U320 Fuel Shut Off Valve - Location/Installation

Topic: U320 Fuel Shut Off Valve - Location/Installation (Read 1790 times) previous topic - next topic

U320 Fuel Shut Off Valve - Location/Installation

December 18, 2017, 03:32:27 pm

I'm in the process of retrofitting my Racor Diesel Filtration assembly and am planning to change the pre-filter element out while I'm in there. I've located all of the parts but cannot find a fuel shut off valve to keep the head pressure from the fuel tank from flowing out of the open holes. Does the 1998 U320 have a manual fuel shut off valve upstream of the filter elements?

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #1 – December 18, 2017, 03:42:09 pm

jrmills76,

No, to my knowledge no Foretravel has a shut-off valve on the inlet to the primary fuel filter from the factory.

But, a diesel-compatible ball valve there makes a LOT of sense and a number have retrofit one there.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #2 – December 18, 2017, 04:35:45 pm

You will probably have little leakage from the fuel line if the tank isn't extremely full and if the front of the coach isn't higher than the rear. While a shut-off valve is probably a good idea, I haven't had any problems changing the assembly without having a shut-off valve.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #3 – December 18, 2017, 04:47:44 pm

Actually, the larger problem is if the primary fuel filter head is HIGHER than fuel level in the tank. Then when you remove the filter, fuel drains out to the tank, leaving you with 30+ feet of AIR that has to be bled out.

So, I would sure like to see a little fuel leaking out the filter head! Also, have the new filter ready to go (I keep a spare clear bowl and set up the new filter before removing the old one).

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #4 – December 19, 2017, 11:57:34 am

Great feedback! I plan to run the tank to ~1/2 full and install a ball valve for future work. One mechanic stated he carries an assortment of rubber stoppers for emergency fuel plugging if required while on the road. I plan to add them to my onboard tool assortment as well. Thanks again for the help!

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #5 – December 19, 2017, 12:10:05 pm

While rubber stoppers are not a bad idea, but, unless you take the fuel line off the filter, I don't see that it would help (the filter head inlet is not really set up to accept a stopper).

Again, a "diesel compatible" ball valve is a very good option, and a heck of an anti-theft device!

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #6 – December 19, 2017, 10:34:26 pm

I bought a couple of fuel line clamps that pinch the lines when I change the fuel filters. There are a number of styles; I've attached one below.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #7 – December 20, 2017, 09:30:19 am

Sven,

Particularly on older fuel lines, I would not use them-- too easy to crack the hose and get a leak.

Heck if OE fuel lines of that vintage, it is very common for cracks to develop that suck air in (suction side of fuel system).

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #8 – December 20, 2017, 10:14:54 am

Quote from: wolfe10 – December 20, 2017, 09:30:19 am

Sven,

Particularly on older fuel lines, I would not use them-- too easy to crack the hose and get a leak.

Heck if OE fuel lines of that vintage, it is very common for cracks to develop that suck air in (suction side of fuel system).

If your fuel lines are in this condition, you have a larger problem than attaching a fuel line shut off valve - time to change the fuel lines! If this isn't possible, you could also cut the hose, use a coupler and a small length of new hose for the purpose of pinching. Whenever I pull off a rubber hose, I squeeze the end and look for cracks around the perimeter. I would no more continue to use such a hose than I would old tires.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #9 – December 20, 2017, 10:35:20 am

A quick identifier for fuel lines in need of replacement is to look at them where they attach to the primary fuel filter. If you see cracks there (usually on the long axis of the hose), it is time to replace all hoses on the coach (supply and return, engine and generator).

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #10 – December 20, 2017, 10:44:18 am

Wolfe, is correct as usual, the problem is fuel draining back to the tank and inducing a large slug of air into the fuel line. Most modern diesels will work the air out eventually, but some you will have to bleed it out at the injectors. A lot of trouble if there is any way to avoid it and a lot of work for the batteries and starter.

Wantabe

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #11 – November 03, 2018, 12:18:06 am

Thought I would bump this thread rather than start a new one on the same subject. I would like to add a ball valve ahead of the fuel filters as suggested. I would like to attach the ball valve directly to the filter housing, between the housing and the fuel line fitting and I would like to buy the fittings before disassembling the system. My question is, what type of hose fitting is this that attaches to the filter housing and how does it seal, o-ring, washer, or just metal-to-metal like a pipe fitting?

Thanks
Richard

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #12 – November 03, 2018, 06:49:31 am

That'll be a JIC fitting on the end of the factory hose. Mine is 5/8", but that's on a 6.8 Cummins. Most likely the fitting that goes directly into the filter housing will be ORB, o ring boss into housing, JIC male for hose connection.
You're installing a new filter housing, right? If you're using the Racor with a built in pump, highly reommended, there's no need for a shutoff as the purge pump will quickly eliminate air from the lines. With one of these rigs there's no need to pre fill filter either, just spin on a new one, hit the pump button, open the valve at top of housing until fuel appears

.Racor 790R30 INTEGRATED ASSEMBLY - 90 GPH

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #13 – November 03, 2018, 09:16:57 am

My Racor had been bypassed by PO or someone for him so I went to a Davco 382 it has c check valve in the filter housing that prevents fuel back flow.
I agree with chuck my hose ends were JIC and the fitting going into the filter housing is o-ring. You can buy a check valve that has JIC ends on it, that you can put in line before filter, they are not very expensive. I think I paid 10 for one on internet
Chris

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #14 – November 03, 2018, 11:36:29 am

Fuel ball valve not only assists filter changes, it has a higher level of use as a theft deterrent. . .

