1981 GL1100 rear Master cylinder

[Mikegl1100]

Does anyone know if there is an after market rear master cylinder for a 1981 Honda Goldwing GL 1100? I have searched and searched I even ordered a rebuild kit which did not do any good Plus ordered a used one off of eBay with no justice. I would even settle for NOS or a good used one that is in working order/ pumps fluid any leads/suggestions would be highly appreciated thank you

[froche]

There is a write up on Naked Goldwings on how to use an 1800 rear master cylinder: https://ngwclub.com/forum/viewtopic.php?f=24&t=44934

Read all three pages because some report needing to change the brake line as well.

And why did the rebuild kit fail?

This guy used a Valkyrie rear mc

https://www.goldwingfacts.com/threads/g ... de.560170/

A master cylinder is a simple piece of metal, generally if nobody strips out any holes they can be reconditioned.
Never clean out the bore with anything abrasive! 3M plastic "scrunge" pads are about the best, I suppose soda blasting is ok as soda blasting removes paint and just about everything but metal.

If you bore is screwed up you can, if you are a machinist, make a cylinder sleeve after boring out the old one.. if you have to pay for this forget about it!

I have rebuilt many master cylinders, some really badly stuck, but when done they always worked.

[pidjones]

I hate brakes, but the job isn't hard. I use brake cleaner and aluminum foil to scrub the bore. Make sure the return (relieve, or splooge) hole is clear - I use a high E guitar string for that. Lube all parts with brake fluid for assembly and prime the MC before final connection of the outlet line. Even a new one will need primed, and if you should go for a Chinabay unit you really should disassemble, clean, and reassemble with brake fluid lube.

[froche]

You know I'd try from Amazon a "universal rear master brake cylinder".
They cost 8.39 (imagine that!)

Amazon

Amazon has many but they all have the same dimensions.
Some of them claim to work up to 1000 cc Suzukis and Honda VTR1000, so if true they should work for a 1100.

You may have to use spacers to mount it, or make a mount. Apparently they have a 13mm bore, I think. Certainly for 8 bucks if I needed one I would try it!

[Mikegl1100]

There is a write up on Naked Goldwings on how to use an 1800 rear master cylinder: https://ngwclub.com/forum/viewtopic.php?f=24&t=44934

Read all three pages because some report needing to change the brake line as well.

And why did the rebuild kit fail?

This guy used a Valkyrie rear mc

https://www.goldwingfacts.com/threads/g ... de.560170/

A master cylinder is a simple piece of metal, generally if nobody strips out any holes they can be reconditioned.
Never clean out the bore with anything abrasive! 3M plastic "scrunge" pads are about the best, I suppose soda blasting is ok as soda blasting removes paint and just about everything but metal.

If you bore is screwed up you can, if you are a machinist, make a cylinder sleeve after boring out the old one.. if you have to pay for this forget about it!

I have rebuilt many master cylinders, some really badly stuck, but when done they always worked.

I have no ideal to why the rebuild did not work I had a friend rebuild it with the ket I had ordered and he says all he gets when he pumps it is air no fluid?? So I am thinking about taking it apart again myself and double check everything.. I do not understand why only air is coming out with the reservoir full of blood any suggestions on what to double check would be very much appreciated thank you all for your comments and advice. In the meantime I will check the other site two custom 1800 rear master cylinder thank you again.

[froche]

I have no ideal to why the rebuild did not work I had a friend rebuild it with the ket I had ordered and he says all he gets when he pumps it is air no fluid??

Well if the kit is incorrect or a cheap kit it might not work correctly. If the bore is scarred it should leak fluid, if it isn't scarred and the rubber plunger fits then it should pump fluid. Was it in the bike when it did not pump fluid? I converted mine to speedbleeders and used a vacuum pump to fill the lines and then manually bled them. Also make sure the Brake cylinder works as well. You can tell if the fluid is coming out of the master cylinder by slightly loosening the banjo bolt. MAKE SURE to surround it with rags !!

[Mikegl1100]

I have no ideal to why the rebuild did not work I had a friend rebuild it with the ket I had ordered and he says all he gets when he pumps it is air no fluid??

Well if the kit is incorrect or a cheap kit it might not work correctly. If the bore is scarred it should leak fluid, if it isn't scarred and the rubber plunger fits then it should pump fluid. Was it in the bike when it did not pump fluid? I converted mine to speedbleeders and used a vacuum pump to fill the
lines and then manually bled them. Also make sure the Brake cylinder works as well. You can tell if the fluid is coming out of the master cylinder by slightly loosening the banjo bolt. MAKE SURE to surround it with rags !!

yes it was on the bike when tested heres The kit I purchased.. as for the cylinder walls being scored I have no idea like I said I wasn’t the one that rebuild it I am going to pick it up and carry it down myself and go from there.. Bc252m kit

[Rambozo]

It's always a good idea to bench bleed any master cylinder before installing it.