OEM parts blues

[tdr1919]

Well this is the second time I bought an OEM part for my 86 and got burnt! and I do not use junk, my first experience was with a replacement clutch slave cylinder, that looked exactly as the original but the hydraulic line threads were different, I ended up rebuiding it with a kit from Rock Auto.
Now I bought a backup light switch, it again appears to be the same as the original, but after close examination the threads are a different size!
Is this is a problem with all the C4 PARTS?
Tom-

 

[vee93]

Well this is the second time I bought an OEM part for my 86 and got burnt! and I do not use junk, my first experience was with a replacement clutch slave cylinder, that looked exactly as the original but the hydraulic line threads were different, I ended up rebuiding it with a kit from Rock Auto.
Now I bought a backup light switch, it again appears to be the same as the original, but after close examination the threads are a different size!
Is this is a problem with all the C4 PARTS?
Tom-

I've yet to have a problem with a parts vendor. Who are you buying your OEM parts from? Cause I'm thinking..., therein lies your problem.

 

[tdr1919]

I've yet to have a problem with a parts vendor. Who are you buying your OEM parts from? Cause I'm thinking..., therein lies your problem.

I got the slave cylinder from Ed at "Not just Vettes" (2x he changed the part) the switch is a Carquest" part, they tried to cross it to Delco but as of yet no luck, it looks like I have to go to Chevy, I tried to fix the bad one but the
contacts are so burnt and uneven I cant get it to work properly.

Tom