Reed valve and work hardening?

by Colin Rhodes
(Yorkshire. England)

I have a 2004 Range Rover fitted with a German made Wabco Air compressor that feeds the Air suspension.


This compressor through the holding tank will normally operate at 188PSI.

Over several months its performance has dropped off to the point where I got only say 40 PSI out of it which meant that the Air suspension was not working.

I changed the Piston ring and I got a marginal increase in pressure to 60/63 PSI, still not good.

My question is could the Reed/flapper valve work harden to the point where it is resistant to opening enough on the suction stroke. Or in other words is the opening too small to allow enough air in?

Or should I be looking at the mating surfaces of the Piston crown and the Reed/flapper valve? It is not really possible to replace the Valve. The increase in pressure would be indicative of a increased efficiency with the new ring ( IE less blow back) which points to the Reed/Flapper valve.

The motor driving the compressor seems to be running smooth enough without any strange noises.

This problem seems to be very common with this make/ type of of compressor. It is fitted to many of the Good makes of European more expensive cars Audio,BMW and Range Rovers. It is common practice to renew the Piston ring with on some occasions with success but on others like mine not so good and it is finally solved by a new replacement at a cost of some £450.00($550.00) here in the UK

Best Regards

I think I have answered the question in my writing this note but have you any ideas?

Comments for Reed valve and work hardening?

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Jul 31, 2016
Valves work hardening
by: Bill

While this is a website about air compressors for workshops and plants, the question has validity in that it addresses the issue of air valves.

Like a piece of wire that is bent back and forth many times - to the point where it finally breaks - I sure believe that flapper valves too experience this phenomenon. In other words, they work themselves to the point of fracture or failure, each result depending on the quality of the valve metal and the duty cycles that valve has experienced.

"..ould the Reed/flapper valve work harden to the point where it is resistant to opening enough on the suction stroke." I think yes.

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