I drive a 2013 Ford Figo. I hear a faint thumping noise from the back wheel on the drivers' side when I brake (at least I am fairly certain that's where the sound comes from). The sound is not repetitive, just a single thump. I have noticed that it happens more often when I brake at a low speed and also only when I've driven for a while. It only happens when I apply the brake, but not when the car is in reverse. I do not feel a shudder from the pedal when it happens. I thought that it might have something to do with the new brake pads I had installed, but it was installed in the front and the sound only started about a month after it was installed. Any ideas? I had this checked out at two auto repair shops, but they cannot pin-point the cause.
I've had these symptoms on my car as well. In my case the rubber parts of the "support arm(?)" was worn. I don't know if the translation of the word I'm using is correct, but it should look like (any of) this:
The Audi dealer said the repair would cost ~600 euro for replacing all four. I bought the parts (4 pieces total) for roughly 15 euro each and replaced them myself, so you can definitely do it as well if you like to get messy.
Again, I'm not 100% sure it's this, but considering the symptoms match, and it's a fairly cheap fix, check it out!
Does it happen again each time you apply the brakes, even if done so repetitively? If so, it's likely that some bushing in the suspension has been worn, or fallen out completely.
Since you suspect the noise coming from the back of the car, here's what you can do to pinpoint the location of the problem better. Apply the parkingbrake, but leave the gearbox is in neutral, and the engine off. Then someone else can push the car, rocking it back and forth with the parking brake applied, to see if this replicates the noise.(it may appear weaker this way though) Meanwhile, you can look under the car to see if any bushing shows signs of wear. Grab each suspension link and try to wiggle it, this may require some force. This way, you can feel if any joint in the links is loose, and subject it to further observation. Make sure you've watched all joints while the car is being rocked back and forth. Any metal to metal contact/sound is sign of a bad link.
If nothing seems out of the ordinary, move to the brakes. A caliper may have play, causing the thumphing sound. Put the car on jack stands and remove the wheels. Reapply the parking brake and try to move the brake discs/drums, to see if the sound is replicated. If so, try and wiggle the caliper. With the parking brake applied, there should be near to none. Only some tiny rotational play can be tolerated, caused by the brakepads' play with their holder.
See if anything obvious can be seen here. The caliper design is likely that of a floating caliper, which means the caliper can slide over two pins, sideways ie. parallel to the vehicle's rear axle. If there is any more play or movement possible, there's an issue with the caliper or its mount(s).
If no sound is replicated, have someone sit in the car pushing the foot brake, now with the parking brake released, and the transmission in neutral. Repeat the rocking back and forth process to see if any sound appears. If so, same procedure as above applies.
Any link with a weak or bad joint should be replaced. Depending on the link, it can wise to replace both links, if it has a symetrical counterpart on the other side of the vehicle. Update the post if you found any.