Weak Front Brakes - Kawasaki Forum :: KawasakiWorld.com
 3Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 27 Old 12-02-2016, 02:42 AM Thread Starter
Senior Member
 
Duck's Avatar
 
Join Date: Jan 2004
Location: Brisbane Australia
Posts: 309
Weak Front Brakes

G'Day All,

The front brakes on my 96 11D have been weak for some time now. I like to use them hard and often, but the braking power is very poor.

I've had it in the shop for other things and asked them to improve the front brakes at the same time. The first time it was revealed some pistons had seized. They cleaned the calipers up and freed the pistons, the dust boots had perished. They put them back together without the dust boots and I haven't had it back to get a rebuild kit put through the calipers. P.S. I won't entertain the thought of doing brakes myself. I rely on them too heavily.

Pads are fine. Oil is fine. If I throw the anchors out hard, the lever will come close to the bar. If I pump the lever several times, it's much much better. After pumping them then releasing, the good pressure is lost straight away.

My mechanic has suggested a master cylinder rebuild, however with the symptoms I've described, I'd really appreciate some experienced thoughts here.

Cheers.
Duck is offline  
Sponsored Links
Advertisement
 
post #2 of 27 Old 12-02-2016, 03:14 AM
Senior Member
 
MetalMagician's Avatar
 
Join Date: Feb 2013
Location: toledo, ohio
Posts: 302
Warped rotors
MetalMagician is offline  
post #3 of 27 Old 12-02-2016, 07:03 AM
Member
 
Join Date: Aug 2013
Location: Staffordshire, UK
Posts: 50
Try pulling the brake on hard and fixing the lever back against the bar with either cable tie or tape. Tap the lines with screw driver or the like and rock the bike from side to side to try and release any trapped air in the system then leave overnight. This should help but you may need to do it a couple of times to get it fully sorted.
As metalmagician says could be warped rotors pushing the pads away but this would only happen when the bikes moving, do you loose the pressure you gain by pumping the lever when the bike is stationary or only when you're riding?

2002 A2 Kawasaki ZX12R (Blue)
1993 Yamaha YZF750R Fast Orange Replica

Bikes defy gravity, cars just suck
Big PJ is offline  
Sponsored Links
Advertisement
 
post #4 of 27 Old 12-03-2016, 02:16 AM Thread Starter
Senior Member
 
Duck's Avatar
 
Join Date: Jan 2004
Location: Brisbane Australia
Posts: 309
Appreciate the input guys.

I don't think warped rotors are a cause. Albeit weak, the braking is smooth.

The brakes have been bled by 2 reputable shops so I can't imagine they'd both leave air in the system.

I think it's one of the following problems and interested in thoughts to the most likely.

Master cylinder rebuild required.
Old flexing brake lines.
Glazed discs (but given I get good braking power after pumping the lever, I doubt it).

Cheers.
Duck is offline  
post #5 of 27 Old 12-03-2016, 03:16 AM
Senior Member
 
MetalMagician's Avatar
 
Join Date: Feb 2013
Location: toledo, ohio
Posts: 302
Warped rotors! Just because you can stop doesn't mean they aren't warped. When to pump your lever does the pressure build? Does it stay if you are riding? Does it stay if you are stopped not moving? Answer these questions then you will know for sure.
MetalMagician is offline  
post #6 of 27 Old 12-03-2016, 05:11 AM Thread Starter
Senior Member
 
Duck's Avatar
 
Join Date: Jan 2004
Location: Brisbane Australia
Posts: 309
Quote:
Originally Posted by MetalMagician View Post
Warped rotors! Just because you can stop doesn't mean they aren't warped. When to pump your lever does the pressure build? Does it stay if you are riding? Does it stay if you are stopped not moving? Answer these questions then you will know for sure.
Appreciate you taking the time to chime in again.

So I've started pumping the lever early about 5 times whilst coasting and it gives me a lot more braking power when on the last squeeze I'll pull hard. Lots of braking power then. After I let go and soon after use the brakes again, it's spongy with way too much travel to the bar again. If I do it with the bike parked, I can also build the pressure by pumping the lever. Otherwise I get too much travel to the bar.

I'd expect to have a lot of shimmy/vibration if it were warped rotors right? I get none, it's smooth from first application of the brakes, even without pumping them.

Thanks
Duck is offline  
post #7 of 27 Old 12-03-2016, 12:54 PM
Senior Member
 
MetalMagician's Avatar
 
Join Date: Feb 2013
Location: toledo, ohio
Posts: 302
Quote:
Originally Posted by Duck View Post
I'd expect to have a lot of shimmy/vibration if it were warped rotors right? I get none, it's smooth from first application of the brakes, even without pumping them.

Thanks
Not necessarily. The calipers are fixed and when applying the brake I would assume that they would hold the rotor true (just my opinion not facts). I wouldn't think you would feel it unless they are badly warped. If when parked you can build the pressure and it stays then it's definitely your rotors.
MetalMagician is offline  
post #8 of 27 Old 12-03-2016, 06:09 PM Thread Starter
Senior Member
 
Duck's Avatar
 
Join Date: Jan 2004
Location: Brisbane Australia
Posts: 309
Quote:
Originally Posted by MetalMagician View Post
Not necessarily. The calipers are fixed and when applying the brake I would assume that they would hold the rotor true (just my opinion not facts). I wouldn't think you would feel it unless they are badly warped. If when parked you can build the pressure and it stays then it's definitely your rotors.
Tried it parked. Pumped the lever, released it, pressure lost after a few seconds. Pumped the lever whilst pushing it forward slowly then stopped the bike, again pressure gone after a few seconds.
Duck is offline  
post #9 of 27 Old 12-07-2016, 11:38 AM
Senior Member
 
BIRD B GONE's Avatar
 
Join Date: Dec 2005
Location: Barrie,ON. Canada
Posts: 479
Steel brake lines are a must for the 11, the brakes are crappy and always have a spongy feel to them, they made a world of difference on my Zed. I think your travel issue is the master! you should also try to mic the rotors to see if there in spec.

