swivelrat
4th January 2021, 11:56 PM
Short story... the ABS light won’t go off following considerable effort to bleed both modulator and lines. Traction Control goes off okay, brake pedal pressure good, haven’t seen any evidence of air for a while now. No fault codes on Hawkeye showing. Any ideas?
Long story... decided to replace pads, rotors, check bearings and seals, calliper pistons didn’t look good so decided to run piston and seal kit on front and back. Did rear first, thinking I had the pipes blocked with rubber pipe with a screw in one end, it decided to drain whole reservoir over night (the thread in the screw provides a fine capillary doesn’t it) So with the whole system drained, I thought I’d just re fill it and deal with the headache of bleeding the system later. Completed service on all four callipers then used a large syringe and reverse bled each line with different coloured fluid thinking that this would be the only way to remove the air from A circuit. Brakes did not gain any acceptable pedal pressure. Then I used a Hawkeye to bleed the modulator, repeated seven or eight times. Then tried to run power bleed. The pump/modulator ran with nothing but gravity flow from bleed nipple. It was like the pump had air in it. Decided to do manual bleed for all four lines. Got a few bubbles, not many, though pedal firmness back to normal. ABS light won’t go off when test driven. Did the whole thing over, no advance in pedal pressure but light persists. Is the light a tell tale of the sensors in the wheels or the modulator or both? I was hoping that the TC sensor would be related to the modulator to help isolate the two. Again, no fault codes presenting. Power bleed still not working?
On another note, with all four wheels off and axles supported, I thought I’d throw the girl in gear, couldn’t hurt and I can monitor brake pedal pressure. Considering TC logic, with no ground to move wheels at a similar speed, I would have thought it would be a good test to see TC at work, braking hubs turning to force the non rotating ones to drive. It didn’t, which I thought either it is smarter than I or maybe I’ve stuffed the whole thing. It drives fine, abs works on lock up, just a pesky light won’t go off.
cheers
Long story... decided to replace pads, rotors, check bearings and seals, calliper pistons didn’t look good so decided to run piston and seal kit on front and back. Did rear first, thinking I had the pipes blocked with rubber pipe with a screw in one end, it decided to drain whole reservoir over night (the thread in the screw provides a fine capillary doesn’t it) So with the whole system drained, I thought I’d just re fill it and deal with the headache of bleeding the system later. Completed service on all four callipers then used a large syringe and reverse bled each line with different coloured fluid thinking that this would be the only way to remove the air from A circuit. Brakes did not gain any acceptable pedal pressure. Then I used a Hawkeye to bleed the modulator, repeated seven or eight times. Then tried to run power bleed. The pump/modulator ran with nothing but gravity flow from bleed nipple. It was like the pump had air in it. Decided to do manual bleed for all four lines. Got a few bubbles, not many, though pedal firmness back to normal. ABS light won’t go off when test driven. Did the whole thing over, no advance in pedal pressure but light persists. Is the light a tell tale of the sensors in the wheels or the modulator or both? I was hoping that the TC sensor would be related to the modulator to help isolate the two. Again, no fault codes presenting. Power bleed still not working?
On another note, with all four wheels off and axles supported, I thought I’d throw the girl in gear, couldn’t hurt and I can monitor brake pedal pressure. Considering TC logic, with no ground to move wheels at a similar speed, I would have thought it would be a good test to see TC at work, braking hubs turning to force the non rotating ones to drive. It didn’t, which I thought either it is smarter than I or maybe I’ve stuffed the whole thing. It drives fine, abs works on lock up, just a pesky light won’t go off.
cheers