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Fri Nov 21, 2008 12:46 pm

Yes I searched,I am surprised there is not more info on this. My current plan is to take my stock vdo sender(67) and grind and pop out that little insert disk at the pivot and find a suitable new piece of rubber and put a hole in it to go over the pivot .Does anyonehave an easier solution or a preferred material,I just filled up newly restored bug and that shitty white plastic one leaked worse and attacked my paint. AAArgh. Steve

this might be up keifernets alley as he fixed my carb leak .

Fri Nov 21, 2008 1:22 pm

I may be wrong, but I'm pretty certain that that rubber boot is a secondary seal. If that's true, then the main seal is an O-ring that is inside. I know for certain that the Magura type sending units use an O-ring (and no rubber boot) - Mexican-made VDO replacement tank units that used to be available 15 years ago, those didn't have the rubber boot either, and thus had to have an internal seal. One nice thing, is that those earlier Magura tank units, have set-screws which makes it fairly simple for you to take them apart and change that O-ring. I don't know if there's a way to take the VDO types apart though. The Magura ones, you can, and I did so with a couple of them earlier this year. I bought a pack of teflon O-rings to use. I got those because the little O-ring buyer's guide on McMaster-Carr seemed to indicate they'd be the most ideal. What I didn't take into consideration is that teflon O-rings won't stretch, so they were incredibly difficult to install! But once I managed to get them on there, they've worked perfectly. Both tank units were leakers before, and I tested them both afterwards and neither of them leak now.

But, I just don't know if the VDO tank units can be dismantled like that.

Below is a pic of what the shaft going through the middle of the Magura type sending unit looked like once I'd loosened the setscrew on the arm that the gauge-cable attaches to, and pulled it out - as well as the worn-out O-ring after I'd removed it (it was hardened and cracked as you can see when I went to remove it)

-Andy

Sun Nov 23, 2008 11:56 pm

Thanks G, ill check it out. More info anyone ?I cant believe that everyone is driving around in molotov cocktails and huffing gas fumes.The aftermarket has only responded with crap. Steve

Mon Nov 24, 2008 1:59 am

By the way, I wrote up some of my history in mucking around with tank gauges and sending units in this thread:

http://www.thesamba.com/vw/forum/viewtopic.php?t=231562

Now about aftermarket sending units... in that thread, plus reposted below, is a picture of a different brand of aftermarket sending unit. There is/was a brand out of Brazil called Instron.

Now, I don't know if anyone still sells the Instron brand sending units any more. I ran one in my baja for a while before converting it to a 1968 electric setup. It's got slightly better production values than that white plastic piece of rubbish. I say slightly because the one I used a few years go did start leaking, not in the middle though, rather from a crack in the plastic under one of the mounting screws. (I'm sure I must have overtightened it, but still...) And I had to go in and change out the float because the one it came with sprung a leak, so I had that extra opportunity to overtighten it. I have this photo comparing the two types of sending units in my Gallery:

Mon Nov 24, 2008 6:35 am

I used some Indian Head sealer on the gasket and screw threads with good results on the type of leak you describe.