Rear Brake master cylinder


Information and questions on GL1500 Goldwings (1988-2000)
Post Reply
Ridgeback46
Posts: 15
Joined: Fri Apr 26, 2013 3:27 pm
Location: Grande Prairie, Alberta
Motorcycle: 1994 Honda Gold Wing 1500 SE

Rear Brake master cylinder

Post by Ridgeback46 »



My brake pedal had an excessive amount of travel, so I tried bleeding the system which i know entails bleeding both the the front and rear wheel cylinders.
When this did not help I got a kit and rebuilt the master cylinder and went through the bleeding again - still a very low pedal.
I desperation I got a complete master cylinder and fitted the new master cylinder and once again went through the bleeding procedure.
I still have not managed to get a pedal that only moves a small amount before applying the brakes.
What am I missing or not doing that i should be doing?
PLEASE HELP I am at my wits end.


User avatar
LittleGoldy
Posts: 128
Joined: Sun Jul 26, 2015 11:41 pm
Location: Lake Worth FL
Motorcycle: 1983 GL1100I, 1982 GL1100 Aspencade (parts bike, ugh got shafted on ebay, BUT it is being resurrected as a naked and it RUNS ......woot. 7/31/2021 Keep y'all updated with photos soon, not that anyone cares :D) 1981 CB750C, 1981 GL1100 Interstate (Project)1983 XJ750 Seca Sold, 2003 Kawasaki ZX1R Sold, 1980 GS750E Sold, 1973 Kawasaki H1 Triple 500 (first bike ever) Sold

Re: Rear Brake master cylinder

Post by LittleGoldy »

Not sure but this may help:


   Never miss a video: Subscribe to the GoldwingDocs YouTube channel today!

Rear:

   Never miss a video: Subscribe to the GoldwingDocs YouTube channel today!

I always check youtube for vids if I am having difficulty. Sometimes it helps a LOT.
Did you check the tiny bleed back hole in the master cylinder? If it is slightly clogged it may trap the air you are trying to remove.
Good Luck
You can do anything, but not everything.
Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away. :ugeek:
User avatar
newday777
Posts: 2146
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: Rear Brake master cylinder

Post by newday777 »

Excessive travel of disc brake pedal and lever is usually caused by worn pads and or worn rotors.
Measure the thickness of the rotors to check if they are in spec.
User avatar
DenverWinger
Posts: 1969
Joined: Thu Jun 23, 2011 2:20 pm
Location: Denver, CO
Motorcycle: (s)
1980 GL1100 STD Vetter (2005-)
1993 GL1500 Aspencade (2017-)
1983 Trav-Lite Camper (2010-)
Past rides
1972 CL350 (1980-1988) sold
1978 Suzuki GS550 (1985-2005) sold
1977 GL1000 (2002-2006) sold

Re: Rear Brake master cylinder

Post by DenverWinger »

Ridgeback46 wrote: Fri Dec 04, 2020 4:05 pm My brake pedal had an excessive amount of travel, so I tried bleeding the system which i know entails bleeding both the the front and rear wheel cylinders.
........
I still have not managed to get a pedal that only moves a small amount before applying the brakes.
The 1500 by nature has a goodly amount of travel on the rear brake pedal, many posters have come here to ask about this and in the end it was determined the brake pedal travel they were experiencing was normal.

So three questions to consider before we decide there's actually a problem here:
1) Can you measure how many inches of travel we are talking about at the end of the pedal between rest and where you get good resistance?
2) Does the pedal feel excessively spongy?
3) Most important, does it stop the bike good?

If it's a spongy-feeling pedal and doesn't have good stopping power, then we would consider there's either still air in the system, or maybe need to upgrade the flexible brake lines to stainless steel.

