View Full Version : Broken brakes and the runaway Suzi...
Disco Dan
8th May 2007, 15:53
As some of you may be aware, my bike is getting on a bit... almost 'granny' status: A 1989 GSX600f
I was having problems with the front end, and was never really happy with the front brakes or the shocks. Yesterday I replaced the fork oil and wow what a diference it made. However this is when my problems began....
It wont stop.
I can pull on the front brake lever with all my might and it takes AGES to start slowing down. To give you an idea, im pulling the lever as hard as I possibly can (progressive of course) and past the point where the front used to lock! On a hill, if I sit at lights and grip the front as usual the bike will roll back. I need to use the back brake or pull on the front - something which becomes painful quickly!
The interesting thing is it will actually stop quicker using the rear brake only oppossed to front only! (with clutch in both tests)
Before anyone asks... no I did not spill any fork oil on the pads or disks. Not even a drop.
The brake fluid is due for replacement, but should not be causing the brakes to be this bad. Also the pads are about half worn now.
Any suggestions?
I was thinking that maybe after my trip to Taupo on the old girl that I may have glazed the pads a bit?
Help!
well while ya changing the brake fluid
why not clean the calpiers, maybe not all the pistons are working correctly, to be on safe side,
imdying
8th May 2007, 16:15
Yeah, just service it properly and you'll be fine.
if you have problems after doing fluid, checking capliers
bistard
8th May 2007, 16:29
It sounds like you might have seized pistons in the brake caliper
Remove the caliper,pull the pads out,gently pump the brake lever & see if the pistons move,if they move out,get an old tooth brush & hot soapy water & clean the pistons,unless you want to strip them,then once clean,push the pistons back in,reassemble & bleed the system
ArcherWC
8th May 2007, 16:43
I was thinking that maybe after my trip to Taupo on the old girl that I may have glazed the pads a bit?
HAhahahahahaha, sorry Dan, you dont go fast enough or brake hard enough to glaze your pads
Disco Dan
8th May 2007, 17:21
It sounds like you might have seized pistons in the brake caliper
Remove the caliper,pull the pads out,gently pump the brake lever & see if the pistons move,if they move out,get an old tooth brush & hot soapy water & clean the pistons,unless you want to strip them,then once clean,push the pistons back in,reassemble & bleed the system
Will do... off to the gassy to get some brake fluid now.
Will pull the lot to bits, clean, check and re-assemble.
Cheers everyone.
DD
paturoa
8th May 2007, 19:17
Before you go pulling stuff apart, bleed them first. Only takes a few minutes and is easy to do.
Disco Dan
8th May 2007, 20:59
Before you go pulling stuff apart, bleed them first. Only takes a few minutes and is easy to do.
Pulled the lot to bits. Could not find anything wrong. All the pistons worked fine in the calipers. Did not take them out as I dont have new seals. Only thing I did do was split the calipers in half and cleaned them up. Manual said to clean with brake fluid, which I did... after getting half way through the first one with turps... whoops. gave it a good clean up and hopefully have not buggered the rubber seals.
I gave the pads a rub with some sandpaper front and back before putting them back in the calipers.
All back together now, with fresh fluid and bled.
Sprayed everything down with diluted dishwashing liquid to get rid of any brake fluid on the disks/paint etc. Good hose off...
Off for a test ride now.... Im betting there will be no difference. But you never know....
DD
Disco Dan
8th May 2007, 21:24
Back from the test ride. No significant change. Still takes a flipping long time for the brakes to stop the bike with me pulling the lever with all my strength!
Could it be a faulty master cylinder?
There just is not enough pressure getting to the calipers?
Dam thing.
Need to bleed them again tomorrow. Think there is still a wee bit of air in there. When I release and reapply the brake its firmer.
bah...
May leave the flipping thing in the garage and use the ZX till I get it sorted... despite its gas guzzling and tendancy to lift the front wheel off the ground... at least the brakes are good.
Time to open that box of beers I think....
paturoa
8th May 2007, 21:30
I was having problems with the front end, and was never really happy with the front brakes or the shocks. Yesterday I replaced the fork oil and wow what a diference it made. However this is when my problems began....
It wont stop.
