Does my 68 need its vacuum tank?

[Michael M.]

I had trouble today with my wiper door opening and closing, something that had been recently reapired by a local shop. I started verifying the vacuum hose connections and noticed that the shop had connected together the two hoses that plug into the vacuum tank, thereby bypassing th vacuum tank.

I eventually got the wiper door working but didn't need to re-connect the vacuum tank. The headlights and wiper door work fine without it. Is the tank there only to be able to operate the headlights and wiper door without the engine running? I don't think it leaks, but I was just curious what other people think about leaving the vacuum tank bypassed. Thanks for any replies.

[Terry M.]

Re: Does my 68 need its vacuum tank?

The vacuum tank is there so you can raise the headlamps or wiper door under periods of low engine vacuum -- when accelerating hard for example. It serves the ancillary purpose of allowing operation of these vacuum operated items when the engine is off (or recently off, but that raises another issue).

[Michael D.]

Re: Does my 68 need its vacuum tank?

You might want to ask the folks at the shop why they by-passed the tank.

[Gene M.]

Re: Does my 68 need its vacuum tank?

Michael,
If the system works without the tank but not with the tank, the tank may have a leak. The leak could be just a pin hole but that is enough to not hold vacuum.

Test tank with a hand held vacuum pump and gage to check out vacuum drop of. If it hold steady it's a good tank.

[Michael M.]

Re: Does my 68 need its vacuum tank?

Thanks guys. The problem ended up being a mis-adjusted wiper door actuator, so nothing directly related to the vacuum tank. I haven't tried it yet with the tank connected. I guess I should do so, just to see if it works.

I was none too happy that the shop bypassed the tank without telling me, I generally don't like these types of "workarounds". They may have bypassed it for troubleshooting purposes in order to eliminate it as a point of failure and then just forgot to restore the hose connections. Who knows.

If it doesn't work with the tank connected, then I'll know why they did it, but that wouldn't explain why they didn't tell me about it. I'll restore the tank into in the mix this coming weekend and see what it does.