Necessary to Remove T3 Master Cylinder?

[Dimples]

Can the T3 upper master cylinder be rebuilt while attached to the handle bars? I was planning to knock out the old cylinder and then press in the new parts using a socket and large C-clamp to seat them. I can't easily remove it because the switch is wired through the handlebars. Will this be more difficult than I imagine?

[Antietam Classic Cycle]

I guess it's possible to rebuild it on the 'bars, never tried it myself.

[moto]

Can the T3 upper master cylinder be rebuilt while attached to the handle bars? I was planning to knock out the old cylinder and then press in the new parts using a socket and large C-clamp to seat them. I can't easily remove it because the switch is wired through the handlebars. Will this be more difficult than I imagine?

I think you must mean the stoplight switch. But it is not wired through the handlebars. It operates from a hydraulic junction below the headlight on the front fork, plumbed into the front brake tubing.

[Stevex]

If its anything like my mc the switch should be removable, as it would need replacing if it was u/s. Mine can be removed by first removing the lever on the mc as the nut holds the switch bracket in place.

[JoeW]

I have rebuilt the master without removing it from the handlebar.
I think you must mean the stoplight switch. But it is not wired through the handlebars. It operates from a hydraulic junction below the headlight on the front fork, plumbed into the front brake tubing.
He is talking about the headlight/turn signal switch. The wires run thought the handlebar. It's not an easy thing to R&I.

[Dimples]

If its anything like my mc the switch should be removable, as it would need replacing if it was u/s. Mine can be removed by first removing the lever on the mc as the nut holds the switch bracket in place.

No, not the brake light switch. The original T3 starting switch gear has its wiring fed internally the handlebars. That makes it a project to remove.

[moto]

No, not the brake light switch. The original T3 starting switch gear has its wiring fed internally the handlebars. That makes it a project to remove.

Of course. Silly me. I don't see why the on-handlebar rebuild wouldn't work, if it is only seals that are needed. I hope the original poster will update us how it goes.

[jhem68]

When I rebuilt mine, I took it as an opportunity to replace the original switches with the much-improved aftermarket items available through MG Cycles. I really disliked the functionality of the originals and had problems with the Molex plug at the headlight that occasionally acted as an independent kill switch at times.

Still have my original switches but I would never use them again.

I'm sure you could rebuild the master cylinder in place assuming the cylinder bore is still in good shape, but even if you like the original switches, it is not that difficult to find the tool for removing the Molex plug and removing the switches.

YMMV

John H