Shaking while braking at 60+ *Fixed*

[Me9141]

Thought I'd post this up to get a second opinion.

I'm getting shaking while braking usually at 60mph+ the faster the more violent the shake. Its through the steering wheel only. I cant feel any fedback under the pedal but I can feel where the pads are getting more grip.

They are Pagid discs and pads, done 2.5k miles on them, put them on last April.

Changed the rear discs and pads as there were worse for wear and re-balanced the wheels.

Technician has put a dial test and he reports a 0.8mm difference in the discs on both sides. He says this shouldn't cause the shaking.

Before I go ahead and change the brakes wondering if anyone else has had the same experience, could it be the steering rack, ABS pump or something else?

Any help greatly appreciated.

[Bepis]

My bet is on warped front discs although there is only 0.8mm run out it may be just enough to feel at higher speeds as you mention usually 60mph+ but maybe also getting the wheel balance on front checked wouldn't be a bad idea as you haven't put a lot of miles on the brakes. If it was the ABS pump you would hear it turn on with the audible judder of the brakes pulsing. I am also getting strange behavior from my brakes which are also pagid discs and pads front, shoes and drums rear, where the braking force seems to peak and then stall at around halfway through the pedal but the force stays consistent. New DOT 5.1 fluid with around 1K miles.

[littlepolo]

0.8mm is quite a run out on a single disk rotor. I'd say that would be enough to cause vibration at speed. I fitted Febi brake discs and never had a problem with them warping. However, I did have a problem with binding brakes (changed the calipers and slide pins) and that could cause overheating and warping, I guess.

[RUM4MO]

My older daughter's late 2009 SEAT Ibiza 1.4 SC with rear drums, starting doing that, maybe only 5K miles after I had replaced the front discs with Pagid and Pagid pads, the previous discs got replaced because they had started to look a bit rusty and were close to the wear limit.

This might have started soon after she fitted a set of all season tyres, so she got all the wheels rebalanced but not a complete cure, I never experienced this so I don't know if there really was an improvement or she just chose to consider there was as the wheels got rebalanced.

Next I swopped the front wheels for the rears, again still the same issue under certain conditions which always included heavy braking from over 60MPH - again I could never replicate this issue.

So, I replaced the discs and pads again with same parts, as usual from ECP, I think just to appear appreciative of my work she said that there was an improvement - but that issue still existed.

So, when she was away abroad on holiday, I checked disc run out which was very minimal, also compared that with hub run out and alloy wheel rim, both inner and outer run out, from doing that I discovered that one wheel was slightly "out" but it was now on the rear.

Next I replaced both track rods and track rod ends, both inner sockets were very slightly worn, mileage by this time was 60K miles, and as one of the rear dampers was extremely rusty, I replaced both of them.

End result was it was still slightly an issue under heavy braking from above 60MPH, so I suggested that she adjusted her driving to avoid needing to do that as I had reached the end of guessing what the root cause was, it could have been that these Kleber Quadraxer tyres were the issue, but proving that was not going to be easy as they were bought from Germany as UK do not cover that size of all season tyres. My last option was to swop her wheels for the wheels from my wife's 2015 Polo, but I was reluctant to do that as it might take a week or more for her to be able to see if that fixed it - and then what!

As that car was, in my mind, coming to the age that it should get replaced as it was now almost 10 years old and I was not really willing to continue working on it for her, she agreed and replaced it with a new SEAT Leon Cupra and sold the Ibiza to a trader - so that sorted that issue out for us!

I had never ever considered that it would take more than replacing the front discs to sort this out, I've had (or wife had) a 2002 Polo 1.4 16V 75PS that ended up with an advisory at MOT time for worn inner joint in the track rods, but that car never ever exhibited any braking issues while having that issue - I did replace both tracks rods soon after that MOT though.

Sorry to be so negative about what normally is a simple problem to fix, maybe consider that you have a wheel and/or a tyre issue causing this - or don't quite yet rule that out.

[Me9141]

Just an update to this:

Replaced the front discs and pads. Solved the issue. No more judder and I cant feel the on/off bite on the brakes when pressing the brake pedal.

To confirm, before posting on here, I had already balanced the wheels and new rear discs and pads were fitted. Also in the last few years the rear calipers were changed, brake fluid changed, front hubs changed, front shocks/springs changed, drop links changed as per wear and tear.

[littlepolo]

Good to hear that you solved the problem. Probably warped discs before. Any idea of the cause?

What brand of discs and pads did you fit this time?

[RUM4MO]

Good outcome, just the normal and expected root cause - lucky you!

[Me9141]

No idea of cause, I can only think my brother may have been driving it hard.

Replaced with Brem Tech.