Identifying crush washers

[BennSport]

Hello everyone, I’m having some trouble identifying the copper crush washers for the fuel pump on my 1983 944. I’m specifically looking for the washers that go on either side of the banjo bolt to fuel line connection. Does anyone have a pn or measurements to help me figure out which ones I should order? There are so many crush washers online it’s hard to figure out which ones I need. Thanks in advance

[Tom]

The online PET catalog says it is part:

N 013 812 3 Sealing ring 2
A 12 X 15,5

I'd measure the ones you have to be safe, as I recall there being some confusion in PET about the early cars. Either way, I'd get the official Porsche part. I bought a box of assorted copper sealing rings on Amazon and they are worthless in terms of sealing gas lines. Ask me how I know....

[usury]

I've had good luck re-annealing copper crush washers. Hang them on a steel wire and heat with a propane torch until glowing red. I let them air cool. Others quench in water.

Either way, once they are cool, I lay a sheet of 220 grit sandpaper on a very flat surface (MDF or glass) and hand sand each side using a figure-eight motion until smooth and pit-free.

I've logged thousands of miles on multiple vehicles doing this and had no related issues. Motorcycle brakes/carburators. Car brakes. Even my late 944 fuel pump fittings.

[Tom]

I've had good luck re-annealing copper crush washers. Hang them on a steel wire and heat with a propane torch until glowing red. I let them air cool. Others quench in water.

Either way, once they are cool, I lay a sheet of 220 grit sandpaper on a very flat surface (MDF or glass) and hand sand each side using a figure-eight motion until smooth and pit-free.

I've logged thousands of miles on multiple vehicles doing this and had no related issues. Motorcycle brakes/carburators. Car brakes. Even my late 944 fuel pump fittings.

I tried that on the cheap-o Amazon 'copper' washers I got and it didn't help. In hindsight, I think there was very little actual copper in those things... It did work on the original 'single use' copper washers I took out of my old Mercedes though...

[BennSport]

Thanks guys! I ended up ordering some on pelican parts because I don’t have any installed on my car.

[BennSport]

Well it turns out my issue wasn’t related to those crush washers fortunately! It looks like someone got hungry and decided fuel hose would be a good snack.

IMG_6213.jpeg (4.4 MiB) Viewed 1993 times

[Tom]

Well it turns out my issue wasn’t related to those crush washers fortunately! It looks like someone got hungry and decided fuel hose would be a good snack. IMG_6213.jpeg

Well, in the critter's defense, it does look tasty. Squirrels have been doing that to the irrigation lines in my yard. Their behavior is rewarded by a refreshing drink of water when they're done. In your case, the critter must have had a much different experience when it got to the gasoline!

[BennSport]

Yea, I can only imagine the reaction that animal had when it finally got through! Maybe I’ll have to put some hot sauce on my fuel lines so it won’t happen again

[dr bob]

I can't see enough of the hose markings to tell, but... Unless that's a low-pressure fuel return hose, all the real work is done by a polymer tube inside that armored shell. The outer layers offer abrasion resistance, some structural support to limit kinking, and apparently to limit teething damage. Unless and until that inner plastic tube is breached, leakage won't be a problem.

If it is a low-pressure return hose, the structural description is the same except the liner is not a hard plastic. It will fit safely on sharp-barbed fittings and requires clamps though.

And a possible hint on the crush washers used on banjo fittings as well as many drain and fill plug bolts. The washers seal by slightly galling or smearing the washer metal to fill any imperfections in the sealing faces of the fitting or bolt. A very thin film of Teflon thread sealing paste on the sealing faces offers a similar result without actually galling the washers. On banjo fittings particularly, the inner sealing washer normally won't move enough on tightening to displace metal especially if you are holding the banjo to maintain a hose or pipe alignment. At some point the bolt thread itself starts to gall especially if the threads are dry, not at all a desirable situation. Using the sealing paste means you'll be able to get a satisfactory seal without as much bolt torque. Usually the spec torque is enough, where washers often seem to demand spec-plus torque to actually get a good seal.

On hard fuel system fittings where a flared or ball-and-seat seal is needed, a very thin film of that same Teflon thread sealing paste will help a lot in getting a good seal without he-man tightening of the nut. This is especially helpful on used fittings, where prior tightening and motion might have galled or just distorted the sealing faces slightly. A little on the fitting threads make tightening a lot smoother too, even though the threads aren't a direct part of the seal function. Reduce your torque spec by maybe 20% when using the paste to lubricate otherwise dry threads like these.

I learned these hints from gas turbine mechanics, who also use a nuclear grade non-metallic anti-seize for the same duties when temps are more extreme. For us mere mortals on our engine-compartment fittings, many cooled by fuel, coolant or oil flowing through, the Teflon thread-sealing paste is more than adequate plus a Lot cheaper and easier to find locally. A small tube or can will last longer than you remember where you stored it. At least in my case.

HTH!

[BennSport]

That’s all good to know Dr Bob! Digging up some research on the hose it appears to be Cohline 2633 high pressure hose, which I don’t believe is even fuel safe. Pretty sure this was replaced at some point by the PO, as it wasn’t the traditional fuel line with two different sized ends. The end that was connected to the fuel strainer was pretty damaged internally too.