Discussion
OK - need help.
Having delusions of mechanical competence I decided to strip and rebuild the front brakes on my 1999 Blade this week. Good job too because when I took the callipers apart most of the pistons were binding really badly.
Sooooooooo. Rebuild kit ordered, callipers nicely cleaned up, new stainless steel pistons and seals all round and callipers back on the bike ready for me to quickly and simply refill the system with new brake fluid and achieve that lovely firm brake lever feel.
Except I have just spent the last 3 hours getting covered in brake fluid as I try, and repeatedly fail, to refill the brake lines.
The internet tells me to use the reverse fill method - where you ever so slightly crack off the calliper bleed nipple and then using a syringe and appropriate tube, force brake fluid up in to the system from the slightly loosened bleed nipple in the callipers.
YouTube is full of videos showing me how easy this is. Crack open bleed nipple, press plunger on syringe, smile as you show me how simple all of this is, wipe away a few small drops of brake fluid and then tell me how amazing the brake lever feels.
But when I try to do it, all that happens is the f
king brake fluid pisses out all over the calliper and front wheel because it is escaping through the ever so slightly loosened thread of the bleed nipple. I'm finding it literally impossible to apply any pressure on the syringe plunger without all the fluid just seeping through the bleed nipple thread and on my bd brake pads!
What am I missing? Do I need to put some PTFE on the bleed nipple thread?
Or should I give up on the reverse fill approach and just use the traditional vacuum method where I pull fluid down the brake lines using a brake bleed kit.
Having delusions of mechanical competence I decided to strip and rebuild the front brakes on my 1999 Blade this week. Good job too because when I took the callipers apart most of the pistons were binding really badly.
Sooooooooo. Rebuild kit ordered, callipers nicely cleaned up, new stainless steel pistons and seals all round and callipers back on the bike ready for me to quickly and simply refill the system with new brake fluid and achieve that lovely firm brake lever feel.
Except I have just spent the last 3 hours getting covered in brake fluid as I try, and repeatedly fail, to refill the brake lines.
The internet tells me to use the reverse fill method - where you ever so slightly crack off the calliper bleed nipple and then using a syringe and appropriate tube, force brake fluid up in to the system from the slightly loosened bleed nipple in the callipers.
YouTube is full of videos showing me how easy this is. Crack open bleed nipple, press plunger on syringe, smile as you show me how simple all of this is, wipe away a few small drops of brake fluid and then tell me how amazing the brake lever feels.
But when I try to do it, all that happens is the f
king brake fluid pisses out all over the calliper and front wheel because it is escaping through the ever so slightly loosened thread of the bleed nipple. I'm finding it literally impossible to apply any pressure on the syringe plunger without all the fluid just seeping through the bleed nipple thread and on my bd brake pads! What am I missing? Do I need to put some PTFE on the bleed nipple thread?
Or should I give up on the reverse fill approach and just use the traditional vacuum method where I pull fluid down the brake lines using a brake bleed kit.
Ive been in this exact predicament when I did my first set of calipers. Honestly just buy a break bleed kit for £10, youre done in minutes. The Only pain is keeping an eye on the reservoir levels whilst you're at the caliper when doing it yourself. But if you have a helpful assistant just get them to monitor and top up as you go.
Thanks guys - I clearly needed an injection of common sense.
The irony is that I already own a brake bleed kit - but was just too stupid to use it, having been convinced by smiling YouTube mechanics to do something other than the obvious.
I will clean up all the oily blue roll and puddles of brake fluid later this morning and do what I should have done all along.
FWIW I do wonder if I was not opening the bleed nipple enough yesterday, but that will just have to be a question I answer another time because I used up my entire swear word allocation for the month yesterday!
The irony is that I already own a brake bleed kit - but was just too stupid to use it, having been convinced by smiling YouTube mechanics to do something other than the obvious.
I will clean up all the oily blue roll and puddles of brake fluid later this morning and do what I should have done all along.
FWIW I do wonder if I was not opening the bleed nipple enough yesterday, but that will just have to be a question I answer another time because I used up my entire swear word allocation for the month yesterday!
