Driving me nuts guys, got a 1977 K30 master cylinder going into my Toyota truck. Rear brake portion is a 3/16" line, with a 5/16" fitting.
Front one is the bitch though, its a 3/16" line but its not a 3/8" fitting(too big) or a 5/16" fitting(too small).


Anyone have a part number to go from whatever size fitting it is to something I can find in a parts store like 5/16":D

Toy truck will have metric fittings. that 5/16 fitting isn't 5/16, it's metric too.

Toy truck will have metric fittings. that 5/16 fitting isn't 5/16, it's metric too.

Talking about the GM master cylinder. I'm running all new hard lines, and trying to find the fitting that goes into the front port to adapt down to a 5/16 fitting. right now I don't even know what the thread size is for the front port. Not 3/8 and not 5/16

Toy truck will have metric fittings. that 5/16 fitting isn't 5/16, it's metric too.

He already said its a 77 k30 master cylinder.

Shouldnt be metric but ya never know.

He already said its a 77 k30 master cylinder.

Shouldnt be metric but ya never know.

Its not metric. The back port a 5/16 fitting goes in great, the front bigger than 5/16, but smaller than 3/8. Figured it ised some sort of GM adaptor

Just take the whole master cyliner into napa and go through their droor of fittings till you find one.

Just take the whole master cyliner into napa and go through their droor of fittings till you find one.

Sweet, if I hadn't been to every part store in 20 miles I wouldn't need pirate.

Why do you think I'm asking for a part #?

bump to bring this back up. I am having no luck in the 10+ autoparts stores, parker dealers, etc.
So has anyone figured out what fitting size is used for the smaller port?

Cannot exactly pinpoint what you want without seeing the master but you can try this: I'm thinking maybe the 121039

http://www.plews-edelmann.com/brochure.cfm?brochure1859&location_id=2516



link doesn't work like I wanted, but type in the 121039 in the search then click on the highlighted inverted flare tube fittings