Front Brake Spongy - Page 2 - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Wheels, Suspension and Brakes
Everything to do with wheels, tires,
suspension, forks and brakes

 1Likes
Reply
 
LinkBack Thread Tools Display Modes
post #11 of 18 (permalink) Old 05-03-2019, 03:31 PM Thread Starter
Senior Member
 
Jason Pittenger's Avatar
 
Join Date: Apr 2018
Location: Northern Illinois (Not Chicago)
Posts: 237
iTrader: (0)
 
Garage
Yes I did


'89 Vulcan 750 Bought 4/12/18 @ 17805.9 miles $800
Purchased stock. Wrecked once
22490.0+ miles

Completed modifications:
Removed mufflers, straight pipes out of GB
110/90 Front Tire
Pick-up coil re-gapped to .020"
Compufire 55402 r/r series regulator
USB Outlet + Voltmeter
Repainted Metallic Blue w/ new tank bages
Ear Shave (wo/ coasters) 40/140 NO shims 45MPG
MCCT conversion

Planned modifications:
Custom LED turn signals
Windshield
Highway Pegs
(Possible) ignition advance
Jason Pittenger is offline  
Sponsored Links
Advertisement
 
post #12 of 18 (permalink) Old 05-06-2019, 04:11 AM
Members who have donated towards server costs
 
Join Date: Nov 2007
Location: Chandler, Arizona
Posts: 2,850
iTrader: (0)
 
I have never had that procedure fail, on bikes or cars. As long as you don't let the fluid in the master cylinder get low, air cannot get into the system. Gravity will draw fluid through the system until there is no more air in the lines. It's possible you may have mechanical problems, like a leaking seal in the master cylinder.

I am a motorcyclist, NOT a biker.


1997 Vulcan 750, purchased about a week ago
2006 Sportster 1200 Low
2013 Royal Enfield Bullet 500, converted to carb
2001 Yamaha XT225, heavily modified
2004 Honda Rebel 250
1979 Vespa P200E
2002 Vulcan 750 parts bike
1994 Yamaha XT225 parts bike
VN750Rider/Jerry is offline  
post #13 of 18 (permalink) Old 05-06-2019, 11:14 AM
Senior Member
 
calebj's Avatar
 
Join Date: Sep 2015
Location: Roanoke, VA
Posts: 495
iTrader: (0)
 
Garage
Quote:
Originally Posted by Jason Pittenger View Post
I ran a pint through this morning. I didn't have any hoses to put on the bleeders, so I used a drip pan to collect the fluid. It made it worse! I have a coworker with a vacuum bleed system. I might give that a try.
Not having a hose to put on the bleeder valves is almost certainly the root of your issue.
GDI likes this.

1986 VN750 27k miles
1999 EN500 32k
1983 GL650i in pieces. Someday it will ride again.
calebj is offline  
 
post #14 of 18 (permalink) Old 05-09-2019, 10:18 PM Thread Starter
Senior Member
 
Jason Pittenger's Avatar
 
Join Date: Apr 2018
Location: Northern Illinois (Not Chicago)
Posts: 237
iTrader: (0)
 
Garage
When you're squeezing the front brake lever, and the cover is off, is it normal for the fluid to come squirting out the top? I don't fully understand how the master cylinder actually works.

A squeeze on the liver, causes fluid to come out one of the two small holes inside the chamber. If I squeeze it rapidly enough, the fluid squirts out into the air. Is that normal behavior? I don't get any leaks when the cover is on.


'89 Vulcan 750 Bought 4/12/18 @ 17805.9 miles $800
Purchased stock. Wrecked once
22490.0+ miles

Completed modifications:
Removed mufflers, straight pipes out of GB
110/90 Front Tire
Pick-up coil re-gapped to .020"
Compufire 55402 r/r series regulator
USB Outlet + Voltmeter
Repainted Metallic Blue w/ new tank bages
Ear Shave (wo/ coasters) 40/140 NO shims 45MPG
MCCT conversion

Planned modifications:
Custom LED turn signals
Windshield
Highway Pegs
(Possible) ignition advance
Jason Pittenger is offline  
post #15 of 18 (permalink) Old 05-10-2019, 08:00 AM
Senior Member
 
Spockster's Avatar
 
Join Date: Nov 2012
Location: WV
Posts: 6,572
iTrader: (5)
   
Quote:
Originally Posted by Jason Pittenger View Post
When you're squeezing the front brake lever, and the cover is off, is it normal for the fluid to come squirting out the top? I don't fully understand how the master cylinder actually works.

