So I have a 170A (sn 18877) and I swapped in the much nicer master cyls from a B model thinking I could use the Newsletter dated 6-5-1952, however the letter states it applies to Serial number 20041 and up, and mine is below that.
So what's the deal with using the Cessna master cyls instead of the old crappy goodyears?
Thanks!
Master cyl swap out with Service Newsletter
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Re: Master cyl swap out with Service Newsletter
Schu,
Welcome to the Forum!
I think you're misreading the SNL. It starts with Cessna bragging about their "experience and know-how" with hydraulics. This new master cylinder - "the best master cylinder yet installed in Cessna airplanes" - replaced the earlier Scott and Goodyear master cylinders beginning with s/n 20041 on the C-170A. The newsletter goes on to say "Cessna master cylinders may be installed in place of either the Scott of (sic) Goodyear ... ." In other words, Scott and Goodyear were only used before s/n 20041 and these can be replaced with Cessna master cylinders (p/n 0541138-1 and -2). I know this doesn’t jive with fig. 24 of the 170A IPC. The 170A IPC doesn't even show 0541138-1 and -2; they first appear at s/n 20267, the 1952 B model. I think the 170A IPC is in error and the SNL is correct. In my opinion replacing the Goodyear master cylinders with Cessna ones is a logbook entry as a minor alteration. Of course it's your mechanic's opinion, not mine, that matters.
Welcome to the Forum!
I think you're misreading the SNL. It starts with Cessna bragging about their "experience and know-how" with hydraulics. This new master cylinder - "the best master cylinder yet installed in Cessna airplanes" - replaced the earlier Scott and Goodyear master cylinders beginning with s/n 20041 on the C-170A. The newsletter goes on to say "Cessna master cylinders may be installed in place of either the Scott of (sic) Goodyear ... ." In other words, Scott and Goodyear were only used before s/n 20041 and these can be replaced with Cessna master cylinders (p/n 0541138-1 and -2). I know this doesn’t jive with fig. 24 of the 170A IPC. The 170A IPC doesn't even show 0541138-1 and -2; they first appear at s/n 20267, the 1952 B model. I think the 170A IPC is in error and the SNL is correct. In my opinion replacing the Goodyear master cylinders with Cessna ones is a logbook entry as a minor alteration. Of course it's your mechanic's opinion, not mine, that matters.
Gary