1999 Honda GL1500A Rear Master Cylinder Rebuilt (Still no pressure


Information and questions on GL1500 Goldwings (1988-2000)
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AZBadger2332
Posts: 9
Joined: Thu May 06, 2021 11:40 am
Location: United States
Motorcycle: 1999 GL1500

1999 Honda GL1500A Rear Master Cylinder Rebuilt (Still no pressure

Post by AZBadger2332 »



I noticed a few months ago that my Goldwing had no rear brake pressure. I tried bleeding the brakes, but nothing came out. I used a vacuum system that worked a bit, but there were some air bubbles. I still had no pedal. I removed the master cylinder and cleaned everything up. It all looked fine inside, with no scoring, and no cracked seals.

I was bench bleeding it and realized that when I fill the reservoir up and pump the M/C, fluid isn't even making its way into the piston screw. When I remove the circlip, pull the piston out, and push all the way in, fluid pumps, but only with the circlip out.

Any ideas?


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Rambozo
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Motorcycle: 1992 GL1500 Aspencade
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Re: 1999 Honda GL1500A Rear Master Cylinder Rebuilt (Still no pressure

Post by Rambozo »

Sounds like the holes between the reservoir inlet and the cylinder are clogged. Often you have to poke them out with a fine wire, just to get cleaner in to work on them.
anilv
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Joined: Tue Apr 25, 2023 10:04 pm
Location: Kuala Lumpur
Motorcycle: Kawasaki ZR7. GSXR750WP. No Gold Wing yet.

Re: 1999 Honda GL1500A Rear Master Cylinder Rebuilt (Still no pressure

Post by anilv »

also note that when using a vacuum bleeder some air will leak past the threads on the bleeder screws. You can address this with some teflon tape on the bleed screw or just tighten/pump/hold/loosen-repeat once you're almost done.

Doesn't help your main problem but you'll eventually get there.

Anilv.

*Newbie to the gold wing but not to bikes.
Thombar
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Motorcycle: 93 gl1500

Re: 1999 Honda GL1500A Rear Master Cylinder Rebuilt (Still no pressure

Post by Thombar »

I put a new rear master on my 1993 and used vacume pump with little success. I hot glued a syringe to an old reservior lid and forced the fluid into master until got pressure in pedal.


krismoto
Posts: 26
Joined: Mon Jun 12, 2023 3:10 pm
Location: Canada
Motorcycle: 1998 GL1500SE

Re: 1999 Honda GL1500A Rear Master Cylinder Rebuilt (Still no pressure

Post by krismoto »

Hang something heavy on the pedal and leave it overnight. Sometimes 2. People argue about how it works but seam to agree that it does work. Somehow the air finds its way out of the system. Of course you should do your best work to bleed the brakes first. I use a vacuum bleeder that hooks up to an air compressor. Trick is to start the vacuum before you crack the bleeder and close the bleeder before you stop the vacuum. It moves a lot of air but it doesn't go backwards into your system. If you look at how the brake line bends down to the rear slave cylinder you can see where the air gets trapped. If you remove the slave and put it up higher that will help get the air to the bleeder, I haven't traced the lines through the rest of the bike but I see that as a possible issue right off the bat. Could be more places for air to hang out in the system.

I am about to flush my brakes this weekend. Got the bike with no rear brake pressure at all. I hung a big rock off the pedal overnight and had brakes in the morning.


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