At my wits end... which in my case might not be all that far.....
I am having problems with my hydraulic brake cylinder and cannot figure it
out. Trying to resolve ground looping problems - always to the right - I
discovered that the left brake "fades" quickly so on applying brakes on a
short runway I sometimes ended up slow-looping to the right despite pressing
as hard as I can on the left brake.
In a previous post I asked how to top up the fluid and did the
pump-from-the-bottom-til-it-squirts-out-the-top thing and it seemed to be
better on quick-stop tests, until I looped again. I have attached a picture
of the cylinder as I don't know the manufacturer.
I took apart both cylinders, the left one had an O ring at the top that was
the wrong size and not seated properly. I thought "aha!" and replaced that O
ring on both with proper sized, and also the ring on the piston. Cleaned
both thoroughly, pumped old fluid out of the system bottom-to-top,
re-installed both cylinders and pumped til it came out the top screw, and
tested. Right one fine - left one makes gurgle noises and goes full travel,
no fluid leaks. Once it bottoms out - no more left brake.
I disassembled the left one again, filled it with fluid with no parts in it
to ensure no air, put parts in and sealed the outlet rather than attach the
brakeline, reassembled and pushed on the plunger and it still bottoms out
with gurgles. All parts are identical in both cylinders, seem to fit the
same, yet one develops pressure and the other gurgles (sound of fluid
through an orifice more accurately).
I see there is a hole in the piston and that if pressure is placed on it in
compression it seals, at least it does when I lip test it. The spring in the
piston tube that provides that pressure is loose and springy as it should
be. Testing both cylinders the same way they appear to be the same.
I'm stumped - any ideas what to check next? All
guesses/wisdom/answers/advice appreciated in advance.
Bob Brennan - N717GB
1991 UK Model 2 ELSA Kitfox
Rotax 582 with 3 blade prop
Wrightsville Pa
