Rear master cylinder


Information and questions on GL1100 Goldwings (1980-1983)
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Thegnargoyle
Posts: 1
Joined: Sun Jul 09, 2017 2:01 pm
Location: New Jersey
Motorcycle: 1980 GL1100 standard

Rear master cylinder

Post by Thegnargoyle »



I have an 1980 gl1100 standard and I have been having a lot of trouble with the rear master cylinder to the point where it's now totaled I just got in a new rear master cylinder for a 1983 gl1100 interstate anybody out there have any suggestions on how to make it work with just a single piston caliper?


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RBGERSON
Posts: 3233
Joined: Tue Mar 09, 2010 7:57 am
Location: SCOTTSDALE, AZ
Motorcycle: 98 SE GL 1500
had every year from 75 to 83

Re: Rear master cylinder

Post by RBGERSON »

should be able to just hook it up but you have a port/line you'll have to plug..as the 83 had linked brakes so there was a line that went to one of the front calipers.
HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB
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jeffcosmo
Posts: 228
Joined: Thu Aug 22, 2013 9:26 pm
Location: Burlington, WI (Honey Lake)
Motorcycle: 1983 GL1100 Aspencade
1983 GL1100 Aspencade
1983 GL1100 Aspencade (parts bike)

Re: Rear master cylinder

Post by jeffcosmo »

What is the diameter of the piston?? Most M/C have that cast into the casting on the M/C. Match that, and it does not matter what it came from, it will work the same.

Larger will give harder pedal, less travel and less braking force; smaller the exact opposite.

Cosmo
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argosybob
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Joined: Wed Nov 20, 2013 6:18 am
Location: Middletown, New Jersey
Motorcycle: 1983 GL1100I Interstate, 1983 GL1100A Aspencade, 1982 GL1100 Interstate (project bike) 1985 California Sidecar Wingliner Trailer

Re: Rear master cylinder

Post by argosybob »

RBGERSON wrote: Tue Jul 11, 2017 5:55 am should be able to just hook it up but you have a port/line you'll have to plug..as the 83 had linked brakes so there was a line that went to one of the front calipers.
Uhhhh... Nope. The difference between the 2 rear masters is that the 80 uses a Banjo bolt, and the 83 has a small brass orifice in the brake line fitting and uses a more "automotive" type fitting and a hard line. That hard line goes to a proportioning valve that then splits to the right front caliper. I delinked the brakes on one of my 83's because the master was roached out beyond repair (cracked body that leaked like mad). I used a rear master from an 81, and had Ray Chan make me a new set of lines. I used the front splitter from the same 81 up front. I can report that the 83 front master has plenty of power to work both 2 pot calipers, though it took a few miles to get used to the brakes not being linked. The 81 rear master works the 83 2 pot caliper with no issues. Ray does a great job on the brake lines, BTW.
RMBLOldwinger
Posts: 15
Joined: Wed Aug 09, 2017 7:36 pm
Location: Paragould, Arkansas
Motorcycle: 1983 GL1100 Interstate

Re: Rear master cylinder

Post by RMBLOldwinger »

I may be needing a new rear master cylinder, but so far have had no luck finding one. Where did you find a new rear master cylinder? Mine is an 83. Thanks!
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argosybob
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Location: Middletown, New Jersey
Motorcycle: 1983 GL1100I Interstate, 1983 GL1100A Aspencade, 1982 GL1100 Interstate (project bike) 1985 California Sidecar Wingliner Trailer

Re: Rear master cylinder

Post by argosybob »

I seriously doubt you'll find a new old stock one. Used ones turn up occasionally for an 83 from time to time on ebay, but not all that often. That's part of the reason I elected to delink my brakes. I got my 81 rear master and front splitter via ebay. I rebuilt the 81 rear master before installing, of course.
RMBLOldwinger
Posts: 15
Joined: Wed Aug 09, 2017 7:36 pm
Location: Paragould, Arkansas
Motorcycle: 1983 GL1100 Interstate

Re: Rear master cylinder

Post by RMBLOldwinger »

I am sure you are right about not finding NOS item. Could you elaborate a bit on the 81 rear master and the front splitter. I know that the 83 rear master splits off front to rear after it leaves the master cylinder, and the primary difference in the 83 and the earlier models is the larger piston to handle two calipers, but does the front master then handle both front brakes when using an 81 rear master?
RMBLOldwinger
Posts: 15
Joined: Wed Aug 09, 2017 7:36 pm
Location: Paragould, Arkansas
Motorcycle: 1983 GL1100 Interstate

Re: Rear master cylinder

Post by RMBLOldwinger »

As it turns out, the master cylinder cleaned up very well. I guess I dodged a bullet on that one. Thanks very much for the feedback!
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argosybob
Posts: 43
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Location: Middletown, New Jersey
Motorcycle: 1983 GL1100I Interstate, 1983 GL1100A Aspencade, 1982 GL1100 Interstate (project bike) 1985 California Sidecar Wingliner Trailer

Re: Rear master cylinder

Post by argosybob »

I'm glad yours cleaned up ok. To elaborate, on my 83, I'm using an 81 rear master that is driving the 83 rear caliper. Since I delinked the brakes, I removed the proportioning valve and all of the hard brake lines from the bike. My new braided SS line in the rear goes direct from the master to the caliper. The front master feeds a splitter mounted at the bottom of the triple tree, which then feeds both front calipers. The only thing I changed was the rear master and the lines, plus I added the splitter.
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brianinpa
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Location: Lebanon, PA
Motorcycle: 1984 GL1200 Standard
1987 GL1200 Interstate

Re: Rear master cylinder

Post by brianinpa »

Just to throw another option on the table for the future...

An 1800 rear master cylinder can be modified real easily with a simple mounting plate. Used MC are plentiful as they are taken off for trike rebuilds and parts are plentiful.


Brian

If you aren't having fun doing it, find something else to do.
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