It sounds like you could have moisture in the brake lines. When cold, the
brakes function ok. But, as braking raises the temperature of the brake
fluid in the caliper, the water boils. The steam causes the spongy feel
that you are experiencing. Try changing your brake fluid and obviously
bleeding the brakes. That might do it.
Chris
On Thu, 10 Aug 1995
Mike=McDevitt%WasteWaterEng%TWDB_Engineerin@vines.twdb.state.tx.us wrote:
> Over the past few days, my '77 B has developed a case of spongy brakes. At
> first, the pedal would occasionally go soft at a stop, but then would pump up
> and be okay for the next 20 stops. Yesterday, I noticed that the pedal was
> getting soft at every brake application; not _to the floor_ soft, but
> definitely there was more pedal travel than what I am accustomed to. After
> I got home,with the engine off, the pedal would still be soft although
>firmer
> than when the motor was running. With a cold engine (i.e. after setting
> overnite), and with the engine not running, the pedal is hard. I have not
> been into the brake system since last summer, so unless it has picked up air
> on its on, I don't think I have air in the system, but I don't know what else
> to check. Am I experiencing a problem with the brake servo? If it is the
> servo, how difficult are they to repair? The Bently repair manual indicates
> special tools are needed, and the Haynes manual that I have indicates that
> service is best left to a garage. The servo does not appear to be leaking
>the
> best that I can tell. Could the problem lie elsewhere?
>
> All thoughts on this matter are greatly appreciated.
>
> Mike McDevitt
> '74 and '77 B's
>
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