My B7610 will on occasion creep forward a bit after I let up on the Foward end of the HST pedal. I just lightly hit the reverse end of the pedal and the pedal return springs seem to work properly again. I suppose I could have this adjusted but it really doesn't happen that often.
I've noticed it most often when on fairly steep down grades. But, I can still get it to hold on HST only even on quite steep down grades. I never trust the HST braking only in these situations though. If I have to get off the tractor on steep grades, besides using the parking brake, I make sure the bucket is digging in also. [Which is sensible in my case, because the only time I've gotten off the tractor on steep down hill slopes is when I've been scooping up boulders. And, the reason I'm off the tractor is to chain the boulders to the bucket so I can drag them back up the hill or to hold 'em in the bucket when I lift and tilt the bucket back. These are more than 500 lb boulders. I've got a backhoe as a counter balance, so it feels fairly stable, even though it's got quite a load on the down hill end.]
I haven't noticed this happening in reverse. I've seen this in some rental tractors too. I asked the rental yard mechanic about this and he said it was difficult to keep adjusted on the high hours rental tractors and he suggested doing what I was already doing. He did say it was more prevalent on some models rather than others--in his case more on the B21s than the other B-series he also had.
I never get off my tractor without setting the parking brake. Even on the most gentle of slopes on my property. One exception is after the tractor is parked in the shop with the engine off and the transmission in neutral.
