My mother gave me her Allegro last year after my step dad passed away. I have fixed or updated just about every nut and bolt on the Allegro. Does your RV have the sprayed on foam underneath from the cab to the back bumper? Mine used to until I scraped it all off.
Being a Minnesota RV it was a mess underneath. I replaced the propane tank, all of brake lines, fuel lines, wiring etc etc. I replaced every belt, hose, spark plugs, injectors, replaced all the fluids etc on the motor. I took out the fuel tank black, grey and freshwater tanks and the Thetford toilet. I removed both rear dining table seats to access the furnace, fresh water tank and water pump on one side and the electric panel and generator electrical panel on the other side.
There is no refrigerator or hot water heater but I don't need them anyway. I can use an electric house water heater by cutting out a section in the middle and then weld the top back on to fit the compartment. I have done a complete rebuild of the gennie which is a Kohler with a Tecumseh TVM-140 engine. I replaced the relays, capacitors and wires on the roof A/C. I dismantled and checked the furnace for cracks and bee hives
I have the wiring diagrams of the A/C,generator, generator panel, the circuit breaker assembly and the Suburban furnace. I have the parts catalog for the Kohler generator, the Tecumseh engine and the Haynes Manual for the Chevy part of the Allegro.
When I saw how Tiffin Motorcoach installed the auxillary fuel line for the generator, I just shook my head and chuckled. They had taken a hammer and pounded a depression on the top side of the tank, drilled a 1/4 inch hole, inserted a piece of soft copper, then melted solder around and into the depression. For those that aren't aware (Tiffin) of the fact that SOLDER DOES NOT STICK TO A STEEL GAS TANK you have just been told.
I am a gearhead from way back in the day and I am very handy with mechanical and electrical issues. If you want any of the info I have or you just want to ask a question about an 86 Allegro motor home with a Chevy Astro 4.6 V6 engine with an auto tranny you can post it here or e-mail me at firstname.lastname@example.org
And I got 14.3 mpg from Minnesota to Montana driving at 70-75 MPH all the way back. At 60 MPH I should get maybe 16-17 mpg.