brake pedal to the floor off and on
- Thread starter Randall
- Start date
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Frisbeeguy
Member
Please keep us posted on the updates & results as you replace the MC again. - Really hope it solves the problem.
if you have problems, pm me when you post a topic. i can bring up electrical diagrams and testing to help you out.
sdpatt
Sr. SHO Engr.
After reviewing the Chilton's manual's description of the ABS system functionality, I was convinced that the only mechanism of failure was leakage past the master cylinder seals. The ABS hydraulic control unit (HCU) has solenoid valves that are normally open and are actuated to the closed position for the wheel hydraulic circuit where the ABS sensor detects a reduction in rotational velocity (locked).
I acquired another Fenco M2613 from AutoZone and installed it on Friday, Jan 27. During the bench bleeding before installation, I found the cylinder piston to move in a jerky motion. The piston did not extend to its iniitial position with ease and seemed to hang about 3/4" from full extension. I installed it with my fingers crossed. Sure enough, during bleeding from the line fittings at the master cylinder, I found the brake pedal to drop to the floor without resistance and not fully extend upon retraction. The count was now up to two faulty remanufactured parts. This one was badly failed.
After emitting a loud vocal indication of extreme displeasure, I once again traveled to a different local AutoZone for my third Fenco M2613 box. This was still Friday and I was ready to install my second master cylinder in one day and third over that last two weeks. Bench bleeding revealed this unit to operate with full functionality and a smooth travel of the piston. The air was easy to remove from this version where the last cylinder was very difficult to purge. I was getting my hopes up. The installation was completed and the local bleeding found the pedal to be firm with the lines snug and smooth with the lines loosened. Repeated presses (>100) of the pedal with the engine off found no cases where the pedal dropped to the floor, but was instead, very firm. The test drive revealed the brake pedal to be firmer than with the original master cylinder and no instances where the pedal dropped to the floor.
On Saturday morning, an 80-mile trip to a horse ranch in East Texas for a campout with my 8-year old daughter and mountain bikes on the hitch mounted rack, confirmed that this may indeed be a good, remanufactured master cylinder. The return trip to Dallas showed no unusual behavior with the brakes. The SHO is now back in the stable. Giddyup!
I acquired another Fenco M2613 from AutoZone and installed it on Friday, Jan 27. During the bench bleeding before installation, I found the cylinder piston to move in a jerky motion. The piston did not extend to its iniitial position with ease and seemed to hang about 3/4" from full extension. I installed it with my fingers crossed. Sure enough, during bleeding from the line fittings at the master cylinder, I found the brake pedal to drop to the floor without resistance and not fully extend upon retraction. The count was now up to two faulty remanufactured parts. This one was badly failed.
After emitting a loud vocal indication of extreme displeasure, I once again traveled to a different local AutoZone for my third Fenco M2613 box. This was still Friday and I was ready to install my second master cylinder in one day and third over that last two weeks. Bench bleeding revealed this unit to operate with full functionality and a smooth travel of the piston. The air was easy to remove from this version where the last cylinder was very difficult to purge. I was getting my hopes up. The installation was completed and the local bleeding found the pedal to be firm with the lines snug and smooth with the lines loosened. Repeated presses (>100) of the pedal with the engine off found no cases where the pedal dropped to the floor, but was instead, very firm. The test drive revealed the brake pedal to be firmer than with the original master cylinder and no instances where the pedal dropped to the floor.
On Saturday morning, an 80-mile trip to a horse ranch in East Texas for a campout with my 8-year old daughter and mountain bikes on the hitch mounted rack, confirmed that this may indeed be a good, remanufactured master cylinder. The return trip to Dallas showed no unusual behavior with the brakes. The SHO is now back in the stable. Giddyup!
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Randall
SHO Member
Great job getting this beast of a problem solved! Looking at what happened to you, I feel lucky that my M2613 was good the first time through! Congrats!
:bbounce:
and congrats. Like i said... reman parts are a dime a dozen bad. thankfully you investigated and found the problem yourself.
just think of all the free work you could have gotten if you had a dealership do it in the first place
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