'60 Apache Front Disc Brake Conversion MC to Prop Valve Lines

[Too Slow '90]

I installed a 1990 1500 booster for the conversion and purchased the matching master cylinder. I couldn't find a proportioning valve local so I ordered one supposedly specific to the master. The front line out of the master is 1/4" with a 9/16-18 thread. The front line in the proportioning valve is 3/16" with a smaller thread.

I was considering returning everything and ordering a combo kit from Summit etc... but the tech rep said he couldn't guarantee that their combo would work with the booster. He suggested I install an adapter in the larger port to fit a 3/16" line.

Has anyone run into this issue? Has anyone installed a specific master, prop valve and line kit on this booster? Is installing the suggested adapter a viable solution?

I thought I would finish this today but it never works out that way. I appreciate whatever help you guys can lend.

[caseyjones]

I can't seem to find an OEM version of the proportioning valve anywhere, so you might be stuck with using the adapter if you want to keep the 1990 booster/master cylinder setup. I doubt the adapter would cause any problems.

[Too Slow '90]

Originally Posted by caseyjones

I can't seem to find an OEM version of the proportioning valve anywhere, so you might be stuck with using the adapter if you want to keep the 1990 booster/master cylinder setup. I doubt the adapter would cause any problems.

Thanks for responding. I'm stuck with the booster. I already cut and threaded the shaft. I have not been able to find the adapter locally. I also wondered if there was a master and proportioning valve from another GM vehicle that will fit the booster I have. So far I haven't had much luck.

[caseyjones]

If you haven’t already I’d take the master cylinder into a NAPA store and compare the mounting flange and piston position to a 1973-ish C10 master cylinder. If they are close you won’t have a problem finding a valve and lines to match the MC.

[Too Slow '90]

Originally Posted by caseyjones

If you haven’t already I’d take the master cylinder into a NAPA store and compare the mounting flange and piston position to a 1973-ish C10 master cylinder. If they are close you won’t have a problem finding a valve and lines to match the MC.

I took it in yesterday. Everyone says to use the adapter. One is inbound. Hopefully it works.

[SkinnyG]

I bought the right nuts to run 3/16" brake line everywhere.

Wilwood adjustable proportioning valve to the back, Line Lock to the front.

It works fine.