Fuel system plumbing question

[luna]

Those threads between the hose and the socket don't form a seal for whatever is being transmitted down the hose.
The seal between the hose and the fitting is made along the fittings taper where the drop of oil is being applied in step 3 and the inside bore of the hose.
The socket helps effect the seal as it does not allow the hose to expand as the taper is forced in by the turning of the nipple.

The hose and fitting are rated for a minimum of 400 psi. Whats the pressure in your fuel delivery system?

 

[Bmarler]

I think the part that's being missed is that the elbows are normal cast pipe. Normally on any JIC or SAE fitting, there are 2 hexagon areas. One is the swivel as part of the fitting on the hose and the other would be the adapter going into that cast pipe elbow. In post #76, fittings marked 1 and 2 one have one hexagon area.

There are cast jic fittings, but you are correct about these. I take back my earlier comment that they are flare.
They are more likely a different type of swivel fitting based on pipe thread but seal only at the end of the thread. I can’t remember what this is called right now, but maybe it will come to me. They’re common in hydraulic installations.

 

[O C Diver]

From what I think I see in the pictures, the JIC or SAE fittings that make the final connections are on each side of the pump. I don't see any pipe sealant on one thread section on each side of the pump. That would lead me to believe they're straight thread (flare fittings) at one joint, between the elbow and the pump body.

Ted

 

[Bmarler]

Have a look at this fitting. Salesforce B2B Commerce

I think the ones Jay pictured are the crimp on version of this. There’s a tapered cone at the base of the fitting that seals against the inside of a pipe thread nipple like the one coming from the elbow.

 

[paulga]

Those threads between the hose and the socket don't form a seal for whatever is being transmitted down the hose.
The seal between the hose and the fitting is made along the fittings taper where the drop of oil is being applied in step 3 and the inside bore of the hose.
The socket helps effect the seal as it does not allow the hose to expand as the taper is forced in by the turning of the nipple.

The hose and fitting are rated for a minimum of 400 psi. Whats the pressure in your fuel delivery system?

thanks, it's interesting to see how these fitting work.

I remember the fuel system is not pressurized, so 400 psi is adequate.

 

[paulga]

I think the part that's being missed is that the elbows are normal cast pipe. Normally on any JIC or SAE fitting, there are 2 hexagon areas. One is the swivel as part of the fitting on the hose and the other would be the adapter going into that cast pipe elbow. In post #76, fittings marked 1 and 2 one have one hexagon area.

Ted

the female fittings can have either 1 or 2 hex.
with an adapter, there could be 2 to 3 hex.

 

[O C Diver]

the female fittings can have either 1 or 2 hex.
with an adapter, there could be 2 to 3 hex.

View attachment 156746

You're missing the point. The adapter screwed into the pipe elbow, would also have a hexagon shoulder in addition to the fitting on the hose.

Still think the fitting to disconnect the assembly is located between the pump and the elbow.

Ted

 

[paulga]

You're missing the point. The adapter screwed into the pipe elbow, would also have a hexagon shoulder in addition to the fitting on the hose.

Still think the fitting to disconnect the assembly is located between the pump and the elbow.

View attachment 156747

Ted

Between the pump and elbow are a reducer and bushing. are you saying this is where the pump should come off? but there is no swivel part here.

 

[O C Diver]

Between the pump and elbow are a reducer and bushing. are you saying this is where the pump should come off? but there is no swivel part here.


View attachment 156751

I could be wrong, but screwed into the pump appears to be the adapter, then threads, then a larger hexagon nut. If the theads don't have any sealant on them, I would think that is the fitting that comes apart. IMO, the assembly includes the center hexagon nut and the one screwed into the elbow. Basically, if I'm correct, you want to put a wrench on the adapter screwed into the pump and another wrench on the center hexagon nut. I would look carefully for sealant on the threads in question first.

Ted

 

[luna]

It's not that I disagree with you, at this point I'm not sure, but what actual sealing design do you expect to find inside the center hex nut, should it be where the assembly initially comes apart?

If in fact the assembly is constructed in this manner that means that the order of assembly was that the constructor had to assemble the fittings, including winding the elbows onto the end of the loose hoses which already had their lengths fixed, then assemble the fittings that lie horizontal, connect them to the pump and finally mount the pump's motor to the bulkhead.

