Front Brake Jams On for NO reason????
Discussion
My car did this once, or something similar. More mass in the car, so i didn't notice anything so severe - it just pushed on through.
What had happened was the pad had seized onto the disc. That is, it had siezed in a position which put it against the disc, rather than the disc/pad being stuck together. Thereis a slider (a steel dowel) which guides the motion of the pad/caliper and the seals around this slider can, and do, stick if not used often - such as with a classic.
Tht's where i'd look first. Bear in mind, that for me, oiling the chain is a major mechanical project...
What had happened was the pad had seized onto the disc. That is, it had siezed in a position which put it against the disc, rather than the disc/pad being stuck together. Thereis a slider (a steel dowel) which guides the motion of the pad/caliper and the seals around this slider can, and do, stick if not used often - such as with a classic.
Tht's where i'd look first. Bear in mind, that for me, oiling the chain is a major mechanical project...
this classic bike, has it been used much recently?
reason i ask is the seals in my old bonnie went hard & caused a very sticky brake.
oh & if you've filled the fluid right to the top try taking the cap off & see what happens. there might be water in there which has expanded with heat & pressurised the system. you'll want something to catch the fluid if its over the bike though. mines got a rubber thing under the cap that seals the top, if yours has simialr remove that too.
reason i ask is the seals in my old bonnie went hard & caused a very sticky brake.
oh & if you've filled the fluid right to the top try taking the cap off & see what happens. there might be water in there which has expanded with heat & pressurised the system. you'll want something to catch the fluid if its over the bike though. mines got a rubber thing under the cap that seals the top, if yours has simialr remove that too.
the fluid level will go down as the pads wear down...set the fluid to the max line with the pads pushed right back in the caliper then you should never need to touch the fluid level as when it gets to the low mark its time to change the pads
if that makes sense
unless you have a fluid leak in that case get it looked at and stop riding it
if that makes sense
unless you have a fluid leak in that case get it looked at and stop riding it
This problem happens from time to time on cars, perhaps you have run into a similar problem. The symptoms are a build up of pressure in the brake circuit. If you open the bleed valve to release the pressure the brakes unlock.
The hydraulic circuit is supposed to be open to the reservoir when the brakes are off, and the first tiny movement of the master cylinder closes off the port to the reservoir and seals the hydraulic system so that you can build up pressure and apply the brakes. If anything prevents the master cylinder from moving back far enough to open the port again then it will remain a sealed system. Now, as the brakes warm up and the fluid expands it has nowhere to go so it builds up pressure and makes the brakes drag. This warms the brakes up so the fluid expands more and before you know it the brakes are jammed on solid.
On cars there is usually an adjustable pushrod between the pedal and the master cylinder (sometimes hidden inside the servo) which can be adjusted to take up slack - adjust it a fraction too tight and you can get this problem. I've also seen this problem occur where the master cylinder had worn and got gunged up internally to the extend that the piston wouldn't *quite* retract far enough to open the port. Sometimes, stamping the pedal is enough to get it to move back that fraction to open the port and release the pressure. On a bike I guess this would mean thumping the brake lever.
If it keeps happening you will need to find out whether it's a pushrod adjustment problem or an internal problem in the m/c.
The hydraulic circuit is supposed to be open to the reservoir when the brakes are off, and the first tiny movement of the master cylinder closes off the port to the reservoir and seals the hydraulic system so that you can build up pressure and apply the brakes. If anything prevents the master cylinder from moving back far enough to open the port again then it will remain a sealed system. Now, as the brakes warm up and the fluid expands it has nowhere to go so it builds up pressure and makes the brakes drag. This warms the brakes up so the fluid expands more and before you know it the brakes are jammed on solid.
On cars there is usually an adjustable pushrod between the pedal and the master cylinder (sometimes hidden inside the servo) which can be adjusted to take up slack - adjust it a fraction too tight and you can get this problem. I've also seen this problem occur where the master cylinder had worn and got gunged up internally to the extend that the piston wouldn't *quite* retract far enough to open the port. Sometimes, stamping the pedal is enough to get it to move back that fraction to open the port and release the pressure. On a bike I guess this would mean thumping the brake lever.
If it keeps happening you will need to find out whether it's a pushrod adjustment problem or an internal problem in the m/c.
id go with overful resivor still. there is a rubber seal im sure you've seen under the lid, if you fill the resivor to the brim & 'force' the rubber in & stick the lid on your causing pressure in the circut then as it expands when its warm it sticks on.
id say your mate whos 'fixing' it for ya is the sort of person who needs to practise on his own bikes first
id say your mate whos 'fixing' it for ya is the sort of person who needs to practise on his own bikes first
So what's the plan then James? You going to get rid and replace it with something a bit newer?
Personally I think you'd be better getting a bigger bike. If you can get a couple of grand together you could get your hands on something quite interesting.
My falco only owes me 2 and a bit K.
Phill
Personally I think you'd be better getting a bigger bike. If you can get a couple of grand together you could get your hands on something quite interesting.
My falco only owes me 2 and a bit K.
Phill
James, I know how you feel about cars, I was the same when I had a Corrado VR6 and loved it.
But... A quick bike is a different prospect all together, riding it well is far more rewarding, the amount of performance you get for the money is astounding and chicks dig bikes.
The bigest difference is that I used to get frustrated sitting behind slower cars...not a problem on a bike!
But... A quick bike is a different prospect all together, riding it well is far more rewarding, the amount of performance you get for the money is astounding and chicks dig bikes.
The bigest difference is that I used to get frustrated sitting behind slower cars...not a problem on a bike!
anonymous said:
[redacted]
If it makes you feel better then have the caliper serviced but I'd put a tenner on it being the master cylinder as GreenV8 said. New master cylinder to be sure and safe, bleed it through and put the correct level of fluid in the reservior. Should be fine !If your mate overfilled the reservior it should have squirted out of the cap, there is a rubber seal in them but there's also a small pressure release hole on most modern caps, yours may or may not have had that.
Don't give up on it. As frustrating as it is really your problems seem to be:
1. Hydraulic issue in the brakes. Drain all the fluid, refill and bleed properly. If it happens again then do the above but change the master cylinder at the same time and that should solve that.
2. Slipping clutch, just tighten the cable and see if that helps.
If the above solves the problem then there is no need for a newer bike. Bikes are really simple and once you get into it, its great fun keeping on top of things. My old R100 GS is always being pulled apart to do stuff - seals etc but I would never be without it. Last time I did major surgery on an old BM we rode it into my mates dads lounge and proceeded to pull it apart there. Worked all night and the following day and rode it out. You don't get that with modern bikes. Once you are into it, its hilarious!!!!
1. Hydraulic issue in the brakes. Drain all the fluid, refill and bleed properly. If it happens again then do the above but change the master cylinder at the same time and that should solve that.
2. Slipping clutch, just tighten the cable and see if that helps.
If the above solves the problem then there is no need for a newer bike. Bikes are really simple and once you get into it, its great fun keeping on top of things. My old R100 GS is always being pulled apart to do stuff - seals etc but I would never be without it. Last time I did major surgery on an old BM we rode it into my mates dads lounge and proceeded to pull it apart there. Worked all night and the following day and rode it out. You don't get that with modern bikes. Once you are into it, its hilarious!!!!
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