Thread size for Mast Cylinder

I spent the better part of today searching for the brass plug i pulled out of my old master cylinder. I DID find a 1.5 Dellorto main jet i lost just before thanksgiving. The garage is much cleaner and organized, but still no brass plug. Im going to buy a new one. Anyone know the thread size?

NOT a standard brass plug. Plugs are normaly a taper. The master cyls for the lines are a straight cut thread size 6x1.0mm and the bottom of the tube is the seal. They use a special plug. The stop light switch hole is usually 1/8 pipe.

Hope it helps.

Dave,

Thanks for the info. So the real question is, where do i get a replacement? the parts stores i call have a hard time understanding what I am asking for.

Go to a brake parts speciality store. The local Kragens or Auto Zone stores are filled with a bunch of idiots.

they are as clueless as i am... big difference being i dont pretend to know. auto parts specialty stores are getting harder to find. they are all being replaced buy these big box chains. Whatever happened to the local "foreign auto".

On my car there are two stop light switches, one being the backup in case of failure of the primary. If all else fails, just get a spare switch.

Thanks Lane. I had actually thought about doing that very thing.

The tapered brass 1/8" plug available from Lowe's or The Home Depot, or conventional hardware stores works just fine. I have never used anything else in the several VW based cars I have built / repaired / restored /owned. One thing to watch for though....the 1/8" plugs I have bought most recently have a "cup" in the inside surface that makes the cylinder harder to bleed as it tends to trap air.

I do suspect the proper plug would be "better" if you can find them, if not, the brass plugs are not the end of the earth. I have never had a leaking problem with any I have used.

Thank you sir... Ordered a brake switch this morning to use in its place. Will put that in the spares kit for my road trips. Will head to Lowes this evening.

If you are pluging up the switch hole it is 1/8" pipe. The line holes are the special sizes. I thought I mentioned it in my earlier post. Always good to have a spare stop light switch. Dot 5 fluid is hard on them for some reason.

You did mention it... i was confused. Bought the plug, brakes are bled, new speedo cable installed and i am back on the road. too bad it was 8 degrees outside. Just purchased an eberspacher heater to take care of that little problem. Now where to put it and how to plumb the thing. I have lots of reading to do.

I hate cold Concrete (i hate the cold period, grew up in Florida), I hate brake fluid, yet i am willing to head out to a 36 degree garage and deal with both on a Tuesday night at 9 pm. Madness indeed.