Dear all,

by the chance do you know the size ( diameter, length and wire size) of the spring that goes inside of the piston?

kind regards

 

I assume you are talking about the spring in the thermal expansion cup? If so I do not, but trying to match the spring rate might also prove to be very trying to say the least. The spring rate would need to be matched against the thermal expansion of the oil I would think. Just a swag in my part. I have heard of people buying the parts to rebuild. However if you look at the post just below this one, I just purchased a rebuilt pump from a Canadian rebuilder that offers a pretty good warranty, had lots of good reviews and had a really good price.