MEP-802/803 fuel return improvements

[m-35tom]

I know there has been a lot of discussion about 3.5mm being the right size but 4.0mm is readily available and about 50 cents per foot and is just .020 thousandths larger so it goes on just as tight.

 

[Guyfang]

As long as it works, it works!

 

[Daybreak]

Howdy,
FUEL RETURN LINE = very low pressure
To each there own.
I used the braided original style line. With keeping it filled with diesel #2 and not using JP8, it will last longer than the military fuel type use.

The MEP-8xx series of generator all use diesel fuel return lines. After sometimes sitting with no fuel, or heat cold, no-use etc... they start to fail. The main issue is the lines start weeping fuel.

NSN 4720-01-483-6467 part N20353.5 HOSE,NONMETALLIC

Name	Value
CROSS-SECTIONAL SHAPE STYLE	ROUND
INSIDE DIAMETER	3.5 MILLIMETERS NOMINAL
LAYER COMPOSITION AND LOCATION	OUTER LAYER BRAIDED COTTON CORD
INSIDE SURFACE CONDITION	SMOOTH
SPECIAL FEATURES	COMES IN A 20 METER ROLL (66 FT.)
MATERIAL	RUBBER BUTADIENE-ACRYLONITRILE CLASS NBR TUBE
MEDIA FOR WHICH DESIGNED	FUEL/OIL, HYDROCARBON SINGLE RESPONSE AND WATER SINGLE RESPONSE AND AIR SINGLE RESPONSE

The fuel return line is 3.5mm ID. As you can see by the above posting the details of this line. Some have used other sizes and hose clamps. But purchasing the correct 3.5mm ID fuel hose makes it stay tight on all the hose barbs without issue.

It is a 3.5mm fuel hose made by CRP CONTITECH. This is a roll which is 5 meters long which will give you enough to replace all your lines and have some in reserve. You can search for below

CRP N203535-5 CONTITECH Diesel Hose


Or
Gates Safety Stripe II - 1/8 Inch Hose Part 27000 which is 3.2mm ID

 

[Light in the Dark]

Thanks for this info csheath. Was running my 802 before work this morning, and notice a nice pressurized leak coming out of one of the short fuel lines from the common rail, blasting diesel all over the right hand door. O-Reillys it is on the way home. Thanks again.

 

[Light in the Dark]

What should I do about the end of the return line, that goes into the tank? Can I get that fitting somewhere, that has a barb, that I can use hose clamps with? Or maybe a double male end barb, that I could cut the stock line an inch or two back from the OEM fitting, and install with dual duct clamps?

 

[Bmxenbrett]

Dosnt the fuel return at the tank just push on a hose barb? That small 3.5mm of return line a hose clamp may not be the thing to use. You can use SS wire. I used small zip ties.

Also i have ordered the contitech hose daybreak posted from amazon. It was enough to do two 802a, cant remember the exact length.
Heres the amazon link.
https://www.amazon.com/CRP-N203535-...89344&sr=1-1&keywords=CRP+N203535-5+CONTITECH

 

[Light in the Dark]

I don't know if that fitting has a barb. If it does, nothing more I need to do except strip the stock hose off of it and replace.

 

[Bmxenbrett]

Yes just a brass hose barb. You can see it prety good in this pic. Its the smaller hose next to the red wire on the right side.
https://www.google.com/search?q=mep...AUIEygC&biw=360&bih=559#imgrc=thxhW51PRz4MNM:

 

[Light in the Dark]

Oh I know the line (the rear sheet is off my set as we speak). I just didn't know if there was a barb, or if the nut 'captured' the hose, as it is not a high pressure line. Thanks

 

[Daybreak]

Howdy,
Yes, the 3.5mm stuff is what is factory. So, it goes right on top the barbs and stays on. No need for any clamping on the fuel return lines.

 

[Ray70]

I didn't notice the length of the hose you guys bought on Amazon, but I've been buying it in 15' rolls on ebay for $30 and free shipping.

https://www.ebay.com/itm/5-Meter-Ro...-Diesel-TDI-/132214703557?hash=item1ec89c45c5

 

[EFR]

Gentlemen: I just bought a 2010 MEP 803A with 86 hours. Machine looks nice. I started it for the first time and found that it is leaking diesel. After finding this post, I believe it is the fuel return line. Thanks to this post, I know what I need. My question though, does the cabinet have to come off to replace this line? How much of a bear is it to get the top cover off?

Thanks, Erik

 

[Bmxenbrett]

Yes take the top cover off.. how hard is it? Its a bunch of bolts with a 5/16 head. Unless you like working with a mirror and tiny plyers its alot easier to pull a fiew pannels.

 

[EFR]

Thanks Brett. I was looking at it the other day (in the barn, poor lighting), looks like some of the nuts on the inside will be tough to get to.

 

[Bmxenbrett]

Taking the air filter out can actualy help on the hardest ones. Most of the rest have captured nuts. A bit of never seeze can really help down the road if your in a damp climate.

 

[Daybreak]

Howdy,

You could start here MEP-802A MEP-803A Filters and Parts and the 2nd post has quick links.

Being a 2010 unit, I would think it has caged nuts. Much easier taking the panels off. Not every single bolt has caged nuts, but lots are.

Careful removing the hose from the TEE's. A careful split with a sharp razor blade helps with the removal. Just not to deep to mess the barbs.

Think about some stainless steel bolts when going back together too.

 

[EFR]

Thanks Mike. I found the page (and saved it) in your link doing the research on my problem. Main reason I went with the 803A is from information from this site. I only looked at it for a bit (cabinet), but it looked like a chore to take the top cover off. I did not know most of the nuts are captive; that is a big difference. I was trying to figure out how to put a wrench on the bottom of the nuts behind the insulation to the rear panel behind the radiator. If they are captive, that will make it much easier.

 

[Light in the Dark]

If only ALL were captive, our lives would be so much easier. Sadistic people I tell you...

and howdy from Western MA

 

[Daybreak]

Thanks Mike. I found the page (and saved it) in your link doing the research on my problem. Main reason I went with the 803A is from information from this site. I only looked at it for a bit (cabinet), but it looked like a chore to take the top cover off. I did not know most of the nuts are captive; that is a big difference. I was trying to figure out how to put a wrench on the bottom of the nuts behind the insulation to the rear panel behind the radiator. If they are captive, that will make it much easier.

Howdy,

Don't get to carried away. Older units do NOT have captive nuts. and its a real pain to get way up in the air cleaner area.

I know for a fact my 2007 units do not have captive nuts. The 2009 units do. So somewhere in between they changed over to that nice captive nut style.

 

[Guyfang]

Thanks Mike. I found the page (and saved it) in your link doing the research on my problem. Main reason I went with the 803A is from information from this site. I only looked at it for a bit (cabinet), but it looked like a chore to take the top cover off. I did not know most of the nuts are captive; that is a big difference. I was trying to figure out how to put a wrench on the bottom of the nuts behind the insulation to the rear panel behind the radiator. If they are captive, that will make it much easier.

Good Lord, its not that hard. Even with a wrench and a 1/4 inch drive ratchet, its only a few screws, cant be more then 20. Try getting at your hoses without taking the top off. THAT is work.