Some 20 years ago, I drove a company truck (a 91 Freightliner, 3406 under the doghouse) with a mechanical pump and a clever linkage.
Cat made the lever on the pump sorta 2-piece, spring loaded, so that if you pressed the pedal beyond wide open, it'd kinda "break over", the spring and outer lever moving, but not the pump control shaft.
Now I'm trying to find pictures of that, because it'd come in handy in the underside of a pedal steel guitar (want one knee lever to give way and allow activation of a lever behind it).
Does anybody have any such pics?
I tried my local Cat dealer, but they said that without an engine serial number, they couldn't help me

 

Crap I think I know what your talking about. I haven't seen one of those in a while. And I drive a Pete with an old 3126 cat. I'll see if I can find something.