Original problem sorted, thanks

[Visitor Q]

Brake system;

Braking has got progressively worse, i got some new pads, quite good ones infact, drained the system, and set about fitting them.

Have discovered BOTH seals on one side of my four pot non-sliding brake caliper are buggered and the pistons pretty much dont move (hence why only one pad is worn down and the other isnt that bad), so i had to really squeeze in the other side. Now they are bloody far in and the pad and old pad that hadnt worn much are in and it fits round the disc. But in doing so (i had the caliper off) i accidentally ended up draining the caliper (when turned upside down/pistons pushed in etc)

Anyway put it all back together, filled reservoir at the top and undid nipple. SOme bubbles came up but NOTHING else. None is moving through. I am not an expect on brake systems whatsoever however i knew draing the calipers is not good. But is there anyway people can suggest to fix it? Or at least why it is doing this, if its a common fault and easy to fix etc.

Quick reply would be excellent as all the stuff is out at the moment and i dont wish to lose anything.

(ps mods i know this is a repost and it IS in workshop already but no one is browsing that and i need help asap)
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From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[Kickstart]

Hi

Bleeding brakes from an empty system can be a pig of a job. Took about 2 hours to get them to bleed through on Mikes CBR250.

One trick to try is to use a large syringe with a section of pipe to try and push the fluid up from the bleed nipple. Only any use if you have a large syringe handy.

Other thing to try, that takes ages, is to try and get the air bubbles out of the top of the system. Turn the handlebars such that the m/c is at a slight angle (ie, the holes from the reservior into the piston area are slightly higher than the brake line banjo bolt). Tap the brake lines / banjo bolt with something like a screw driver handle (not hard, just need to tap lightly and the plastic handle of a screw driver will not damage the m/c). Every so often just pull the brake lever very lightly, litterally about 5mm or so. You should see bubbles come up in the fluid in the reservior. Keep doing this and hopefully much of the air will come up.

Eventually you will have enough fluid in the system that you can bleed them through conventionally.

I think what happens is that the air in the system compresses so easily that it will not push the fluid out of the bleed nipple, and when you release the lever it just expands again rather than drawing in fresh fluid.

Hope this idea works.

All the best

Keith
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[Visitor Q]

Thanks kickstart, G got to it first (posted in workshop) and suggested syringe/washing up liquid bottle. I took a contact lense solution bottle and used that. Took a bit but wasnt in the realm of 2 hours. More like 10-20 minutes of fiddling.

Altho if anyone could help, how big a job is replacing the piston seals? is it a case of poke them until they go in after taking the piston out... or are specialist tools required. ATM my major concern about doing it is that there are 4 high torque bolts holding the calipers together (they are opposing pot not sliding) and they are bloody impossible to undo. To get at the pads and inspect the pistons is easy. But to get them out fully... That would be a job and a half.

Plus i would imagine you would need compressed air. Which i dont have. Unless you can connect it to a automatic tyre compressor some how. Again any suggestions as to how to do that?
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China traffic/travel bike vid - When I make a sweeping statement, please add the word 'statistically' in to the sentence before you bitch...
From September 2014 to January/February 2015 I will not be using any English, nor reading any. As such, I won't be on here. PM at will, but I won't be checking/posting unless in emergencies. Certainly not for the first couple of months. Please berate me savagely if I break that rule...

[Kickstart]

Hi

The bolts holding the 2 halves together should be tightened to 39Nm I think (I assume it is the same caliper as used on the 1200 Bandit).

According to the manual gently pump the pistons out, but do not allow opposing pistons to touch. Then split the caliper body and remove the pistons, then remove the seals (using something wooden or plastic to remove the seals so as not to damage the caliper body), then discard the seals (you will need new ones). Clean out using brake cleaner. Put the new seals in lubricated with fresh brake fluid, put the cleaned up pistons in place and reassemble the caliper.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Visitor Q]

[Kickstart]

Hi

Go to Halfrauds and get a decent allen key bit. They are not that expensive. The professional range is fair quality.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Visitor Q]

[McJamweasel]

He said allen key bit - i.e. something that fits on a ratchet just like a socket.
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[Visitor Q]