 Saltire Could Be A Chat Bot

Joined: 11 Apr 2013 Karma :     
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 Saltire Could Be A Chat Bot

Joined: 11 Apr 2013 Karma :     
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 Saltire Could Be A Chat Bot

Joined: 11 Apr 2013 Karma :     
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 sickpup Old Timer

Joined: 21 Apr 2004 Karma :     
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 Teflon-Mike tl;dr

Joined: 01 Jun 2010 Karma :    
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 Posted: 05:52 - 01 Apr 2014 Post subject: |
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This is the point of hydraulic disck brakes, they are 'self adjusting'. You cant 'set' the running clearance between pad and disc.
You press the brake pedal, that pushes fluid into the calliper, that pushes piston out of the calliper, pushing pad against the face of the disc. When you take your tow off the brake pedal, it relieves the pressure in the calliper, and the seal between the piston and the caliper, which was twisted a little, as the piston moved, pulls the piston back just enough to let the brake pad come away from the disc.
Every time you press the brake pedal then, you push the piston out, taking up the gap made by any wear between the pad and disc, but when you let go, that seal only lets piston back enough to maintain the running clerance. Hence 'self adjusting'.
The rod, between the brake pedal and master cylinder isn't adjusting the running clerance, its adjusting the brake pedal position; If you have tried to use that, to adjust running clearance, its possible you have set the lever position so that it's not letting the brake come 'off' and travel on the master cylinder return fully, and let the oressure off the caliper, so that every time you brake you 'jack up' the brake pushing the pad harder and harder into the disc.
But more likely, the piston is 'sticking' in the caliper, and not returning because its corroded, and gummed up with dirt and old brake dust.
Also likely to be a 'floating' caliper, that has just one piston on one side of the caliper, so that as the piston comes out and pushes that pad against the disc, it moved the caliper on sliding pins, pulling the other pad into the other side of the disc against it.
Again, if the disc is gummed up with grap and crud and corrosion, the caliper wont slide on those pins, so when pulled against the disc when on, wont slide back when off.
Hence Sickpups advice. Strip it, clean it, and service it. You may need new seals and pistons in the caliper if the piston is badly corroded.
However; you say 'it's the arm and cable between brake pedal and brake'... this does not sound like a disc brake, but a drum. Are you SURE its a disk brake? ____________________ My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?' |
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