This is exactly backwards as to what an experienced hydraulic installer would do as SOP would dictate that you mount the fixed parts first and make the hose length the final variable and the hose itself the final connection. This method of assembly also results in the luxury of when the hose fails, you can easily remove and replace only the hose leaving everything else intact. What a concept!

It's a 40' Marine Trader, likely 40 years old, the surprises it holds are legion.

 

[O C Diver]

It's not that I disagree with you, at this point I'm not sure, but what actual sealing design do you expect to find inside the center hex nut, should it be where the assembly initially comes apart?

If in fact the assembly is constructed in this manner that means that the order of assembly was that the constructor had to assemble the fittings, including winding the elbows onto the end of the loose hoses which already had their lengths fixed, then assemble the fittings that lie horizontal, connect them to the pump and finally mount the pump's motor to the bulkhead.

This is exactly backwards as to what an experienced hydraulic installer would do as SOP would dictate that you mount the fixed parts first and make the hose length the final variable and the hose itself the final connection. This method of assembly also results in the luxury of when the hose fails, you can easily remove and replace only the hose leaving everything else intact. What a concept!

It's a 40' Marine Trader, likely 40 years old, the surprises it holds are legion.

What makes you think a professional installer had anything to do with this?

The installer intentionally builds a design where the horizontal line valve can't be opened all the way and then fails to put isolation valves on either side of the pump at the horizontal line tees.

My only logic for the installer planning the disconnect fittings on either side of the pump was to be able to remove the pump for the inevitable impeller or pump replacement from such a FUBAR design.

Ted

 

[Bmarler]

While a coupling on either side of the pump isn’t a bad idea, I don’t believe that’s what we see.
I see a pipe thread to o ring boss adapter going into a male by female ( or a hex coupler and close nipple), into a bushing, then the elbow.

 

[luna]

It looks like from the pump body design that this is a gear pump, so no impeller to change.

The large hex fitting on both sides of the pump could well be the pressure reducing valve that Reverso provides on some of its pumps, see below.

GP-302B-12

Bypass Pump - GP-302 Series 12 Volt - 10 PSI - is available at Reverso Pumps

reversopumps.com

If so, it is not a fitting designed to come apart as there is tape sealing the NPT? threads that are used to assemble the valve.

I guess that the installer felt that 2 valves we needed as the pump reverses, but it does not appear to me that as plumbed the 2 P. R. valves would actually work as there is no place to vent the excess pressure.

 

[paulga]

While a coupling on either side of the pump isn’t a bad idea, I don’t believe that’s what we see.
I see a pipe thread to o ring boss adapter going into a male by female ( or a hex coupler and close nipple), into a bushing, then the elbow.

this is an 3/4"-16 ORB (also known as UNF threads) to hose barb elbow. The only part that swivels is the the locking nut (yellow arrow). After ORB thread is hand tightened, before setting the locking nut, how to adjust the direction of the barb?

 

[Bmarler]

this is an 3/4"-16 ORB (also known as UNF threads) to hose barb elbow. The only part that swivels is the the locking nut (yellow arrow). After ORB thread is hand tightened, before setting the locking nut, how to adjust the direction of the barb?

View attachment 156757

You assemble it till there is no more thread to make a complete turn, then aim and tighten the lock nut.

 

[paulga]

You assemble it till there is no more thread to make a complete turn, then aim and tighten the lock nut.

Thanks. so apply the lock nut just before the orb is fully hand tightened

 

[Steve DAntonio]

That setup is an accident waiting to happen. The first pipe nipple after the filter looks to be thin wall brass. Brass fatigues from vibration and is easy to shear off. Normally a manifold is mounted to a wall with a hose between it and the filter to reduce the mechanical leverage on that first nipple.

To your question: if the valve is closed on the other end, a one pint container would easily catch all the fuel in hose. If you plan to replace the hose, a pair of Vise grips or clamp can be used to pinch the hose closed just past the fitting you are removing it from. Always good to have a roll of paper towels or several boat diapers handy when working with diesel, oil, or antifreeze.

Drain the filter bowl first!

