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Fuel level sender unit replacement?

PostPosted: 15 Aug 2017, 17:24
by Gary.
Once again, here I am asking questions! I've checked the Wiki and there is no info on replacing the fuel level sender.

Mine has bailed out, was erroneous anyway! I tried disconnecting the plug and socket and ended up ripping the connections from the sender unit - whoops! Should the white two pin plug thing come apart? I just cannot budge it.

I'll pick up a replacement sender from brickwerks, but can anybody advise on anything else that I might as well sort out whilst doing the job?

Re: Fuel level sender unit replacement?

PostPosted: 15 Aug 2017, 18:15
by silverbullet
You will of course need a new seal and the two horseshoe stud plates that secure the sender into the tank.

Sent from my S60 using Tapatalk

Re: Fuel level sender unit replacement?

PostPosted: 16 Aug 2017, 11:06
by Gary.
silverbullet wrote:You will of course need a new seal and the two horseshoe stud plates that secure the sender into the tank.

Sent from my S60 using Tapatalk


Are there just two plates to the outside? Mine seem pretty clean, so do I need to replace?

Re: Fuel level sender unit replacement?

PostPosted: 16 Aug 2017, 11:46
by bene
The two plates are on the inside of the tank...
I didnt replace mine as they were in good condition (the diesel kept them from rusting), the threads (that are on the outside of the tank) did need a good clean up though.
The seals are worth replacing no matter their condition as they are cheap!
https://www.brickwerks.co.uk/fuel-sende ... yncro.html

I still need to set mine up properly... thanks for reminding me!

Re: Fuel level sender unit replacement?

PostPosted: 22 Aug 2017, 12:15
by Reverend
When you do it, make a write up how you did it :oops: :oops: i have to do the same to mine. Its in crappy place for sure

Re: Fuel level sender unit replacement?

PostPosted: 22 Aug 2017, 17:56
by muileach
I have done it a couple of times, replacing the sender unit itself is not too bad a job providing you clean and lubrication everything before you start. The biggest problem I had was with the electrics, getting the plug off, cleaning and refitting it in situ is a nightmare. the second time I did it one of the pins fom the old sender broke off and was stuck in the connector. I ended up having to cut the wires and remove the conector to get the pin out. I fitted the conection to the sender on the bench as it was easier and rejoined them wires once everything was back together.

Re: Fuel level sender unit replacement?

PostPosted: 22 Aug 2017, 18:07
by Gary.
muileach wrote:I have done it a couple of times, replacing the sender unit itself is not too bad a job providing you clean and lubrication everything before you start. The biggest problem I had was with the electrics, getting the plug off, cleaning and refitting it in situ is a nightmare. the second time I did it one of the pins fom the old sender broke off and was stuck in the connector. I ended up having to cut the wires and remove the conector to get the pin out. I fitted the conection to the sender on the bench as it was easier and rejoined them wires once everything was back together.


That connection is a complete sod, it just will not come apart. I believe I will also be cutting the wires and connecting on a bench!

Re: Fuel level sender unit replacement?

PostPosted: 02 Oct 2017, 19:39
by Gary.
Reverend wrote:When you do it, make a write up how you did it :oops: :oops: i have to do the same to mine. Its in crappy place for sure


OK, I will...

I'm no mechanical genius, but managed to sort this out within a few hours. Firstly, it's worth noting that it is and always has been a diesel, this is worth noting as you may also want to consider buying retaining rings along with the sender unit. (https://www.brickwerks.co.uk/t3-parts/t3-syncro/engine/turbo-diesel/fuel-system/fuel-sender-retaining-ring-half-t3-syncro-genuine-vw.html) The only reason you might buy these is if the existing threads are really corroded. The main plate sits on the inside, but the threads poke through into the wheelarch area:

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My truck has only done 40k, so these were still in pretty good condition. If you can, give the area a good clean with a pressure washer in advance.

Make sure you either run the tank down or syphon your fuel down so that it's below the level of the sender unit. I thought I had, but soon found out I had not after drenching the garage floor with many litres of fuel!

I dabbed penetrating oil on the nuts several times days before the job was done.

Remove the cable from the little plug on the existing unit. Mine just wrecked off as would not come apart, this is quite usual apparently.

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I dribbled some penetrating oil in the plug and eased it apart using two pairs of mole grips. The little connection has a tendency to rust, not surprising given the position in the wheelarch.

The nuts are 10mm, which will most likely be fairly corroded. Using a screwdriver, clean up as best as possible. I used a long extension bar and a knuckle to release all but two of the nuts.

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There is a plate along the top, no idea what this would have been for? Looks like it was cable routing or something similar. The return pipe has a clip, which I could not quite figure out how to remove, so I wrecked it off with some mole grips. The pipe slid of fairly easily, but I did have to temporarily plug it as diesel kept dribbling out.

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I used a short flat bladed screwdriver and prised the send unit away, being careful not to scratch the plastic tank. This is where I wished I had cleaned the area as some dirt fell straight into the tank!

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At this stage I decided not to use the retaining rings as the ones there were in perfectly good condition. If it's not broke, don't fix it! Plus I did not want to risk upsetting the internal seal. Clean the seal area and use a new seal. I fixed the replacement unit back on with new nuts and washers.

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