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Old May 7, 2016 | 05:42 PM
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before I push this thing over I have a question. I upgraded my single caliper single piston brake on my fxr to a dual 4 piston caliper set up. instead of doing 1 line from the master into a T fitting, I used a dual line banjo bolt at the master, so there are 2 seperate lines running from the master. one to each caliper. the master is an 11/16the and the all banjo bolts are 3/8th or 10mm. I can't get this thing to firm up for anything. it works, but it goes straight to the bars. any help?

never had a problem like this with my single caliper set ups. once they started getting fluid they would get firmer and firmer. I've used almost a bottle and a half of brake fluid on this current set up.
 
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Old May 7, 2016 | 06:50 PM
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you doubled the volume by using two lines.
master can only push so much volume..
you need a bigger master , or cut down on the lines
 
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Old May 7, 2016 | 07:02 PM
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Those 4 piston calipers are a bear to bleed. I'm hesitant to blame the issue you're having with the line setup you have.
 
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Old May 7, 2016 | 08:35 PM
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If you have abs, be careful, they blow up, I'm told
 
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Old Jul 2, 2016 | 10:18 AM
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just to update anyone that cares, the right caliper has a piston that was seized up. I switched back to my dual single pistons and everything is good to go.
 
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Old Jul 2, 2016 | 12:18 PM
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But that's not why the lever wouldn't get firm....
 
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Old Jul 2, 2016 | 12:40 PM
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Originally Posted by heybaylor
you doubled the volume by using two lines.
master can only push so much volume..
you need a bigger master , or cut down on the lines
The lines may be part of the problem, but you doubled the amount of pistons that the brake fluid has to move to apply the brakes, so you need a master designed for a system with double the capacity of the original. Both ends of the system have to work together. You need a master designed for the type and number of the calipers and pistons you are using.

A master designed for operating two pistons will not have the capacity to properly operate four.
 

Last edited by deadhawg; Jul 2, 2016 at 12:43 PM.
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Old Jul 2, 2016 | 04:17 PM
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Originally Posted by hdbob2006
But that's not why the lever wouldn't get firm....
well its firm now amd I did nothing but switch calipers.

Originally Posted by deadhawg
The lines may be part of the problem, but you doubled the amount of pistons that the brake fluid has to move to apply the brakes, so you need a master designed for a system with double the capacity of the original. Both ends of the system have to work together. You need a master designed for the type and number of the calipers and pistons you are using.

A master designed for operating two pistons will not have the capacity to properly operate four.
I did switch the master. it isn't the stock one.
 
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Old Jul 2, 2016 | 04:38 PM
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Originally Posted by agove
just to update anyone that cares, the right caliper has a piston that was seized up. I switched back to my dual single pistons and everything is good to go.
For what it's worth I prefer the single piston calipers.
 
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Old Jul 2, 2016 | 06:44 PM
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Just guessing but your master may be 5/8 and you may need 3/4.
 
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