Leaking tank connector

[LostAtB]

Hello,
I’m new to posting on the forum, but have certainly learned lots by lurking and reading other posts, so thanks!

I have enough mechanical experience to generally muddle through and figure out most maintenance and repairs, but one area where I lack experience is in diesel storage. We noticed a small amount of diesel in the bilge and traced it to the hydraulic hose connecting two of our tanks. I need to replace this hose and would appreciate any insight. The specific questions I have are:

What type of hose is it? I’ve been unable to track down the material of the hose, I’m certainly open to using something different, but would like to have the current material in the running as I make a selection. I believe it’s 5/8” I.D. and 1 1/16” O.D.

I’ve not been able to find the exact fitting, but the closest thing I can find requires a mandrel to install it on the new hose. Is this absolutely required (or can it just be done cautiously and if damaged is it detectable)? If so, is it the same as one used for the high-carbon steel fittings that look similar?

Also, I plan to take the 2 smaller tanks offline while we’re just sailing locally. Last season we used around 1/3 of our total capacity, this would make it closer to ½ if we do the same amount again this season. I plan to clean the tanks and use fogging oil on the inside. Does this plan sound reasonable? And would this be a good choice for the gaskets on the inspection covers: https://www.amazon.com/Small-Parts-B...0075DXOCG?th=1

[GordMay]

Greetings and welcome aboard the CF, LostATB.

Hardwall 100-0340 is a high temp. (250°F) water hose, to SAE J2006-R2, for non-fuel uses.
➥ - 100-0340 TRIDENT 3/4" ID x 50' coil-Trident Hard Wall Wet Exhaust/Water Hose, Black, 250°F, SAE J2006-R2, Lloyd's | MMIMarine.com
I can't identify the other, unmarked hose.
Diesel fuel hose should be USCG Type A1-15, and SAE J1527, ISO 7840 compliant.

[a64pilot]

If that hose isn’t a Hydraulic hose, it’s doing an excellent job of imitating one, take it to a farm tractor place, it will take them five minutes to make and pressure test you a replacement.
If in a rural area any NAPA parts house can also do it, but even in a city there are forklifts etc so hoses are easy to have made up. Yes you can do it yourself, but I never bothered.

[LostAtB]

Thanks for the replies. Yes, I do think it is hydraulic hose, I was wondering if it was anything special, most things I've been able to find with a braided cover are in stainless steel. And I liked the idea of being able to field service the hoses, but yeah, you're probably right about not bothering with it. Especially for a hose that could relatively easily be bypassed by manually transferring fuel.

[a64pilot]

Almost all hydraulic hoses are high pressure and as such most all have a braided steel covering, but it’s mild steel, that is actually stronger than stainless steel, they also have a rubber protective cover over the braided steel.
Usually the ends can be removed and reused, but it takes special tools to do so correctly and unless you have a spool of hose and replace busted hoses frequently, it’s far easier to just take the old one into a shop and in literally 5 min they will have you a new hose identical to your old one, and usually pressure tested too.
Probably not technically legal as fuel hose, but I can imagine that it exceeds by a large margin anything a fuel hose is required to meet, including permeability.

[Steve Bean]

Hydraulic hose and proper hydraulic fittings seem like expensive overkill for a low-pressure diesel fuel application.

[a64pilot]

Originally Posted by Steve Bean

Hydraulic hose and proper hydraulic fittings seem like expensive overkill for a low-pressure diesel fuel application.

It is, I was figuring though on everything is already there, just replace the hose if it’s needed is easier than converting to regular hose. Should last well forever pretty much too.

[LostAtB]

I agree on the overkill, from what I've seen that's a couple hundred dollars worth of fittings on the 2 lines! But since that's money already spent, I'll look into having just the hoses replaced. I'll keep in mind that I could just buy some nipples and regular fuel hose if that turns into too much money. Thanks.

Any thoughts on amazon gasket material? I like the price and convenience for sure, but don't know if there are better options. tanks are medium-thin steel (sorry for the lack of precision!) x2 and 1/8" aluminum x2. All covers are around 9" square or circle.