My M725 filler rubber elbow had actual cracks/holes in it that could have eventually caused a fire if I ignored it. I gave up on trying to find a durable replacement rubber fuel filler elbow for my Ambulance and decided to make one myself for around $100.
I researched options for petroleum friendly rubber tubing and 16 ga stainless steel tubing so this part will be something I’ll never have to mess with again.
If you want to build one of these, you’ll need to be able to weld and cut stainless and mild steel. The finished product still looks stock from everywhere except under the vehicle where the new stainless steel filler elbow can be seen- but it looks pretty awesome from down there too, just not stock.