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #15 – November 03, 2018, 11:59:12 am

Be sure what ever valve you use had sufficient ID as to not restrict flow. Some valves are significantly smaller ID than the hose.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #16 – November 03, 2018, 12:18:41 pm

The fittings on both the RACOR R90P that came on our ISC and the Davco 382 that I put on our coach had NPTF pipe threads on the inlets and outlets. I believe the Racor had ⅜" NPTF and the Davco has ½" NPTF. The fuel line FOT installed in our coach was put in using DOT air brake compression fittings with male pipe threads on one end. Note this is for the Parker-Hannifin HTFL fuel line which looks similar to air brake line. Parker-Hannifin has their own branded fittings but calls out the DOT air brake fittings as being a suitable alternative. I installed a fuel shut off accessible from under the bed in line with the Parker-Hannifin HTFL. At the time I was doing this, I couldn't find a ball valve that was specifically rated for diesel, but I used one rated for WOG (water, oil, and gas). It is a half inch full flow ball valve connected with male pipe thread to ⅝" DOT compression fittings. The fittings used air brake lines look the same as the compression fittings used in plumbing, but the air brake tubing (and the Parker-Hannifin HTFL) is slightly larger OD and the brass ferrule from the fittings used for plumbing water lines won't fit (without extreme force) over the air brake lines. The DOT fittings are stamped with DOT and the size. Though the Davco 382 has a check valve on the inlet, I wanted the valve in case I needed to remove the filter housing and because I needed to extend the fuel line that FOT installed to place the Davco at the rear of the engine compartment. Aside from being much easier to service, the Davco instructions call for the housing to be at the top of the full tank fuel level to prevent siphoning. This would not have been achievable in the original location over the chassis battery bank.
Don

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #17 – November 08, 2018, 11:24:58 am

There will be a ball valve put on my 8.3.. The first service I did I had below a half tank of fuel and after changing primary filter she was a booger to start.. I ended up with 30 ft of air in lines. The motor home was in my shop at the time which made it "easier" but I don't want to even think of tackling that on the shoulder of the road replacing a clogged filter.. I don't plan on doing that twice.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #18 – November 08, 2018, 11:56:09 am

I don't understand why some Forum members have such a problem when changing fuel filters, and for others it is such a simple job.

On our coach, it is a simple job. I pre-fill both filters with clean fuel. Start the engine, warm it up to operating temp, shut it down. Remove the first filter (mounted on the frame above the start battery) and install the fresh filter. No fuel runs out of the filter base, so no mess. Then I start the engine, let the idle smooth out (only takes a minute), and shut it down. Change the second filter (on the side of the engine block) following the same procedure. Again, no fuel runs out, only a few drips that I catch with a paper towel. Start the engine again, and this time we go for a 30 minute "exercise run" to fully warm up the engine oil. At the same time, we run the generator and the air conditioners to exercise them. Return home, shut down, check to make sure no fuel leaks at filters. Done.

We don't have a shutoff valve at either filter. Never had any problem with starting after changing filters. One or two 5 second cranking sessions and it always fires right up. EASY!

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #19 – November 08, 2018, 12:04:20 pm

Chuck,
A number of different filters were used over the years. And different engines have different priming requirements.

On quite a number if level of fuel in the tank is different than the filter head (so, depends on how full the tank is, whether nose higher or lower, etc) removing the primary fuel filter will allow EITHER fuel to run out filter head OR fuel to drain back to the tank. Neither is good.

A simple "fuel compatible ball valve" solves this.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #20 – November 08, 2018, 12:16:27 pm

As said above, if you have a coach where the filter base is higher than where the fuel is drawn out of the tank, gravity alone will drain the line into the tank.. My 3208 cat was lower at the filter base and I had same results as you Chuck.. Elevation is the key.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #21 – November 08, 2018, 10:28:44 pm

Light air pressure on fuel tank filler cap opening will lightly pressurize tank forcing air out of hose to filter. After prefill fuel filter installed, the first start needs full throttle for a moment to keep from stalling.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #22 – November 09, 2018, 08:54:25 am

No matter what you do there will come a day when you will say "I sure wish I had a prime pump on this *&^^^er." Most likely while standing alongside a busy road.

There was a time when they were standard equipment on pretty much all diesels, for a good reason.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #23 – November 09, 2018, 12:47:44 pm

8.3 Cummins has a primer on the pump.. Very hard to get to from underneath but easy from under the bed. I use a hammer handle to reach the rubber bulb to save reaching so with my arm... As far as compressed air thru the tank I would regulate the air to no more than 15 lb. I have gone full bore with air in the tank when we go to start a truck following replacing a head but as hard as these air lines are to replace I would regulate air on my coach.. ANYTHING but either.. I don't care if mfg do install either canisters on units I don't like using it unless I were sitting in the middle of a busy intersection with a dead motor and then wouldn't like it.

Re: U320 Fuel Shut Off Valve - Location/Installation

Reply #24 – November 09, 2018, 12:55:30 pm

Ether start will not work over 50 degrees.

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