Davie_GLA said:
This takes me back to when i rebuilt the calipers on my 03 R1. I'm fairly certain i caused a global shortage of brake fluid until, you guessed it, PH offered up the vacuum method.
My first attempt with tokico 6 pots I bought a 5 litre jerry can of brake fluid and I don't remember much being left. Mind you I just had tubing with a ball bearing acting as a non-return valve to do it. They wee litre tubs now seem to last an age with the vacuum kit.
moanthebairns said:
My first attempt with tokico 6 pots I bought a 5 litre jerry can of brake fluid and I don't remember much being left. Mind you I just had tubing with a ball bearing acting as a non-return valve to do it.
They wee litre tubs now seem to last an age with the vacuum kit.
Well I'm just off out to buy some more as I'm almost out and my brake lever has virtually no bite t it at all. In fact the brake pads are not even in contact with the discs yet. They wee litre tubs now seem to last an age with the vacuum kit.
So what is the trick now? When I pull the brake lever in and crack the bleed nipple I am betting brake fluid coming out - but still no pressure in the lever.
Do I need to use a bungie to hold the brake lever al the way in for 24 hours to let the air rise up out of the system, or do I need to keep flushing with another few litres of fluid?
TorqueDirty said:
moanthebairns said:
My first attempt with tokico 6 pots I bought a 5 litre jerry can of brake fluid and I don't remember much being left. Mind you I just had tubing with a ball bearing acting as a non-return valve to do it.
They wee litre tubs now seem to last an age with the vacuum kit.
Well I'm just off out to buy some more as I'm almost out and my brake lever has virtually no bite t it at all. In fact the brake pads are not even in contact with the discs yet. They wee litre tubs now seem to last an age with the vacuum kit.
So what is the trick now? When I pull the brake lever in and crack the bleed nipple I am betting brake fluid coming out - but still no pressure in the lever.
Do I need to use a bungie to hold the brake lever al the way in for 24 hours to let the air rise up out of the system, or do I need to keep flushing with another few litres of fluid?
OK, I AM A tt.
After many more hours of doing the same thing and expecting a different result I took the callipers off again and noticed something suspicious.
On both callipers the outer sets of pistons were protruding out a fair bit from the calliper body - as you would expect after I had pumped the sodding brake lever 16,000 times. HOWEVER the inner sets were still completely flush with the calliper body.
And then it dawned on me that maybe I had inadvertently put the inner half of one calliper back together with the outer half of the other one. They look identical.
I spent ages looking for identifying marks that would tell me which halves go together but I couldn't see anything. I actually had the callipers on separate parts of the work bench to make sure I kept the right halves together but I must have mixed them up when I was cleaning them.
So, callipers taken apart and guess what - the oilways between one half of the calliper and the other did not match up at all so no wonder I was getting nowhere.
Callipers now reassembled correctly, brake lines filled and brake lever pressure restored. It is still a little spongey so I will bleed them again tomorrow but I'm done for the day. Jesus wept!
t.After many more hours of doing the same thing and expecting a different result I took the callipers off again and noticed something suspicious.
On both callipers the outer sets of pistons were protruding out a fair bit from the calliper body - as you would expect after I had pumped the sodding brake lever 16,000 times. HOWEVER the inner sets were still completely flush with the calliper body.
And then it dawned on me that maybe I had inadvertently put the inner half of one calliper back together with the outer half of the other one. They look identical.
I spent ages looking for identifying marks that would tell me which halves go together but I couldn't see anything. I actually had the callipers on separate parts of the work bench to make sure I kept the right halves together but I must have mixed them up when I was cleaning them.
So, callipers taken apart and guess what - the oilways between one half of the calliper and the other did not match up at all so no wonder I was getting nowhere.
Callipers now reassembled correctly, brake lines filled and brake lever pressure restored. It is still a little spongey so I will bleed them again tomorrow but I'm done for the day. Jesus wept!
trickywoo said:
Anyone who s ever worked on their own bike has been there.
At least no harm done and looks like you are 99% finished.
Updates are always good to hear.
The kind words are greatly appreciated! At least no harm done and looks like you are 99% finished.
