Possible concern with DMCH fuel module hoses

I purchased an all-in-one DMCH fuel pump module secondhand, so I can't verify if the hoses I have are original, although they probably are. Module was installed in fall of 2016.

Today I had my main feed hose slip off of the barb on the hardline. Luckily I was only a block from the car show I was just attending and did a quick field repair. Close inspection later revealed that the liner had softened, and because the K-jet hose barbs are a fairly smaller OD than the ID of these 5/16" hoses, the softening allowed the hose to slowly work off of the barb even with the FI clamp fully secured. Pieces of the hose had actually broken loose and the hose had to be trimmed slightly so it could be temporarily refit.

These are Gates hoses which appear to be resistant to modern fuels. Gates 4219BF specifically. The bottom hose section in this photo shows a series a marks
inside the hose. I was able to do this with my fingernail.

I personally dislike rubber fuel hose regardless of markings and will be working up a PTFE solution. I was able to easily build new temporary hoses using 5/16" fuel injection hose from Advance, but I suspect given enough time issue will occur again.

Attachment 57108

So I guess the question is, are these the OEM hoses on the new fuel pump module? If so, they should be inspected.

I had a similar issue last week with a DMCH rubber hose on my fuel accumulator. I had bought the replacement "Fuel Accumulator Kit" back in late 2014 when we started restoring the car. Last Saturday, I was at a Cub Scout event where they wanted my car for a static display and the fuel hose (Part No. 106997) came off the barbed fitting on the end of the accumulator and left me stranded and I ended up having to get towed home. When I found the problem and repaired it on Tuesday night, I noticed the inside of the hose seemed a liittle "mushy". I trimmed about an inch off the hose and put it back on and cranked down on the clamp until I felt is was secure.

Those definitely look like the hoses that are on my car!

Guess I will have to look at mine before the VR6 swap is complete...

My hoses from My DMCH fuel pump are most certainly disintegrating from the inside like yours.

The pump itself died after about 20k miles. Overall, not impressed.

You think they could do better for $400+

I have a small assortment of quick disconnect adapters & nylon fuel hose on the way. Hopefully I can ditch the rubber completely. Being able to drop the check valve makes it easier though since I don't have to find a replacement for that with the right size and fittings to fit the nylon tubing.

Next step after this is an accumulator delete along with those associated rubber hoses.

Here's my fix:

Purchase:
-5/16" (8mm) nylon fuel tubing. Need about 4 feet minimum but would suggest a little extra for practice (Dorman 800-074 is 10')
-90 degree 5/16" steel quick disconnect to 5/16" nylon tubing fitting (Dorman 800-081)
-90 degree 3/8" steel quick disconnect to 5/16" nylon tubing fitting (Dorman 800-091)
-K-jet users need an inline EFI rated check valve w/ 6mm
-Earless clamps in the 9mm range

Tools & supplies:
-15/17 LONG crescent wrenches to remove barbs from supply/return lines. I think 15/17 are the right sizes. Long for leverage as these will be stuck fast.
-Nylon tubing jaws for a vice (I built my own by drilling a hole through a 2x4 and cutting it in half)
-Hair dryer
-Assembly oil, probably any lightweight oil is fine

Homework:
-Watch some YouTube videos on how to install fittings on nylon fuel hose

Procedure:
-Remove original hoses from fuel pump & supply/return lines
-Remove 2x barbed fittings from supply/return lines
-Install one 3/8 and one 5/16 angled QD fitting onto approx 2.5' of nylon tube
-Crimp ear clamps at tube to barb connection
-Measure and final cut tubing to length. I would leave a little slack for the future, there's no need to make these hoses super short
-Install tubing onto OEM K-jet barbs. Don't forgot to slide a new ear clamp onto the tubing first.
-For K-jet users: Install in-line check valve and clamps.
-Flush your new hoses of debris and install.

Tubing on QD fittings:
Attachment 57283

My 2x4-based tubing holder mounted in a vice
Attachment 57284

All done!
Attachment 57285

I'll also cut some spare hose lengthwise and install over the nylon tubing as an anti-chafing / anti-rattle jacket. Basically just like the stock hoses.

I should note that removing the barbed adapters from the supply/return lines may not be required, but getting the leverage to seat the nylon tubing with them in place was challenging.

A tool similar to these pliers would make it pretty easy.