Former VWDieselParts.com Forum

Yes, the crush washers are soft copper.

It might be a vacuum caused by a fuel line restriction,..

but a bad shaft seal or crush washer would allow fuel to syphen back immediately also.

I don't think you need a check valve,.. don't know where to get one that won't restrict the line.

i believe i have removed all the fuel line restriction possibilities. removed the water separator, removed the check valve, replaced fuel line front to back, new fuel filter, cleaned the pick up screen in tank....

if i hook up a pressure gauge inline will it let me know if a vacuum is being created in the tank?

The injection pump never looses its prime. Tonight there was a huge air bubble taking up nearly the whole line going to the pump from the filter. but the car fired nearly instantly. not sure if thats helpful or not, but it dosent seem like air is entering the pump.

If you put a vacuum gauge on your fuel line and it shows a restriction, then yes you could have an issue with the tank itself, or the vent system. The siphoning back to the tank may not be fast enough to pull all the fuel back from the IP. So, you're left with some fuel towards the IP, but air up towards the fuel filter. The fuel filter is the highest point in the fuel system.

To insure that a copper washer reseals (if you reuse them), anneal them before you put 'em back. Heat them red hot with a torch and then immediately dunk them in water. Softens 'em right up.

Aircraft mechanics do this with the copper spark plug washers in aircraft engines every time we remove them to clean the plugs.

TonyB
81 Dasher 1.6na

To anneal steel, you cool it slowly,
is copper the opposite?

Cooling steel quickly makes it hard and brittle, not soft

Fatmobile wrote:To anneal steel, you cool it slowly,
is copper the opposite?

Cooling steel quickly makes it hard and brittle, not soft

With copper, it essentially does not matter how fast or slow it is cooled:
- http://en.wikipedia.org/wiki/Annealing_%28metallurgy%29

I think you need to use sophisticated cooling equipment to cool copper fast enough to get the hard/brittle effect.

BTW: I air cool my copper sealing parts.

ok....so this weeks goal is to get a vacuum gauge. and then soften up my crush washers. thanks for the info guys

So I finally got to hook up the vacuum gauge. Had a alternator belt break and that set me back a bit. Anyway. The gauge only shows 1-2 inches when the engine is running and never changes under any load. So i dont think I have any sort of blockage or vacuum being created in the tank.

I guess my next option is to check the crush washers. After that all thats left is a Pump Reseal? The thing that drives me nuts is that I never see any fuel leaking.

I usually don't see much fuel around a bad shaft seal,
I can usually rub my finger behind the injection pump sprocket and come back a little diesely.

I once pulled the line off the fuel filter and had fuel flow out of the bad shaft seal.
I'm pretty sure:
Because of passageways that allow residual pressure from the pressure regulator to feed back to the front of the pump and shaft bushings:...

The shaft seal is at the same pressure as the front of your pump so with a small vacuum, air would be pulled in,..
fuel would not be pushed out.
vacuum should be close to zero but up to 5 isn't bad.