air hissing noise from brake pedal

[jbuds690]

So my 87 4.0 has always made this noise when you step on the brakes like it was pushing air out but now today after fixing the water pump and power steering I can hear it constantly. Not loud but enough. Just curious if this is normal for all yall too or maybe yall can point me to what's going on

[Fernando87mj]

It could be your brake booster going bad .

[onlyinajeep726]

Diaphragm in the booster is likely going bad.  If you determine this is in fact the case, it would be a good time to upgrade to the '95/'96 XJ dual-diaphragm booster and master cylinder.  100% better braking power, a worthy upgrade.

[cruiser54]

Diaphragm in the booster is likely going bad.  If you determine this is in fact the case, it would be a good time to upgrade to the '95/'96 XJ dual-diaphragm booster and master cylinder.  100% better braking power, a worthy upgrade.

Or a 99 to 2004 wJ master and booster.

[jbuds690]

Thanks will do