Brake Pedal Slowly Goes to Floor
08-12-2009, 09:33 AM
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Brake Pedal Slowly Goes to Floor
I just picked up what appears to be a very nice 92 Integra GS, with the 4 wheel disk brakes and anti-lock system.
The brakes seem to work just fine while driving, and even during emergency type stops, however, when sitting at traffic lights, the brake pedal slowly goes to the floor, and the car begins to creep forward (auto-transmission). A quick pump of the pedal restores the brakes, until the pedal slowly floors again. There are no leaks, and the fluid is topped up. I have heard people say this is characteristic of ABS systems, but it just doesn't seem right to me.
Is this normal? If not, is this a common problem with Integra's, and what is the solution? Is there something in the ABS system that might cause ths? Any help appreciated.
CraigK
The brakes seem to work just fine while driving, and even during emergency type stops, however, when sitting at traffic lights, the brake pedal slowly goes to the floor, and the car begins to creep forward (auto-transmission). A quick pump of the pedal restores the brakes, until the pedal slowly floors again. There are no leaks, and the fluid is topped up. I have heard people say this is characteristic of ABS systems, but it just doesn't seem right to me.
Is this normal? If not, is this a common problem with Integra's, and what is the solution? Is there something in the ABS system that might cause ths? Any help appreciated.
CraigK
08-12-2009, 01:24 PM
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This has nothing to do with ABS.
Your master cylinder has an internal leak, allowing sustained pressure to sink the pedal to the floor. This can be especially dangerous going down a long hill. Replace the master cylinder and she'll firm right up.
Your master cylinder has an internal leak, allowing sustained pressure to sink the pedal to the floor. This can be especially dangerous going down a long hill. Replace the master cylinder and she'll firm right up.
08-13-2009, 01:45 PM
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08-13-2009, 11:50 PM
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08-14-2009, 12:30 AM
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08-14-2009, 06:37 AM
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A master cylinder rebuild kit was $32, and the remanufactured unit $34. I will have to transfer the reservoir though with the reman unit - no biggie compared to a rebuild.
I'll post the results next week.
CraigK
I'll post the results next week.
CraigK
08-15-2009, 01:30 PM
#9
Usually if someone can't diagnose the problem odds are they don't have the competence to rebuild it properly themselves. I was just stating that for simplicity. That is all 
Last edited by JoePoonani; 08-15-2009 at 01:32 PM.
08-19-2009, 02:45 AM
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MC Change Results
Just an FYI for others that might have the same issue . . .
I replaced the master cylinder yesterday with a remanufactered unit ($34). This took almost exactly three hours, more difficult than it should have been as the nuts on the brake lines into the MC would not break free before rounding off (yes - I soaked for 24 hrs. with penetrating fluid, and used a good wrench). Also, the procedure for purging the air from the new MC took almost an hour, but I haven't done this before and was taking my time. I did not bleed the brakes after replacing the MC (the set of new self-bleed bleeder valves I had ordered didn't come in until late afternoon - Dorman Help! item# 12705). The good news is that the pedal sinking is completely gone. Brake feel is much improved, and the pedal stays where it is at stops.
The brakes still feel a bit "mushy", but I'm sure there is still air in the lines, and I think I'll replace all the pads with ceramic units, and bleed the entire system next weekend.
CraigK
I replaced the master cylinder yesterday with a remanufactered unit ($34). This took almost exactly three hours, more difficult than it should have been as the nuts on the brake lines into the MC would not break free before rounding off (yes - I soaked for 24 hrs. with penetrating fluid, and used a good wrench). Also, the procedure for purging the air from the new MC took almost an hour, but I haven't done this before and was taking my time. I did not bleed the brakes after replacing the MC (the set of new self-bleed bleeder valves I had ordered didn't come in until late afternoon - Dorman Help! item# 12705). The good news is that the pedal sinking is completely gone. Brake feel is much improved, and the pedal stays where it is at stops.
The brakes still feel a bit "mushy", but I'm sure there is still air in the lines, and I think I'll replace all the pads with ceramic units, and bleed the entire system next weekend.
CraigK