Lee Dutton Posted December 29, 2021 Report Share Posted December 29, 2021 Hi all, hope you all had a very merry Christmas, I have some jobs to do on the 4a one being replacing the fuel sender unit, I fitted one about 10 years ago and the new one I received looks just as flimsy the fuel gauge reads full when I fill up then goes down to quarter full after 50 miles or so and I am sure my mpg is much better than that. I had to resort to the wooden stick method to check fuel levels on our run outs last summer, so I really need to sort this out. Any advise on fitting the new one(can't remember how I did it 10 years ago) only that it leaked around the electrical fitment at the top as it is covered with some sort of petrol resistant silicone. Cheers to all Lee Quote Link to post Share on other sites
keith1948 Posted December 29, 2021 Report Share Posted December 29, 2021 Hello Lee Disconnect battery first to avoid any sparks! Suggest you buy a viton seal to replace the cork gasket between the sender and tank. Moss sell these part number 293-401. There is also an anti rattle o-ring on the float. Measure this and get a replacement Viton ring from simplybearings.co.uk. You will then be E10 safe for these parts. Can't help yet on removing old unit and fitting new one. Just about to do that myself. Should be (just) a case of removing the fixing screws after disconnecting wires and taking old one out with some manoeuvring of the part. Removing cork gasket without dropping bits into the tank might be a problem. Have a look on the TR6 forum at the pinned post on calibration of fuel gauge that may help. Keith Quote Link to post Share on other sites
rcreweread Posted December 29, 2021 Report Share Posted December 29, 2021 Guys - be aware that some repro sender units have mounting holes which are not an exact match to the originals, necessitating opening out the holes to correctly match original spacings - unfortunately don’t know which ones are the culprit cheers Rich Quote Link to post Share on other sites
aardvark Posted December 31, 2021 Report Share Posted December 31, 2021 Hello all. I’ve not long ago done this on a TR6. I bought the new sender from TRGB and it fitted and worked spot on. Readings are bob on too - no adjustment needed. I used a cork gasket with heldite. I fitted a new tank at the time but still got bits of new gasket into the tank via putting the screws in through the gasket. I also tried a viton gasket and the same thing happens (the screws shave off some of the gasket as they are wound in). It was easy for me to hoover out the tank afterwards as the tank was new. It you have fuel already in your tank then expect some gasket to fall in there. cheers, HNY. Dave Quote Link to post Share on other sites
Lee Dutton Posted December 31, 2021 Author Report Share Posted December 31, 2021 Keith thanks for the info on the TR6 site how to calibrate the unit, ingenious. Also thanks to all for your advise. PS best way to drain the tank? cheers Lee Quote Link to post Share on other sites
keith1948 Posted December 31, 2021 Report Share Posted December 31, 2021 Hello Lee. You don't need to drain the tank to fit the sender unit. Just make sure the battery is disconnected. You could use a petrol siphon but that will leave some fuel in the bottom of the tank. The fixing screws for the sender to the tank have fibre washers to prevent vapour leaking past the threads and into the boot area. This is in addition to the gasket between the sender and tank. If you really want to drain the tank then the rubber hose or connection to the fuel filter by the mechanical pump on the engine is approximately the same height as the bottom of the fuel tank. So raise the back of the car a few inches, clamp the hose, pull it off the fuel filter and then drain it into a suitable petrol canister. This is not easy and you will likely have spillage so have the garage doors open and no naked flames! Once you have done that then fit an in-line fuel tap just before the fuel filter before the rubber hose. This means that in future you can drain the tank more easily by turning off the tap rather than having to clamp the hose. https://www.demon-tweeks.com/uk/mocal-in-line-fuel-cut-off-tap-2000072/ I fitted one I got from Demon Tweeks. It also enables you to work on the fuel filter or pump by just turning off the tap if you have a full tank of fuel. Note however that you will still have some fuel in the pipe that runs under the car after draining the tank. Finally DO NOT use a domestic vacuum cleaner to hoover out the tank. Others have tried this suicidal method only to be 'surprised' when the fuel vapour is ignited by the sparks from the vacuum cleaner motor producing initially a rather spectacular blow torch followed by an even more spectacular explosion. https://www.youtube.com/watch?v=39a8gdPvp5I A full tank is also safer than an empty tank. It is the vapour that can cause problems https://www.youtube.com/watch?v=HZ5Aajp0X80 I am always very wary working on fuel systems as you can probably guess from my cautionary notes. I always do this in very well ventilated areas or outdoors. Keith Quote Link to post Share on other sites
Lee Dutton Posted January 1, 2022 Author Report Share Posted January 1, 2022 Thanks so much Keith, everyone should watch the last video it will surprise a lot of people. I will attempt to fit the sender unit without draining the tank ...no point really. I will fit a fuel cut off tap however as will be useful in future. And will never hoover the boot or anywhere near fuel vapour. A really interesting and informative post, thank you Very best regards Lee Quote Link to post Share on other sites
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