JB.
New member
I first noticed the frequent running of the accumulator motor in late 2012. It failed in late 2015. I would periodically, randomly measure the cycle times whenever I thought of it and make note. The length of time the motor was actually running changed very little over the years. Always in the neighborhood of 1-2 seconds. It was the intervals between pulses that changed and they were always perfectly consistent during each individual test. Typically, the times were taken with the engine at idle, in Park, and foot off the pedal, with no thought given to how much braking had taken place beforehand.
For those unfamiliar, this is a phenomenon that has been written about under many descriptions. Buzzing behind dash, vibration in brake pedal, etc. The sound can be heard from the drivers seat, felt in the pedal, and easily seen in the engine compartment by looking at the accumulator cylinder in the (pic) . If you're skeptical whether the drivers seat sound and/or pedal "click" sensation are connected to the accumulator cylinder, just time the sound and/or pedal sensation cycles and then go time the accumulator sound/vibration cycle (easily observed) in the engine compartment.
Fwiw, I charted the continuous cycle times (in seconds) that I had documentation for over the last three years up until failure.
If anyone has the cycle symptoms and decides to let the unit go to failure, which apparently can be many years, it's important to realize that if the system fails and even if you don't get one last good braking action from one last pedal push (which has been hypothesized), there will be brakes (along with a continuous warning beep and Christmas lights on the dash). You just have to be prepared to push them hard (they will be down near the floor).
How much braking power? Well, it literally depends quite a bit on leg strength. I have high relative leg strength but I'm a light weight, so as far as single, isometric push strength (male), probably about average, if even that. Obviously, anyone who is compromised for any reason in this regard would want to take that into consideration.
For me, I would estimate maximum braking power to be roughly the same as a somewhat quick deceleration for a yellow light, but not much more. Certainly not as much as one of those brake assist moments most people are familiar with. I never quite fully experimented with an all out push so I can only estimate.
The booster failed above 11,000 feet, with a difficult off-pavement descent yet to come. It turned out to be very fortunate timing. I soon got comfortable with the braking and came to realize that the braking action was in many ways superior to boosted brakes in those conditions (wish there was a way to turn off boost in low range). Nice, slow, smooth application of braking power with none of the abrupt stops that compress the front end that sometimes happen when a bump forces unintended pedal push. By far the worst part was having to endure the continuous beep, but I became comfortable enough with the braking action that I didn't panic when back in civilization and decide to pay to get it fixed 600 miles from home for no doubt premium pricing. Got home and bought a new unit from Boch Toyota South, thanks [MENTION=25953]eng208[/MENTION]. Thanks [MENTION=100496]blackworks[/MENTION] for trying to help with the beep even though I decided against the attempt to disconnect. I had become so comfortable with the braking, I decided I'd better leave alone my incentive-to-fix, for my own good.
Drove the 600 miles home with earplugs which is a story in itself. I had nothing to do but enjoy the scenery and pay constant, close attention to my driving (in higher than normal gearing). Presumably, few have ever had reason to drive in such a manner but it was novel, a little surreal, and the time flew by in a way it seldom, if ever, has before. Would have never guessed.
For those unfamiliar, this is a phenomenon that has been written about under many descriptions. Buzzing behind dash, vibration in brake pedal, etc. The sound can be heard from the drivers seat, felt in the pedal, and easily seen in the engine compartment by looking at the accumulator cylinder in the (pic) . If you're skeptical whether the drivers seat sound and/or pedal "click" sensation are connected to the accumulator cylinder, just time the sound and/or pedal sensation cycles and then go time the accumulator sound/vibration cycle (easily observed) in the engine compartment.
Fwiw, I charted the continuous cycle times (in seconds) that I had documentation for over the last three years up until failure.
If anyone has the cycle symptoms and decides to let the unit go to failure, which apparently can be many years, it's important to realize that if the system fails and even if you don't get one last good braking action from one last pedal push (which has been hypothesized), there will be brakes (along with a continuous warning beep and Christmas lights on the dash). You just have to be prepared to push them hard (they will be down near the floor).
How much braking power? Well, it literally depends quite a bit on leg strength. I have high relative leg strength but I'm a light weight, so as far as single, isometric push strength (male), probably about average, if even that. Obviously, anyone who is compromised for any reason in this regard would want to take that into consideration.
For me, I would estimate maximum braking power to be roughly the same as a somewhat quick deceleration for a yellow light, but not much more. Certainly not as much as one of those brake assist moments most people are familiar with. I never quite fully experimented with an all out push so I can only estimate.
The booster failed above 11,000 feet, with a difficult off-pavement descent yet to come. It turned out to be very fortunate timing. I soon got comfortable with the braking and came to realize that the braking action was in many ways superior to boosted brakes in those conditions (wish there was a way to turn off boost in low range). Nice, slow, smooth application of braking power with none of the abrupt stops that compress the front end that sometimes happen when a bump forces unintended pedal push. By far the worst part was having to endure the continuous beep, but I became comfortable enough with the braking action that I didn't panic when back in civilization and decide to pay to get it fixed 600 miles from home for no doubt premium pricing. Got home and bought a new unit from Boch Toyota South, thanks [MENTION=25953]eng208[/MENTION]. Thanks [MENTION=100496]blackworks[/MENTION] for trying to help with the beep even though I decided against the attempt to disconnect. I had become so comfortable with the braking, I decided I'd better leave alone my incentive-to-fix, for my own good.
Drove the 600 miles home with earplugs which is a story in itself. I had nothing to do but enjoy the scenery and pay constant, close attention to my driving (in higher than normal gearing). Presumably, few have ever had reason to drive in such a manner but it was novel, a little surreal, and the time flew by in a way it seldom, if ever, has before. Would have never guessed.
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