I go along with mockturtle except I used an "L" shaped piece of coat hanger to clean crud out of the groove, usually "tp" left over from a careless flush. Now we use a stiff toilet brush to clean the edges of the round hole that accomdates the ball.....
On the MH toilets I have had to fix, There was never a ball valve.
In my experience with leaking MH toilets, mine was the rubber seal, and dirty flush valve plate. It isn't difficult at all to remove the toilet and replace the seal and clean the valve blade or plate. The part or parts aren't expensive, for the seal, and you can get almost any parts you need to fix it. Fortunately the toilet sits on a rubber gasket as well, not a wax ring like a toilet at home does.
Wheel Estate wrote: the gasket is leaking? that's my guess from your description. There is toilet seal lubricant and conditioner (mine is from tetford). I did not think much of the idea to start with ...but it brought a seal back to life for me . and i used a FRACTION of what the directions told me.(SEVERAL times) mine was doing the same thing, (i think) flush...water that normally stayed on top of the valve seal slowly dripped through. And come to think of it not all that slow. I checked ( with a straighted wire with a hook, for debris in the seal lip, it didn't fix it . so put the lub/ conditioner to it ...
ditto
I took mine apart and cleaned the gasket still leaked then used conditioner as per instructions and I have a seal that worksa again. I will continue to use the conditioner during the year and for storage.
Randy and Annie FMCA-371966
1996 Coachmen Destiny DP
300 Cummins CTA 8.3
6 spd Allison
Spartan Raised Rail Chassis
FROG 06 Wrangler Rubicon Unltd
Dollied 03 Toyota Corolla