Mine stopped wiping altogether recently.On inspection the slide was staying fully out, keeping the vacuum diaphragm out (pushrod pushed). This keeps the contacts inside the plastic case in the paused position, and stops the wipers running - check the wiring diagram elsewhere. I obviously was too free with greasing the internals,and enough got pushed out to make the slide stick in place. A bit of cleaning fixed it.
When I first got the car thhe delay did not work - the spring was missing. When i got the valance off I found the spring underneath the wiper motor.
Mine works well, the delay is variable between 1 and 11 seconds, I just wanted to put some silicon grease on the white control valve to perhaps increase the delay interval, in case some vacuum is being lost around the circumference, or the clearance between it and the valve body. I can’t seem to be able to remove it…..
With the spare delay control, it doesnt come apart. Looking from the left of the column, turning the white knob clockwise it should stop, and no air leaks there. It turns a bit more than 3/4 to fully open. Since it seems to work,dont intend to push my luck forcing it open. Next time I have the steering wheel off I will replace the dud unit.
Mine wasn't working at all and it turned out to be a defective control valve. Replaced it - works again. But I also revitalised the whole system, including fitting a replacement piece of (quality car wash) sponge in the delay governor. Now I have 0-30 seconds of delay at my fingertips.
I assume you speak of the air valve on the column housing? When I swap in my spare I will open the bad one to try to diagnose how they work. The air valve on the white unit on the motor is a whole different thing -I have a spare of those, and know how they work - do you want pics?
Thanks jp928, I have two delay units that fit to the motor, both working fine. Yes I’m talking about the control valve on the steering column, I‘ve had a search but can’t find a replacement valve. I think that the white valve must be pressed into the black body somehow, and not designed to be removed at all. But I also need to check the tube fitting, it only needs to be very slightly loose and vacuum will be lost. I’ve already repaired a poor fit at the motor end with silicon tube, so will probably do the same at the control valve end. The original plastic tube is now quite rigid so is no longer a tight fit.