blimpy
New member
During the annual today, I discovered that my right (Scott #4000 ) master cylinder was indeed leaking.
No surprise, really.
Pulled it out to overhaul it, and found it full of dirty muck.
Cleaned it, replaced the O-rings that went fine.
Became obvious that we had to flush the brake lines. So-called fluid would not drain by gravity
with lines open at top and bottom. Not nice.
Tried to force clean fluid through with oil can.. No Dice !
It took compressed air to blow the stuff out which was the consistancy of slightly warm honey, and
a similar color.
Bought a hydraulic pressure guage today, which we will mate to the brake line... and MEASURE what kind of pressure the scott master can produce.
Cleveland graph shows 500 psi for an aircraft with a gross weight of 2150 lbs.
So if that is achievable with "normal" brake pedal pressure... and no leakage... then I will go ahead
with the installation of the Cleveland brakes - after flushing the other side too !
If not enough pressure... then I'll flush out the Hayes Expander Tube Brakes, and keep flying with them until I can figure out what kind of master cylinders WILL work without welding and an act
of congress to install and get 337 'd.
At least this now explains Both problems...
1. Having to refill every other flight with no obvious leak .
Under the belly inspection plate found the tell-tale puddle.
2. Why the right brake seemed more often than not to be " all or nothing" High pressure gum does not
a good brake system make.
It will be fun trying to clean out the expander tube ! It's sort of like a roach motel.. they go in but never come out.
No surprise, really.
Pulled it out to overhaul it, and found it full of dirty muck.
Cleaned it, replaced the O-rings that went fine.
Became obvious that we had to flush the brake lines. So-called fluid would not drain by gravity
with lines open at top and bottom. Not nice.
Tried to force clean fluid through with oil can.. No Dice !
It took compressed air to blow the stuff out which was the consistancy of slightly warm honey, and
a similar color.
Bought a hydraulic pressure guage today, which we will mate to the brake line... and MEASURE what kind of pressure the scott master can produce.
Cleveland graph shows 500 psi for an aircraft with a gross weight of 2150 lbs.
So if that is achievable with "normal" brake pedal pressure... and no leakage... then I will go ahead
with the installation of the Cleveland brakes - after flushing the other side too !
If not enough pressure... then I'll flush out the Hayes Expander Tube Brakes, and keep flying with them until I can figure out what kind of master cylinders WILL work without welding and an act
of congress to install and get 337 'd.
At least this now explains Both problems...
1. Having to refill every other flight with no obvious leak .
Under the belly inspection plate found the tell-tale puddle.
2. Why the right brake seemed more often than not to be " all or nothing" High pressure gum does not
a good brake system make.
It will be fun trying to clean out the expander tube ! It's sort of like a roach motel.. they go in but never come out.