Master Cylinder filler plugs

[captbp]

Anyone have a source for the original master cylinder plugs p/n 9510292? I'm in need of 2, tried a new set p/n 140-01900 from Parker Hannifin but they don't fit.

Thanks,

Bob

[GAHorn]

Got a pic?

[170C]

Couple of years ago I purchased a handful of those plugs from Spruce. I don't recall if they had the small hole drilled in them or not, but if not its a simple deal to drill one. (For a '56 C-172)

[GAHorn]

Couple of years ago I purchased a handful of those plugs from Spruce. I don't recall if they had the small hole drilled in them or not, but if not its a simple deal to drill one. (For a '56 C-172)

Frank, I’m thinking he must mean something other than those little plastic 1/8” NPT plugs.... and wonder what he means by “original”. (IE what specific master cylinders he has... IF they are truly “original”... just because you have an old airplane with old master cyls doesn’t mean they are “original” at all)
Also, he has tried Cleveland plugs that didn’t fit... so it makes one wonder what make cyls he has. They could be Scott, McCauley, Grove, Matco... or ??? A pic might help.

[captbp]

Found a local supply. The new caps from Parker Hannifin have an extra little rim above the threads that acts as a stop. Unfortunately the rim is too wide that hits a raised plate on the cover of the reservoir.

Thanks for all the replies.


Bob

[n2582d]

Bob,
Welcome to the C-170 forum! By the part number you gave I assume you have a '48 C-170 with the serrated shafts as shown here:

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There has been a lot written on this site regarding brake master cylinders, especially regarding the parking brake system having a nasty habit of engaging inflight. But that should not be an issue on your early style brake cylinders if that is in fact what you have.

[Bruce Fenstermacher]

Just make sure your locally purchased 1/8" NPT plugs have a breather hole drilled in them. They won't work right if they truly plug the hole.

[n2582d]

Bruce,
I was curious about that as I've never seen this style of master cylinder. It appears there is a hole in the cover. Is that a vent hole?

Screen Shot 2020-09-13 at 8.36.39 AM.png

[GAHorn]

Bruce,
I was curious about that as I've never seen this style of master cylinder. It appears there is a hole in the cover. Is that a vent hole?

Screen Shot 2020-09-13 at 8.36.39 AM.png

Isn’t that the pin-hole for attaching the knife-edge locking-lever?

[Bruce Fenstermacher]

I can't look at mine cause I sold the plane, but my serrated shaft master cylinders had a vent hole in the plug I can assure you.

[DaveF]

I hate the little drilled plastic plugs. I always drop one and they seep fluid.

Maybe these will work better? 1/8” NPT to 1/16” barb.

Haven’t tried them yet, but they look like they’ll be easier to handle and may(?) squirt less 5606 out the vent. And they’d work for bleeding the brake if you work slowly.

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