Hi All,
Feeding off the good info on several other threads on getting my washer pump back up and running.
I was getting the clicking sound from the pump when pressing the switch in, so I know I was getting mechanical and electrical function. Just no fluid getting pumped, so I opted to get a new seal kit for the valve block. That went together pretty well, but still no fluid pumping.
Now I am wondering if something is broken in the piston retainer. The "pushrod" that cycles the piston has a spring clip on the end that looks like it is supposed to engage in the piston's backside "doghouse" slot. (first photo) It will fit in there and semi-retain, but will not stay put as the piston cycles, and it looks like something may be broken. I had a small piece of broken plastic come out with the dis-assembly, so I'm suspecting it was some kind of cross-piece that retained the clip so that the rod would push AND pull the piston through the cycles. (2nd photo) I think I'm getting push, but not pull. How is the clip supposed to secure the push rod to the piston? And if its broken, can that part be replaced?
I'm not finding those detailed views anywhere.
Also, there was a small silver bracket that fell loose from the armature that cycle the cam using the magnetic pick-up. (3rd photo) This bracket had a second small coil spring (that I'm still searching for !) I can't figure out what function that performed, and how it would go back together.
Once again - thanks for all the expertise readily available on this forum!

 

Your first picture, looking into the cylinder of the pump shows the clip and the broken off bottom of the piston attached to the rod. The second shows the broken piston. The piston does not appear to be serviceable, but you should be able to find a used one.
My pictures show 2 pistons; one broken similar to yours and the lower one still retaining the metal retainer, but with a chip missing and the upper cracked. I'd send you this one, but it looks ready to totally break soon. Also, here what the spring set up looks like. Good luck. It's good to see you fixing your original parts.

 

Wow Toylman! Amazingly detailed pictures! Thanks.
Looks like I'll need a new piston assembly. I found one on the Bay f0r $20 and it includes the cylinder and the pushrod already connected to the piston. It doesn't say it's specifically for corvette, but may Chevy's, and it looks compatible, other than the color. Wondering how they mold that part with the clip inside? Must be a 2-piece injection mold, because that retainer clip looks like its captured within the plastic doghouse.
Hopefully, disassembling the other end of the pushrod from the cam system won't be too much of a disruptive project. (don't want anything else breaking!).


On that silver bracket, any idea what its function is? Looks like it may be an additional measure to pry the lever away from the magnet when it's not energized, to ensure the washer pump turns off when the cycle is complete? I only say this because, without it now, the washer is cycling constantly as long as the wipers are running.

 

Also, any idea where to find replacement coil springs for the brackets shown? I know the one that actuates that secondary bracket is long gone.

 

Interim Update on my repair:
Just got back from a 1 1/2 week Alaskan family vacation, and finally got a chance to try out the NOS replacement washer pump piston/push-rod assembly that I bought for $20.
After putting it all back together, I was very pleased to get fluid pumping up from the reservoir to the valve outlets!!! (who knows how long its been since we've had good flow like that?)
Now I need to get that second coil spring replaced so I can get that second bracket installed properly as in Toylman's photo.
I've got to believe that bracket has some function as a shut-off for the washer pump. Because when I turn on the wipers now, the washers run constantly, and do not turn themselves off. The added bracket and spring must act to pry the lever away from the magnet when needed to turn off the pump cycling while the wiper motor continues to run.
Once that is figured out, I've got a new set of hoses to run for the whole system (wipers and headlight spritzers), and then need to confirm the separate headlight valve solenoid is functional.

 

Good job! I have had pumps apart to clean and repair, but have not tried to actually pump water. I'd say that new piston w/new o ring was the key part to get is flowing. Also priming the pump first; getting the water to the piston was important, but you are beyond that. Using the dimensions I gave you, try a hardware store for the spring.

 

OK Toylman - So I was able to pickup a nice assortment kit of coil springs at Harbor Freight yesterday for about $8. There a at least two springs that could fit, and I'm trying each.
But having trouble now understanding the function of that secondary bracket? From your last photo in post #2, it looks like that bracket rests between the magnet and the lever arm "pawl". What is it's true function in the pump On/Off cycling?
With the spring I have connected to that secondary bracket, the only way I can get the pump to start its cycle, is to lift on the bracket with my finger slightly, which then causes it to also **** a little rearward until the cam makes one full rotation of pumping, and then the system shuts back down again.
Is there some kind of functional diagram of how this detailed system is supposed to work? It's not even clear to me if the magnet is supposed to be energized for Pump On, or for Pump Off at this point.
Frustration at this point is only that I've got good flow now, but I just can't control it (donthca' just hate when that happens?!?).

 

I know this thread is 8 months old, but I am also looking for a diagram or description of how the washer pump system works. My pump levercurrently shoots towards the passenger side when I push the wash ****, then slowly pulls back out toward the drivers side. This seems somewhat backwards to how the pump should work, I feel it should pull out quickly to the drivers side, drawing in water in then pumping it out as the piston moves towards the passenger side

 

G'day All,
The following link is for a Youtube video on how to test and repair a chevelle wiper motor and
washer pump. Now I know that this is not a corvette, but they can't be that much different.
Hope you find it useful.