Rear Master Cylinder Alternative?


Information and questions on GL1000 Goldwings (1975-1979)
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truefire5
Posts: 11
Joined: Sun Jul 30, 2017 5:10 pm
Location: Indianapolis, IN
Motorcycle: 1976 Goldwing 1000 LTD

Rear Master Cylinder Alternative?

Post by truefire5 »



Background
I have 1976 GL 1000 LTD and have rebuilt the Rear Master Cylinder with kits two times.
The brake will work for a little while but then ends up leaking fluid out the bottom boot seal.
There is no OEM or Aftermarket replacement that I'm aware of.

Question
Is there a newer model GoldWing Rear Master Cylinder that will work on the 1976 version?

Thanks,
- Jason


akuzmanoff
Posts: 1
Joined: Fri Jul 07, 2017 9:44 am
Location: Boston, MA
Motorcycle: 1976 GL1000LTD

Re: Rear Master Cylinder Alternative?

Post by akuzmanoff »

Hi Jason,

I just had this same issue with my 76 rear master cylinder. I was able to fix it by giving the rear master cylinder a through cleaning before putting the parts back together. I removed all of the parts from the unit, hit it with brake cleaner, and used compressed air to blow out all of the buildup that was partially blocking the passages.

There was also a really tiny fluid return hole that I cleaned out with a bristle that I cut off of a wire brush. I believe that this blockage was causing a pressure buildup in the cylinder and causing the brake fluid to escape past seals on the bottom which then leaked past the dust boot.

I hope it helps.

Alex
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johnfm3
Posts: 29
Joined: Fri Aug 25, 2017 3:34 pm
Location: Sumner, Wa
Motorcycle: 1976 GL1000

Re: Rear Master Cylinder Alternative?

Post by johnfm3 »

truefire5 wrote: Sun Aug 20, 2017 9:50 am Question
Is there a newer model GoldWing Rear Master Cylinder that will work on the 1976 version?

Thanks,
- Jason
Assuming the problem is a 40 yr old part which has worn out exceeding the inner diameter than the sealing parts can allow, is there a reason you can not have the master cyl bored and re-sleeved? This is something which was done on classic cars when people would rebuild hard to find drum brake cyl's.
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SnoBrdr
Posts: 784
Joined: Fri Mar 07, 2014 9:01 am
Location: Providence, Rhode Island
Motorcycle: 1978 GL 1000

131K Original Owner

Re: Rear Master Cylinder Alternative?

Post by SnoBrdr »

johnfm3 wrote: Wed Sep 06, 2017 9:31 am
truefire5 wrote: Sun Aug 20, 2017 9:50 am Question
Is there a newer model GoldWing Rear Master Cylinder that will work on the 1976 version?

Thanks,
- Jason
Assuming the problem is a 40 yr old part which has worn out exceeding the inner diameter than the sealing parts can allow, is there a reason you can not have the master cyl bored and re-sleeved? This is something which was done on classic cars when people would rebuild hard to find drum brake cyl's.
There have been others who bought a generic MC on EBay and adapted it to work.


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