# 1975 Case 680E CK hyrdraulic Sight Gauge



## Jacob Smith (Feb 3, 2018)

Hi Everyone, 
I am new to the forum. There seems to be a real wealth of information here! I joined in hopes of finding an answer to my question. Thanks in advance for any information!

I am working on my uncle's backhoe. It is a 1975 Case 680E Construction King. I repacked the two loader lift cylinders and both stabilizer cylinders. Also, the hydraulic reservoir level sight gauge tube is cracked and leaking air out. The gauge part number is L53208 superceded by L79110. The sight tube part number is D75820. Both are not available from Case. The tube is a type of plastic 1/2" dia by 1-3/4" long. I thought if I bought a piece of acrylic tube from McMaster Carr, I could cut a new one. I live several hours drive each way from my uncles house. So, I removed the cylinders and gauge tube to take home for repairs. In doing so, I lost the adjustment plug that puts tention on the sight tube and two rubber gasket washers. As I recall the plug is made of aluminum with male threads, has a recessed seat for the washer, has a hole in the center for fluid to flow through, and a slot cut into the other end for a slotted screw driver. My thinking is it is about 1/2-9/16" in diameter. I think it is a long shot at best, but I was wondering if anyone had what diameter thread and tpi the male threads of the plug are? If so, I could make a replacement on the lathe.

I would be greatful for any information!
Thanks, Jacob


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## sixbales (May 18, 2011)

Howdy Jacob, welcome to the tractor forum.

I think we can find a fluid level sight glass that will fit in place of the original. What you need to establish is the connection size/thread required to mount it on the tractor, approximate length, and diameter. There seems to be plenty of them on the internet, prices not too bad. Incidentally, it has to be vented in some manner or it will not read correctly. Does it look like this?










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