So what exactly did u do when you changed the fork oil. Do your forks have a drain screw at the bottom or did u have to take them out of the bike and turn them upside down?
Disco Dan
8th May 2007, 21:36
So what exactly did u do when you changed the fork oil. Do your forks have a drain screw at the bottom or did u have to take them out of the bike and turn them upside down?
Drain screw. Drained the oil out, pumped the forks etc and left it to drain etc.
Measured the oil, put it in the top. Did up the tops and went for a spin. Forks feel great. Maybe a teeny bit soft but heaps stiffer than before I changed the oil.
EDIT: Just went and bounced the forks again. I have three 'dial' settings on each fork 1-3 soft-hard always used 2. Went and bounced them with the front brake on and it 'almost' hits the triple clamp - about 5-10mm away. Thats trying pretty hard though. Not sure if its the forks that are the problem...
paturoa
8th May 2007, 21:41
You could take it for another ride and use the brakes. Check the temp of the disks, is one disk significantly hotter than the other. If it is then that is normaly a sign that the problem is at the disk end of things. If they are the same / similar temp then more LIKELY to be at the master end of things (still wouldn't rule out air bubbles)
Disco Dan
8th May 2007, 21:46
You could take it for another ride and use the brakes. Check the temp of the disks, is one disk significantly hotter than the other. If it is then that is normaly a sign that the problem is at the disk end of things. If they are the same / similar temp then more LIKELY to be at the master end of things (still wouldn't rule out air bubbles)
Sweet as, thanks for your help Paturoa :yes:
I will have another ride tomorrow and check.
Cheers
DD
another good opinion is throw a zip tie around brake lever and hold it in over night.
good for trying to get rid of thsoe air bubbles
Clamp the hose out of the master cylinder with smooth-jawed vice grips or a G-clamp to block it. Now squeeze the lever.
If it is un-squeezable, the problem will probably be air in the system. If you can squeeze the lever in, the master cylinder seals and/or piston have the F syndrome.
Just a thought - your bike doesn't have the brake line pressure-driven anti-dive system on the forks, perchance?
limbimtimwim
9th May 2007, 08:14
Just a thought - your bike doesn't have the brake line pressure-driven anti-dive system on the forks, perchance?I was thinking the same thing.
Those crazy 80's and their anti-dive. What a decade.
Disco Dan
9th May 2007, 12:49
Clamp the hose out of the master cylinder with smooth-jawed vice grips or a G-clamp to block it. Now squeeze the lever.
If it is un-squeezable, the problem will probably be air in the system. If you can squeeze the lever in, the master cylinder seals and/or piston have the F syndrome.
Just a thought - your bike doesn't have the brake line pressure-driven anti-dive system on the forks, perchance?
Interesting idea, unfortunatly the bike has braided lines!
No I dont think so, both systems appear seperate to me.
I will bleed the system again today.
dickytoo
9th May 2007, 14:40
although it may not be visible, you may have a little fork oil on your rotors. give it a clean with brake cleaner and test.
i had the same with another bike awhile back. i left a tiny bit of grease on the rotor (from dirty hands) and the bloody brakes behaved exactly like yours.
Disco Dan
9th May 2007, 14:44
although it may not be visible, you may have a little fork oil on your rotors. give it a clean with brake cleaner and test.
i had the same with another bike awhile back. i left a tiny bit of grease on the rotor (from dirty hands) and the bloody brakes behaved exactly like yours.
oh cheers, yeah that could be possible... i cleaned the roters using dishwashing liquid and hosed off? Did not make any diference. The rotors look dark instead of bright and shiny like they used to.
dickytoo
9th May 2007, 15:28
i would use some sort of solvent. dishwashing liquid is a little slippery for my tastes!
Disco Dan
9th May 2007, 17:43
All sorted...
back from Motohaus and a new set of pads fitted... solved the problem! Pads were glazed from the heat! ...must have been going fast enough Archer ey ;)
imdying
9th May 2007, 18:20
All sorted...
back from Motohaus and a new set of pads fitted... solved the problem! Pads were glazed from the heat! ...must have been going fast enough Archer ey ;)
More than likely your calipers are (were?) seized and they were holding on which is what caused them to glaze.
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