The Craftmans Shop > New from Old
It's BIG, Yellow and digs holes! JCB 3CX Project 8 is joining the Tractor Shed
awemawson:
The replacement diesel level sensor arrived this morning, so first measure it's full and empty values:
Full = 13 ohms
Empty = 285 ohms.
Now to fit it. I had already pumped 20 litres out of the tank last night to avoid it flooding out when I removed the flange, and that black plastic trim bit was already off so it was 'just' a case of unbolting the six flange screws, lifting out the old and inserting the new.
Well of course it wasn't quite like that - as I had feared the long stem on the sensor clashed with the cab floor prevented it tilting enough for the variable resistor bit to come out through the hole. With rather more force than desirable eventually it came out by levering it with a screw driver and bending the case. Obviously the new one couldn't go back like that, and I wasn't going to drop the tank.
I ended up bending the long stem allowing the box of tricks to pass through the hole, then as far as I could bent it back in situ. If I ever have to do this again I will cut the stem and make up a coupler collar with grub screws to put it back together.
What I've done obviously will change the calibration a bit but not too much I hope.
Then to dismantle the old one and find out what failed. It's resistance element is nichrome wire wrapped round a shaped former, with a springy contact finger rubbing up and down as the float angle changes. End to end the nichrome wire was OK giving sensible readings, but it's end termination had given up the ghost and was broken. Theoretically I could mend it but probably won't !
awemawson:
So not willing to chuck out a potentially repairable diesel level sensor I pulled it apart.
The break in the nichrome wire was very close to the riveted end connection - so after a bit of a clean up with brake cleaner I drilled out the riveted terminal connector, unravelled a bit of the resistance wire to give enough to wrap round the bolt that I replaced the rivet with, and screwed it all back together.
I bit of tin bashing on the box housing the resistance element to make it back to original shape (damage caused by me levering it out), and it looked almost presentable. Bending the wiper to give a bit better pressure I re-assembled it. bending it's fragile lugs back to retain the halves together.
A quick ohms test shows that it works - so it's been bagged up in the packaging of the replacement one and put on the shelf for next time.
vtsteam:
That is some fine wire!
awemawson:
--- Quote from: vtsteam on June 20, 2022, 09:51:53 AM ---That is some fine wire!
--- End quote ---
Oh yes Steve - I definitely needed my magnifying glass !
WeldingRod:
And a fun coil to get a complex taper!
BTW, it's probably not nichrome. Probably manganin.
Sent from my SM-G715A using Tapatalk
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version