ok went for a ride and the rear brake lever had about 10 mm of movement was bloody hard.... left it for ten minutes or so ..(seeing man about a dog) got back on.... NO rear brakes. lever goes all the way to the floor so to speak and no pressure build up. ok.
fresh full fluid. bled the system repeatedly, no air bubbles or any crap coming out, i dont think its the plunger assembly as im getting fluid coming out nipples..... i reckon i have damaged the seals but there is no weeping or dripping or nothing rear unit is clean. im going to pull it out this weekend...( sux cos im a back braker.... fronts are for last minute OSHIT!!!! stops :good2:) all im sorta wanting to know is... is it a major pain in the arse? am i better stripping it out and taking the whole caliper and dropping at grease monkeys? or have you lot done this sort of thing aforee and its just a bit fiddly with a lot of verbal lubrication to get it all back together?
got new rotor put on about 2 months ago maybe new pads, they still have a lot of pad left.... bought these "organic"? brake pads on recommendation from bike shop, they dont wear it seems they just throw a lot of crap about and make my brakes sound like old unserviced drum brakes. squel like a stuck pig when you pull up... so im going back to ebc brakes....
long winded its probably a simple fix, just pushed for time havnt really got the time to dick with it. any info a great help. o and for all my gloating bout bt45 battleaxe tyres? about 12000k's front cupped on rh side rear flattened off and a big crack in my rear.... who says life isnt exciting? :bad:
Good opportunity for you to learn to use the front brakes. ;-)
Should you need a rear caliper, I have one spare you can have for postage.
Cheers,
Arnie
In most cases when a rear caliper fails you will have excess wheel drag and the pedal is very stiff. In most cases you can disassemble the caliper and scrub the parts with a light penetrating oil to free them up. I like to polish the pistons with a fine emory cloth and penetrating oil as well. You should wash the parts in brake fluid to remove the oil before reassembly.
It sounds like you problem may actually be an issue with the master cylinder. I would disassemble it and inspect. You will probably find that the rubber seal has failed.
+1 on the relative value of the front breaks. I've read (and experienced first hand) that the fronts provide something like 80% more breaking power than the back. The rotors are bigger, there are two of them, and the compression of the forks helps to 'load' them and further slow the bike more effectively. (I think that's how it works +/-) You really should learn to use the fronts more than you use the backs. I think you'll find that the bike stops MUCH faster and with more control.
For me, I'm the opposite of you, I only ever go for the back in a panic stop situation.
Dan
Front brakes supply between 100% and 50% of the braking force, depending on the road conditions (and rider's ability/preference).
Should have the ability to use both or either on command at any time, comfortably, in case of a failure at one end or the other.
Using the rear brake is more for helping control the chassis movement in various situations, but it can be used to stop too, if you're on the street and going sensible speeds.
Dan: The bigger rotors help dissapate heat better than the rear, provide more clampable area, and have better leverage on the wheel. The forks don't have to compress in any way for the weight on the front to increase though, as the bike sees negative g-loading (decelleration) it effectively moves weight forward onto the front contact patch and off the rear one, until the bike flips completely over. It doesn't have to compress the fork springs to do so, though it will if they're functional, the sag basically increases as the weight does.
I have always used both front & rears and like it that way. Once you get used to using them both, it becomes a natural habit I don't have to think about.
It has saved me on a couple occasions from losing it due to oil/sand where I surely would have lost it using just the front brakes. My rear brake lights also seem to light up as soon as I depress the rear brake pedal vs. having to add a little more front braking to engage the lights so I can warn traffic behind me without slowing down much.
sounds like your brake master is shot.
use your front brakes :blum1:
Oil and sand on the road qualifies as a panic stop situation for me. I use the back brake when the front may not be enough to slow me in time, or may loose traction. maybe 5% of the time. I have felt where it can help to 'settle the chassis' coming into a corner/ bumpy corner too hot -but I've always suspected that it may be simply a matter of shedding unwanted speed at that point, no so much 'settling the chassis' -not sure though.
Still, I probably over compensated for the fact that I used to use the back waaaay more than the front.
Dan
By settling the chassis, talking about using the rear brake with the front in trail braking (keeps it from trying to stand up), using the rear brake while on the gas to increase ground clearance, and yes, using the extra force for taking some load off the front.
I've ridden too many bikes with garbage brakes at one or both ends (and garbage suspensions, and motors, and tires, and so on....), so it's just gotten to be a habit to be very aware of both if not using both. There's places where I'll go for just one or the other, but they're far between!
There's a reason there are 2 braking systems on motorcycles.
Doohan used the rear brake enough to develop the thumb rear brake after he injured his right foot. Similar systems are now used on practically all racing motorcycles. Nicky Hayden was known for his use of the rear brake. The Honda people went to great lengths to discourage him from using it by giving him a smaller rear rotor.
I've seen far too many young sportbike riders that proudly say they NEVER use the rear brake. And probably just as many stupid cruisers that say they never use the front brake. Both groups are missing an important component to safe riding.
Yes, if you're blazing down the straight and then braking hard enough to float the rear wheel, the rear brake is not of much use. However, if you're riding at a slightly more sane pace where that kind of braking is not required then the rear brake is a very useful tool.
