1946-1949 Master cylinder Top

[Upnorth]

Good morning I appear to be suffering from a extremely stuck master cylinder cap on my 1947 Series 62.

One issue is I cannot seem to find a wrench to fit the bolt  I thought it was 11/16

Also even with vice grips etc. it will not budge any thoughts on my dilemma would be most helpful , I would like to avoid removing it from the car.


If I do have to take it off are there and tricks on opening bleeders and bleeding the brakes

Thank you  Up North

[harry s]

Some of the caps are cast material and will break with too much pressure. I would try soaking with PB Blaster and using an adjustable wrench. If that doesn't work it would be best to remove and drain so you can use some heat. As far as bleeding be sure not to let fluid drain from the lines and then bleed at the line connection after re installing. Good Luck   Harry

[toybox]

Once you do get it open DO NOT put it back on with any tools. Fingers only and a a little yellow teflon tape on the threads.  I know things are cramped down there but tapping it with a hammer will help getting it open .I would be very carefull with any oils like WD40 or PB blaster as they will destroy the rubber inside the master. Tim

[Rossoroo]

7/8" wrench works on mine. Lots of different types of caps out there.
Maybe a little heat from a heat gun [NO FLAMES!!] would help. Brake fluid is hydroscopic [hygroscopic] so it may be rusted on the inside.You may want to take it out [2 nuts, 2 brake lines] and make sure there is no rust in the reservoir.

[Upnorth]

Hey all great ideas thank you for your input I will put down my giant hammer and spray and be patience

Cheers Up North