[69-er]

I'm rebuilding or buying all new brake components for my 69. Is the metering valve, (round valve below M/C that is in-line with the front brake lines), the differential switch, (distribution block/brake warning switch below the M/C) and the frame mounted proportioning valve rebuildable? Are they available new? All I can find is the combination valve, which combines all three valves, plus the residual valve, from MP Brakes. I'm thinking as a last resort, I can gut the metering and proportioning valves, remove the residual valve from the rear M/C port, and use the combination valve. I can’t figure out how to disassemble the differential/distribution block. The proportioning valve and metering valve looks like they are easily taken apart, but are kits available for all of these valves?

[ohcscott]

They all have rubber, so are rebuildable if you can get the parts. There are no kits I know of. The round valve under the master is available new repro.

The switch is not easy IMO. I had an extra one I took apart. If you take out the electric connection and there is no dripping fluid, I would leave it alone, except for flushing it out. Otherwise you need to remove the 2 end brass flares and the connector to get the spring and pistons out from one side (push from the front out the rear I think). The 2 end brass flares I think should be the same size as the ones in the master cyl.. or maybe just the one in the rear port... These come with m/c rebuild kits at least. I have not reassembled it. There were 2 small orings that I saw.

I would also leave the residual valve in the master if it is less than 10yrs old, even if adding the combo valve.
2 in line res. valves should not give double pressure. One should hold the other open. Some GM disc/drum systems might not even have had it at all... even for the rear brakes. I just took apart a '69 OE m/c, sitting since 1972, which had none. Maybe the large rear line held enough fluid weight to make up for it[?] (about 2psi), but having one or 2 10psi valves shouldn't hurt. The drum springs are reported to hold back about 90#s. 10psi on a 7/8 rear cyl I think works out to only about 12lbs of total piston pressure per side.


A combination valve is a better unit IMO, but if you are going for originality, it's not really an option.

[Gary L]

I had my metering valve rebuilt by Karp's Brake in So. Cal. (909)985-0800. $65.00