JW,

You will need to pull the entire speedo assembly from your dash to get in there and do the head lubrication.

See Page 12-33 of the '48-'51 Shop Manual for how to remove the speedometer and head assembly from the housing.

For further "lube" work on the speedo head, check out this video. It isn't for an actual truck speedometer, but the early Chevy speedometer being worked on is similar enough to your needed disassembly and lubrication process. Sorry about the length of the video and the inevitable ads. The meat of the lube process starts after about the 21 minute mark.

I would say have fun getting to this, but getting the speedo cluster out is not a "fun task" in my book.

Don't forget, for safety sake, disconnect your battery before getting under there. Don't want to let any "smoke" out under the dash. big_eek

Good luck and hope your knuckles retain most of their skin! wink

~ Dan
1951 Chevy 3 window 3100
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US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)