Its me again
Big thank you to you all.
Im not electrically biased as such. Iv always been and worked on the mechanical side of life
Your problem solving checked out the dead compressor and also the spare
Electrically I found the spare had a failed thermal switch. The current pump with the burnt out 12V feed did not
After following all the tests i decided to break down the current frazzled pump, what do i have to lose
I found the bushes on the spare to be in a much better state than the current so i swapped them over. I then also discover that the current pump has a seized bearing on the piston arm. Bingo
I imagine thats enough to melt something and also when jumping pin 5 and 3 on Relay 20, explains the audible click. not a relay but the actual pump trying to move
I will hold my hand up and say even though i had a spare seal to replace on the piston. I just dont have the nack in swapping them. I can cut the old one off, but im dire and refitting
So i split the piston arm away from the knackered bearing and replaced it on to the bearing coming from the spare pump.
Reason i did this is that the spare pump has a very worn piston seal and liner with scoring, so it made sense in my strange mind to re use the bearing instead.
Result, i now have a solid working pump. I do feel it runs too often. I changed the seals in the block. Re sprayed all the bags and connections yesterday also. Still feel like its leaking somewhere
Thanks again for the tips. Certainly learnt some new lessons and it also allowed me to make it to the Lincolnshire aviation museum yesterday to watch some tanks and planes feed the senses