Now the fun begins. The knurled, round knob secures the big "U" bracket that holds the speedo into the instrument panel. The thin hex nut holds the speedo "innards" to the outside case. I have to be careful with the relatively delicate gubbins from here on.
I built a holding fixture [in red, below] to hold the speedo securely in my vise so I don't slip and bust some tiny part while I'm trying to replace damaged bits.Then I clean and re-lube the working gizzmos. The 40 year-old grease in these babies gets real stiff. I use a dentist's pick [AKA "torture tool"] to clean the old grease off the gears!
The gear train for resetting the odometer trip meter register is on the lower left on the speedo inner frame. The round drum is where the magnet and speed needle cup are located. At the top is the main odo register [with numbers] and above that the advancer sprockets that allow only the correct number wheel to rotate.
I reversed the mount fixture [red] so I can get to the "innards" easier. See the wee gear train on the side.... these gears are changed to make the speed and miles read correctly for the different transaxle final drive ratios that Saab used over the years.The rest of the "innards" are the same.
My next blog will be more about taking it all apart, with more special tools, steady hands and a lot of TLC.
City Car Design
6 years ago