The International Cessna^® 170 Association

I need to replace my flexible brake line p/n MS28741-4-0100 that runs from the master cylinder to the hard lines.
I can not find that on part at Aircraft Spruce. Which company might have the brake hose with the fitting??? Is there a new part number?? Thanks.

You can call Spruce, they have a hose shop and should be able to cross reference the number.

Cessna part number S1167-4-0100, Spruce part number 05-12083

They are handed left/right. While you’re in there…you might consider replacing both. (Different PNs, of course)

https://www.aircraftspruce.com/catalog/ ... -12083.php

GAHorn wrote:They are handed left/right.

No, same part number for both. Fig 58, index 4.

DaveF, very nice picture.
Those seem to lay down better than my old ones.
Are they standard length (11.9") or shorter?

Yes, the flexible brake lines are the same in the IPC.
The elbows going aft are different. One is 45 and the other 90 degrees.
The elbows coming out of the master cylinders are both 90.

Keep in mind there are occasional errors in the IPC… my earlier comment was intended to encourage replacement of both and based upon this chart:

The hoses lay flat. You just have to watch for chafing where they come close to stringer/stiffener flanges.

The -0100 means they're 10 inches long, measured between sealing flats.

DaveF wrote:… The -0100 means they're 10 inches long, measured between sealing flats.

Yes, MS28741-4-0100 is not really a Cessna part number as much as it is standard way of identifying hydraulic hoses.

MS28741 is a medium pressure hose as, I’m guessing, was AN859 which is the first part of the ”part number” listed for these hoses in the ‘48 C-170 and the C-170A IPC’s.

The “-4” indicates the diameter of the hose. This corresponds to the O.D. of the rigid tubing which would fit with this hose, measured in 1/16 of an inch increments. You’ll find that in later years Cessna downsized the diameter of these hoses from 1/4” to 3/16” (on C-172’s at least).

-0100, as Dave has pointed out, indicates the length of the hose measured from the outer ends of each nipple, not the actual rubber hose length which would be shorter. I was puzzled as to what units of measurement they used to come up with 0100. It turns out that the last digit is length in eighth of an inch and the preceding digits indicate length in whole number inches. So, for example, an MS28741-04-0107 hose would be 10 and 7/8 inch long. It’s interesting that the the Aircraft Spruce replacement part ends with -0101 — 1/8” longer than the original part.

These assemblies are easy enough for your A&P to fabricate assuming he/she has the appropriate mandrel. Fittings can be reused if still in good condition. The advantage to getting them from Aircraft Spruce is that they will be pressure tested. I’d recommend replacing the hoses at the caliper end (assuming your aircraft has them) at the same time. Recommended replacement intervals for hoses are all over the map. These hoses are not subject to the heat and vibration that engine compartment hoses experience. I’ve read replacement intervals as low as every five years for those. Spruce suggests 8 years. My brake line hoses were rock hard. One gets the feeling the replacement time in real life tends to be proportional to how inaccessible they are — the harder they are to change, the longer the replacement interval.

A method to pressure test “home made” hoses is to submerge them in water and apply air pressure from your shop compressor. While not the standard test…120 psi is probably sufficient for low-pressure hoses such as this and fuel lines, etc.