Topic: '74 CB550 brake master cylinder lever stuck

[RAFster122s]

I'm getting my (new to me) '74 CB550 back on the road after having not been on the road since the mid-80s.
The brake lever is frozen and not moving.
Am I looking a new master cylinder for this bike?
I'm guessing it has oxidized around the piston locking it in place. I  haven't removed it from the handlebars to pull the boot to see what the exterior view of the piston area looks like.

Any advice or thoughts?

Thanks!

David

[KingCustomCycles.com]

soak it in penetrating oil, warm it up with a propane torch, remove the line and insert a punch to convince it to come out.  It is retained by a C clip so that has to come out first.  Enjoy.

[TwoTired]

Look inside the reservoir.  Has the fluid crystalized?  If so, soak it in brake cleaner for a while.  Heating is good, but too much heat can make rubber into a sticky, tarry glue.  An open flame can destroy external finishes, too.

You most certainly have to get that snap ring out at the lever side.  Not just the c ring holding the rubber boot, but behind that is a snap ring that fits in a groove.

You can connect another master cylinder and use it's hydraulic pressure to push the piston out, but you have to have a pretty good seal on the reservoir cap.

Cheers,

[RAFster122s]

Thank you KingCustomCycles and TwoTired!

The hose has that lovely orange patina of rust covering the end of the fitting (humid California storage apparently)
The bowl is very clean and there's a smidge of white powder/crystals from fluid on the rubber cap/diaphragm and the Cap was wired on (really odd I thought).

All the cables on the bike wouldn't budge a bit.
Going to have to pull it from the handlebars and follow your advice.

I'll try to snap a few photos and post them this weekend.

Thanks again!

David