1956 CJ5 Willys master cylinder question

Has anyone rebuilt the old master cylinder on these old Willys? The rebuild kit is pretty cheap $20 dollars versus $85 dollars for a new cylinder. Question: can you rebuild with the Master cylinder in place or is it better to take out then repair? Looks like only two bolts hold it in and the line connecters to the front and back brakes. My system is all original but leaking on the back seal under the rubber cup/ cover. Rebuilding through the access hole looks possible but kinda close quarters. What do you guys think?

 

Typically brake cylinders leak because of corrosion. Which means they need to be honed. The master cylinder needs to be removed to inspect the cylinder and to rinse the surfaces after honing.

 

Ditto. Take it out. You need totally clean conditions.

 

Yup, what they said. No way you're gonna get all the debris out of the cylinder with it in place and the lines/fittings hooked up. In fact, all you'd do is flush anything in there right into your wheel cylinders and most likely damage them.

 

I just went ahead and replaced the old one with a new one. Bench bled it and installed it. Minimal bleeding of the rest of the system that way.

 

I just bought a new one. to me it was well worth it

 

I vote for replacing also. Brakes ain't a place to cut corners on to save a buck.

 

Thanks,
I will replace with new one then I know it will be right. I will also tear apart the old and tell you what it was that was causing the leak.
Al

 

being over 50 years old has a lot to do with it.