Small fuel leaks.

[minerigger]

So I recently installed the DHD super high flow fuel block and lines. All in all a great product, only issue is I can't get any of the fittings in the block to seal and the hoses are slowly seeping even with clamps on them.

So my question is, can you use pipe dope on them? I have a can of blue monster pipe dope and it says it is diesel oil rated, but I don't know that the fuel system is pipe dope rated. Curious what you more experienced guys have used in the past

 

[Ne-max]

I had this issue also. Just kept going tighter. Finally they sealed. I'm not impressed with mine.

 

[56taskforce]

Use the sealent just ensure to leave the fist few threads bear. Assemble the fittings and unit on the bench then install it on the truck. Replace all the rubber hose and use new quality hose clamps. The quality of any part is only as good as the quality of the install:thumb:

 

[LBZ]

What kind of fittings does it use?

 

[56taskforce]

What kind of fittings does it use?

Good catch I was assuming they are pipe let me rephrase that, use the sealant if they are pipe thread:hug:

 

[minerigger]

I had this issue also. Just kept going tighter. Finally they sealed. I'm not impressed with mine.

You used the dhd setup? I'm afraid if I go tighter with the brass fittings I'll break them or the aluminum block

What kind of fittings does it use?

Brass barbed fittings with npt threads into an aluminum fuel block

 

[LBZ]

Ok. Ya one definitely wants to use pipe dope on NPT threads. Liquid Teflon is preferred to tape if available.
I'm not a fan of brass into aluminum but it works. Anodized aluminum or stainless fitting would be better IMO if available.

 

[Ne-max]

You used the dhd setup? I'm afraid if I go tighter with the brass fittings I'll break them or the aluminum block

Brass barbed fittings with npt threads into an aluminum fuel block

Yes. I tried tape. No luck.

 

[minerigger]

Well shit. I put em in a vice and cranked them fittings in. Guess I'll try some dope and see where I get. But I need some better clamps to. Those crappy screw type don't get tight enough before they strip and come loose

 

[Ne-max]

I noticed that myself. The bad part is that its low pressure and still leaks

 

[minerigger]

Exactly. I couldn't imagine if it were high pressure

 

[minerigger]

Any idea on where to get some better clamps?

 

[Dallas S]

My local hydraulic shop stocked tiny tbolt clamps. Have some on 5/8" and 1/2" line.

 

[Awenta]

I hate those screw clamps. Always leak. I switched to Oetiker style clamps and never looked back. Hold 200 psi air with no leak in over a year.

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[Awenta]

Oh and I prefer gasoila as far as pipe dope goes. Put a turn or two of the yellow Teflon and dope over that.

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[minerigger]

I hate those screw clamps. Always leak. I switched to Oetiker style clamps and never looked back. Hold 200 psi air with no leak in over a year.

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Do you need a special crimp tool? And will blue monster pipe dope and tape work or would a soft set be better?

 

[Awenta]

Do you need a special crimp tool? And will blue monster pipe dope and tape work or would a soft set be better?

It helps but you can get away with using end nips like this and go by feel. I have the tool but end up using a knapex version of these most of the time.

http://www.amazon.com/gp/aw/d/B000N...SX200_QL40&dpPl=1&dpID=31H0PjPo6jL&ref=plSrch

I prefer a soft set just for future disassembly. But it should be fine. Don't use the white Teflon, it dissolves. And just a turn and a half will do it. More is not better here haha.

On a side note I don't use Teflon anymore for air or hydraulic fittings. Just gas and water. I switched to loctite 545 and it's awesome stuff. Doesn't leak. Don't know if it's rated for diesel though.

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[minerigger]

I know the blue monster with ptfe is diesel fuel oil rated but I figured the white stuff was not. When you say turn and a half you mean once the fitting is in just a turn and a half?

Thanks for the link

 

[Awenta]

Sorry, I meant a wrap and a half of Teflon tape. Get the fitting snug.

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[LBZ]

I have been using the white 565 Loctite for 20 years and it is fine for diesel. The 545 is also good. 565 is fast cure, 545 is high temperature. Both are anaerobic and cures in the absence of air-like most loctite products for thread sealant.

The reason it is a good thing that it dissolves is that if somehow some of it gets in your fuel or hydraulic system etc. it washes away and doesn't block or get stuck anywhere. This is where Teflon tape is not the most recommended material to use on any fittings where small valves and moving parts are in the system. I've seen it first hand. It is a pia. That said if you don't clean both of the threads well and it has fuel in them, there is a good chance it will never cure. It has to be clean.

The primary purpose of it isn't just to seal but also be a lubricant to help obtain positive thread engagement of the tapered threads hence the Teflon, and the sealant part helps fill in the imperfections in the mating surfaces. If you have really bad threads or egged fittings/holes not much will help you. This is why black pipe needs thread tape as it has more imperfections.

IMO brass into aluminum, although it works, is a piss poor way to go. Anodized aluminum fittings into aluminum are much better but more costly. I would even go stainless over brass. Brass and aluminum together react and cause corrosion. I've rounded too many fittings off trying to get them out of aluminum ports in low pressure hydraulic and air valves after a couple years.