Author Topic: Squat for rear brakes B12 (Read 7947 times)

Robertbarr · « **on:** October 21, 2005, 08:53:03 PM »

I bought a B12 recently and noticed that I have very poor rear braking. I bled both nipples & checked the level of the fluid reservoir, and I'm 99% convinced that the problem isn't hydraulic -- at least up to the caliper.

I have a good firm pedal, and I do get a little braking, but very little. It wouldn't be possible to lock the rear, for example, even standing on the pedal. I don't see anything obvious wrong. The only thing that comes to mind would be a stuck piston.

I pulled the caliper and lowered it down (still attached to the torque link) and operated the pedal slowly. One piston extended, and one stayed put. Now, that doesn't really tell me much, other than one has a bit more friction than the other. Not much of a test, I guess...

How would I go about forcing the other piston to extend a bit? Has anyone else had this problem?

2005B12S · « **Reply #1 on:** October 21, 2005, 09:05:57 PM »

The rear brake on my 2005 B12S is very weak also. I attributed it to just being a 500lb bike with all of the weight in front of the brake. I rarely even use the rear, so I did not give it too much concern. I will post results when I change over to Galfer lines as I just ordered lines for the front, clutch, and rear brake. I don't expect much of a change though.

Ride On, Ed.
2005 GSF1200SZ
1983 GS750ED

PeteSC · « **Reply #2 on:** October 21, 2005, 09:16:28 PM »

Bleed it again....and again. Mine did that once after changing brake fluid. I just had to keep bleeding it, until I got it right.

terrebandit · « **Reply #3 on:** October 22, 2005, 12:20:57 AM »

I think there are two bleeders on the rear caliper. Do the outboard first and then the inboard bleeder. You might have some air trapped in there. The rear brake on a bandit is soft so don't expect much. The rear brake on my SV is awesome.

Dave

Red01 · « **Reply #4 on:** October 22, 2005, 01:11:12 AM »

You don't really want to lock the rear brake anyway, but you'll get more out of it if you dump the rubber brake hose for a braided stainless steel line you'll get more response. An upgraded pad will help too - if you can find one. (Galfer didn't have an HH pad listed for the B12 when I bought my new pads.)

oremike · « **Reply #5 on:** October 22, 2005, 01:46:14 AM »

I changed out my pads to DP ones, much better than stock, and if I don't wipe the exess chain lube off my chain I'll need to wipe the rear rotor off with brake or electric cleaner to get the brake to grab again.
Mike M.

Ronin · « **Reply #6 on:** October 24, 2005, 04:19:43 PM »

I just put the Galfer SS lines on replacing the original front/rear brake and clutch lines. You won't notice much difference in the rear brake but you will in the front.

I'm running stock pads with about 13K on them with the new SS lines. I went to test the bike to make sure all was OK and I wasn't really trying too hard but I got the rear tire to raise up. You will absolutely notice a difference after putting the SS lines on.

And terrebandit is correct there are two bleed valves on the rear brake. I hand bled all the lines I replaced without any problems thus far so if you can't find a MityVac or other brake-bleed aide don't fret too much. They help but aren't absolutely necessary to do a thorough job.

Bob Holland · « **Reply #7 on:** October 24, 2005, 08:36:42 PM »

While I was riding my Bandit saturday, I tried to lock up the rear, and it would not slide the tire on pavement, which is OK with me, I use the front brake mostly. Actually, any time you apply one brake, you should apply both.

Daytona · « **Reply #8 on:** October 24, 2005, 08:55:43 PM »

Robertbarr
New user!

Joined: 25 Sep 2005
Posts: 4

Posted: Fri Oct 21, 2005 11:53 pm Post subject: Squat for rear brakes B12

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I bought a B12 recently and noticed that I have very poor rear braking. I bled both nipples & checked the level of the fluid reservoir, and I'm 99% convinced that the problem isn't hydraulic -- at least up to the caliper.

One word, sintered pads! Any thing on the rotor? Armorall, soap, spray wax,Wd40, chain lube, will take some time to wear off. The rear should have no problem locking up if needed, even though its not the best too. If you push one pad in (or puck) the other one should come out! Sounds like you must have a seized puck Let me add this! Sintered pads should only be used with calipers that are made for their use, the pad will fit and work fine in the older non OEM sintered models, but in race or heavy use may cause hi heat that could boil DOT 3 or 4 if it has some water in it, causing brake drag or lock up! Not a good thing. I use them on my 98 cause they don't fade,last much longer. But i mostly use my Bandit for commuting.

