Fuel tank sender unit, early vs late bay

[kee]

Hi, I ordered a fuel tank sender unit from a company for my 69 westy. The problem is that the unit I got was of the late bay style. When mentioning this to the company they answered that they didn't have the one for the early bay. My question is, before returning the sender unit, what is the difference between those two models technically speaking? Are they interchangeable? Could I use it in my 69? Otherwise I might just have to return this unit and start looking for the correct one abroad.

The late style unit:

http://www2.cip1.com/ProductDetails.asp?ProductCode=VWC%2D211%2D919%2D051%2DA

The early style unit:

http://www2.cip1.com/ProductDetails.asp?ProductCode=VWC%2D211%2D919%2D051%2DGR

 

[currylager]

If the fuel tanks of the two vintages are physically the same you might be in with a chance. It depends on whether the resistance/deflection of the two senders are the same. You could be cheeky and connect the sender up externally using a fly lead to ground and observe how the fuel gauge behaves for different simulated fuel levels?? :roll:

 

[Justin & Muttley]

You could be cheeky and connect the sender up externally using a fly lead to ground and observe how the fuel gauge behaves for different simulated fuel levels?? :roll:

That's a great shout Currylager - must be the easiest option!

 

[slammedkustom]

i thought the bolt pattern of the senders was diferent?

cant see the pics but the early one should be a tube type and the late one should be a float type.

 

[slammedkustom]

now i can see the pics. the fitting is different. earlys bolt in and lates twist in.
also the early bay and splits look the same but there is a five bolt fitting and one is a six bolt fitting

 

[bruce]

Replaced the sender out of my early bay that was the cylinder type.

got it from just kampers @£40

still does not give me a true fuel reading as i have a different speedo from a beetle.

something to do with resistance that when the gauge shows empty i still have a half a tank left .

 

[Justin & Muttley]

At least it doesn't work the other way around - I'd be running out of fuel every week!!!

 

[bruce]

:lol: Lucky you thought of that its a good point

 

[kee]

Thanks for the replies. I'm going to return the wrong sender unit, and I'm not shure whether I'll get a new one since it's not aviable in Sweden as far as I'm concerned (I'll do some more investigation).

Allthough my repair manual suggests that a new one is bought, I am curious of trying to repair the existing one. There's no physical defective on the original one but I'm starting to think that there's simply oxide (not visible) on the two threads on which the float guides through. The symptom is that when tank is full the instrument shows about one quarter of the tank is filled. And after a couple of miles it safely rests on zero fuel. If the resistance in the sender is maximum at the lowest point shouldn't oxide on the threads increase resistance in the sender unit to give the signal that the tank is empty when the float have actually only moved a tiny bit along the threads.

What do you guys think? Come on, give me some qualified quesses!