TheSamba.com :: View topic

Sun Nov 17, 2002 11:05 am

I have a 63 Single Cab with a new gas tank and an NOS gas cap after driving through about 4 gallons of gas there is a great deal of vacuum in the tank, it is so strong when you turn the cap to take it off off you have to wait for the tank to equalize berfore the cap comes off, and you can hear the tank expanding, I have gone from full to almost empty and the truck runs fine (never fuel starved), shouldnt the cap vent the tank to prevent this?

Sun Nov 17, 2002 12:50 pm

Yes, the cap should vent the tank but it sounds like it's not doing it. I have had Busses that have done that before and it's hilarious to hear the tank "bonking" as it expands and retakes it's shape.

Sun Nov 17, 2002 12:53 pm

The cap is responsible for letting air into the tank. It sounds like you might need a new cap. Whether or not you could repair yours, I'm not sure. Some people have been known to drill really small holes at the top of the neck to allow for ventilation but then you are polluting quite a lot.

Sun Nov 17, 2002 1:21 pm

Just try a new seal in the cap. Wolfsburg West sells them for like a couple bucks. Make sure you get the cork one though.

Andrew
'58 Panel Bus
'60 European Beetle
'67 Deluxe Bus

Sun Nov 17, 2002 5:44 pm

this supposed "nos" cap, is it a gas cap, or is it an oil cap, disguised as a gas cap? i don't think those caps that say "kombi" on them are really gas caps. maybe i'm wrong, but...those are the ones i've seen this problem with. any pics? regardless, the cap must be vented, or you'll destroy your tank and/or cause cracks in the tank and then it will leak....
good luck.
3:-0

Tue Nov 19, 2002 11:33 am

Thanks For all the help, The NOS cap I have does have a part number on it I am going to check that number and make sure it is for a Type 2 and that is actualy a gas cap not an oil cap.

Tue Nov 19, 2002 3:24 pm

be careful, the tank can kind of implode. my gas cap does not have a way to vent so I drilled a small hole in it. before I did this, my gas tank got sucked in so far it stayed sucked in. I had to blow compressed air in the tank to push the walls back out.

Wed Nov 20, 2002 7:46 am

I took the cap off for now and put the BMW cap I was using back on and it vents the tank. The part number on the cap is 113 201 557 Z, I don't think it is for an old type 2 because it has a VW and an Audi symbol on it, I will probably just buy one from Motorwerks or Rocky Mountain, anybody want to buy an almost new cap with that part number?