Pagoda SL Group
W113 Pagoda SL Group => General Discussion => Topic started by: lurtch on March 24, 2006, 18:23:53
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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
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quote:
Originally posted by lurtch
Could this problem indicate some air by-passing around or through the diaphram?
Yes
quote:
Originally posted by lurtch
I have seen mention on this site that these boosters are known to be very durable and trouble-free.
Larry,
My 1966 230SL still had it's factory original booster when I bought the car in 2000. It needed replaced, so I don't know how many years it really lasted. The car still stopped, but it stopped MUCH better after the booster replacement.
Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both tops
1994 E420