[M.Acorn]

Started having issues with mine the other day,this is my 3rd in 9 years and desperately need this one to last a bit longer.
What was happening was ,it would come on and heat and as soon as it got to temperature that was it,it wouldn't kick back into heating the solution again,so guessed thermo issue.
Took off the cover where they are mounted on the side,top one has a sort of reed switch,so when it gets hot it pushes a little pin out which stops the metal coming into contact so breaking the circuit,this was a bit corroded up, so went at it with some emery and got it all nice and clean again,it's now working fine again.
Was just wondering if it is possible to replace them ?
And how the heck do I do that ? Some sort of box spanner or deep socket,does the plastic part come off or is it one unit ?
Ta