But if you are expecting a hard pedal with less than an inch of travel, you won't get it. A full two inches of travel on the rear brake pedal on the 1500 is NORMAL. :) :)
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
♫ 127 Little Bugs in the Code. ♫ ♪ :shock:

~Mark
User avatar
Rednaxs60
Posts: 2584
Joined: Wed Nov 18, 2015 12:44 pm
Location: Victoria, British Columbia, Canada
Motorcycle: 1985 GL1200 LTD
2014 Can-Am Spyder RT LE
1995 GL1500 SE CDN Edition (sold)
2012 Suzuki DL1000 VStrom (sold)
2008 GL1800 (sold)
Ontario 1985 GL1200 LTD (sold)

Re: Rear Brake master cylinder

Post by Rednaxs60 »

newday777 wrote: Sat Dec 05, 2020 6:09 am Excessive travel of disc brake pedal and lever is usually caused by worn pads and or worn rotors.
Measure the thickness of the rotors to check if they are in spec.
Was just thinking the same. Rotors are generally overlooked when refurbishing the brake system. If the rotors are close to being out of spec, replace.
"When you write the story of your life, don't let anyone else hold the pen"

Ernest
Ridgeback46
Posts: 15
Joined: Fri Apr 26, 2013 3:27 pm
Location: Grande Prairie, Alberta
Motorcycle: 1994 Honda Gold Wing 1500 SE

Re: Rear Brake master cylinder

Post by Ridgeback46 »

Thanks to all those that have posted replies to my problem.
I will try again after I have replaced my timing belts and adjusters.
hickeybond
Posts: 36
Joined: Wed May 14, 2014 2:46 pm
Location: Hobart, Indiana
Motorcycle: 1991 gl1500 interstae

Re: Rear Brake master cylinder

Post by hickeybond »

two days ago i rebuilt the rear caliper and flushed with new brake fluid. i have watched all the utube stuff on this and i agree, with everything new and within specs, there is def a good two inches of travel before you have back brakes! nature of the beast i guess
User avatar
MikeB
Posts: 3526
Joined: Fri Dec 04, 2009 12:54 pm
Location: Tacoma, WA
Motorcycle: 1998 - GL1500 Aspencade
186K Miles
2017 - GL1800 Audio Comfort
20K Miles
Contact:

Re: Rear Brake master cylinder

Post by MikeB »

Here is a short video of what the brake pedal travel looks like on my '98 GL1500 Aspencade.
It is an indication of how it has always been and the brakes have always worked as designed.
Yours should be similar.
https://imgur.com/3zUEznB
By the way, I can not say that I have ever seen where worn brake pads or worn brake rotors give an indication of increased brake pedal travel. Brake pads always ride lightly on the rotors when the brake is not engaged. The caliper pistons extend to apply the pressure on the brake rotors from behind the pads. When pressure is relaxed from the brake pedal or lever, the pistons only retaract as far as the pads push them. They do not return to a predetermined position. That is why the brake fluid level in a reservoir will go down as pads and rotors wear.

Old and worn rubber brake lines would be more likely the cause of increased pedal or lever travel with brake application than worn pads or rotors I would think.
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
Solo So Long
Posts: 395
Joined: Thu Mar 26, 2020 4:07 pm
Location: Northern Nevada
Motorcycle: 1999 GL1500 50th Anniversary SE
1989 GL1500 FOR SALE
A pack of Super Cubs
Formerly (in order):
Honda Super Cub (bought 1968, sold ?)
Kawasaki Coyote (early 1970s)
Honda 350 (mid 1970s)
Kawasaki KZ900-PS (1977)
Honda Super Cubs (various years)
Kawasaki KZ1000C (1978)
Kawasaki KZ1000P (various years, 1980 - 2005)
Honda 360 (1983)
BMW R1150RT-P (2001)
BMW R1200RT-P (various years 2007 - 2018, NEVER AGAIN)

Re: Rear Brake master cylinder

Post by Solo So Long »

Remember, that pedal works TWO separate brake calipers, with a lot of hose going to the front one. That inch you were used to on another bike only worked ONE, so two is pretty much the same level of performance.

The only thing likely to improve it is going to braided hoses.


Post Reply