Bad Vibrations/Shudder Under Braking

HI All

2.4 Tourer Auto (2004 vintage)

Now before everyone auto defaults to discs this is what I have done so far:

TRW Discs/Pads all round around March 2017, both new rear calipers (old ones had seized) at the same time. Everything was fine until a few months ago when I started to notice vibrations under braking, progressively got worse and now shakes the whole front end. All the hub faces and mating faces when I did the brake job were spotlessly cleaned so everything is sitting on a good surface (disc to hub, wheel to disc).

I have been under the car and crow barred all the mounts and bushes front & rear, all seem solid to me. Replaced both front wishbones complete as front bushes were deteriorated and I thought this could be the cause, no change.

Taken apart front brakes, verified front caliper pistons is sliding in and out smooth and the front pins are not seized, cleaned everything again and re-fitted.
Taken apart rear brakes, verified rear caliper pistons are sliding in and out smooth and all slider pins are not seized, cleaned everything again and re-fitted.

Brakes bled.

Front & Rear wheel balancing is done and no issues with wheels or tyres (16").
Wheel alignment is fine.

Disc runout with DTI:
Both front= 0.02mm
Both rear= 0.04mm
Service limit= 0.1mm

Checked all wheel bearings for roughness and play, nothing found.

Checked Tie rod ends, ball joints, drop links (replaced during wishbone replacement), coil springs.

None of the shocks are leaking or showing any signs of failure.

All CV joints feel fine at the front.

I am at a loss and its doing my head in. Car drives smooth and in a straight line, no vibrations on normal driving at high speeds whatsoever. As soon as I touch the brakes the front shakes/shudders pretty bad. Feels like whole front end and steering wheel all at the same time. Braking from 70mph feels like my teeth are going to fall out, its bad enough that I see distortion on the speedo needle like its out of focus. Braking from about 40mph you can visibly see the steering wheel wobble side to side about 5mm defection. I would have thought something worn this bad I would see it when poking around with a crow bar.

Any ideas? anything else common on these on the front end that can wear and cause my symptoms? My brain is going toward a balancing problem on the front discs even though the runout seems fine could they just be out of balance already?
Typically if anyone verbally talked to me about a problem like this I would say front discs if it only happens when pressing the brake pedal and no other signs of a seized caliper/pins but I've checked it all and this is where I am.

Thanks for input.

Have you swapped tyres around?
Bad tyres can produce symptoms like that.
Try another set if possible.

Have you checked for sticking calipers!

f2raf said:

Have you checked for sticking calipers!

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See original post, yes.

Bounder said:

Have you swapped tyres around?
Bad tyres can produce symptoms like that.
Try another set if possible.

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Rears - Bridgestone
Fronts - New Avons

My regular tyre fitter found no issues with the tyres or balancing.

If tyres/wheel problem would I not expect to see vibration regardless of touching the brakes? its smooth as silk otherwise.

I used TRW rear discs and was unimpressed. They didn't look/feel well made to me when I fitted them, were corroding within weeks during mid-summer, and so badly scored after a year that I replaced them. They weren't cheap to buy either.

The best I've used are Unipart, ATE and genuine.

Not saying it is or isn't the disks and pads in your case - just recounting my own experience of TRW.

Bad tyres can manifest themselves under load transfer, swap back to front and see if the problem remains.

Bounder said:

Bad tyres can manifest themselves under load transfer, swap back to front and see if the problem remains.

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OK will do. Not to discount your suggestion as I appreciate it but I have been over the tyres a few times and couldn't relate the issue to them but to eliminate this I will do it later.

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Cliffordski said:

I used TRW rear discs and was unimpressed. They didn't look/feel well made to me when I fitted them, were corroding within weeks during mid-summer, and so badly scored after a year that I replaced them. They weren't cheap to buy either.

The best I've used are Unipart, ATE and genuine.

Not saying it is or isn't the disks and pads in your case - just recounting my own experience of TRW.

