1970 WASHER PUMP

[Kenneth B.]

I lost 25 points because my washer pump would not work. What is the purpose of the small plastic hook lever that ingages the teeth that turn the pump. When I take the screw out & turn the back it seems to work the pump. I have not tried to hook it to the motor. What am I missing? THANKS

KEN 7808

[Pat M.]

Re: 1970 WASHER PUMP

Hi Ken. I've rebuilt several 5-port pumps (which I assume you have) for my 70. But I'm not quite sure what you're referring to as the "small plastic hook lever". Could you be a little more detailed?

[Jack H.]

Re: 1970 WASHER PUMP

I was also confused by the terminology. I'm guessing he's referring to the ratchet dog and hasn't cracked open his copy of the Chassis Service Manual (CSM) which provides theory of operation + bench test proceedures & nice pictorials of the WSW motor and washer (Electrical-Body & Chassis, Section 12).

The only drawback to the CSM is the book was released at the start of the 1970 model year when Chevy was still building 1969 Corvettes, so the unique 5-port pump isn't addressed. But, other than the larger piston/cylinder + 5-port inlet/outlet, it's functionally identical to the 3-port pump which is discussed.

BTW, the purpose of the ratchet dog is to hold the control caurosel's position when the pump cocks and releases the pump piston...keeps it from going backwards and losing indexing.

[Mike G.]

Re: 1970 WASHER PUMP

who rebuilds these pumps? i dont know if mine works or not but need to be prepaired. i am going to clean up and restore the motor and pump tomorrow. any advice on what i should or should not do?

[Jack H.]

Re: 1970 WASHER PUMP

Advice: NEVER let the pump go dry! That's what kills the rubber gasket + umbrella valves....

[Pat M.]

Re: 1970 WASHER PUMP

Hi Greene. I've rebuilt several using pieces from different pumps I've bought off ebay. You can also get most pieces from a new, black plastic 3-port Chevy still sells for about $65, part number 12494836.

There are so many things that go wrong with these pumps it's hard to list everything.

The first thing to look for is cracked or broken pieces on the plastic piston and 5 port head. The nipples get broken off pretty easily, but I've been able to repair these by getting the smallest copper tubing you can, which has an outside diameter slightly larger that the inside diameter of the original nipple. Then you drill out the existing nipple hole just enough so you can snugly jam the copper tubing inside the hole. Then, if you have the broken off nipple (or you can buy a white replacement from a three-port repair kit) you can drill it out so it just slides over the tubing, and then epoxy it to the tubing, which also fills in any voids. Finally, if you experiment with mixing yellow and brown paint you can paint the nipple so it matches the color of the pump. And once the washer tubing is inserted over the nipple, it's virtually impossible to tell the nipple was ever broken, and it works just fine.

The other plastic part that usually breaks is the bottom of the piston, where it slides onto the metal pump housing. But if you have the broken off piece, I've been able to JB-Weld them back together, and it's held after repeated use.

Other than broken plastic I'd say the number one thing that fails on these pumps is that the main plunger seal eventually shinks and then fails to pull up and push out water. Some people have replaced the seal with O-rings successfully, but I've found the best way is to use the plunger seal from a new black 3-port. You simply disassemble the two-part plunger head with a screwdriver and replace the seal. Every time I've done this, the pump works like new, and pushes water with amazing force.

Also, don't forget to put the pump back in the proper position on the motor once you take it off or it'll break. To do so, you must insert a small allen wrench or wire into the small hole just below the plastic piston on the front of the metal housing, and then pass it through the little hole in the large star wheel on the back of the pump. This holds the star wheel off to the side while you screw the pump back on so it'll properly fit onto the motor's metal nipple that drives the star wheel. BUT DON'T FORGET to pull the wrench out before you start the pump, or it'll break just the same!

As I say, there are a lot of other problems these pumps have, and if you have one in particular let me know and I'll try to help.

Regards, Patrick Moresi #45581

[Mike G.]

Re: 1970 WASHER PUMP

thanks, thats what i will do. i took it apart yesterday and cleaned it up. it looks like new. i will order the rebuild kit.