Now I know why my rear brake was so shite. I've just replaced the brake fluids and I didn't realise that the rear brake caliper has two bleed nipples, one for each side. About 4 cubic feet of air came out of the inside one when bled :0/ -- Mark ZX12R-B1 (Blue) CG125 (hers) Blata Ninja 3.4 BOTSWCAW#3
Funnily enough I decided to strip down all the brakes on the FJ today. I also dec ided to change the brake fluid. However, I did notice it had two on the rear. To my delight all the bleed nipples came undone without any problem at all. I did manage to find out why it has been uneconomical lately, finding the R/H front caliper was sticking, and a nasty burnt smell from the pads. The linings are Ok, but I shall be contacting 'The Doc' for some new ones anyway.
I've always just pumped the lever/pedal until no more air comes out then closed off the nipple with the lever/pedal held in/down - no opening and closing of the bleed nipple between pumps. Perhaps you're giving the air time to travel back up the pipe by stopping to tighten the nipple? Just a guess. Si
Fucked hoses? Still got air trapped in the master cylinder upper part of hoses. When you undo the nipple the air bubble travels down the hose. You close the nipple and the air bubble then rises back up the hose ad infinitum etc Moisture in the fluid - was it a new and sealed bottle? You're crap at bleeding brakes? ;0) -- Mark ZX12R-B1 (Blue) CG125 (hers) Blata Ninja 3.4 BOTSWCAW#3
If they were so knackered that they'd let a lot of air back in that quickly I reckon they'd leak fluid too. Si
On brakes that seem to take ages to bleed, I usually pump the lever or pedal a lot, keep pressed down, then open / close the nipple, then pump a lot again and repeat. I used this method on a bike that a mechanic friend couldn't bleed the brakes on. I usually re-use the washers, but am careful to fit them in the original order, as they can become stepped and maybe let fluid / air in or out.
Maybe the master cylinder seals or bore are shot. Or you've got a shaken up bottle of brake fluid, or you're sucking in air through the reservoir somehow?
Bear says... Cable tie the brake lever back to the bars, leave overnight and then try bleeding again.
Sometimes (frequently) very worn disc pads make the lever spongey. Yes, I know they should be self-adjusting, but it's happened to me often enough for me to shrug. Secondly, when bleeding, don't just pull in the lever once before opening the nipple. Pump it half a dozen times, which builds up pressure, and if there is any air in there, it comes shooting out. Another tip is to loosen/remove the master cylinder cap after bleeding, and tie back the brake lever with gaffa tape/rubber band etc. I shall leave it to someone else to reproduce this as quoted text.
Also, try tapping the hoses - if you've got part of the system where the air may be pooling then you might not get it out without jiggling the whole thing, tilting it side to side or something. When bonwick helped out with the brakes on the daytona ISTR it was a bit of an arse as each time we swapped sides more air would come out. In the end we'd had enough - the lever was alright, so I decided I'd have another go later on to see if I could get it any better. If it really is that crap then either crack it all open and start again or find someone with a mityvac.
I've got to say, I've never ever had any problems bleeding brakes (apart from the odd seized nipple on a SOB).
How do you define a problem then? I'd say if that's not a problem then having to go back and forth between sides isn't a problem.
Well, I've never had any air trapped, or that sort of thing. Just bleed and ride. I guess I've been lucky. These days, I *always* play a blowlamp on any bleed nipple that looks like it hasn't been touched for more than a couple of years, especially on SOBs, and - touch wood - haven't had one shear off on me since I started doing that.
I doubt he's owned that many with two-pot calipers. -- | ___ Salad Dodger |/ \ _/_____\_ GL1500SEV/CBR1100XXX/KH500A8/TS250C |_\_____/_| ..73392../..18192.../..3184./.19406 (>|_|_|<) TPPFATUICG#7 DIAABTCOD#9 YTC#4 PM#5 |__|_|__| BOTAFOT #70 BOTAFOF #09 two#11 WG* \ |^| / IbW#0 & KotIbW# BotTOS#6 GP#4 \|^|/ ANORAK#17 IbB#4 '^' RBR Landmarks: 0 Points: 0 Miles: 0
Heh. Probably not. The Ducati has four-potters, as does the Trumf, and I've bled those fine. I've never owned a bike with six-potters, that's for sure.
Sometimes (frequently) very worn disc pads make the lever spongey. Yes, I know they should be self-adjusting, but it's happened to me often enough for me to shrug. Secondly, when bleeding, don't just pull in the lever once before opening the nipple. Pump it half a dozen times, which builds up pressure, and if there is any air in there, it comes shooting out. Another tip is to loosen/remove the master cylinder cap after bleeding, and tie back the brake lever with gaffa tape/rubber band etc. I shall leave it to someone else to reproduce this as quoted text.[/QUOTE] Well seeing as they are *my* brakes under discussion and Bear was working on them without my knowledge or consent and seeing as I'm also in the kill file someone will have to follow this up as well. If I wanted advice on *my* brakes from the FOAK *I* would have posted here. As it was I spoke on the phone to a UKRMer I trust and got their advice and the offer of the use of a vacum pump. Another closer UKRMer has lent me their pump. I'd already decided tying the lever to the bar over night was an option from previous advice here. I've got braided hoses today, new copper washers and we'll see what that and the application of the vacum pump achieves.
Well seeing as they are *my* brakes under discussion and Bear was working on them without my knowledge or consent and seeing as I'm also in the kill file someone will have to follow this up as well. If I wanted advice on *my* brakes from the FOAK *I* would have posted here. As it was I spoke on the phone to a UKRMer I trust and got their advice and the offer of the use of a vacum pump. Another closer UKRMer has lent me their pump. I'd already decided tying the lever to the bar over night was an option from previous advice here. I've got braided hoses today, new copper washers and we'll see what that and the application of the vacum pump achieves.[/QUOTE] I want to put braideds onto the ratfighter. Slowing down from an indicated 156 today had a worrying "where the **** are my brakes" moment.