A squeeze on the liver, causes fluid to come out one of the two small holes inside the chamber. If I squeeze it rapidly enough, the fluid squirts out into the air. Is that normal behavior? I don't get any leaks when the cover is on.
It's normal, the cover should be in place when pumping.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf
Spockster is offline  
post #16 of 18 (permalink) Old 05-12-2019, 10:18 AM Thread Starter
Senior Member
 
Jason Pittenger's Avatar
 
Join Date: Apr 2018
Location: Northern Illinois (Not Chicago)
Posts: 237
iTrader: (0)
 
Garage
Quote:
Originally Posted by Spockster View Post
Plugged return port in the bottom of the master cyl. can do the same. With the cap removed, very carefully squeeze the lever and see if fluid squirts up out of the reservoir. Use rags so fluid doesn't end up on your paint.
So fluid squirting up and out of the chamber is not normal behavior? I'm confused.


'89 Vulcan 750 Bought 4/12/18 @ 17805.9 miles $800
Purchased stock. Wrecked once
22490.0+ miles

Completed modifications:
Removed mufflers, straight pipes out of GB
110/90 Front Tire
Pick-up coil re-gapped to .020"
Compufire 55402 r/r series regulator
USB Outlet + Voltmeter
Repainted Metallic Blue w/ new tank bages
Ear Shave (wo/ coasters) 40/140 NO shims 45MPG
MCCT conversion

Planned modifications:
Custom LED turn signals
Windshield
Highway Pegs
(Possible) ignition advance
Jason Pittenger is offline  
post #17 of 18 (permalink) Old 05-12-2019, 11:14 AM
Senior Member
 
Spockster's Avatar
 
Join Date: Nov 2012
Location: WV
Posts: 6,572
iTrader: (5)
   
Yes, it's normal, see post #15.

2003-21k mi
Shaved w/UniPK92+Stock Jets-TPE/MOSFET-Shinko Tires-AGM batt-bags-chrome-LEDs...more
__________________________________________________ ____________
Repair Manual: http://www.mediafire.com/file/mj7z81..._Catalogue.pdf

Owner's Manual: http://www.mediafire.com/file/nscb5f...ers+Manual.pdf
Spockster is offline  
post #18 of 18 (permalink) Old 06-11-2019, 06:53 PM Thread Starter
Senior Member
 
Jason Pittenger's Avatar
 
Join Date: Apr 2018
Location: Northern Illinois (Not Chicago)
Posts: 237
iTrader: (0)
 
Garage
I thought I'd follow up with this, as I finally got it working!

I did the clamp on the brake lever overnight trick a few times. Every time, it'd be very firm in the morning.
But as I would ride, the lever would lose that firmness. At the end of the day, I could pull the lever back to the bar without locking the front.

How I finally fixed it was I put the clamp on the lever. I then sharply hit the calipers, hose, and the block behind the horn starting at the calipers and working my way up. I used a metal ruler to provide a sharp hit, but minimal weight so it would bounce back just as sharply. A 10mm wrench would also work for this. The theory being that any small air bubbles should be dislodged and head up the line.

It worked! It's not quite as firm as it was before I bled the brakes, but it's consistent over several days.


'89 Vulcan 750 Bought 4/12/18 @ 17805.9 miles $800
Purchased stock. Wrecked once
22490.0+ miles

Completed modifications:
Removed mufflers, straight pipes out of GB
110/90 Front Tire
Pick-up coil re-gapped to .020"
Compufire 55402 r/r series regulator
USB Outlet + Voltmeter
Repainted Metallic Blue w/ new tank bages
Ear Shave (wo/ coasters) 40/140 NO shims 45MPG
MCCT conversion

Planned modifications:
Custom LED turn signals
Windshield
Highway Pegs
(Possible) ignition advance
Jason Pittenger is offline  
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Once registered, your User Name"cannot be changed". We can make exceptions within 7 days, but after that, it is set in stone.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome