Honeywell L4064 fan/limit switch - issue with auto/manual knob - can it be fixed

I have a Honeywell L4064 fan/limit switch on my garage heater (forced air gas). These have a knob that you push/pull which sets it into auto mode or manual (constant on). Over the years of constantly pushing it in and out, the knob has become loose to the point where contact isn't made unless I put some type of wedge so the knob is being pushed to the side a little. Sometimes though the wedge wiggles off causing the fan to simply not fire on (or stop mid way).

Anyone ever opened up one of these to fix the contacts? Or am I better to just bit the bullet and buy a new one for $150 ish.

Thanks