2003 disco II - 4.6L.

I had the entire brake system (minus the master cylinder) replaced last February (calipers, pads, rotors, lines - front and back). Brakes were
working fine up until today. Noticed that it is now pulling slightly to left side when brakes are applied. Pedal feels soft now. Pumping has
not much difference. I can stop...but not confidently.

So, I'm thinking a sticking brake piston in one of the calipers on the passenger side?

Note that the fluid level in the reservoir was down a bit...topped it off to max line. Not seeing any brake fluid on the ground or on any of the
brake calipers. No SES lights/ABS etc on dash.

Next steps??

 

Might be! You could put that theory to the test with an infrared heat-sensing gun. Rotor temperatures should be within close range of each other after a modest drive around a few blocks. But a sticking caliper would make the rotor too hot to touch. Your issue may be elsewhere though, in steering linkages (left inner or outer tie rod?), lower ball joint.... the whole long list!













but a

 

Also a slightly dirty or wet brake pad, will grab (even slightly wet with oil, if very wet it will do the opposite). This doesn’t answer your soft pedal though.

 

I checked the calipers the day before and they were dry, no visible sign of brake fluid or oil on them. I'll be dropping it off at the mechanic
who installed the lines, pads & rotors on wed. hopefully, it's something simple and not expensive.

Reading on others posting with soft mushy pedal...noticed to check the vacuum line to the intake. On my rig, the vacuum line going into
the intake is a solid plastic line. On the intake where it inserts there is no black piece in front of the red flange that you have to depress
to remove the hose. I wonder if this is causing a vacuum leak... See the pic below. Came across another thread where a guy figured
out how to resolve removing the original one and putting a new one in. That black pieces on the outer side is for installation so you
don't distort the red piece during install.

 

update...took the brakes apart, cleaned and relubed everthing good. the passenger side anti-rattle spring on top of the pad was not in its correct down position.
this caused a groove to be worn on the top of one of the pads. I replaced them. bled the front brakes and now have working brakes again.

go figure.

 

when testing the braking at each wheel and subsequent release of the pedal ...testing to make sure each wheel was letting the fluid correctly back to the
line...I noticed the the back brakes are not completely locking the wheel when the pedal is pressed. Is this normal/typical?

 

Problem was a loose flexible brake line to the caliper on passenger wheel. Noticed it was dripping still after bleeding. This was letting air into the system.

Snug it up, rebled that wheel good and how working like it should.

 

Good news.