A fuel strainer/filter and a check valve are located at the rear of the car.  The strainer/filter is the standard cast brass construction identical to the pilot fuel strainer/filter.  See the discussion on the pilot fuel strainer/filter for additional information.

The check valve, located close to the fuel supply tank, keeps fuel from draining back to the fuel supply tank when the car in not being used.  This check valve also serves as the suction side check valve for the hand fuel pump.  When the hand fuel pump's handle is pulled back towards the front passenger seat this check valve keeps the fuel from returning to the tank.  This means that the fuel line between this check valve and the power fuel pump is under pressure as the fuel is forced past both check valves of the power fuel pump and into the fuel pressure tanks.  See the discussion on the water check valve to learn how a check valve operates.

Under the hood a Stanley car is a maze of black malleable or forged steel and iron pipe along with an assortment of copper tubing. Black iron pipe is used around the bottom of the boiler for blow-down lines and where support of a valve or other device is needed. Either 1/4", 3/8", and a limited amount of 1/2" pipe is used. The use of galvanized pipe, stainless steel pipe, and brass pipe is not recommended for steam service for various reasons. With the heat and pressures present pipe used for boiler connections should be Schedule 80 minimum with Schedule 40 being used for all other connections.

Stanley cars contain many feet of copper tubing and a vast assortment of SAE 45-degree flare fittings. Copper pipe is sized according to it's inside diameter which varies slightly depending on the thickness of the wall. The outside dimension is always 1/8" more than the stated size.  Soft copper tubing that is easily formed with a tubing bender is used for water, fuel, and steam on a Stanley.  As shipped from the factory 3/16" ID was used for most air lines; 5/16" ID was used to supply the Pilot with fuel; 9/32" ID tubing was used for the burner fuel; the water lines from the pumps to the boiler check were 7/16" ID.  Rare sizes in today's market place for sure.  Additionally some tubing found on Stanleys wasn't copper but was brass ~ in particular the 9/32" ID tubing.

Today the most common sizes of copper tubing available are 1/4", 5/16", 3/8" and 1/2" ID sizes.  For those wanting to duplicate the original Stanley tubing sizes the only alternative is to use either stainless steel or aluminum tubing both of which are non-Stanley materials.  For these small diameters of soft copper tubing the working pressure ratings are well above the normal operating pressure of the boiler. The following are working pressures for copper tubing; 1/4" - 1400 PSIG; 5/16" - 1200 PSIG; 3/8" - 1000 PSIG.  The heavy-wall refrigeration grade tubing is often selected. 

For some applications such as the steam line to the rear of the car or for the feed water heater water line copper piping is used. Coppering piping is durable and is available in three basic grades. Type M is the most basic grade, is thin-walled, and is marked for identification with red lettering. Type L is about twice as strong as type M and is marked with blue lettering. Type K is the strongest and is recommended for use with a Stanley even though it is the most expensive. Type K is marked with orange lettering.  Tubing should never be bent by hand as the softness of the copper walls make the tubing prone to kinking.  The best way to make uniform, smooth bends with copper tubing and pipe is to use the proper tubing bender (shown at left) or pipe bender (such as an electrician's conduit bender).

A tubing cutter (shown at right) is the best tool for cutting copper tubing and pipe. The cutter is placed on the tubing or pipe and rotated around the tubing or pipe to cut it. Turning the handle to tighten the blade against the pipe or tubing as you twist the cutter around the pipe in a circular motion cuts through the tubing or pipe. Several turns are usually sufficient to cut through the tubing or pipe. Most cutters also include a reamer tool--a short blade used to remove metal burrs after the pipe has been cut. Sometimes for tight spaces a mini-cutter (shown at left) can be handy.

For connecting soft copper tubing to valves and automatics special fittings are used. While compression fittings (shown below at left) may seem applicable (and could be used in an emergency) the use of flare fittings (shown below at right) are recommended. A flare fitting consists of a flare nut and flare body. There's no ferrule because the copper pipe flares out, forming a lip that is sandwiched between the nut and body. Solid brass flare fittings create a stronger connection than can be achieved with soldered or compression fittings. The long flare nuts provide extra support and vibration resistance to the connection. Flaring the pipe requires a specialized tool.

In order to properly install a flare fitting, cut the tubing to the desired length. Remove any burrs from the tubing ends, and slide the flare nut onto the pipe. Push the flare nut back far enough on the tubing so that it will be out of the way when you use the flaring tool. Clip the pipe in the flaring tool, keeping the end flush with the face of the tool. Slowly turn the handle on the tool until it bottoms out making a bell end at the end of the copper tubing in the flaring tool. Unscrew the handle and remove the tool to check the quality of the flare. A properly flared tubing end is smooth and evenly bell shaped. Mate the tubing to the flare fitting body and hand-tighten the flare nut. Proper tightening of a flare fitting requires two wrenches, one on the flare fitting’s body and the other on the flare fitting’s nut. The wrench on the fare fitting’s body keeps it from turning while the nut is tightened.