A good practice is once your by the bike and done your first checks cockpit, mirrors, lights etc is as you start off check both front and rear brakes are functional.
No front brake!
- Thread starter Slime Bomb
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NicD
Registered user
One ought to separate two different ideas:
1. when finished working on anything the might affect brakes, check and double check brakes
2. when you get bike out every day, hit brakes to check working before ride off
Doing 2 is not a substitute for doing 1
1. when finished working on anything the might affect brakes, check and double check brakes
2. when you get bike out every day, hit brakes to check working before ride off
Doing 2 is not a substitute for doing 1
One of the best things I was told was to move your bike forward a about a yard before setting off. Brakes disc lock puncture funny noises etc. Anyone ever set off with a soft wheel? A little push will tell very quickly. JJH
Thanks for the few positive responses.
I always check before riding and I do pump them after taking them off but this time I got distracted by a neighbor and that was that. Only human you know.
Anyway, it's like the piston in the master cylinder is stuck. It can not pump at all. Had the lever off and it's fine. There is no leaks and nothing has been tampered with...
I always check before riding and I do pump them after taking them off but this time I got distracted by a neighbor and that was that. Only human you know.
Anyway, it's like the piston in the master cylinder is stuck. It can not pump at all. Had the lever off and it's fine. There is no leaks and nothing has been tampered with...
Air lock?
I've had a problem with my front brake for over 60,000 miles where the brake bites, slows and stops the bike no problem but if you keep pressure on the lever it will come all the way into the bar.
Put a warranty in to my local dealer when the problem first developed and they wanted to change all the discs and pads before they would entertain treating it as a fault, I changed all of the above with Brembo parts but they still wouldn't do anything about it under warranty as they weren't genuine BMW Brembo parts.
Still have that issue to this day but learned to live with it and it's not noticeable enough to show up on the Mot brake test.
I remember the problem started after I was trying to pump out a stuck piston, I heard a pop and the lack of firmness has been there since.
I think there must be a one way seal in the master cylinder which turned back on itself with the pressure of trying to push out the stuck piston and that's my problem.
Unfortunately the Master cylinder is a non serviceable unit so if the fault lies within then you'll need to buy a new master cylinder.
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In all fairness if you were working on the system and caused the problem I can’t see how you are going to get a warranty claim. JJH
It sounds like it is more than just pumping the pistons back out after all, sorry.
I wonder if you push the pistons in the calipers back in again if the back flow might shift something in the M/C to allow them to be pumped out again. Keep an eye on the fluid level though.
No information regarding the bike.
But if ABS 2, it only takes the a few small air bubbles trapped in the abs unit to give a very spongy front brake lever.
Always use the GS911 to carry out the bleed test on front and rear brakes. This also exercises the abs pump and will help stop the brushes "time" siezing through lack of use.
To give an idea of master cylinder displacement, when changing brake fluid I push the pistons fully back and insert wooden blocks so there is a minimum of fluid in the calipers when bleeding new fluid through.
With half worn pads it takes 20 full strokes of the front brake lever to get the pistons back to where they should be.
It will be ABS 2 as it's a 2012 bike I would asume. Also I've tried pushing back the pistons in the caliper to no avail. The lever is slack so you can't pump anything. It travels to within half an inch to the grip and stops as though hitting metal. It's just like the piston inside the master cylinder has stayed pushed in and wont come out, if that makes sense.
I'm booking it in with a good bike mechanic today but he can't get to it till another 4 weeks!
I'm booking it in with a good bike mechanic today but he can't get to it till another 4 weeks!
If the piston does not return fully back it will not uncover the inlet port in the master cylinder.
Hence you will not be able to get any fluid into the master cylinder.
It might be a little bit of corrosion in the master cylinder bore stopping the piston returning.
Hence you will not be able to get any fluid into the master cylinder.
It might be a little bit of corrosion in the master cylinder bore stopping the piston returning.
not only are you making a great stab at killing yourself, you are endangering the lives of others…. you shouldn't even ride 1/2 a mile to a repair shop at 20mph with this fault
you might have got away with it, but as you know there is a fault and it won't improve, you are being exceedingly reckless. It may fail completely at any point
the mastr cyl or seal needs to be checked out by someone competent. Get off public roads till its sorted.
Well according to John Clark Mottorad and the Mot station I use there is nothing wrong with it.
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….very risky,
if it can come back to the bars with light pressure applied its almost always a seal fault.
Air will compress up and go stiff, a damaged seal will allow fluid to weep past (unless enough pressure forces it to deform enough so it kind of seals a bit) the issue here is the damaged seal. It will continue to deteriorate until one day it no long manages to hold pressure... then you have no brakes and die
if it can come back to the bars with light pressure applied its almost always a seal fault.
Air will compress up and go stiff, a damaged seal will allow fluid to weep past (unless enough pressure forces it to deform enough so it kind of seals a bit) the issue here is the damaged seal. It will continue to deteriorate until one day it no long manages to hold pressure... then you have no brakes and die
No it needs a lot of force to get it back to the bar.
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Could be a pipe bulging under pressure. Might even be a combination of things each contributing to the problem. It needs sorting. JJH
NicD
Registered user
Do you have very strong hands and wrists?
agree you have to try, but achievable
its why the early R1200GS is dangerous… the throttle cable runs between the grip and the brake lever and the housing is pinned there.... brake hard the lever hits a physical stop !!! used to happen all the time and it doesn't stop any more!
if you are on road tyres pretending to be rossi and maybe get a smidge of ABS judder that's enough to hit the stop just when that's the last thing needed, get a lot of ABS on more than one occurrence during a single application (easily done on variable grip surfaces from high speed and you end up with no brakes at all). Later TC throttle housing sorts the danger (cable runs where it should always have - and in my mind should be a safety recall)
If the piston has jammed fully in the master cylinder you could try pushing all of the caliper pistons fully into the calipers. Do them in opposing pairs and chock the first pair with a suitable sized block of wood. You may need to use a wood clamp or something to creat enough pressure to push the master cylinder piston back to where it should be. Keep an eye on the master cylinder fluid level.
Then refit everything and pump the brakres without the necessary force to again jam the piston until you have a firm lever.
Then refit everything and pump the brakres without the necessary force to again jam the piston until you have a firm lever.
Thanks for that Packer. Will give that a go.
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