Ted

There is no problem using cast or machined (thin wall water plumbing would be a problem) brass pipe fittings with fuel systems, they are actually pretty durable, and very common, however, I agree this is an accident waiting to happen. Hose A appears to be connected to the rigid plumbing using a pipe nipple rather than a pipe to hose adapter, that's not good and it is a violation of ABYC standards, fuel supply hoses cannot be terminated on threads or smooth pipe. Fuel hoses and wiring cannot be supporting each other or bundled together, that too is an ABYC violation.

Filters lack heat shields and metallic drains.

All that leverage, yikes! Too much rigid plumbing connected together, it either needs support (mount on a bulkhead) or it needs be be isolated with hose.

KD Tools does make a locking pliers that is designed to pinch off hoses. https://www.lowes.com/pd/KD-Tools-Automotive-Radiator-Hose-Pinch-Off-Pliers/50190595

 

[mrfixit48]

The engine racor input is leaking at a joint, I'm going to disconnect the three hoses A B C, then remove in order the copper pieces DEFG (blue), clean and reapply thread dope then reassemble, then monitor if the leak would continue. The question is how to make a smaller mess in this process.

View attachment 156405

First, the thicker hose A is traced back to the valve on the portside fuel tank.

View attachment 156406

Because the same valve on the starboard side tank has always been off.

View attachment 156407

With the port side valve shut off, there are still lot of fuel in the hose.

Second, hose B and C are in and out of the priming pump. There is also fuel in these hoses

Do you use some tool to plug the hole immediately when taking the hose off the barb?

Depending on the condition of your fuel hoses (pliable or brittle) which changes with age, you can simply pinch off the line close to the fitting and retain all the fluid in the line. This will also help minimize the amount of bleeding you will need to do after your repairs. They make pliers specifically for thus purpose in a variety.of sizes to accommodate the different size hoses on your engines cooling and fuel systems. Not a bad thing to have on board for emergencies either. You could use vice grips or a c-clamp in a pinch but both those options run the risk of damaging your hose if not used with some sort of protective material. The hose pinch pliers are designed not to damage the hose. Be sure to have plenty of oil absorbent pads handy as well. Good luck with your leak, never a fun task.

 

[paulga]

Depending on the condition of your fuel hoses (pliable or brittle) which changes with age, you can simply pinch off the line close to the fitting and retain all the fluid in the line. This will also help minimize the amount of bleeding you will need to do after your repairs. They make pliers specifically for thus purpose in a variety.of sizes to accommodate the different size hoses on your engines cooling and fuel systems. Not a bad thing to have on board for emergencies either. You could use vice grips or a c-clamp in a pinch but both those options run the risk of damaging your hose if not used with some sort of protective material. The hose pinch pliers are designed not to damage the hose. Be sure to have plenty of oil absorbent pads handy as well. Good luck with your leak, never a fun task.

yes, i also thought pinching a twenty years old rubber hose risk cracking it.
I bought some barb inserts to cap the hose quickly.

 

[paulga]

I tested some large wrenches on the 3 way valve. photo 1 shows a new valve. Photo 2 and 3 show the actual setup where holding is needed. The only way to apply some grip I found, is using a 22mm open end wrench (photo 4) or a pipe wrench ( photo 5) around the bull, due to the unique shape of the valve, as shown in photo 1. I'm not confident about holding it this way.

I have also considered a channel lock, but there is not something nearby to lean the handle against. I noted there is a machine screw on the metal rack directly behind the valve. is it possible to make a 90 angle metal bar or something similar to install on the rack to provide leverage to the channel lock?

 

[O C Diver]

I tested some large wrenches on the 3 way valve. photo 1 shows a new valve. Photo 2 and 3 show the actual setup where holding is needed. The only way to apply some grip I found, is using a 22mm open end wrench (photo 4) or a pipe wrench ( photo 5) around the bull, due to the unique shape of the valve, as shown in photo 1. I'm not confident about holding it this way.

I have also considered a channel lock, but there is not something nearby to lean the handle against. I noted there is a machine screw on the metal rack directly behind the valve. is it possible to make a 90 angle metal bar or something similar to install on the rack to provide leverage to the channel lock?





