2001 Ranger - brake pedal goes soft only when sharply turning left


#1

I have a 2001 Ford Ranger 4x4 that developed an odd problem almost two years ago that no mechanic I’ve taken it to has been able to find and fix, and I and my more car-savvy friends haven’t had any luck with either.

About maybe 50% of the time when I sharply turn left (only left, never right) the brake pedal goes “soft” and the vehicle’s braking power drops dramatically (but not entirely). Because of the sharp angle required to make this happen, and the low speeds I have to be moving at to even handle that sharp of a turn with this vehicle, this has only ever happened when I pull into a parking spot, and the vehicle still manages to come to a complete stop safely before being in danger of hitting anything. It never ever happens at any other time, and brakes like a champ normally.

I’ve had numerous other issues with the brakes in this vehicle in the last two years, all of which I’ve fixed. This one eludes me and every mechanic I’ve taken it to, though. I’ve replaced both calipers, both rotors, the brake pads, bled all four brake lines, and had the ABS control unit and ABS motor replaced.

At the time the issue first appeared, I had two damaged calipers caused by shoddy brake pads disintegrating on me (almost new, barely worn, but covered in pockmarks, looked like a Michigan road) and clogging up the calipers. That caused the vehicle to lurch to a halt with screeching tires if I so much as barely tapped the brake pedal. Replacing the calipers and brake pads fixed that issue, but did not fix the soft pedal issue when turning left. I ended up with the same screeching sudden stop problem recently when the ABS module went bad, replacing it fixed that, the brake pads and calipers are still in good condition, and replacing the ABS did not fix the soft pedal issue.

I’m literally out of ideas and no mechanic so far has managed to help me with this. Any suggestions at what else could be the cause would be most highly appreciated. Thanks!


#2

A wheel bearing issue can cause this. If a wheel bearing is loose, turning left can put additional stress on it, causing the hub to cock, spreading the brake pads and causing a soft brake pedal due to the extra piston travel needed to compress the pads into the rotors. If this were the case, I would think someone would have found it by now as a bad wheel bearing is usually hard to miss.


#3

The problem might be with the brake hose going to the left front caliper. During a sharp left turn that hose is being stretched while at the same time asked to articulate with the brake caliper as the vehicle turned sharp left. If inner hydraulic part of the hose has developed minute cracks and these cracks open up when the hose is put under this condition, the hydraulic pressure will go to outer jacket of the hose. The outer jacket of the hose will then swell from the hydraulic pressure and the brake pedal sinks during a sharp left turn.

To check for this, take a pair of hose-pinch-off pliers and pinch off the left caliper brake hose up by the steel brake line to isolate that hose from the brake system. Now take the vehicle for a test drive. Now you won’t have left front brake caliper function, but if you can take a sharp left turn without the brake pedal sinking, that hose is probably causing the problem.

Tester


#4

check all axle hubs and bearings. even the rear axles. sounds like you might have excessive axial runout. the best way to check them is with the calipers and rotors off. move the axles in and out, there should be very little movement. you can consult the service manual for spects.