Take care and cut it straight across - 90 degrees- and not at an angle.
Next, the flexible hoses were made. It is important to have flexible lines from the master cylinders to the parking brake valve and from each master cylinder to master cylinder connection. This is because of the movement of the rudder pedals. Also, you need flexible lines where the hard lines meet the top of the landing gear because there is movement there as well.
For the flexible lines, I chose to go with Aeroquip 303-4 hose and Aeroquip 491-4 fittings. The following will outline the proper techniques for installing the 491 fittings on to the 303 hose ends. To install the ends you will need a special assembly mandrel ($31.80 from Aircraft Spruce at the time of this writing)
1. Cut the hose to the proper length making sure to allow for rudder
pedal travel and allow for the length of the fittings (each fitting will
add about 1/2" to the length - so 1" total for both ends). The book
says you can cut the hose with a hacksaw but I do not recommend
it. You will have a MUCH cleaner cut by wrapping the hose tightly with
some electrician's tape and then cutting it with a cut-off wheel:
Take care and cut it straight across - 90 degrees- and not at an
angle.
2. Clamp the fitting base in the bench vice. Be careful to not clamp
it so tight that it gets crunched out of shape. Just tight enough to
hold it. The end of the hose must be screwed into the fitting base. Here
is the tricky part - The base has left handed
threads!!!! Make sure you turn the hose counter-clockwise
to thread it into the fitting base. Took me about 1/2 hour of grunting
and sweating trying to get the hose into the fitting base before I finally
figured that one out.:
Press the hose firmly into the fitting base while turning it counter-clockwise.
Screw the hose into the fitting base until it bottoms out and then back it
off 1/4 turn.
3. With the end of the hose screwed into the fitting base, wrap some masking
tape around the hose where it meets the fitting base. This will allow
you to see if the hose moves or slips out of the fitting base while doing
the next step:
Here is the Assembly mandrel and the remainder of the 491 end fitting:
4. Clamp the mandrel tool into the vice and screw the hose fitting onto the
assembly mandrel. Important! -
Tighten the fitting to the assembly mandrel with wrench so it won't spin.
Oil the the fitting liberally:
After oiling, push the hose end onto the fitting to get some oil inside the
hose. Remove it and re-oil the fitting again (you need to have it well
oiled for the next step).
5. Firmly press the hose end (with fitting base) onto the oiled fitting
and assembly mandrel as shown below while turning it
clockwise:
Note: You have press really firmly until the first few threads are
started, then you can wrench it on from there.
7. Once the fitting threads catch hold inside the fitting base, you can use
a wrench to thread the fitting base down onto the fitting:
Only thread it on until there is about a 1/32" gap between the fitting base
and fitting nut:
Note that the blue masking tape is still close to the fitting base indicating
that the hose did not move during the above operation.
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