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Re: Brakes Tonykart
Posted by 'Hootsman' on 25 Jan 2009 @ 20:44


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Hootsman
Joined: January 2008
Total Posts: 35
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Hi gokart00

I think greg jersey is right, the problem is probably in the master cylinders. I wrote this in an earlier reply, but see if it applies to you.

Also, is the retaining pin for the pads in good condition, if it is worn, the pads could jam on it stopping them from releasing properly.

Hope this helps


On the OTK brake system, the spring in the master cylinder keeps the piston to the rear against the circlip.

I have not measured it, but the reservoir appears to feed into the system in front of the piston seal.

When you bleed the system, you remove the bleed plug and connect your bleed tool. Then remove the reservoir cap and open the bleed tool and let the reservoir fill up to about 1/2 to 2/3. You need to leave a gap for fluid to come back into the reservoir when its hot. Turn off the bleed tool and fit the reservoir caps.

Now open the bleed tool and then open the bleed screw and the fluid should come through. Close the bleed screw when the fluid in the tube is free from air bubbles. Then close the bleed tool. Remove it and put the bleed plug back into the master cylinder.

Do the same on the other cylinder and then try the brakes. If they are not hard, do it again.

Once you have all the air out of the system you effectively have a tube of solid fluid pushing on the brake pad.

When you push the pedal, the piston moves forward, compressing the spring, and the fluid pushes the pad against the brake disc.

When you release the brake pedal, the spring in the master cylinder pushes the piston back which applies suction onto the piston in the caliper and pulls it back into the caliper. The magnet in the piston pulls the pad off the disc.

If the fluid level in the reservoir gets too low, there will not be enough fluid to fill the line so the piston in the caliper will not apply sufficent pressure to apply the brakes.

If the fluid level in the reservoir is too high, there will always be pressure in the line due to the rubber caps in the lid and when the brakes are hot the fluid will expand and there is the risk of the pad being held against the disc until the fluid boils and then you will have no brakes.

When the pads wear down, the reservoir will maintain the fluid in the system to keep the line between the master cylinder and the caliper full. The piston in the master cylinder will continue to apply suction and will maintain the distance between the pad and the disc. If the pads wear down a lot you may have to top up the fluid level. This can be done through the reservoir cap, just make sure that you do not overfill the system.

As long as your seals are in good condition, the caliper is kept clean and the reservoir level is maintained, the system should be maintenabce free.

If you pump the brakes whilst you are bleeding them, the fluid will take the line of least resistance and possibly just push fluid from the reservoir into the bleed tool or into the gap between the two seals on the piston in the master cylinder. Either way it could leave air trapped in the caliper and soggy brakes.

Message Thread:

Brakes Tonykart  by 'Gokart00'   (25 Jan 2009 @ 19:47)
Re: Brakes Tonykart  by 'gregjersey'   (25 Jan 2009 @ 19:58)
Re: Brakes Tonykart  by 'Gokart00'   (25 Jan 2009 @ 22:24)
Re: Brakes Tonykart  by 'Hootsman'  << You are here!
Re: Brakes Tonykart  by 'Gokart00'   (25 Jan 2009 @ 22:35)
Re: Brakes Tonykart  by 'Gokart00'   (25 Jan 2009 @ 22:40)
Re: Brakes Tonykart  by 'Hootsman'   (26 Jan 2009 @ 6:26)
Re: Brakes Tonykart  by 'RWR'   (26 Jan 2009 @ 19:04)
Re: Brakes Tonykart  by 'Hootsman'   (26 Jan 2009 @ 22:51)
Re: Brakes Tonykart  by 'Gokart00'   (27 Jan 2009 @ 4:40)
Re: Brakes Tonykart  by 'Gokart00'   (04 Feb 2009 @ 11:10)

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