The International Cessna^® 170 Association

Maybe someone can help.

After some further investigation, the only thing not checked was the brake master cylinder body.

We did swap the internals and those from the right worked perfectly in the left and those from the left didn't work in the right.

Looking for the the brake master cylinder for an early 1952 C-170B

Thanks.

Bill Preston

Hi Bill-
Maybe I can help. Below are pictures of the master cylinders removed from 1951 170A, N1715D, s/n 20158 in 2006 when I had new master cylinders installed. They may be original from the factory but I have no way to tell, no part numbers are visible on either cylinder. Attach holes are 3/16"dia with 1/8"npt hose connections.

These were both working when removed but should be rebuilt before installing in another plane, at least with new Lock-O-Seals and o-rings. I don't know of any problems with them. Also, as discussed in other threads, the parking brake should be removed to prevent inadvertant setting of the brakes.

Email, PM, or call me and we can discuss options.

Click on picture to enlarge-

I am looking for a set of master cylinders for my 1950 C-170A, I understand what I have ( Scott Master cylinders ) is not what the plane should have.

Andy,

Your 170A may have come with the surated piston shaft style master cylinders. There is a Service Bulletin to replace these master cylinders though at the moment I can't put my hands on it.

Your cylinders may have been replaced with Scott cylinders. Just because they are Scott does not make them the wrong master cylinders, just not Cessna cylinders. Is there a paper trail for them? Who said they were wrong?

Bruce Fenstermacher wrote:Your 170A may have come with the surated piston shaft style master cylinders. There is a Service Bulletin to replace these master cylinders though at the moment I can't put my hands on it.

Bruce, You also mentioned this SB in this link. I've been unable to find any such Service Bulletin. Could it be you're thinking of Cessna Service Kit SK 7051-2? This Service Kit updates the parking brake hardware for S/N 18003-19200 aircraft which had the serrated shafts to match that of post-S/N 19200 aircraft which have the Cessna non-serrated shafts. Pg. 43 of the C-170A IPC also references Conversion Kit 52-3-870 which appears similar to SK 7051-2. There has been some debate regarding the safety of the serrated shaft master cylinders. Here's what the International Cessna 195 Club says: "There was discussion of the original brake master cylinders that have serrated piston stems, and the tendency for them to fail due to breakage at one of the serrations. It's a good idea to replace them if your aircraft is so equipped. They were primarily on earlier airframes."

The servce information summary listed in the 1962 and prior service manual says that cessna master cylinders were installed on serial number 20041 and up 170b's and may be installed in place of either the "SCOTT" or "GOODYEAR" with only slight changes. Your 170A would have had one of these originally. Mine has the Scott.

Thanks Gary and Fred.

First what I'm thinking of may not have been an SB or an SL and may have been a SK but I know the serrated versions are not desired and Cessna called for their replacement somewhere.

Gary SK7051-2 is for the parking brake linkage and i'm talking about replacing the whole master cylinder.

Fred it would appear from you reference of the '62 and prior service manual that Scott or Goodyear master cylinders would be appropriate for the 170A. I don't know who made them for the 170A really. Andy probably as the correct master cylinders already.