Updates are always good to hear.
The brake lever actually feels pretty good now, so all that is left to do is fork out £70 for a new set of pads. My current pads were in great shape before Captain Spanner got to work and ended up getting brake fluid everywhere by trying to force the bloody stuff through a solid wall of aluminium inside the callipers.
The pads actually look OK and I have given them a good clean with brake cleaner - but think it would be best to get some new ones right? No point risking having contaminated pads, given that this entire comedy sketch only came about because I wanted to improve the braking on my bike.
TorqueDirty said:
OK, I AM A tt.
After many more hours of doing the same thing and expecting a different result I took the callipers off again and noticed something suspicious.
On both callipers the outer sets of pistons were protruding out a fair bit from the calliper body - as you would expect after I had pumped the sodding brake lever 16,000 times. HOWEVER the inner sets were still completely flush with the calliper body.
And then it dawned on me that maybe I had inadvertently put the inner half of one calliper back together with the outer half of the other one. They look identical.
I spent ages looking for identifying marks that would tell me which halves go together but I couldn't see anything. I actually had the callipers on separate parts of the work bench to make sure I kept the right halves together but I must have mixed them up when I was cleaning them.
So, callipers taken apart and guess what - the oilways between one half of the calliper and the other did not match up at all so no wonder I was getting nowhere.
Callipers now reassembled correctly, brake lines filled and brake lever pressure restored. It is still a little spongey so I will bleed them again tomorrow but I'm done for the day. Jesus wept!
Since we're confessing....t.After many more hours of doing the same thing and expecting a different result I took the callipers off again and noticed something suspicious.
On both callipers the outer sets of pistons were protruding out a fair bit from the calliper body - as you would expect after I had pumped the sodding brake lever 16,000 times. HOWEVER the inner sets were still completely flush with the calliper body.
And then it dawned on me that maybe I had inadvertently put the inner half of one calliper back together with the outer half of the other one. They look identical.
I spent ages looking for identifying marks that would tell me which halves go together but I couldn't see anything. I actually had the callipers on separate parts of the work bench to make sure I kept the right halves together but I must have mixed them up when I was cleaning them.
So, callipers taken apart and guess what - the oilways between one half of the calliper and the other did not match up at all so no wonder I was getting nowhere.
Callipers now reassembled correctly, brake lines filled and brake lever pressure restored. It is still a little spongey so I will bleed them again tomorrow but I'm done for the day. Jesus wept!
I didn't know that the rubber o-rings were tapered the first time i did this and they passed the pressure test when i put them back together... Once.
Took the beastie out for a hurl and of course why take it easy! it's an R1 Mate! THat was my first near death experience on that bike as the taper being installed wrong either caused the piston to jam on or create more heat than it should. Just as well i taught Rossi how to ride....
Davie_GLA said:
Since we're confessing....
I didn't know that the rubber o-rings were tapered the first time i did this and they passed the pressure test when i put them back together... Once.
Took the beastie out for a hurl and of course why take it easy! it's an R1 Mate! THat was my first near death experience on that bike as the taper being installed wrong either caused the piston to jam on or create more heat than it should. Just as well i taught Rossi how to ride....
Ooof! I didn't know that the rubber o-rings were tapered the first time i did this and they passed the pressure test when i put them back together... Once.
Took the beastie out for a hurl and of course why take it easy! it's an R1 Mate! THat was my first near death experience on that bike as the taper being installed wrong either caused the piston to jam on or create more heat than it should. Just as well i taught Rossi how to ride....
Yet another thing I have been worrying about.
I have searched and searched on this topic and have been reliably informed via multiple sources that the pressure rings for my 1999 CBR 900RR Nissin brakes are in fact symmetrical, it is the o-ring grooves in the callipers that are asymmetrical - which achieves the same result.
I also looked really hard at the o-rings to see if they showed any sign of asymmetry and I can't see any evidence that they are.
But of course I will now add the possibility that I have been misinformed to the long list of things I will worry about when I go out for my first ride.
On the plus side I live in Scotland so I have a good while yet before I'll be tempted to take the bike out for its first run of the year, and therefore have plenty of time to un-f
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