Slow Injector Pump Leak

[shanegeard]

I have a Perkins 4-108 that has a couple of slow drips from where the injector pump outlet pipes connect to the pump body. I've tried replacing the two steel washers at each connection with no luck.
Bearing in mind that it was a whole day operation to remove the pump, can anyone offer a tip on a sure way to seal these connections? Are copper washers better? Should I use some kind of thread lock?

[captd44]

I would definitely use copper.

[rbk]

^^Ya I'm pretty sure they're copper or aluminium washers and should be replaced each time they are removed.

[billknny]

I would strongly suggest that unless you REALLY know what you are doing, messing with the high pressure side of the injection pump and its associated plumbing is a job for a specialist. Even the typical mechanic doesn't have the tools or test equipment to open up an injection pump and get it put back together reliably.

It is possible that the tubes are cracked. If they weren't before, they might be now if you used steel washers in an attempt to seal them and cranked down tight to try to stop the leak.

[Compass790]

Yep use new copper washers. As a last resort I have found that putting a thin smear of Loctite 518 flange sealant on both sides of problem washers can stop them leaking. BUT you must run the motor before it cures in case any gets in the fuel ( within say 10 mins )
Thought I'd better add that warning before someone screams " you can't do that"
Well guess what I've done it a few times.
Let us know if copper washers cure the problem. Brake repair shops have lots of them if you don't know of any easy source of copper washers

[shanegeard]

Thanks for the replies... I'll try copper washers on the leak I can access without having to remove the pump.
I'll certainly report back on the results.

[bioandy]

Definitely, use copper crush washers. If you must reuse any copper crush/sealing washers, you can heat them with a propane torch till they're cherry red hot and let cool to restore their softness and sealing properties. remove any imperfections in the sealing surfaces of the washers by lightly sanding them against a flat surface with very fine sandpaper (220grit or finer).

[oldtom]

Originally Posted by shanegeard

I have a Perkins 4-108 that has a couple of slow drips from where the injector pump outlet pipes connect to the pump body. I've tried replacing the two steel washers at each connection with no luck.
Bearing in mind that it was a whole day operation to remove the pump, can anyone offer a tip on a sure way to seal these connections? Are copper washers better? Should I use some kind of thread lock?Attachment 189420Attachment 189421

that's your problem ( the steel washers) should be copper cav have tin coatin go to a fuel pump shop they have the correct ones get a set plus spares very cheap

[01kiwijohn]

Should be copper. No loctite nor sealant. Check mating faces for any imperfections.

[boatnerd]

Definitely dont put any sealant on them. Just use new ones. Get the CAV seal kit with all the bits n bobs. If your brave reseal the entire thing. Its not that difficult. The CAV can be serviced by a competent mechanic. Checkout "Bundy Bear Shed" on youtube. I did our CAV. Kit cost $30 and took under 2 hours to change out 20 seals, washers, tiny filter, and a ball bearing. Most important is to not alter any setting and be clean/organized. I did it all in the cockpit and work out just fine.

[Compass790]

Yep knew that people wud say you can't use sealant like an anaerobic type. Betcha not one of them has tried it tho. At least none of them has screamed. I still say that new copper washers shud be ok tho.
Boatnerd sounds like a good tip.
P.s. I rebuilt our injection pump despite the fact that everybody said it was impossible for a layman. Took me 2 attempts but now I'll never be afraid of an old style mechanical injection pump again.
If I can do that you can fix leaking high pressure injection lines I'm sure

[boatnerd]

Good source for perkins parts.

[shanegeard]

Originally Posted by boatnerd

Good source for perkins parts.

That looks like a great site, thank you. I had the pump rebuilt professionally about a year ago, so the seals should be good. I'll try the copper washers when I manage to get into town to get them.