Author Topic: Two Rear Brake Bleeders - Who Woulda Thunk?  (Read 7720 times)

Offline Eupher

  • Arena
  • Full Member
  • ***
  • Posts: 255
  • Country: us
  • U.S. Army, Retired
Two Rear Brake Bleeders - Who Woulda Thunk?
« on: January 26, 2021, 02:07:33 AM »
OK, I'll admit it. I don't wrench on my bike all that often. I have, just not like some of you guys.

Once in the past, I flushed and bled the front & rear brakes, and clutch system. I had purchased speed bleeders at that time, but it turned out they were the incorrect part numbers so I did things the old-fashioned way. Seemed to work fine.

Time to do this again, and this time I have the speed bleeders offered by Murph's Kits. He sells 7 bleeders and an optional collection system. The bleeders themselves are broken down in two part numbers:
  • 2 each SB8125 - these are for the front brake and clutch master cylinders
  • 5 each SB8125L - these are for the front brake calipers (2); the rear brake caliper (2); and the clutch slave (1)

I was puzzled because while the front brakes have two calipers, one bleeder for each caliper, I had thought that the rear caliper would have only one.

WRONG. The rear caliper has two bleeders. One is inboard (kinda hidden unless you're looking for it, but visible from the rear) and the other is outboard, plainly seen.

And the clutch slave has only one. So all 7 bleeders are accounted for - I thought for a wild moment there Murph sold me one extra.

Idle question - Fred Harmon, in his video on brake bleeding, does NOT (to the best I can tell) bleed from the inboard bleeder on the rear brakes. He bleeds from the front only, again best I can tell. He goes into significant detail on the front brake bleeding process, but doesn't go into as much detail on the rears.

Does anybody bleed from both bleeders on the rear caliper?
2012 C14 Arabian Candy Red
2003 Honda 919
1981 Suzuki 650E
1965 Honda S90

Offline Boomer

  • Full Member
  • ***
  • Posts: 862
  • Country: gb
  • Wickford, UK
    • Boomers GTR Site
Re: Two Rear Brake Bleeders - Who Woulda Thunk?
« Reply #1 on: January 26, 2021, 05:07:51 AM »
You only need to bleed the inner nipple on the rear caliper if you've had the caliper off the bike.
It's needed to get air out of the inner piston due to it being in the 180° position (bottom of the rotor), rather than 0° or 90° position used for most brake calipers.
George "Boomer" Garratt
Wickford, UK


Offline VirginiaJim

  • Administrator
  • Elite Member
  • *****
  • Posts: 11333
  • Country: england
  • I've forgotten more than I'll ever know...
    • Kawasaki 1400GTR
Re: Two Rear Brake Bleeders - Who Woulda Thunk?
« Reply #2 on: January 26, 2021, 05:59:59 AM »
When I had my C14 I bled the rear system using both bleeders.
"LOCTITE®"  The original thread locker...  #11  2020 Indian Roadmaster, ABS, Cruise control, heated grips and seats/w/AC 46 Monitoring with cutting edge technology U.N.I.T is Back! Member in good standing with the Knights of MEH.

Offline Texas Concours14

  • Jr. Member
  • **
  • Posts: 102
  • Country: 00
Re: Two Rear Brake Bleeders - Who Woulda Thunk?
« Reply #3 on: January 26, 2021, 01:47:00 PM »
I discovered the second bleeder on the rear brakes in exactly the same way, and did not feel too stupid since Harmon's video makes no mention of the second rear bleeder. But it made me wonder about my powers of observation since I had the bike for 8 years before the discovery and had performed multiple brake fluid bleeds. BTW - wish I bought the speed bleeders years ago; greatly simplify the process.
2010 C14 ABS

Offline Eupher

  • Arena
  • Full Member
  • ***
  • Posts: 255
  • Country: us
  • U.S. Army, Retired
Re: Two Rear Brake Bleeders - Who Woulda Thunk?
« Reply #4 on: January 26, 2021, 03:49:02 PM »
You only need to bleed the inner nipple on the rear caliper if you've had the caliper off the bike.
It's needed to get air out of the inner piston due to it being in the 180° position (bottom of the rotor), rather than 0° or 90° position used for most brake calipers.

Thank you for this useful information. I've spent a fair amount of time reading through brake threads on this forum and I don't believe I'd seen anything regarding two bleeders on the rear caliper.

Your explanation makes sense.
2012 C14 Arabian Candy Red
2003 Honda 919
1981 Suzuki 650E
1965 Honda S90

Offline Eupher

  • Arena
  • Full Member
  • ***
  • Posts: 255
  • Country: us
  • U.S. Army, Retired
Re: Two Rear Brake Bleeders - Who Woulda Thunk?
« Reply #5 on: January 26, 2021, 03:50:45 PM »
I discovered the second bleeder on the rear brakes in exactly the same way, and did not feel too stupid since Harmon's video makes no mention of the second rear bleeder. But it made me wonder about my powers of observation since I had the bike for 8 years before the discovery and had performed multiple brake fluid bleeds. BTW - wish I bought the speed bleeders years ago; greatly simplify the process.

I didn't see it till yesterday. It's kinda hidden on the inside portion of the caliper, pointing toward the rear of the bike. Easy to miss as the stock bleeder is black with a black dust cap. The speed bleeders are brass colored and easier to pick out, though that may change with road grime.
2012 C14 Arabian Candy Red
2003 Honda 919
1981 Suzuki 650E
1965 Honda S90