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Unclemeaty · 04-05-2012, 09:36 PM

*UPDATE*
I think I've confirmed the problem using the above brake line guages, but just wanted to post the scenerio observed.

Rear brakes: With the car running, both guages are able to hit ~1300PSI. Both gauges react at almost the same time, in the same way/fassion. Smooth pressure rise on the guages.

Front brakes: The FR (which I believe has always been close to the worst or problem) measures fluid pressure much slower than the FL. With the engine running, the line pressure will reach ~1300 PSI on both sides, however the rising rate of the left is greater/faster than the right. Under gental brake engagements, the FR sometimes does not measure at all or takes up to 2 seconds to even poll a reading, while the FL is as-soon-as the pedal is pressed.

More observation on FR: If the brakes are pumped hard a few times, the presure seems to be get better; both FR/FL will pressure rise at the same pace after being pumped. If the brakes are left to sit for maybe 30 seconds, the FR will then start to delay in rising pressure.

Summary, RR, RL, and FL all react the same - pedal and instant pressure. FR has a slight delay of 0.5 to 2 seconds depending on pressure applied, and if pumped.

Solution: Bleeding isnt helping at all. I've literally bled about 1Q of fluid through this thing in over a year and nothing has improved.

Should I try rebuilding FR caliper? SHould I rebuild both FR/FL at the same time? Am I missing something? Right now I am thinking that since/if the FR caliper is seized, that is it retracting/reacting slowly and causing pressure to be lost inside. I'm kind of thinking a piston resisting it's new place is heading back inside of the caliper; where re-presurizing requires time for the piston to move back out in play. Does this sound correct?

04-05-2012, 09:36 PM	#28 (permalink)
Unclemeaty Base Member Join Date: Aug 2010 Location: Atlanta Posts: 203 Drives: 150cc Scooter Rep Power: 15	UPDATE I think I've confirmed the problem using the above brake line guages, but just wanted to post the scenerio observed. Rear brakes: With the car running, both guages are able to hit ~1300PSI. Both gauges react at almost the same time, in the same way/fassion. Smooth pressure rise on the guages. Front brakes: The FR (which I believe has always been close to the worst or problem) measures fluid pressure much slower than the FL. With the engine running, the line pressure will reach ~1300 PSI on both sides, however the rising rate of the left is greater/faster than the right. Under gental brake engagements, the FR sometimes does not measure at all or takes up to 2 seconds to even poll a reading, while the FL is as-soon-as the pedal is pressed. More observation on FR: If the brakes are pumped hard a few times, the presure seems to be get better; both FR/FL will pressure rise at the same pace after being pumped. If the brakes are left to sit for maybe 30 seconds, the FR will then start to delay in rising pressure. Summary, RR, RL, and FL all react the same - pedal and instant pressure. FR has a slight delay of 0.5 to 2 seconds depending on pressure applied, and if pumped. Solution: Bleeding isnt helping at all. I've literally bled about 1Q of fluid through this thing in over a year and nothing has improved. Should I try rebuilding FR caliper? SHould I rebuild both FR/FL at the same time? Am I missing something? Right now I am thinking that since/if the FR caliper is seized, that is it retracting/reacting slowly and causing pressure to be lost inside. I'm kind of thinking a piston resisting it's new place is heading back inside of the caliper; where re-presurizing requires time for the piston to move back out in play. Does this sound correct? Last edited by Unclemeaty; 04-05-2012 at 09:42 PM.