crazy rpm
07-30-2013, 01:18 AM
#16
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Model: Cherokee
Might be a good time to upgrade to the newer style double diaphragm booster:
http://www.jpmagazine.com/techarticl...stem_upgrades/
Upgrade video:
To replace the booster with an exact replacement (not upgrade):
Remove the 2 bolts holding the master cylinder on and carefully set the M/C aside just a bit.
Next remove the vacuum hose from the booster and move it out of the way.
Next disconnect the brake linkage that attaches to the brake pedal by pulling the retaining clip.
Next remove the 4 bolts holding the booster to the firewall. They're on the inside too.
Remove booster.
Install new booster.
Install 4 retaining nuts.
Re-attach brake pedal linkage.
Compare the length of the booster push rod between the new booster and the old. It's the rod that pushes into the master cylinder. They should be exactly the same, if not your pedal travel won't be right. The rod is adjustable if need be.
Install master cylinder, tighten 2 retaining nuts. If there was a gasket between the master cyl and the old booster- replace it. Some have it, some don't.
Install vacuum line.
http://www.jpmagazine.com/techarticl...stem_upgrades/
Upgrade video:
To replace the booster with an exact replacement (not upgrade):
Remove the 2 bolts holding the master cylinder on and carefully set the M/C aside just a bit.
Next remove the vacuum hose from the booster and move it out of the way.
Next disconnect the brake linkage that attaches to the brake pedal by pulling the retaining clip.
Next remove the 4 bolts holding the booster to the firewall. They're on the inside too.
Remove booster.
Install new booster.
Install 4 retaining nuts.
Re-attach brake pedal linkage.
Compare the length of the booster push rod between the new booster and the old. It's the rod that pushes into the master cylinder. They should be exactly the same, if not your pedal travel won't be right. The rod is adjustable if need be.
Install master cylinder, tighten 2 retaining nuts. If there was a gasket between the master cyl and the old booster- replace it. Some have it, some don't.
Install vacuum line.
07-30-2013, 07:17 PM
#20
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
09-25-2013, 09:52 AM
#21
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Hello guys, i finally got around to replacing the brake booster yesterday and i still have the same issue 
I have no idea what to do next. Do you guys have any more ideas of what this could be?
I have no idea what to do next. Do you guys have any more ideas of what this could be?
09-26-2013, 04:42 PM
#25
CF Veteran
O2 SENSOR.
TransmissionControlUnit uses it to determine shift points, EmissionsControlUnit uses it to adjust fuel/air ratio. I'd hate to see you keep throwing parts at it but I'm pretty confident its your O2 sensor.
TransmissionControlUnit uses it to determine shift points, EmissionsControlUnit uses it to adjust fuel/air ratio. I'd hate to see you keep throwing parts at it but I'm pretty confident its your O2 sensor.
09-26-2013, 05:07 PM
#26
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Year: 1990
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Are you on crack? O2 sensor has nothing to do with shift points or high idle.
09-27-2013, 10:19 AM
#29
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09-27-2013, 10:21 AM
#30
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