Hello. I replaced my front break pads 2 weeks back then all of asudden it starts pulling to the left hard when the brakes are pressed. I figured a caliper was sticking or hose was bad so I replaced both calipers and hoses on both sides, then bled them. It still pulls to the left with the new parts and replace the calipers on the left side because it's making a thumping noise but with the new caliper it still has it. Anybody ran into this problem for why is it pulling left? Do I need to reset the portion valve? Need help. Thanks

 

Does it pull to the left only while you're stepping on the brake, or does it continue to pull even after you let off the brake? A sticking caliper usually pulls for a while after you release the brake.

Jack up the left front wheel and turn it by hand to see if it turns freely. Also see what happens if you have a helper step on the brake while you're turning the wheel. If anything is binding, it should be apparent this way.

If the left side seems normal, you may have some air in the line going to the right side. It's a much longer line, so you might need to bleed it another time or two. The proportioning vavle shouldn't be causing this, it detects pressure variations between front and rear only.

 

could be a defective set of pads, for the He11 of it try swapping pads side to side and see if anything changes

 

I did swap pads and it still pulls left. If I start it cold it does not pull but as i drive it it starts getting worse and worse as it heats up. Figured it was the pads but when swapped still went the same direction. I did jack it up and spun both wheels they were free. Hit the brakes stops shows to be good and working properly. I have bled it 3 times and still pulls left for some reason.

 

About the only thing you haven't changed are the rotors....are they clean of grease and non-worn on both sides?

 

So, when running cold you step on the brake and it works fine, but as you drive longer it begins to pull left when you brake?

That sounds like the right side caliper piston sticking and causing the pads to drag slightly. As you drive longer the friction causes it to fade, thereby losing braking power. I know you said you replaced both calipers after this started.

I think there may be another way to troubleshoot this. Do you have an infrared thermometer, you know the ones you point-and-shoot to get the tempurature of a surface? Get your hands on one (they're very useful), and try taking a reading on your rotors after driving a while. If one side is signicantly hotter, you'll know you've got pads dragging on that one and you can focus on that side. If they're the same, it's probably something to do with line pressure.

That thumping noise you mentioned, did you find a cause?

 

back brakes OK? Could be an issue back there acting like a rudder on a sailboat...

 

I did turn the rotors when I changed my pads and they looked fine. I have not figured out what the thumping noise is still looking nothing on the front end seems loose to cause this noise. It only happens when the brakes applied them released under 20 MPh.