1986 Yamaha--- FZ750
2001--- CBRXX 1100 Blackbird
Mystic Black 03-- ZX12R 172 rwhp
2008 --- ZX14
Now Riding 1993 --- ZX-11
BIRD B GONE is offline  
post #10 of 27 Old 12-08-2016, 12:15 AM Thread Starter
Senior Member
 
Duck's Avatar
 
Join Date: Jan 2004
Location: Brisbane Australia
Posts: 309
Quote:
Originally Posted by BIRD B GONE View Post
Steel brake lines are a must for the 11, the brakes are crappy and always have a spongy feel to them, they made a world of difference on my Zed. I think your travel issue is the master! you should also try to mic the rotors to see if there in spec.
Thanks mate.

I'm happy to say the bike is going into the shop tomorrow morning for a master cylinder rebuild and overhaul of the calipers including all new dust boots and seals. Plus new hoops, Bridgestone T30's. It's going to be an expensive day. BTW.. I won't touch brakes with my skill level. Oil changes and some other minor stuff but not brakes.

I'll ask them in the morning to quote on the steel brake lines and see if they can source them same day while they've got the bike.

Oh and... They put a micrometer on the rotors while I was at the shop on Tuesday. They were within spec.

Apart from the big bill, I'm very excited for the old girl!!
Duck is offline  
post #11 of 27 Old 12-08-2016, 01:21 AM
Senior Member
 
SteveW's Avatar
 
Join Date: Jul 2011
Location: Perth Australia
Posts: 1,021
Hey Duck, check out HEL performance for braided lines
https://au.helperformance.com

2006 ZX-12R B6F
Ohlins / TRAXXION Dynamics / NISSIN / HEL / Power Commander / Bear Racing / Akrapovic / BMC / Muzzy / Healtech / ERMAX / Helibars / GSG / R&G / NUI Racing
SteveW is offline  
post #12 of 27 Old 12-08-2016, 01:29 AM Thread Starter
Senior Member
 
Duck's Avatar
 
Join Date: Jan 2004
Location: Brisbane Australia
Posts: 309
Quote:
Originally Posted by SteveW View Post
Hey Duck, check out HEL performance for braided lines
https://au.helperformance.com
G'Day Mate,

I actually looked at them on ebay tonight. Just had a look at their OZ website. I wish I'd ordered them in advance of tomorrow. I'll see what the bike shop can source for me same day. Otherwise I guess it'll be interesting to see what improvement I get from the complete overhaul alone.

Cheers
Duck is offline  
post #13 of 27 Old 12-08-2016, 05:02 AM
Senior Member
 
BIRD B GONE's Avatar
 
Join Date: Dec 2005
Location: Barrie,ON. Canada
Posts: 479
Sounds like your on the right path, money on brakes is money well spent in my books!! It would be cool if they could get the steel lines so they don't have to bleed the system again. I think I paid around $100 Canadian for my lines.

1986 Yamaha--- FZ750
2001--- CBRXX 1100 Blackbird
Mystic Black 03-- ZX12R 172 rwhp
2008 --- ZX14
Now Riding 1993 --- ZX-11
BIRD B GONE is offline  
post #14 of 27 Old 12-08-2016, 05:29 AM
Senior Member
 
SteveW's Avatar
 
Join Date: Jul 2011
Location: Perth Australia
Posts: 1,021
Quote:
Originally Posted by Duck View Post
G'Day Mate,

I actually looked at them on ebay tonight. Just had a look at their OZ website. I wish I'd ordered them in advance of tomorrow. I'll see what the bike shop can source for me same day. Otherwise I guess it'll be interesting to see what improvement I get from the complete overhaul alone.

Cheers
Good luck with it

2006 ZX-12R B6F
Ohlins / TRAXXION Dynamics / NISSIN / HEL / Power Commander / Bear Racing / Akrapovic / BMC / Muzzy / Healtech / ERMAX / Helibars / GSG / R&G / NUI Racing
SteveW is offline  
post #15 of 27 Old 12-09-2016, 12:00 AM Thread Starter
Senior Member
 
Duck's Avatar
 
Join Date: Jan 2004
Location: Brisbane Australia
Posts: 309
Well.. it was a successful day at the bike doctor today. The master cylinder rebuild and caliper overhaul has achieved a massive improvement. I couldn't really ask for better. My mechanic said you can feel some bulging in the bottom of the lines but the improvement has exceeded my expectations, so I don't think I'll be racing out to get braided lines too soon.

I don't mind the little bit of spongy'ness, it allows for more progressive application of the brakes. I had a new ER-6NL as a loaner today. The brakes on it were way too aggressive for my liking and had a very small on/off margin.

It was an interesting ride home with new brakes, new tyres and wet roads :)
Duck is offline  
Reply

  Kawasaki Forum :: KawasakiWorld.com > Kawasaki Motorcycles > ZX-11

Quick Reply
Message:
Options

Register Now



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

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









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



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



Similar Threads
Thread Thread Starter Forum Replies Last Post
Front brakes simlog ZX-12R 5 12-04-2016 01:30 PM
front brake discs replacements robstar Z750 Z1000 0 11-25-2016 11:49 AM
ZX12 ´00 LEFT front FOOT REST COMPATIBLE zx12r_tenerife ZX-12R 2 10-11-2016 04:09 AM
front sprocket ggpostal ZX-12R 4 07-26-2016 07:19 PM
Venhill front brake lines BigSkip765 ZX-12R 0 07-22-2016 10:42 AM

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