Arvid,
I don't know where you are located, but if the weather is hot and the
brakes are hot, the moisture in the calipers/wheel cylinders may be
heating up enough to make steam. After cooling off the steam condenses
and the breaks work correctly again. Try taking the car for a trip where
you will be using the brakes enough to really heat them up. If that
causes them to require 2 strokes to stop the car I'd recommend changing
the brake fluid. Most cars don't get it changed often enough, just
topped off as necessary, leaving a fair amount of water in the system.
Please let us know what you find.
Peace,
Pat
Thusly spake Arvid Jedlicka, On 8/30/2010 11:23 AM:
> 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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>
--
Pat Horne, Owner, Horne Systems
(512) 797-7501 Voice 5026 FM 2001
Pat@HorneSystemsTx.com Lockhart, TX 78644-4443
www.hornesystemstx.com
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