Fuel leak, old subject & looking for an idea

[Claude L.-Auger]

My turn to be hit by a fuel leak. Can't really complain as I have not had any in at least a decade. Yanmar 3Gm30F. Replaced both Racor filter and Yanmar small filter (# 104500-55710) late last year and have had a leak since. Looked like it was coming from the Yanmar fuel bowl, and I had pads under the engine to collect the spilled fuel).
So this week-end, although I had already done so when changing the filter, I replaced the O'Ring with another original (# 24341 000440). Still leaking so I got another O'ring, this time not a Yanmar, but same diameter and slightly a little thicker. Case closed or so I thought. No more leak at fuel filter !
But enough of a leak at both the fuel lift pump outlet (circled on pics) and at fuel line inlet into fuel bowl that I could now see the droplets falling. So, I installed new banjo washers at both ends of meshed fuel line. Solved the leak at fuel bowl inlet end of line, but still leaking at fuel lift pump outlet.
And the problem seems to be that I cannot tighten the line tight enough. And putting more torque lets it slip rather than sitting it tight enough. I can replace the washers again but wonder about the impossibility to tighten it correctly ?

So my questions are twofold: 1) Could the threads in the lift pump have been damaged by my torquing it too much, and 2) If that is the case, can a Helicoil be used to repair the threaded area or do I need to buy a new lift pump (outch that will probably hurt $$$$)
Inspection with a paper towel and bare hand show all areas on pics to be dry as a bone except the fuel line connection at the lift pump, in spite of the new banjo washers.

 

[Charles Erwin]

Copper crush washers. Try this. Remove washers. Grab with pliers. Heat til red drop in water. This makes them soft. Then hand tight plus a bit to seal. Don’t mash them. The seal happens by compression. Too tight they will leak. Otherwise examine surface at pump, banjo fitting and bolt. These need to be dead smooth. No nicks. Pressure here is less than 6 psi so firm tightness is all you need. Check washers for no scores too

Charles

 

[kloudie1]

Helicoil..but be really careful to keep any shavings out of the pump..
Last time I did the fuel filter, I replaced the washers with Dowty washers.. like a copper crush washer but has an o-ring bonded to the inside. Not a leak since.. I don't remember the sizes .. an o-ring supply house should have some.
Hope all is good out your way, Claude.

 

[Charles Erwin]

Oh by the way - these hoses are plain fuel line with woven over jacket. Have had several where rubber failed — invisible because of the over jacket. Replaced with new fuel line, hose clamps, and banjo end fittings. That way rubber hose leaks are no longer hidden. Can send photo if not clear.

ps. If pump then new is $90 US about. Don't discard old. Likely can coil —- if spiffy clean is your forte

 

[lehighsail]

My understanding years ago from Mack Boring, is that these sealer type washers should not be reused.
New replacements every time the joints were opened.

 

[heritage]

Here is a link to purchase the Dowty washers that kloudie1 mentioned: http://shop.toadmarinesupply.com/sh...sults&pn=22190-120002&storetype=mdd&x=12&y=10.

Yanmar is using this fuel seal in their newer engines instead of the copper only washers. There are a couple of the banjo fittings that are 8mm instead of 12mm. The 8mm dowty seals are Yanmar part #22190-080002.

 

[Claude L.-Auger]

Thanks guys, your answers gave me kind of a work in progress idea as I'd like to avoid the hours of work involved in removal of the fuel pump since the pump is not the cause of the leak. So I'll start with Charles' idea of softening the crush washers. If that doesn't work, I'll look for a source for the Dowty washers here in the Montreal area. And if that doesn't work either, I'll resort to either the helicoil or a new lift pump. Considering the time involved for pump removal and re-installation, I'll need to weigh the pro & cons (read $$$) of the helicoil versus a new pump. I'll report on success when achieved and how. Thanks again. And Claude, things not so hot as I'm waiting for open-heart surgery later on this summer so no sailing trip this year. Sailing everyday in the meantime as otherwise I am in great shape.

 

[FastOlson]

Around here those "washers" with an O ring bonded inside an Aluminum outer washer are called "bonded washers" and I found them at a store that sells oil filters and all sorts of hose and fitting parts. Appropriately it's called Oil Filter Service Company, in Portland Oregon. Those guys know a ton (!) of trivia about their niche business.
I was repairing a leak in the banjo fitting for the pan drain hose on our former Universal diesel engine, and the old metal (alum. or copper) washer would not seal. Later the same fix totally stopped a drip from the drain plug on our Hurth transmission.
I found out that these are quite common in industry.... and cost $.50 each. Retail.


It was so exciting that I put up pictures in a Blog posting on the Ericson site.

Claude, all of my best wishes for a happy outcome, regarding the surgery. A friend of mine just spent 12 hours in the O.R. for repairing an aneurism, beside the heart. (!)
He is recovering, but it will take six months plus, at least. He was in great physical shape, but 'stuff happens' even to those who look like they will live forever.
Take care.

 

[Claude L.-Auger]

Thanks FastOlson, thanks for your wishes. And I did find a source right around my home. Around here they're called B-seals and what I got is described as B.Seal - NBR/STEEL. At $1.17 (CDN $) they are cheaper than the Banjo washers from Yanmar.
Charles, thanks for your suggestion. I tried heating until red and then dropping in cold water and it is still leaking. So I will try the Dowty washers tomorrow, even though by now I think the threads are stripped on the pump as I could not tighten tight enough to really seat the banjo bolt properly.
Claude, an automotive machine shop who rebuilds a lot of aluminum heads said that helicoils were not recommended in areas where fuel or oil is being moved. How did they install yours and am I wrong in thinking the fuel pump body is aluminum ? The good news is that much to my surprise the Yanmar dealer only wants $128 (CDN $) for a new pump and has it in stock. I'll know tomorrow if I have to go that way.

 

[Charles Erwin]

I have no doubt you will be back solid not leaking anyplace for any reason. Just hang tough as we say out west.

Personal regards

Charles

 

[kloudie1]

Wishing for a good outcome, Claude.. sorry to hear but good that they're going to get you fixed up !
The pump body is aluminum or some kind of shiny soft metal.. Helicoil folks recommend a pipe dope to seal them .. I am guessing that to install the coil, the top of the pump would have to be removed and doped with fuel proof stuff then cleaned up so none of the dope could get into the injection pump.. Your idea of a new one is probably the way to go for best results..

 

[Claude L.-Auger]

Thanks Claude,
Tried the Dowty washers. Could not seat the fuel line properly to the pump because impossible to tighten even a little bit. Just needed to activate the pump with the lever to get a gusher of fuel. So took pump out and saw the reason for the leak: all threads inside aluminum body of pump mashed beyond use. See pic. Probably my fault in overtightening when first trying to stop leak. . Bought a new pump and gasket as well as banjo bolt and washers and re-installed. Let engine run at 1200 RPM in gear for 20 minutes. No leak anywhere ! Will try to find someone to install helicoil in old pump and keep as spare if cost justified. Thanks everyone.