1981 GL1100 rear Master cylinder


Information and questions on GL1000 Goldwings (1975-1979)
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Mikegl1100
Posts: 8
Joined: Wed Dec 18, 2019 1:35 am
Location: Paris Illinois
Motorcycle: 1981 Honda Goldwing gl1100I

1981 GL1100 rear Master cylinder

Post by 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
Posts: 306
Joined: Wed Mar 12, 2014 1:56 pm
Location: Vista, ca
Motorcycle: 1985 Goldwing Aspencade (GL1200A)
2002 GL1800

Former bikes;
2000 R1100RT
2005 Suzuki Bandit
1979 Yamaha XS1100
1978 Yamaha XS1100 Special
1990 Yamaha XV250
1980 Yamaha XV750
1979 Honda CB750
1968 Triumph Bonneville T120
1973 Honda CB450
1968 Harley Davidson Sportster
1974 Honda CB750
1968 Honda CL72

Re: 1981 GL1100 rear Master cylinder

Post by 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.
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pidjones
Posts: 83
Joined: Sun Jun 03, 2012 2:14 pm
Location: Clinton, Tennessee
Motorcycle: 2006 GL1800A
1978 GL1000 w/'75 engine (project)

Re: 1981 GL1100 rear Master cylinder

Post by 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
Posts: 306
Joined: Wed Mar 12, 2014 1:56 pm
Location: Vista, ca
Motorcycle: 1985 Goldwing Aspencade (GL1200A)
2002 GL1800

Former bikes;
2000 R1100RT
2005 Suzuki Bandit
1979 Yamaha XS1100
1978 Yamaha XS1100 Special
1990 Yamaha XV250
1980 Yamaha XV750
1979 Honda CB750
1968 Triumph Bonneville T120
1973 Honda CB450
1968 Harley Davidson Sportster
1974 Honda CB750
1968 Honda CL72

Re: 1981 GL1100 rear Master cylinder

Post by froche »

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

Amazon
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
Posts: 8
Joined: Wed Dec 18, 2019 1:35 am
Location: Paris Illinois
Motorcycle: 1981 Honda Goldwing gl1100I

Re: 1981 GL1100 rear Master cylinder

Post by Mikegl1100 »

froche wrote: Thu Dec 19, 2019 12:30 pm 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
Posts: 306
Joined: Wed Mar 12, 2014 1:56 pm
Location: Vista, ca
Motorcycle: 1985 Goldwing Aspencade (GL1200A)
2002 GL1800

Former bikes;
2000 R1100RT
2005 Suzuki Bandit
1979 Yamaha XS1100
1978 Yamaha XS1100 Special
1990 Yamaha XV250
1980 Yamaha XV750
1979 Honda CB750
1968 Triumph Bonneville T120
1973 Honda CB450
1968 Harley Davidson Sportster
1974 Honda CB750
1968 Honda CL72

Re: 1981 GL1100 rear Master cylinder

Post by 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
Posts: 8
Joined: Wed Dec 18, 2019 1:35 am
Location: Paris Illinois
Motorcycle: 1981 Honda Goldwing gl1100I

Re: 1981 GL1100 rear Master cylinder

Post by Mikegl1100 »

froche wrote: Thu Dec 19, 2019 6:57 pm 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
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Rambozo
Posts: 525
Joined: Sun Apr 01, 2018 8:36 pm
Location: Disneyland
Motorcycle: 1992 GL1500 Aspencade

Re: 1981 GL1100 rear Master cylinder

Post by Rambozo »

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


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