Disc Brake Hydraulic Actuator pump failure?
Noticed over the past few trips that brakes appeared to be getting weaker. P-3 controller showing proper voltage going to the pump. Pulled wheels and inspected all 4 calipers. Seen plenty of pad remai...
Forum Discussion
stsmark got me thinking air lock when he asked about bleeding at the pump.
I spent a few hours rerouting a heat duct, water line and a gas line to get good access to the pump. Actually removed pump and dumped out old fluid and got some brown crud flakes. Mounted in a different position and then filled reservoir and bleed at pump. Ton of air but expected that since I had dumped old fluid. Did notice pitch of pump was back to normal sound. Went to wheels and got air out of each caliper.
Hook 47 is right about the reservoir capacity being small. Had to start over one time as it ran out. Pump now changes pitch and goes to full pressure "dead headed" sound almost instantly. Not slow ramp up of pitch. Won't get a chance to test drive around until later in the week but real confident that its fixed.
Root cause conclusion:
I think fluid got too low as the pads wore. I thought fluid was only low but I really could not see in original mounting position. I'm now thinking that fluid was out and nothing for the pump to push. Pump got air locked so nothing was happening when I added additional fluid yesterday.
Thanks for all comments , Randu
I spent a few hours rerouting a heat duct, water line and a gas line to get good access to the pump. Actually removed pump and dumped out old fluid and got some brown crud flakes. Mounted in a different position and then filled reservoir and bleed at pump. Ton of air but expected that since I had dumped old fluid. Did notice pitch of pump was back to normal sound. Went to wheels and got air out of each caliper.
Hook 47 is right about the reservoir capacity being small. Had to start over one time as it ran out. Pump now changes pitch and goes to full pressure "dead headed" sound almost instantly. Not slow ramp up of pitch. Won't get a chance to test drive around until later in the week but real confident that its fixed.
Root cause conclusion:
I think fluid got too low as the pads wore. I thought fluid was only low but I really could not see in original mounting position. I'm now thinking that fluid was out and nothing for the pump to push. Pump got air locked so nothing was happening when I added additional fluid yesterday.
Thanks for all comments , Randu
