1988 Jeep Wrangler brake repiar

1988 JEEP WRANGLER
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DGERO5311
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Brakes problem
1988 Jeep Wrangler Engine Size unknown Wheel Drive Type unknown Automatic unknow miles
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My grandson was given a jeep with brake problems
He has been advised to replace BOTH the master cylinder AND,power booster.
Why both?
How often does a power booster go bad? (I've never heard of it in my 59+ years!)
Shouldn't he replace one at a time - master cylinder first because it is easier?
Dec 22, 2007 at 2:00 PM
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MHPAUTOS
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Hi there,

To check the booster operation, do this.

with engine off, pump brakes untill pedal is hard (no Vacuum) with foot on brakes start engine, pedal should suck down a little, this is normal, if the pedal is hard with engine running or you can hear a hiss when idling or brakes are applied booster is leaking vacuum. if no noise and brakes are hard check vacuum check vale is not blocked. These are the basic tests for booster operation, your mechanic should know these tests, if not move on to someone who can help you.

Mark (mhpautos)
Dec 22, 2007 at 6:45 PM