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Hi, I have the black coated ones, high carbon to reduce noise. They seemed good quality out of the box. Have not rusted. I did notice the NSR developed a scour mark in the centre of the disc I took it apart and cleaned it, this was before I had these problems. I put it down to all the crap we had in our terrible roads over winter.

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One other thing is where your discs have a build up of pad material on the surface, the pads grip and slip causing vibration, Skimming the discs or replacing them is the only real fix for that.
braking heavily and holding the pads on the disc can cause this.
I am running TRW on the rear of mine and have no problems and have a set of TRW for the front ready to fit as well.

Check for play in your drive shafts.
Alignment is out or maybe one or more tyres are out of balance

brett said:

Check for play in your drive shafts.
Alignment is out or maybe one or more tyres are out of balance

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Been through this in original post. Tyres out of balance I know from my own experience is felt regardless of brake application. alignment is fine. Thanks.

Bounder said:

One other thing is where your discs have a build up of pad material on the surface, the pads grip and slip causing vibration, Skimming the discs or replacing them is the only real fix for that.
braking heavily and holding the pads on the disc can cause this.
I am running TRW on the rear of mine and have no problems and have a set of TRW for the front ready to fit as well.

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This crossed my mind regarding build up of pad material although I would have expected the DTI to pick that up. I do get a grip and slip sensation when applying the brakes at low and moderate speeds. I wasn't sure how to explain it but grip and slip makes sense.

Long shot: Is the ABS cutting in for no good reason (like it's faulty)?

Matt said:

Long shot: Is the ABS cutting in for no good reason (like it's faulty)?

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Hi Matt, I can confirm its not the ABS. My experience of ABS activating is the sensation felt in the pedal as the modulator pumps and I do not feel that. I tested the ABS when we had a bit of snow and could feel the ABS distinctly different feeling.

Bounder said:

Bad tyres can manifest themselves under load transfer, swap back to front and see if the problem remains.

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Wheels swapped front/back. No difference.
Investigating replacement discs/pads now. It's the only thing left that I can think of.

Its good to eliminate all possible sources of issues, glad that its not the wheels/tyres anyway that makes it cheaper.
Can you get the discs skimmed or would you just buy new ones?
I'd be inclined to go ATE discs as recommended. I have a set of TRW front pads and discs to fit to mine and wonder if its worth fitting them?
I have TRW discs and Bosch pads on the rear and they are fine no problems with them at all apart from the Bosch being very dusty.

Bounder said:

Its good to eliminate all possible sources of issues, glad that its not the wheels/tyres anyway that makes it cheaper.
Can you get the discs skimmed or would you just buy new ones?
I'd be inclined to go ATE discs as recommended. I have a set of TRW front pads and discs to fit to mine and wonder if its worth fitting them?
I have TRW discs and Bosch pads on the rear and they are fine no problems with them at all apart from the Bosch being very dusty.

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Well just got back from a short gingerly drive after fitting new Jurid Coated discs and Bendix pads, I had one of those stonking GSF codes so got the set for £80.
Problem seems to have disappeared although I need to give it some miles before I do any heavy braking.

Very surprised by this as runout was well within spec. Only thing I can think of is the discs have gone out of balance. Couldn't see any evidence of pad material transfer. I wish I new a shop that could put these on a machine and check them for balancing and have them re-surfaced too but I don't, if anyone knows a shop in the South do let me know.

Disappointed with TRW at this point. Mine is an Auto and I would expect the brakes to work harder on the Auto due the the nature of operation for the Auto box. I wonder if the extra heat generated on the Auto variant causes some brands a problem.

I am very careful after fitting new brake components and not one of those who go crazy on the pedal right after fitting new discs/pads so I would rule out abuse on the TRW set causing them to go bad.

Was the old disks drilled and or grooved ?

simpo said:

Was the old disks drilled and or grooved ?

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Nope, TRW don't do drilled or grooved options for the Accord, that I could find anyway.

200miles+ no issues returned. Replaced the rears a few days later due to the disappointment with TRW. Put EBC disc/pad kit on the rear. Overall braking feel and performance has drastically improved over the TRW.