[Duck]

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.

 

[MetalMagician]

Warped rotors

 

[Big PJ]

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?

 

[Duck]

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.

 

[MetalMagician]

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.

 

[Duck]

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

 

[MetalMagician]

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.

 

[Duck]

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.

 

[BIRD B GONE]

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.

 

[Duck]

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!!

 

[SteveW]

Hey Duck, check out HEL performance for braided lines
https://au.helperformance.com

 

[Duck]

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

 

[BIRD B GONE]

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.

 

[SteveW]

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 :thumbup:

 

[Duck]

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

 

[weedy64]

Ok, Im sure it is much better, but there should be little or no bulging or at least even bulging along the line, how old are the OEM lines +5yrs...theyre done unless you need to be really frugal and wait for another paycheck.

The back brake, fine leave it rubber. I vote for front SS lines being worth the money when you can do it. Im not sure that the SS flex type ever need re-replacing unless you damage them. Every bit of bulging is a loss of braking power.

 

[Duck00]

I would agree with getting SS lines for the front, it will complement the refurbishment you have done!

Don.

 

[Duck]

I would agree with getting SS lines for the front, it will complement the refurbishment you have done!

Don.

I also agree Don, the SS lines would complement the brake rebuild to great effect. As weedy64 has hinted to, I do have to be a little frugal now. Yesterdays work (including tyres) totaled $1200. Which isn't ideal just before Christmas.

Question for those that have the SS lines on a ZX11/ZZR1100. Have you retained the splitter or gone for 2 lines directly from the master cylinder??. Mine has a SS line from the master to the splitter, then twin rubber from there on.

Cheers

 

[Duck]

Hey Duck, check out HEL performance for braided lines
https://au.helperformance.com

Just placed an order with them!! Woo Hoo..

Thanks for the tip Steve. $143 delivered.

Hopefully they're in stock and they can meet the 2 day delivery. I'll book the bike back in for later in the week.

I'd been umming and ahhhing and then the alcohol took effect. F*&k the cost

 

[SteveW]

Nice work, I've got the HEL lines on a couple of my bikes. They're pretty good quality