Hello All - -
Lately I have noticed a significant increase in the pedal pressure required to make a "normal braking rate" stop. The pedal feel is very firm , not at all spongy . Hoses are new, wheel cylinders are new, no fluid loss.
Depressing, then releasing, the brake pedal at a stop sign will raise this to 1400 RPM and then drop it to 900 RPM's when I lift my foot.. I realize that some of this increase is normal because of the engine vacuum draw-down required to actuate the booster.
However the RPM's do not wind back down like they should if I maintain pedal pressure. Only by releasing pedal pressure do the RPM's drop off.
The hose over to the booster is all new and a bench check of the check-valve seems to be fine. Connection clamps have all been upgraded and have been retightened.
Could this problem indicate some air by-passing around or through the diaphram?
I have seen mention on this site that these boosters are known to be very durable and trouble-free. However, this particular SL was slumbering in a Texas warehouse for more than five years before returning to service very recently. I suspect the old rubber is beginning to deteriorate and is gaining some porosity.
- - -Ideas from someone who has been here?
Thanks in advance, Larry in CA
