Installing new interconnecting fuel lines on typical Ford fuel rails can be a bit frustrating. With the considerations and techniques I have developed below, re-doing a fuel rail takes all of about 1/2 hour. Follow along and I'll show you how I get this small but irritating job done quickly and effectively without practicing many cuss words.
Whether damaged during service, cleaning 20+ year-old crud out, or just not trusting old rubber-covered plastic on a factory fuel injector supply rail, removing and replacing the semi-flexible hose sections that join the rails can be problematic. You'll note that there are no clamps or other retaining devices on these hose sections. They are pressed-on at the factory and the combination of the special barbs and hose ensures they do not leak or pop-off while running at typical pressures between 25 and 65 psig. [b]Ford does not offer replacement high-pressure hose for this purpose, and while there are one or two suppliers I can get equivalent tubing from, the press-on installation should be performed with special tools and procedures to ensure the leak-free operation
that most of us do not have. This leaves me with three problems - how to get the old hose off without damage, what to replace it with, and how.
In the beginning. . .
First-up is old hose removal. This would seem easy enough with sharp tools, however any scratches, nicks, or other damage to the barbs will result in leaks and likely ruin the assembly for further use. I discovered that sharp tools have no place around these rails the hard and expensive way. So, I now have my slick and simple method to remove the old line without damage – the high-speed wire brush. It's much faster than cutting and, when done gently, will not risk damage to the rail hose barbs. I prefer a bench-mounted soft
wire wheel with light pressure to thin the old hose over the barbed fitting like this:
I do not press hard, I just let the spinning wire brush gently wear the hose layers away. It works by partially melting and partially abrading the hose layers away. It first passes through the soft outer rubber cover layer, and then into the hard nylon plastic inner layer. I run the hose back and forth against the wheel over a length of about 1” to be sure that I thin the whole section along the barbed fitting.
As the inner layer is removed, I will begin to see the shiny tips of the barb ridges begin to show through. To avoid damage to the barbs, I only brush away enough material to allow breaking the hose off the barb, using a motion like breaking a branch off a tree. The hose inner layer is hard and somewhat brittle and will 'snap' off the barb if thin enough. It only takes a matter of seconds to do the whole removal job on each fitting.
Okay, so what we thought would be the hard part was easy! Having removed the old line, I can now measure the barbs to verify what size replacement line I will need. I want to measure the small diameter between the barbs – not the larger outer tip diameter. Since I can't do a reliable job installing hard nylon high-pressure press-on line, I need something that will do the job properly as a replacement. It must be unaffected by common fuels and additives, withstand the constant high fuel pressure, be impervious to engine compartment heat, and be installed successfully in the home garage. While there are a few choices here, the most common and reasonably priced are fuel injection hose rated SAE J30R9, press-on ('socketless') 250 psi CPE fuel hose, and braided stainless steel covered fuel hose. These are all commonly available in various sizes, including the 1/4” (6mm) size generally found on these rails. Here are a few examples of the choices (ignore the sizes):
Goodyear SAE J30R9 rated EFI hose:
Aeroquip FC332 Series Socketless hose:
Earls Perform-O-Flex braided:
CPE Push-on 250psi hose:
***I DO NOT use the common and weaker J30R7 spec designed for low-pressure carburetor use. IT WILL FAIL with the higher pressures of EFI. I use only the J30R9 or better spec. J30R9 has a 100psi minimum working pressure and 900psi minimum burst pressure.***
While the braided SS hose is very sexy, it's certainly is not required, and is quite expensive. The exception is if I intend to race under rules that permit limited 'rubber hose' in the engine compartment. Specific rules vary, but the braided SS hose is usually not considered 'rubber hose' and will generally allow me to pass tech at the track.
Don't push it . . .
Okay, I measured the barbs, chose my hose, and it's time to put it on. Almost. While the factory rails have barbed fittings that did not use clamps, I must use clamps to secure my hose, as the barbs and hose I am now using are not originally designed to be clamp-less together. While I can use most any good quality clamp, I prefer the ABA style fuel injection hose clamps made by AWAB (often called Mini-G) for their full-circle clamping for a good seal and strength. These clamps are sold at most good parts stores and online. The 11-13mm clamps work well for most V8 interconnect hose sizes.
Push it . . .
Let's put it together! Well, this part is simple, sort-of. Because the barbs are meant for clampless sealing, they are larger than typical barbs and take quite some force to get the hose on. So, here's how I do it. I get set-up with my hose (pre-cut to the same length as the old lines plus one inch – explained below), and snug two clamps on facing opposite directions so I can push on them like this:
If I sized my fuel line correctly, pushing the hose on is not a 'slip-on' affair, and I need to use my strength to push on the hose and less to grip it. The staggered clamps help with this.
I lubricate the barbs and the inside of the hose (engine oil is fine), get a good grip with heavy gloves (those clamps can be sharp!), practice some choice words, and push the hose all the way onto the fitting in one shot. I only get one shot. If the installation stops half-way, I can't pull it back off, and it's very difficult to get it moving further on. One method to ease the installation is to dip the end of the hose in boiling water for 1 minute before quickly pushing it on the lubricated barb. Some use a heat gun to soften the hose, but if accidentally overheated, the hose will lose integrity and strength permanently and there is no visual way to confirm this.
Getting the hose on isn't that difficult, but it certainly isn't trivial force needed, so I plan accordingly. Why the extra inch? Now you know – if it gets stuck part-way on, I can cut the hose, wire-wheel the chunk off, and try again without cutting it too short. Having done this a few times, I no longer need the extra length, but it was nice to have the first few times in case I botched it.
With the ends pushed all the way on, I can loosen, move, and re-tighten my clamps over the barbed sections, then step back and admire my simple but effective repair and large amount of cash saved.