Hey there, I'm having a little trouble with my XJ.

Basically when I go from parked and ignition off, to reverse I have extremely soft brakes, as in brake pedal has almost no resistance and is barely effective at full deflection. It has happened the last three times in this situation.

When I go from drive to reverse i don't get the trouble, if I go from parked/ignition off to drive I don't have any trouble. It is a new thing that has developed the last couple of days.

I don't know a whole lot about the brake system so any troubleshooting advice you can offer would be greatly appreciated!

If any of this stuff helps

2000 XJ with the 4.0L and 4WD
3" lift
31" M/T tires
K&N cold air (really doubt this will effect the brake system in any way, but if you wanna get creative go ahead)

Update, Maybe this makes it easier, after living with this issue a little while I have noticed it can happen in drive but less frequently, but always happens at very low speed ie. maneuvering in the garage, or in an out of a parking spot...?

 

any lines or wheel cylinders leaking. Vaccum leak?

 

Probably should have clarified this, the part that has me so confused is my brake fluid is showing slightly low, I'm going to drain and fill it tomorrow and see what happens. No noticeable leaks though, it's garage parked so if anything was leaking enough to drip on the ground I would know about it, and there is no evidence of a leak near any of the visible parts of the brake lines and no evidence of leaking around the vacuum pump.. I'm not very familiar with a the brake system so I suck at figuring this out.

I'm super busy right now so I'll probably just drop her off at a shop and let them do their damage on my wallet, whatever the issue is I have determined I don't have time to fix, and it's my daily driver so I don't really have time for a slow repair.

Thanks for the response though!

 

re & re brake booster .. leaking diaphragm