Ok, here is the story ...
I was out of town and my nephew called. He was driving his girlfriend's 2000
Kia Sephia Spectra. When he stepped on the brake pedal it went to the floor.
On the second pump the brakes worked well enough that he was able to stop
the car. He then drove carefully to a safe parking lot using the "two pump"
method and then called me. I asked him to look at the wheels to see if there
was any sigh of fluid loss and to check the master cylinder reservoir.
Everything looked to be in good shape. I then suggested that he either call
AAA or if he felt comfortable he could take back roads and drive the car
over to my house. He took the latter option.
He called me when he got to my house and said "on the way over it was fine,
the brakes worked on the first try". Given that it was now in my driveway
and thinking that the large hammer principal might discover what might be
amiss I asked him to go out and step on the brake pedal as hard as he could.
The assumption being that if he blows a seal or a rubber line at least it
was in the driveway and easy to fix. He went out to the car and said the
pedal again went easily to the floor but would pump up like it had earlier.
I told him where the keys were for my car so he and his girlfriend could at
least be on their way and told them I would look at the Kia when I got home.
Upon getting home I took the car for a drive and the brakes seemed fine.
Reasonable pedal feel, reasonable stopping power ... after all it is a 10
year old Kia Sephia so the bar was not real high to begin with ... all
seemed to be fine.
I am reluctant to give it back to them with a clean bill of health. The only
thing I can think of is to replace the master cylinder, but that seems like
throwing parts at the problem. But the master cylinder is the only thing I
can think of that might cause a soft pedal without leaking fluid on the
ground and "recovering". The thought of a small piece of rust or what ever
causing an intermittent seal failure between the front and back portions of
the master cylinder is the scenario I was thinking of.
So if anyone has any other suggestions on how to diagnosis this I would
appreciate it. And even if you don't have a firm diagnosis, a well reasoned
"throw this at it" would be appreciated ... assuming it is short of
replacing the car or the entire brake system.
Thanks,
Arvid
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