You should refer to the operators instructions or applicable manual for it. What model is it ? There are numerous and very reasonable books for many of these listed on ebay, link attached.
I am familiar with the old LeTourneau power control units, (PCU) and they require adjustments with regular use, when the D7 was first delivered the brake would not hold the blade up, but after reading the instructions on it, a few simple adjustments, I was able to get the brake to hold, and there was a certain amount of travel of the lever on this PCU. Mine needs a fair amount of work, as I am sure that it was easier to operate when new, or in good mechanical order.
DO NOT EVER adjust one of these while the tractor is running, I have a photo from an old Associated General Contractor association with a safety bulletin on this, whereas the operator tried to adjust a front mounted CCU, while the tractor was running, appears the blade came up and pinched his head or something, photo shows a man upright, and apparently stuck or held in place, bleeding from the head and most likely deceased, could be staged too, might have been, old black and white photo, but you get the point by now I am sure LOL !
I'm comparing apples and oranges here, as these are different, but similar in principle, I'd get the books on it, I think parts are still available for these, don't quote me, but I did recall that was the case, as my PCU is long obsolete since Cat built their CCU's Caterpillar Cable Control Unit This post was edited by Billy NY at 08:38:29 10/17/13.