Return port/valve on rear master cylinder


Information and questions on GL1800 Goldwings (2001-2017)
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Return port/valve on rear master cylinder

Post by goldwinglou »



2013 GW, rear brake pistons not retracting, I cleaned the two ports on the secondary master cylinder but no help. I disassembled/cleaned the rear master cylinder but only noticed the port coming from the reservoir, is there a return port I missed and if so where is it located in relation to the reservoir port. Brake recall was done on 11/15. System has been flushed four times and seals replaced in caliper, pistons were clean, no deposits or sludge on pistons or in piston cylinders.


User avatar
GoldWingrGreg
Posts: 810
Joined: Tue Aug 24, 2010 7:18 am
Location: Zephyrhills, Florida
Motorcycle: 89 GL1500
03 GL1800
04 GL1800(abs)
05 GL1800(abs)
07 GL1800(abs)
Contact:

Re: Return port/valve on rear master cylinder

Post by GoldWingrGreg »

The secondary m/c has a return port also.

Some systems were so poorly maintained that rear brake lock-up returns. Your's might be one. If so, order in the parts from SB-23, and do the recall all over again yourself. The replacement kit is not that expensive.

Pg 3 has the part number for the kit. Be sure to get 6 bottle of brake fluid also.

https://z2y.bc6.myftpupload.com/wp-cont ... cement.pdf

https://www.partzilla.com/search?q=0645 ... =typeahead
User avatar
newday777
Posts: 2144
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Return port/valve on rear master cylinder

Post by newday777 »

goldwinglou wrote: Mon Nov 23, 2020 6:07 pm 2013 GW, rear brake pistons not retracting, I cleaned the two ports on the secondary master cylinder but no help. I disassembled/cleaned the rear master cylinder but only noticed the port coming from the reservoir, is there a return port I missed and if so where is it located in relation to the reservoir port. Brake recall was done on 11/15. System has been flushed four times and seals replaced in caliper, pistons were clean, no deposits or sludge on pistons or in piston cylinders.
When you had the recall done, did they replace the rear master and the secondary master cylinders? 11/15 was the beginning of the last recall so it makes me wonder if you got those parts replaced????
Have you taken it back and had the dealer get in touch with Honda on it as the recall is still in effect and this is the same problem?
User avatar
newday777
Posts: 2144
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Return port/valve on rear master cylinder

Post by newday777 »

Yes there is a return port in the rear master cylinder. It is a tiny hole, the size of a wire from a wire brush. Hold the wire with a pr of needle nose pliers to clear the port. It is under the reservoir inlet tube adapter.
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

newday777, thanks for the info as well as GoldWingrGreg
User avatar
GoldWingrGreg
Posts: 810
Joined: Tue Aug 24, 2010 7:18 am
Location: Zephyrhills, Florida
Motorcycle: 89 GL1500
03 GL1800
04 GL1800(abs)
05 GL1800(abs)
07 GL1800(abs)
Contact:

Re: Return port/valve on rear master cylinder

Post by GoldWingrGreg »

newday777 wrote: Tue Nov 24, 2020 8:11 am Yes there is a return port in the rear master cylinder. It is a tiny hole, the size of a wire from a wire brush. Hold the wire with a pr of needle nose pliers to clear the port. It is under the reservoir inlet tube adapter.
If one chooses to do that, be sure to not push the wire to the point where it mars the inner bore on the far side. A mar on the inside bore can damage the m/c seal.
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

Found the secondary port and cleaned it as well, improved rear caliper function somewhat but still a slight drag. What causes a rear caliper to go bad, I put new seals in, sliders work easily, pads are 6mm thick, pistons are spotless, what am I missing?
User avatar
MikeB
Posts: 3316
Joined: Fri Dec 04, 2009 12:54 pm
Location: Tacoma, WA
Motorcycle: 1998 - GL1500 Aspencade
184K Miles
2017 - GL1800 Audio Comfort
14K Miles
Contact:

Re: Return port/valve on rear master cylinder

Post by MikeB »

I am not sure what you mean by "a slight drag". The pads are always riding on the rotors. They never pull completely away from the rotors, so it may apprear to be slight drag to you.
MikeB
1998 - GL1500 w/184,500 miles ~ 2017 - GL1800 w/13000 miles
USAF Avionics Communications Tech - 1968 - 1986 / Flight Engineer C-130E - C-141B - 1986 - 1992. Retired
Industrial Maintenance Tech - 1992 - 2014
Retired in Tacoma, WA
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

I compared the drag on another wing as compared to mine and their rear tire spun much freer than mine does. You can feel the drag, the center piston is not retracting sufficiently as compared to the outer pistons even with new seals.
User avatar
GoldWingrGreg
Posts: 810
Joined: Tue Aug 24, 2010 7:18 am
Location: Zephyrhills, Florida
Motorcycle: 89 GL1500
03 GL1800
04 GL1800(abs)
05 GL1800(abs)
07 GL1800(abs)
Contact:

Re: Return port/valve on rear master cylinder

Post by GoldWingrGreg »

goldwinglou wrote: Thu Nov 26, 2020 3:56 pm I compared the drag on another wing as compared to mine and their rear tire spun much freer than mine does. You can feel the drag, the center piston is not retracting sufficiently as compared to the outer pistons even with new seals.
To test, crack the upper bleeder on that caliper. When cracked, fluid should not squirt out as if under pressure. Once the pressure is released, the rear wheel should spin free.
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

I'll check and get back to you, thanks.
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

GoldWingrGreg, pumped rear brake pedal, rear brake locked up and unable to move tire. Attached clear hose to top bleed valve, opened valve, fluid moved 1/4 inch into hose, tire still locked up. No pressure buildup on lower valve, tire still stuck. Am I looking at a bad caliper?
User avatar
newday777
Posts: 2144
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Return port/valve on rear master cylinder

