How long from rebuild date should a air brake valve (in this case a 6 ET distribution valve) be considered in good usable condition as a spare? I ask because an engine I was working with this weekend was having air troubles that seemed related to this valve but application of the spare did not help. Both valves were overhauled in April 2003 and the spare was kept sealed.

Do these valves require storage in a particular orientation (mounting flange down)?

If there is a time limit that spares can be held, how should one arrange a replacement schedule to keep a "fresh" valve at hand?

Please note I am not an air brake man (or I'd know the answer). Thanks in advance.

Michael Seitz
Missoula MT

3 years isn't real long for a sealed valve to remain good. If both distributing valves failed to solve the issues, you probably have problems elsewhere in the system. 6ET is pretty bulletproof, without a lot of the plastic and rubber internals that plague more modern stuff.

dave

Echoing Dave's sentiments on shelf life, neoprene and lapped valves and rings should not degrade too much on the shelf. If we get a chance before the valve - usually a triple valve - has to be swapped out, we try to re-lubricate the piston and give it a quick test.