Steering wheel rotates to the left when braking moderately.

[DaveVoorhis]

1999 Colorado VX LWB diesel, approx 200k miles but well maintained and in excellent condition. Weird problem: When braking moderately, the steering wheel turns to the left. If I hold the wheel and prevent it from turning, the vehicle turns slightly to the right. If I let go of the wheel whilst braking moderately, the vehicle tracks perfectly straight but the steering wheel turns 20 - 30 degrees to the left. This only happens when braking moderately. It doesn't occur if I brake softly or hard.

Both lower ball joints and tie rods (both ends) have been replaced, and the steering rack bushings have been replaced. Tracking has been set on an alignment machine. Wheel bearings are good.

Either a sticky caliper or a failed lower control arm bushing sound like possibilities, but the fact that the vehicle tracks straight when braking suggests it's something else. But what?

I'm stumped. Any ideas?

 

[Bob]

My bet would be the calliper. They can stick intermittently and the imbalance may only show up in moderate braking.

 

[silvercruiser]

yep my guess would be sticky right hand caliper

 

[DaveVoorhis]

Thanks - I'll check the right hand caliper.

 

[clivehorridge]

Best buy a kit (or a replacement) and have the caliper apart. The cylinders stick but it's hard to realize sometimes. They can be forced back in with a lever, but if one side is stickier than the other, you'll get imbalance.

Best to do both sides, complete re-build, then you know they're even.

 

[fildigger]

As above ^^^^^

Had all sorts of woes when i purchased mine, ended up with new discs calipers all round to save all the stripping and rebuilding on the original units...with the four pot opposed fronts, by the time you've bough the pistons/seals/dust covers and rebuilt you may as well get a new/re-furbished calipers at around £100 ea'

Good luck.

ps. i didn't need new front discs but with Milners doing them at around £35 all-in for a pair of fronts it was prudent to fit them while doing the job!