Thread: Rotor removal
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Old April 14th 05, 03:14 AM
BDragon
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"WayneC" > wrote in message
...
> I don't know a way to test it directly (although there may be a way),
> nor can I remember how that problem was diagnosed when I had it about 15
> years ago (I may have just had the booster rebuilt on blind faith at the
> time).
>
> Here's the way I understand the booster...
>
> The booster stores vaccuum on both sides of it's large internal
> diaphragm as you drive... the one-way external check valve (that the
> large vaccuum hose connects to) keeps vaccuum in the booster; there is
> another, internal, valve that relieves vaccuum (allows air to enter) on
> the pedal side of the booster when the pedal is pushed, thus using
> ambient air pressure to assist you with the pedal effort. I'm not
> certain, but there is probably another internal check valve that keeps
> ambient air pressure from reaching the master cylinder side of the
> diaphragm from the pedal side. If one of those internal valves
> fails/sticks, or if air somehow leaks in only on the pedal side of the
> booster diaphragm, or if the vaccuum can't easily reach the pedal side
> of the diaphragm, the pedal stays very hard near the top of it's travel
> and the brakes drag until the pressure equalizes... so a pedal that
> seems to get significantly harder (very little movement needed to feel a
> hard pedal) after you drive awhile migh be a clue. The brakes stay
> applied for awhile after you stop because the booster vaccuum bleeds off
> very slowly after the engine is stopped. Since the rear brakes are
> designed to apply first, they are the ones that drag and heat up.
> Possibly if the check valve on the outside of the booster were removed
> from the booster while the car is running and is experiencing the
> problem, the car will then roll easily (but I'm not sure that's a
> prudent thing to try). If the problem is the emergency brake, I would
> think that while you are having the problem, the emergency brake handle
> may manually apply with a lot less effort through it's travel than it
> normally would, ie, it will feel loose until it gets to the very end of
> it's travel.
>
> wrote:
> > Any suggestion son how to tell if it is the power booster?
> >
> >
> > "WayneC" > wrote in message
> > ...
> >
> wrote:
> >>
> >>>Hi Bob,
> >>>
> >>>Wow! Thanks for the quick response!
> >>>I should have been more specific but I'm sure your information is

correct
> >>>anyway.
> >>>
> >>>I am trying to remiove the rear rotors to get to the emergency brake
> >>>parts. I think they are dragging (cables are loose) and causing
> >>>overheating and therefore I get rear lockup after a few miles of

driving.
> >>>After things cool down the car rolls easily by hand.
> >>>
> >>>I can see someone has tried to drill out what appears to be large

rivits
> >>>or screws but without success. Some are drilled off-center and deeper
> >>>than others. They are big rivits if that is what they are, probably
> >>>3/8". Does this sound right?
> >>>
> >>>Thanks again and I will let you know how I make out.
> > wrote in message
> >>>news:Mlc7e.14884$hB6.1104@trnddc06...
> >>>
> >>>
> >>>>How do I get the rear rotors off my 1978 'vette?! I know it will take
> >>>>some gentle hammering but I don't want to miss something I'm be sorry
> >>>>for. Thanks
> >>>>
> >>>
> >>>
> >>>
> >>BTW, the symptoms you are experiencing can also be caused by a bad power
> >>brake booster.

> >
> >
> >

Pump the pedal a couple of times and hold. If the pedal goes slowly down,
the booster should be okay.

I have a 77 which had never had the rotors removed. I also had no emergency
brake. When the rotors came off, the emergency brake shoes were broken in
half and all the parts and springs were powder. Put new gear in, and like a
putz, I forgot to adjust the emergency brake. Now I'm trying to find out if
that can be done without removing the rotors again.


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