UKC

Ive got a recurring odditiy on our dear old Yaris, Ive replaced the front discs and pads 3 times in the last 3 years. Starts as a mild vibration on braking then gets progressively worse with a loud tapping noise up to the point its hard to hold the steering wheel when braking hard.

All the bolts are tight, the sliders and piston have been greased and the seals are intact. Ive cleaned the hub/flange with a wire brush so the disc sits properly. Ive tried two different brands of discs/pads.

Any other suggestions of what could be causing this?

In reply to ow arm:

Cheap discs(cheap metal) was the problem on mine, if you haven't used them already then buy some new from a main dealer. Also try using your gears to slow down minimising brake usage.

In reply to mwr72:

The ones Ive got on her car now are Brembo ones, I thought they were ok?

In reply to ow arm:
Discs normally only warp if they get very hot due to pads rubbing. This could be due to many things possibly air in the lines, or worn seals in the calipers (the seals are often what returns the piston back to it's starting position and you can't easily check them as the important bit is on the inside).

In reply to ow arm:

Had what sounds like the same problem with my 2000 reg focus. Had the pads and discs replaced about 4 times now, and this time it seems to have worked! Absolutely no idea why the previous 3 attempts resulted in the rubbing sound and steering wheel vibration and not this time. I guess the pads were binding somehow. Think I read on here that the lines providing hydraulic fluid to the brakes can become compromised somehow....

In reply to ow arm: you can get deposits building up on discs from pads if you get pads / discs warm then stand with your foot on the brakes instead of using hand brake.

In reply to ow arm:

Have you actually measured any run out on the discs with a dial indicator gauge?

How are you bedding in your new discs and pads? It they aren't bedded in properly then it is likely that you are getting an uneven buildup of pad deposits as the Llama ^^ suggests

In reply to ow arm:

I had this with an ex's car. Likewise I tried everything, eventually we swapped cars for a month while I tried to figure out what was going on. The 'problem' then happened on my car! Turns out she was covering the brakes 'just in case' with just enough pressure to touch the pads on the discs and get the whole system red hot. Needless to say I didn't come out of it well when I explained that she needed to drive differently

In reply to fraserbarrett:

What's her reversing like. And parking?

# be careful

In reply to andymac:

The rest of her driving was fine, but I appreciate where you're coming from. I know just as many men with bad habits, probably myself included, but this happened to be relevant to the op......

In reply to ow arm:

Toyota brakes (and for all I know other makes, but we just have Toyotas at the mo) seem to be vulnerable to -
1. The cylinders sticking in the calipers (sounds like you've covered this)
2. The calipers sticking on the pins (sounds like you've covered this).
3. The pads sticking in the carriers (clean out the recesses where the pads sit in the caliper with a small file, they're normally full of old dust and copper grease residue, which does not help the pads to release cleanly)
If you've covered point 3 as well then I'm out of ideas. What happens if you jack the front of the car up, hit the brakes, then release them and then try to spin the front wheels? Do they spin freely or can you hear the pads dragging?
Good luck
Paul

In reply to ow arm:
Are you sure it's the brakes? Soft tyres, flatspots, suspension misalignment, soft bushes, worn balljoints or even a tired damper could give you the pulsing wobbly steering wheel sensation.

Do you drive it hard then stop and hold it on the foot brake at junctions?

Also, really stupid question but you're not triggering the ABS are you? What you describe sounds remarkably like how ABS feels. If so I'd look for what's causing it to break traction so easily, probably tyres or dampers.

jk

In reply to ow arm:

Mrs RR's car suffers from rusted and juddering brakes especially in winter because she simply doesn't use the brakes hard enough. There has to be a molecular change to the metal on the surface of the discs before they work at their best and hers are never getting hot enough. Sitting with your foot on the brake won't help as it will cause uneven cooling.