Spongy / Shuddering brake pedal when braking whilst turning left only

[onemanonelaptop]

I have a curious problem in that my brake pedal goes soft and shudders while braking but only if i am going slow and braking whilst turning to the left. This usually occurs when i am pulling up to a junction to turn left. The pedal goes soft, shudders a bit then resolves itself.

Has anyone experienced anything like this, the fact that it only happens with the wheels straight or to the left seems to imply that there is something mechanical getting pressed,squeeed or pinched but this is pure speculation on my part.

Any ideas where to start diagnosing this?

 

[C420sailor]

I’ve been dealing with the same for the last few years. Doesn’t always happen, but it’s with the steering near full lock, slow, like turning into a parking space. Pedal depresses further, almost feels like light ABS activation. Very odd, haven’t figured it out yet.

 

[koda2000]

Bad wheel bearing? I had a similar problem on one of my vehicles. It turned out a front wheel bearing was trashed and it also ruined the spindle. The rotor flopping around would push the brake pads out and I'd get a low/spongy feeling pedal until the pads would push back into place.

 

[J_C]

I'm wondering if you have the beginning of an ABS problem and I'd pull the ABS fuse to see if it goes away. If it does then I'd hook up a scan tool capable of showing the speed sensor data to see if one of the front wheel sensors is failing. Since it is turning left, I'd guess the left wheel.

If it turns out to be the wheel sensor, then I'd wonder if the hub is failing, especially if it's the original hub?

 

[donalds]

That's how I fixed mine using forscan
You can see the sensor just drop off while the others were fine at slow speeds only

 

[rasouth]

I had kind of the same problem in a 1978 Fiat convertible I had. Turned out I had a small leak in the brake booster. Something to do with the vacuum pressure at lower RPMs. May not be the same in the newer cars.

 

[koda2000]

OP - As suggested, pull the ABS fuse to remove the ABS system from the equation. If the problem is still there start looking for a mechanical issue.