You should also probably re-read The Pace article about street riding. Either that or list me as your life insurance beneficiary.
DavidR.
I USED to say I never use the rear brake, but now I'd say rarely is more accurate. I had a few bad experiences (on other bikes) with the rear unloading & trying to come around. That was an effective deterrent for me. Now, I'd say when poor road conditions appear or at a stop, is the some total of my rear braking.
YMMV!
Quote from: Arnie on August 24, 2010, 09:09:02 PM
Good opportunity for you to learn to use the front brakes. ;-)
Should you need a rear caliper, I have one spare you can have for postage.
Cheers,
Arnie
Arnie beat me to it...... and he's RIGHT!
maybe 7 years ago, Superbike magazine showed some metrics captured from on-bike monitors of folks as they circled Brand Hatch, a track in the UK. Turns out the vast majority of the folks used the front brake something like 90% more than the back.
In fact, it was this article, in conjunction with realizing I was replacing my back brakes 2:1 with the fronts, that made me consciously migrate to the using the fronts, well, ~ 90-95% of the time. If it's good enough for those folks, it's good enough for me.
Dan
thanks fellas... and thanks arnie will let you know im looking at it this wekend.... my rear braking thing? i dunno i do use the fronts but.... how do i put it? i d rather have the rear come round and get unstuck then lose the front.... dirt bike riding style kinda thing.... i tend to ease the rear on for a while before i reach for the fronts..... also find if im hot into a corner.... not super hot :good2: but hot well i tend to use my rear to wash off speed ... pick my line and then trail the rear round the corner... helps i find to peel it in a bit tighter.... im not saying i dont use the fronts and yes i know its a 70- 30 thing front to rear .... kinda got it drummed into my head when i was younger that you never want to lose the front the back can do what it wants.... so saying i have locked the old girl up a few times and it does swing a bit :good2: but yes. you are all correct. anyhoo i will rip the caliper off on sat and take pretty pictures . besides im blonde so grey hairs from sphincter puckering moments dont show up.... :wacko2:
Quote from: Kopfjaeger on August 25, 2010, 10:13:23 PM
thanks fellas... and thanks arnie will let you know im looking at it this wekend.... my rear braking thing? i dunno i do use the fronts but.... how do i put it? i d rather have the rear come round and get unstuck then lose the front.... dirt bike riding style kinda thing.... i tend to ease the rear on for a while before i reach for the fronts..... also find if im hot into a corner.... not super hot :good2: but hot well i tend to use my rear to wash off speed ... pick my line and then trail the rear round the corner... helps i find to peel it in a bit tighter.... im not saying i dont use the fronts and yes i know its a 70- 30 thing front to rear .... kinda got it drummed into my head when i was younger that you never want to lose the front the back can do what it wants.... so saying i have locked the old girl up a few times and it does swing a bit :good2: but yes. you are all correct. anyhoo i will rip the caliper off on sat and take pretty pictures . besides im blonde so grey hairs from sphincter puckering moments dont show up.... :wacko2:
If you do the brake upgrade on the fj fronts , like springs and emulators and a 17" front wheel ,blue pots and a 14mm master, then you can actually use the front brakes for more than scrubbing speed in a straight line without falling over or standing up in turn.
I have rode tons of junk in my day and have to say I understand the rear brake is your friend deal. :good2:
fix the front end and you will change your religion :wacko1:
ok got the master cylinder off and pulled it to bits. after wading through the piles of rust and dirt under the rubber boot i finally managed to get the piston out... looks like the top seal under the spring is shagged, going to have to get a kit for it (if i can) or order a new master cylinder set of rubbers. is all good just means more front brake practice... took pics and will set 'em up as soon as i can. its only holding pressure at the very last 1-3mm of movement from the brake pedal. joys of motorcycling :good2:
ok :good2:. i have my rear brakes amended. would have pics but the air was a dark shade of blue around work area as i did my neck on thurs had parts friday didnt get to work on it till sunday arvo. helps when you take all the parts out not to reassemble with old parts back in :dash2:. long story. back in and bled all great, did oil change and filter change, put all my dash lights in so that all works put the fuel needle back to where it should be and replaced my tail lights as they were blown on parkers. 140? odd bucks for the rear master kit comes with new piston cup seal , lip seal, spring, circlip, and shaft from clevis to piston with a new rubber boot..... i did worry as it has been running hot of late. oil has done about 5000 ks or so.... as i said new oil and filter, for some reason i took the little screw off the oil filter housing.... normally dont do that... please remeber to put it back in ...!!! i lost about a litre of oil straight across my driveway... :shout:.... alll good also now know my pumps :good2:working good , took the screw out of the engine head to check on flow up there its all good too. me thinks oil be shagged and fresh oil well due. o and the right rear foot plate cannot be removed due to a rounded bolt head, so if you remove the exhaust and then take the cotter pin out of the clevis pin undo the rear brake lever loosen the banjyo fitting on the master cylinder and loosen the master cylinder you can push the brake shaft back juuuuusssst far enought to get the clevis pin out then remove the master cylinder :good2: just sucks when the return spring happens to drop off :dash2: :dash2: :dash2: :dash2: :dash2: