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Removal of float arm from SP250 petrol tank sender.

Posted: Tue Jul 02, 2019 6:28 am
by wadams
Hi All
Can anyone advise how to remove the tubular float arm bar from the housing section of the sender in the petrol tank please?
There appears to be several grooves over a half inch length of the tube towards the opposite end to the float and these are very firmly lodged inside the hole of a tiny bar protruding out from the underside of the sender.

All help welcome please!

Re: Removal of float arm from SP250 petrol tank sender.

Posted: Tue Jul 02, 2019 11:29 pm
by silverdart
Hi, Any chance of a pic. its hard to imagine what you describe.

Dave.

Re: Removal of float arm from SP250 petrol tank sender.

Posted: Wed Jul 03, 2019 7:27 am
by Ian Slade
If it's standard it should come out easily, though I seem to remember the tank needs to be partially remover to access the cover plate and get the angle correct for removing the float through the hole.

Re: Removal of float arm from SP250 petrol tank sender.

Posted: Wed Jul 03, 2019 7:55 am
by wadams
Hi Guys
I have removed the tank itself and taken out the old sender. I can not remove the arm itself from the little hole into which it slides
I know that it should simply be eased/tapped out but mine is pretty solidly held in place and I don’t want to damage it by banging to force it out.

Re: Removal of float arm from SP250 petrol tank sender.

Posted: Wed Jul 03, 2019 10:27 am
by Ian Hastings
If I recall it is crimped in to stop it coming out so I would suggest you leave it well alone unless you specifically need it out.

Re: Removal of float arm from SP250 petrol tank sender.

Posted: Wed Jul 03, 2019 6:35 pm
by #100910
Crimps are view-able on each side.
The bar appears to have been pre-crimped and then forced in to the half-way point:
FTS.PNG

Re: Removal of float arm from SP250 petrol tank sender.

Posted: Wed Jul 03, 2019 7:25 pm
by Alpine Daimler
This is what mine looks like, as already mentioned unless really necessary I would leave alone. If it really needs to be removed it may be necessary to somehow file/grind away the crimps from one side and slide off.
To refit apply fuel proof adhesive and secure with lightweight (plastic?) bush and secure with grub screw also glued to prevent loosening over the coming decades and more?!!
regards
Rob c.

Re: Removal of float arm from SP250 petrol tank sender.

Posted: Wed Jul 03, 2019 7:37 pm
by Alpine Daimler
This is what it looks like from the other side, the internals.
Perhaps that brass hex nut the other side of the pin can be loosend, pin and arm removed for much better access to the crimped surfaces.

On a completely different note but staying with the sender unit if I may?................ I am reaching the end of tank overhaul,, including (hopefully!) successful chemical relining with
POR 15 kit and thought I would clean internals of sender unit, contacts, variable resistor etc, all done and very easy.
But, the sender cover although a very snug and perfect fit cannot be fuel and more importantly fuel vapour tight....or can it? As far as I can tell it must sit in fuel (for a while at least with our cars!) is that safe with contacts, a resistor, heat, poss sparks etc??!!

No seal material or gasket was present on disassembly.

Should a very light stippling of Hylomar blue be applied to that sender body/cover edge to ensure my car does'nt explode?

I hope someone out there can put me at ease!

Thank you for allowing me to hijack yet another post this week :D

Rob C.

Re: Removal of float arm from SP250 petrol tank sender.

Posted: Thu Jul 04, 2019 9:16 pm
by Ian Hastings
Rob. Be assured your tank sender will not explode! The sender units are reasonably well sealed and do not require any more sealant or gaskets. Yes petrol vapour will get in but the casing acts in the same principle as a Davey Lamp used in mining - there is no direct contact with the surrounding vapours or gasses but air can get in to keep the flame burning, but more importantly, the flame cannot get out through the gauze to ignite the surrounding gasses.

The sender unit uses that idea and it works well - there are many millions of them in use throughout the world and they do not explode - I hope.

Re: Removal of float arm from SP250 petrol tank sender.

Posted: Sat Jul 06, 2019 8:13 am
by wadams
Hi Guys
I have managed to remove the float after a bit of persuasion. Thank you for your comments and advice.