Toilet flush sticks on

The Thetford Toilet with side foot pedal flush on my 2012 2552 started sticking near the end of our 4 month long winter trip. 
The water keeps flowing until the pedal popped up and then even with the pedal up it kept flowing for another minute,

I can't see where or how to lubricate anything or even disassemble anything to fix it.

Has anyone experienced this or have any suggestions.   

John,

Yes, that happened to us.  What you have to lubricate is the large looking device (looks like a soft ball) that opens and closes when you step on the pedal.  Step on the pedal to open it.  Spray a heavy dosage of silicone underneath and all around the sides of that that device.  Then work it in by opening and closing it a few times. Try to get the silicone on the inside and outside when it is in the open position.  When ours was sticking I went to camping world and turned one of the display toilets upside down to see what needed to be lubricated.

I had to do this a few years ago and it’s been fine ever since.

Must be this nice, hot weather we’ve been having in Florida.  

Hope to see you next year.