Percy, et al:
As someone stated, the Scott aster cylinder is a low pressure, high volume
device. It was originally intended for the Hayes expander tube brakes. At
SN813 the Goodyear brakes were introduced and the master, while slightly
marginal, was retained. The Clevelands, especially the ones for the later
gear, are at the opposite end of the spectrum, requiring very little flow
but considerable pressure. The Clevelands for the earlier gear are a better
fit for the old master because they have 2 pistons per wheel; higher volume
and lower pressure.
The Skyport master cylinder is a modern, high pressure cylinder and works
well with the Goodyear brakes and both Clevelands. It does not have
sufficient volume for the Hayes brakes.
The Scott master is easy to service using standard O-rings. We have a kit
that includes the O-rings, some service information and cotter pins for
reinstallation. The price is under $4.00.
If your cylinder is leaking out the top where the piston pushrod goes
through the cover, and you can move the rod noticeably in the cover, chances
are the o-ring kit will not correct the problem. Once the hole in the cover
wears, even a new o-ring cannot seal it.
If the master piston seems to have little or no movement, the problem could
be that it is not returning far enough. This prevents fluid from returning
to the reservoir, keeps the brake pads from retracting from the disks, and
causes premature pad wear. Be sure this is not the problem before
proceeding any further. The most common causes are a misadjusted piston
clevis (too long) or a misadjusted parking brake cable (too short).
John Cooper
Skyport Services
518 797-3064
www.skyportservices.net
-----Original Message-----
Howdy, Tech Advisors.
I'm still working on that l-o-o-o-n-g annual. The breaks were
changed to Clevelands, but the master cylendir was not changed. I
kinda remember something about that cylendir pumps out more fluid than
the wheel units can take, so there is little "peddle." Is that so?
The master cylendir moves extreamly little. I still have to look at
the pucks, but thought I'd get the question out there to see who knows
(or think they knows) what. Also on the subject...
* What are the part numbers to rebuild the master cylendirs ("O"
rings, etc.)
* Are parts available through the Usual Outlets or a specialty place?
Thanx in advance,
Percy in NM, USA
