View Full Version : 1940 Commander Master Cylinder

09-29-2011, 08:13 AM
We are about to awaken our 18940 Commander from it's fifty year sleep as soon as a couple of parts arrive. And if that goes well as we expect it to, we also need to be able to stop it. We know a complete rebuild of the brake system will be necessary before we put it on the street we would like to be able to move it in and out of the garage at times when we don't have extra hands to help push. So we were hoping some patch work on the brakes might get us to that point. Unfortunately we can't even begin. Nothing we have tried will get the master cylinder cap off. Does anyone have anything to suggest? Something to try without having to remove the master cylinder?

09-29-2011, 09:53 AM
Kroil, PB Blaster, maybe some heat and repeat. A sharp blow with a small or medium hammer is better than a large hammer. Be sure you have a 1/2 " drive socket that fits tight. Sometimes when these caps do not want to come off, they just wont. If it breaks up, you will have to drive it in on itself , cut, drill whatever it takes to get it off. They can be nasty.

09-29-2011, 10:30 AM
A 6-point socket, mabe even an impact socket would be best. Less chance of the cap head rounding off. Might not hurt using the impact wrench with short burst, after soaking as stated above. Hope this helps.

Dan Miller
Auburn, GA

09-30-2011, 09:52 AM

I recently pulled my master cylinder on my 40 commander sedan.... unmoved since 1960...
So, to be certain, you say "cap", you are referring to the ridged cap correct?

This is not as hard as you might be thinking. By all means, apply whichever anti-rust eater you want, Kroil, Seafoam, PB, etc...
I worked on getting mine off for a week... it was all physics....

Luckily I did NOT damage the cap.... much... I got a little scaring from the slippage, but then in walks my father-in-law one day and he laughs... I was using a 10-12" pipe wrench to do the job (this is how they used to do it he told me).... Being that he worked on Studebakers (1940's) in the 50's.... I listen to everything he says....

He said "I told you to use a pipe wrench..." to which I replied "I am"... and held up the one I was using...
He walked over ot the tool box and grabbed one that was about 16-18" long... he snugged it up and applied some force.... it came right off.... he smiled, handed me the wrench and cap and walked back our to the storefront.

The lesson here is leverage... I did more damage with the small wrench because no matter how much force I tried to apply to it, it wouldn't budge... a few more inches on the wrench length gave it enough leverage to translate into a LOT more force.... It didn't slip, it took one try and it came right off.... no damage.

I suggest using a long pipe wrench... be sure ot spray it down well with rust easter. The added leverage from just a few inches of length really made all of the difference.