Red01 · « **Reply #9 on:** October 24, 2005, 09:27:10 PM »

Quote from: "BHolland"

Actually, any time you apply one brake, you should apply both.

I disagree. Especially on a non-ABS and/or slipper or back-torque limiting clutch equipped bikes.

If you're slowing down using the front brakes and the gearbox the amount of traction available at the rear tire is minimal since weight transfer has lightened the contact patch and the engine braking is already taxing the contact patch.
Application of the rear brake could easily cause a skid in this kind of situation - and rear wheel skids can lead to low sides - or if you panic and let off the brake once the skid starts, a highside.

So, if you have available traction to use the rear brake, by all means, use it for the most effecient stop... but if traction is at a premium, don't.

Bob Holland · « **Reply #10 on:** October 24, 2005, 10:26:35 PM »

Front brakes are 65% of your stopping power and rears are 35%, so if you want or need 100% of your brakes, you ill need to use both. Experienced riders will use the front, but most beginners will try to use only the rear. So if you learn to use them both together, and you have an emergency or have to stop as fast as possible, your natural reaction will be to use both, and it may save your life.

PitterB4 · « **Reply #11 on:** October 24, 2005, 11:13:55 PM »

Quote from: "BHolland"

Front brakes are 65% of your stopping power and rears are 35%...

IIR my MSF course correctly, under heavy braking, the front handles like 90% of the available baking power. Most track riders never touch their rears (enter sophmoric joke here) unless their doing some trail braking.

Red01 · « **Reply #12 on:** October 25, 2005, 01:19:15 AM »

Quote from: "BHolland"

Front brakes are 65% of your stopping power and rears are 35%, so if you want or need 100% of your brakes, you ill need to use both.

Most of the time? Yes. Absolutely. I agree.
Any time? No. There can be times, such as the scenario I described earlier, the rear is going to have near 0%, so you'd want to stay off of it.

OTOH, if you've got mad skilz, you could lock up the back brake, make the tail swing out until you're pointing the other way and let off the brake and go the other way... but that's something I'd rather not experiment with on my street bike. I'll save that for playin' in the dirt.

2005B12S · « **Reply #13 on:** October 25, 2005, 01:59:35 AM »

Quote from: "Red01"

Quote from: "BHolland"
Front brakes are 65% of your stopping power and rears are 35%, so if you want or need 100% of your brakes, you ill need to use both.

Most of the time? Yes. Absolutely. I agree.
Any time? No. There can be times, such as the scenario I described earlier, the rear is going to have near 0%, so you'd want to stay off of it.

OTOH, if you've got mad skilz, you could lock up the back brake, make the tail swing out until you're pointing the other way and let off the brake and go the other way... but that's something I'd rather not experiment with on my street bike. I'll save that for playin' in the dirt.

I agree with Red01 on this. If you are really using the front brakes to maximum capacity, the rear end is too light to provide any effective braking. It is more of a distraction than anything else.

I believe in the 90/10 split front to rear, without weight on the wheel, the rear is useless and ineffective.

This is why transport aircraft have ground spoilers- the large panels on the upper wing that deploy automatically- they put maximum weight on the gear for effective breaking. That is their only function. Without them, stopping distances can increase by over 150%.

Brake On, Ed.
2005 GSF1200SZ
1983 GS750ED

Red01 · « **Reply #14 on:** October 25, 2005, 07:29:59 AM »

Quote from: "2005B12S"

This is why transport aircraft have ground spoilers- the large panels on the upper wing that deploy automatically- they put maximum weight on the gear for effective breaking. That is their only function. Without them, stopping distances can increase by over 150%.

And all this time I thought they gave braking from increased wind resistance, too...

Funny thing is they only automatically deploy when the thrust reversers are deployed - not the wheel brakes.
(And on Boeing commercial planes, they only do that if the pilot has pulled the speedbrake handle into the "Auto" detent. If it's in "Off" they won't come up.)