Windshield washer pump metal finish

[Doug J.]

Is the finish of the metal in the picture's correct for a 1971 5 port pump? It seems to be a zinc finish. Or should it be a cast type finish to match the wiper moter assembly? I have looked through some picture's in the archives and a zinc finish seems to be correct.....I'm just double checking.

Thanks for any help and input.
Doug

[Edward J.]

Re: Windshield washer pump metal finish

Doug that looks to be correct.

[Ron G.]

Re: Windshield washer pump metal finish

Okay, here you go. I did a lot of research regarding the original finish of 68 thru 72 wiper motors. I have discovered that the upper portion is plated a silver cadmium finish as well as the lower part where the label with the part number and date code reside. However, there is one subtle difference in that after the bottom was plated it received a yellow/gold type wash that you really have to look for. What was the intended purpose is beyond me. The mid year pumps do not have this yellowish look to it, only the 68 - 72's.

[Joe L.]

Re: Windshield washer pump metal finish

Okay, here you go. I did a lot of research regarding the original finish of 68 thru 72 wiper motors. I have discovered that the upper portion is plated a silver cadmium finish as well as the lower part where the label with the part number and date code reside. However, there is one subtle difference in that after the bottom was plated it received a yellow/gold type wash that you really have to look for. What was the intended purpose is beyond me. The mid year pumps do not have this yellowish look to it, only the 68 - 72's.

Ron-----


Are you sure it's cadmium and not zinc? By the late 60's zinc had supplanted cadmium for most plated items. Often times, the GM spec would call for either cadmium or zinc in which case I would expect suppliers would go with the zinc since it's less expensive.

The dichromate overplate, when it's used, is supposed to add more durability to the finish. It can be applied over either cadmium or zinc.

[Ron G.]

Re: Windshield washer pump metal finish

Joe,

I should have said zinc on the top and cad on the bottom with a yellowish dichromate wash. I have had several platers look at it and all have concured with my opinion. It is just that based on my experience. I should not have said the top portion was cad as I am sure it was zinc. As you know zinc is brighter than silver cadmium.

- Ron