Post by newday777 »

goldwinglou wrote: Fri Nov 27, 2020 2:34 pm GoldWingrGreg, pumped rear brake pedal, rear brake locked up and unable to move tire. Attached clear hose to top bleed valve, opened valve, fluid moved 1/4 inch into hose, tire still locked up. No pressure buildup on lower valve, tire still stuck. Am I looking at a bad caliper?
Without pumping the pedal, put bleed hose one each of the bleeders and crack open each bleeder to see if one will release the locked caliper. Report back your findings if and which bleeder or not....
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

newday777, opened top bleeder , brake released. Tightened bleeder, applied brake, brake sticks , opened bleeder, brake released. What next or your diagnosis?
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

newday777, opened top bleeder , brake released. Tightened bleeder, applied brake, brake sticks , opened bleeder, brake released. What next or your diagnosis?
User avatar
newday777
Posts: 2144
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Return port/valve on rear master cylinder

Post by newday777 »

goldwinglou wrote: Fri Nov 27, 2020 3:15 pm newday777, opened top bleeder , brake released. Tightened bleeder, applied brake, brake sticks , opened bleeder, brake released. What next or your diagnosis?
Master cylinder return port is plugged.
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

Will clean again, thanks. Will update you later
User avatar
newday777
Posts: 2144
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Return port/valve on rear master cylinder

Post by newday777 »

goldwinglou wrote: Fri Nov 27, 2020 4:12 pm Will clean again, thanks. Will update you later
Did you take the master cylinder apart when you poked the return port?
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

Yes I did, also cleaned the reservoir tube and removed the circlip holding the port in place to access the the two holes, blew them out and shined a flashlight into the master cylinder and saw light reflected through both holes.
User avatar
newday777
Posts: 2144
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Return port/valve on rear master cylinder

Post by newday777 »

goldwinglou wrote: Fri Nov 27, 2020 4:27 pm Yes I did, also cleaned the reservoir tube and removed the circlip holding the port in place to access the the two holes, blew them out and shined a flashlight into the master cylinder and saw light reflected through both holes.
Did you poke it out with a wire brush strand held with needle nose pliers?
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

I did not use wire and pliers, I used a small straight pin to poke the return port from the outside in, pin did not go completely thru as it was too thick , blew it out with compressed air, washed master cylinder with brake fluid , flushed out with compressed air, used a flashlight in cylinder and saw light through both ports. They were clean.
User avatar
newday777
Posts: 2144
Joined: Tue Jan 11, 2011 5:21 pm
Location: Milford NH summer/fall & Oceanside, CA winters(N San Diego) with lots of miles riden between
Motorcycle: 2008 Cabernet Red. Level 4

1983 GL1100A Wineberry 36,000 miles

1975 CB750 K5 Planet Blue 7,800 miles

1976 CB750 K6 Anterris Red 25,000 miles

Past rides
1999A Restored from PO neglect & sold at 19,000 miles

1999SE Totaled by cager at 105,000 miles

Re: Return port/valve on rear master cylinder

Post by newday777 »

goldwinglou wrote: Fri Nov 27, 2020 4:47 pm I did not use wire and pliers, I used a small straight pin to poke the return port from the outside in, pin did not go completely thru as it was too thick , blew it out with compressed air, washed master cylinder with brake fluid , flushed out with compressed air, used a flashlight in cylinder and saw light through both ports. They were clean.
I used to think that way was fine until I had one do the same results as you. Now I always use the wire as it is close to the correct size. I used to know the wire size drill bit some use but the rememberer is broke......
User avatar
GoldWingrGreg
Posts: 810
Joined: Tue Aug 24, 2010 7:18 am
Location: Zephyrhills, Florida
Motorcycle: 89 GL1500
03 GL1800
04 GL1800(abs)
05 GL1800(abs)
07 GL1800(abs)
Contact:

Re: Return port/valve on rear master cylinder

Post by GoldWingrGreg »

goldwinglou wrote: Fri Nov 27, 2020 2:34 pm Am I looking at a bad caliper?
To test ... remove pads and see if caliper can be moved in and out. With the pucks retracted, that caliper should freely move somewhere between 1/4-1/2"
goldwinglou
Posts: 14
Joined: Sun Nov 08, 2015 10:52 am
Location: Brownsville Texas
Motorcycle: 2013 GL 1800

Re: Return port/valve on rear master cylinder

Post by goldwinglou »

With pads removed, pucks retracted I have the movement you stated, sliders greased and I have easy movement in and out.
User avatar
GoldWingrGreg
Posts: 810
Joined: Tue Aug 24, 2010 7:18 am
Location: Zephyrhills, Florida
Motorcycle: 89 GL1500
03 GL1800
04 GL1800(abs)
05 GL1800(abs)
07 GL1800(abs)
Contact:

Re: Return port/valve on rear master cylinder

Post by GoldWingrGreg »

goldwinglou wrote: Fri Nov 27, 2020 8:31 pm With pads removed, pucks retracted I have the movement you stated, sliders greased and I have easy movement in and out.
From here you are describing strong evidence that your issue is not caused from a caliper binding on its slide points. That brings it back to some sort of hydraulic issue. If drag is cause by a fluid pressure, then when cracking rear bleeders to release fluid pressure, and if the rotor is still difficult to turn, that eliminates it being fluid pressure issue. That leaves a couple of thing. When foot pressure is removed from the brake lever, possibly rear caliper puck is not relaxing causing pressure on the pads and rotor. The other possibility is something odd, like aftermarket pads, rotor, and something is not installed correctly.


Post Reply