lengths are off. Most are slightly longer than original, but the long line through the center console is 1.5" too short.

H) PMB sells pre-bent replacement hard lines. Don't know the prices, but I'll go with them the next time I need to replace lines.

I) You have to drop the engine to replace the long center line without bending it. There is insufficient clearance up front to go in from that direction and not bend the line.

When I buy a set of replacement hard lines for my car, it will be from PMB. Eric is a brake fanatic and I know the lines are perfect. There were scanned from an nos set. AA probably went to the lowest Chinese bidder.

Thank you everyone for the great advice. I called PMB and will be putting together a list of stuff. They also recommended that I get the brake pressure regulator rebuilt due to the time it sat undriven. More work than I thought, but I can put a price on safety.

I have to dig mine up to send to Eric. I've been meaning to get that done.

From first-hand experience, I can tell you that it is far, far easier to replace the brake pressure regulator after dropping the engine. It can be done with the engine in place, but it's a royal PITA!