Sicklebar on a '39 B

I had the remains of a drive belt on the mower when we used a dozer to pull the mower out of blackberries where it had lived for who knows how many years... I got a new C48 belt. It looks to be about the same length. If I put it on, the back spacing from the draw bar looks to be right (draw bar in middle hole and the slotted parallelogram spacers end up being level and the spacers are in the stack as well) but then the bars that bolt up to the underside of footrests are too long (they are slotted 3/4" already).

What size belt is anyone else using? Is it best to level the mower first and then play with shims on the pulleys? How many shims does anyone have on there pulleys?

Thanks
Chris

P.S. Rod- Thanks for the info on photos, I have not had a chance to play with it, busy trying to bolt this up...

I'm using a C51 belt and even that is a touch short. I could easily use a C52. The spacers on both the drive and driven pulleys are not for belt adjustment. You use the large washers at the drawbar for belt adjustment. The spacers are used only for changing the sickle speed-to-ground speed relationship. There are 5 spacers on each pulley. You should not have to change that unless you have very unusual cutting conditions requiring a higher than normal sickle speed. You would increase the sickle speed relative to ground speed by remove one or more spacers from the drive pulley and placing them with the spacers on the driven pulley. That makes the drive pulley a little larger pitch diameter and the driven pulley a little smaller pitch diameter resulting in a speed increase with no change in belt tension.

I am using six of the large flat washers on each bolt at the drawbar with the C51 belt. It would a little less with a C52. With the C51 I had to elongate the slots slightly in those two brackets you mention. When I have to replace the belt, I'll probably go with the C52. You adjust the belt, using the flat washers such that, when tightened down, there is approximately 1/2" displacement midway between the pulleys using a moderate finger pressure. Click on the thumbnail to see the relative relationship using the C51 belt:

Rod

If the drawbar is at correct height, the braces that connect to the front fender support can be adjusted. First, place the belt on both pulleys, add enough washers to obtain the correct belt tension. Recheck tension after bolts through drawbar have been tightened. Then, tighten the bolts on the braces at the fender brace. Have been operating one of these mowers since 1944, as one gentlemen commented, they can be a bear to install, but work well. Good luck.

To answer your question, use enough spacers betweeen the drawbar and the mower so the intermediate bars to the foot rests fit within their adjustment range. We used 5/8" flat washers. There should be a set of tapered cast iron spacers to use between the drawbar and the ends of the mower frame to make everything fit together right, but it might not make much difference if you don't have them. Then measure and get V-belt to fit. Number or thickness of spacer will depend on drawbar position. I don't remember exactly where we set the drawbar anymore, but we never moved it, except for removing for the plow and cultivator. Hope this helps,
Paul