View attachment 157620View attachment 157621View attachment 157622View attachment 157623View attachment 157624

All of those should work, probably the best on brass would be a tubing wrench as it will contact more flat surfaces on the fitting. Understand that the best technique is to use two wrenches in this situation. Put one on each fitting so that you are pulling the two wrenches together with one hand, sort of like using a pair of scissors. This works for tightening or loosening.

Ted

 

[paulga]

All of those should work, probably the best on brass would be a tubing wrench as it will contact more flat surfaces on the fitting. Understand that the best technique is to use two wrenches in this situation. Put one on each fitting so that you are pulling the two wrenches together with one hand, sort of like using a pair of scissors. This works for tightening or loosening.

Ted

one wrench on the yellow dot, the second wrench on the purple dot, then squeeze the juicer. will this action prevent the first wrench from rotating? the nipples at both ends of the Y look very vulnerable, even a small rotating on the yellow dot may cause leak later.

 

[O C Diver]

one wrench on the yellow dot, the second wrench on the purple dot, then squeeze the juicer. will this action prevent the first wrench from rotating? the nipples at both ends of the Y look very vulnerable, even a small rotating on the yellow dot may cause leak later.

View attachment 157672

Practice it a couple of times with your new fittings. In essence, if you're pulling against the other wrench (squeezing the two wrenches together), there should be no torque on the nipples. It takes a little practice and proper placement of both wrenches.

Ted

 

[paulga]

Practice it a couple of times with your new fittings. In essence, if you're pulling against the other wrench (squeezing the two wrenches together), there should be no torque on the nipples. It takes a little practice and proper placement of both wrenches.

Ted

I will test it on the new fittings.

but there is also a nipple b/t the Y and T in my photo. This nipple has no hex, so it takes both hands, a wrench/channel lock on the yellow dot and a vise grip on the nipple, to remove it, right? that is where I thought a rigid structure like a metal bracket could provide support.

 

[O C Diver]

I will test it on the new fittings.

but there is also a nipple b/t the Y and T in my photo. This nipple has no hex, so it takes both hands, a wrench/channel lock on the yellow dot and a vise grip on the nipple, to remove it, right? that is where I thought a rigid structure like a metal bracket could provide support.

Don't worry about the close nipple. If it unscrews out of the "Y" valve, put one in with a hex center section. If it stays in, screw the next fitting on to it. If you want to remove the close nipple, use the an easy out extractor.

Ted

 

[paulga]

Don't worry about the close nipple. If it unscrews out of the "Y" valve, put one in with a hex center section. If it stays in, screw the next fitting on to it. If you want to remove the close nipple, use the an easy out extractor.

Ted

last time you mentioned using a pair of vise grips to remove the close nipple.
I have also heard ppl talking about channel lock pliers oftentimes
I have this set of Irwin vise grips. Are these actually channel locks? they have curved, serrated jaws. I have also seen flat jaws, smooth/soft jaws. Are these curved serrated jaws suitable to grip around a plumbing hex or a close nipple?

if I google "vise grip", the most relevant image is this, so there seems to be some nuances within the vise grip category.

 

[dhays]

Naming can be an odd thing. Both Channellock and Visegrip were initially trade names. The first set of pliers you show are adjustable pliers that I would call channel locks. Growing up, my dad called them "water pump pliers". The jaw width is adjustable but they don't lock closed.

The second is what I would call vise grips. It has adjustable jaws but the key is that they have a cam-lock which allows them to grip something without you having to continue to squeeze them.

However, just because I call them that doesn't mean that is what they really are.

 

[paulga]

The first step is to disconnect the 3 rubber hoses. This requires some wiggling actions that are risky for this delicate system. Is it easy to cut through the close nipples as shown below, using an oscillating saw blade on a multitool?

 

[KnotYet]

The first step is to disconnect the 3 rubber hoses. This requires some wiggling actions that are risky for this delicate system. Is it easy to cut through the close nipples as shown below, using an oscillating saw blade on a multitool?

View attachment 157721


View attachment 157722

I wouldn't advise doing that. Getting the hoses off is no obstacle, I've never once
thought I needed to saw a perfectly good fitting instead of removing a rubber hose.
Don't over think this. None of this is particularly challenging or even difficult.

 

[luna]

Should you saw through the close, how do you later grab the 2 halves to remove them?