FDC Bypass Hose Question

[Hummer Guy]

I'm currently on the last part of bypassing the FDC which is routing the hose from the back of the filter to the hydrualic head but for some reason, I cannot for the life of me get the hose to seal up with the fitting, sleeve, and inserts. The question I have is do anyone know if there's a pre compressed hose with the fittings already on? Or is there any hose that's already crimped that I can get? I can't use the old hose, it broke soon when I bent it a little.

 

[cattlerepairman]

Depending which line, you can use DOT air line (replacement for the injector return line type of line; 1/4 inch with ferrules, inserts and fittings) or go to NAPA and get some line and quick change fittings for the larger diameter lines. Just bring all the takeoff stuff with you.

Instead of looping the line, you can plug all these openings:

FDC bypass info (yes, again)

Trying to bypass the FDC due to lots of fuel in the oil so hopefully this will fix the problem. Please check my work here, I don't want to tear up anything. I read all the FDC posts and just want to verify that I did it right (or wrong). 1. I installed the fuel line from the final filter...

www.steelsoldiers.com

 

[Hummer Guy]

Got a hose made at the local hose shop, they got me some really good high pressure fuel hose, definitely much better than the plastic hose on the truck and the hose that I got from napa to use with the ferule fittings.

 

[LowTech]

Depending which line, you can use DOT air line (replacement for the injector return line type of line; 1/4 inch with ferrules, inserts and fittings) or go to NAPA and get some line and quick change fittings for the larger diameter lines. Just bring all the takeoff stuff with you.

For some reason I was under the impression that I had two sizes of fuel lines around my secondary filters, but now i find that I have three. The 1/4" lines from my return, the 3/8" off my secondaries, and the as of yet unknown size that is connecting my secondaries to the bottom of the IP. Is that normal? I do have the FDC bypassed and plugged.

And what are these "quick change" fittings you're talking about.

 

[cattlerepairman]

For some reason I was under the impression that I had two sizes of fuel lines around my secondary filters, but now i find that I have three. The 1/4" lines from my return, the 3/8" off my secondaries, and the as of yet unknown size that is connecting my secondaries to the bottom of the IP. Is that normal? I do have the FDC bypassed and plugged.

And what are these "quick change" fittings you're talking about.

There are different styles, but the essence is the same. Cut hose, insert fitting into hose end (some have barbs and need to be pushed/pressed on, others have a nut-type tightening mechanism) and couple to outlet. Easy to disconnect and many styles have an automatic shutoff when the fitting is disconnected. That did not exist in the 1950'...........

Something like this, for example: https://www.aircraftspruce.ca/catalog/appages/quickdisline.php

 

[Jeepsinker]

All the fuel line upstream of the boost pump is either 3/8" or 1/4" . Just use DOT air line and compression ferrules with inserts. If it didn't seal you got something wrong. Check out some of my YouTube videos on this on tactical repair channel on YouTube.

 

[LowTech]

All the fuel line upstream of the boost pump is either 3/8" or 1/4" . Just use DOT air line and compression ferrules with inserts. If it didn't seal you got something wrong. Check out some of my YouTube videos on this on tactical repair channel on YouTube.

Not leaking as I haven't changed anything yet. I think it was an optical illusion. I had picked up enough 3/8" air line to replace old lines and then noticed that the particular line running between the two appeared larger diameter.
I didn't actually do anything as rebuilding the brake air pack is the current project, just picked up the line while I was getting other things.
This thread had me going back to it and checking w/ the only calipers I have on hand . . . an adjustable wrench, and they are the same 3/8", so we can disregard that statement.

 

[Floridianson]

If you're going to switch out to Synflex air line you have to buy two new DOT Synflex compatible fittings one for the head and one for the final fuel filter! Napa carries what you need. Final fuel filter gets a 90°, the head gets a 45°. Also don't be afraid to crank down on that nut as that Synflex is pretty tough stuff.

 

[LowTech]

If you're going to switch out to Synflex air line you have to buy two new DOT Synflex compatible fittings one for the head and one for the primary fuel filter! Napa carries what you need. Final fuel filter gets a 90°, the head gets a 45°. Also don't be afraid to crank down on that nut as that Synflex is pretty tough stuff.

Are you taking about changing the copper line from the primary?

 

[Floridianson]

Are you taking about changing the copper line from the primary?

Sorry I changed it yeah you caught me I said primary when I should have said final fuel filter. Whenever I use my phone and use the talk and text I usually mess up that and I don't prove read.

 

[LowTech]

Would I have to change out the fittings for all three of the lines coming off the finals, or just for that one?

 

[Jeepsinker]

For the record, I've never changed any of the original fittings when installing synflex. BUT.. you do have to get the right compression ferrules, which aren't as long. There's two types of ferrules. One is tapered like a sharp cone on each side with a pronounced rib in the center ( this one doesn't work). The other is shorter, has no rib and resembles a simple gold men's wedding band. The ribbed one is just too long and won't allow the nut to slide into the fittings far enough to engage the threads. You can make them work if you have no other option and take the time to file each side down and shorten them up but it's not advisable as they usually don't crush properly.

 

[Floridianson]

Would I have to change out the fittings for all three of the lines coming off the finals, or just for that one?

Instead of a long post it'll be easier if you went to Jeepsinker YouTube call tactical repair and watch it a couple times. And there's plenty other YouTube videos on bypassing the FDC and adjusting the fuel rate afterwards.

 

[LowTech]

For the record, I've never changed any of the original fittings when installing synflex. BUT.. you do have to get the right compression ferrules, which aren't as long. There's two types of ferrules. One is tapered like a sharp cone on each side with a pronounced rib in the center ( this one doesn't work). The other is shorter, has no rib and resembles a simple gold men's wedding band. The ribbed one is just too long and won't allow the nut to slide into the fittings far enough to engage the threads. You can make them work if you have no other option and take the time to file each side down and shorten them up but it's not advisable as they usually don't crush properly.

Thank you very much! Exactly the kind of info I need.

 

[LowTech]

Instead of a long post it'll be easier if you went to Jeepsinker YouTube call tactical repair and watch it a couple times. And there's plenty other YouTube videos on bypassing the FDC and adjusting the fuel rate afterwards.

My question was just about changing the type of lines used and whether I needed to change all the fittings. My FDC was bypassed about 15 years ago, like I stated earlier. I have no confusion about how to do that.

 

[Floridianson]

My question was just about changing the type of lines used and whether I needed to change all the fittings. My FDC was bypassed about 15 years ago, like I stated earlier. I have no confusion about how to do that.

Got confused this thread was about bypassing the FDC and the hose and fittings required. Trying to think of what lines you're wanting to replace and if they're not leaking why replace them.

 

[LowTech]

Got confused this thread was about bypassing the FDC and the hose and fittings required. Trying to think of what lines you're wanting to replace and if they're not leaking why replace them.

Right. Wanted to replace the line I bypassed the FDC w/ years ago and while I was at it I was just going to change the other two off the secondaries as well.
I've always liked using clear line so that I could see certain fuel issues but have learned over the years that the desert is hard on them. When they get "desert cooked" they break way too easy. It's a hard place for plastic & rubber.
Figured it's cheap insurance to replace/upgrade now while I'm working on other things and in "civilization" as opposed to somewhere out in the wilderness which is my usual repair place.
I may still use clear for 1/4" lines, that's undecided, but definitely don't feel like I need that on the lower 3/8" lines off the secondaries.

 

[Jeepsinker]

I wouldn't even bother with clear for the small lines. The returns always have air in them no matter what.