Warped Porsche discs? Opinions pls

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Lovegroover

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O.K lets start with the fault.
Under braking from speeds only above 35mph I am getting shaking through the steering. This is not everytime I use the brakes and it varies in it's violence. Sometimes there is no fault but 80% of the time some shaking of varying ferocity is noticeable mainly through the steering, it's bearably noticeable through the pedal most of the time although sometimes there is a slight pulsing feel. There is never a shake under 30mph, and sometimes no shake atall even when stopping from 80+mph???

I have recently fitted brand new Discs and pads upfront which on mine is a Porka 993 TT 'Big red conversion' so not cheap (about 3000 miles ago). I'm not a track or street racer and due to the capacity of these brakes find it hard to believe i could've warped them? Especially seeings the ones I took off were cracked (previous owner) and delaminating and still gave no shake.

I've been under the car and checked how they're wearing and all looks good the state of the discs is good with no grooving etc and i've checked all caliper bolts etc are tight. All ball joints and bushes seem in good nick, with the only suspect rubber possibly being a slightly perished but not broken rubber mount for the control arm, this didn’t seem to give any excessive play though. However a noticeable bit of play was found in the steering arm where it enters the power steering box! I understand from searching this can be removed by an adjustment on the PAS box, which is on my list of things to do at the weekend.

Basically I’m convinced by the feel it’s a steering issue rather than brakes! (and due to it's inconsitentcy) But wanted to pick your brains so whilst I’m under there I can look for any other possible culprits, before I bite the bullet and pay to have the disks checked for run out – also where can I get this done presumably most garages will have the facilities to check?
Sorry for the long post and thanks for any input, Joe
 
I'm assuming the discs are 2 piece so did you replace just the rotors on the existing bells? If so were checked to make sure they were 'true' and balanced? I really doubt they're warped, other possibility is a build up of pad residue in one patch on the disc surface, some hard braking from high speed should clear that.
 
Are you running spacers to clear the calipers? and are they hubcentric. The bushes on my lower track arms failed on my S3, and this cause my steering to wobble under braking, I thought it was warped disks at first!
 
I have the same problem and I've convinced myself that its the discs. It seems to happen when braking steadily rather than heavy breaking. I have'nt bit the bullet and bought new discs & pads Maybe its the bushes as JoJo mentioned. I'd also like to know everyones thoughts on this rather than blowing money left right and centre trying to get the problem resolved.
 
I'm not 100% sure how to test the bushes, but the guys at AmD(a few years ago now) showed me that my front wheels had 1" of play on my front wheels, you could see it moving forwards and backwards with the car suspended on the ramp. It was this mocement that was causing the steering wobble under braking.
 
JoJo - so is it a case of getting new tracking arms or is it the wishbones which need replacing?
Cheers for your input
 
Aky said:
JoJo - so is it a case of getting new tracking arms or is it the wishbones which need replacing?
Cheers for your input
Click to expand...

I had both the track arms replaced with facelift items, they are lighter and slightly different shape, but everything lines up was told. Not expensive for the complete arms, something like £25+vat each?, needs 4 wheel allignment after though, so labour isn't your best mate here.
 
I checked for pad residue/build up as i also thought this but only found clean shiney discs!
I do run Spacers and they are hubcentric, i checked and these seemed tight and true in locating into the wheel.
Also yes the discs are two piece, and subsequently replaced the rotors onto the existing bell. Was pretty careful to make sure the nuts were all tight and true but this is a consideration - although for the first 2-3000 miles all was fine. I suppose getting run out checked on the discs would identify this.
I'm sure you can feel its worse braking on bumpy roads which would link to the bushes on the wishbones (which were cracked if i'm honest)!
 
I am also getting shuddering under braking which is also inconsistant but im currently gettin a knocking noise. Ive just been out and checked the shocks, they dont seem to have gone. I also jacked up both sides and put a bar through the alloy to see if there was any play in the top mounts which there doesnt seem to be. If it were my lower arm bushes gone could this cause a knocking noise? The knocking doesnt seem to happen when going over speed bumps etc... more in terms of bumps on the road surface. Best way too hear the noise is too roll down a hill in neutral. The knocking will be a continuous tapping (imagine driving over a load of cats eyes in the centre of the road - just not as harsh). Input would be welcome!
 
audi upgrades
yer im pretty certain I can feeling it through the steering....might have too take her out again in a sec. Just spoke too the audi workshop.... £10 for the bushes or £55 for new complete arms.... after labour charges thats £260ish for the bushes as they have to be pressed in or £270 for new arms.:crying: really dont want to be paying that sort of money. Anyone done the job themselves?
 
if you are into diy car stuff they wont be very hard to do, pressing bushes in is hared than new arms so its how good you are as to how hard the jobs is tbh.

havn`t done the audi but have done hondas and fords in the past for mates.
 
I believe the bushes require approx 10 ton per square inch pressure to force them in, so its mostly cheaper to get new arms
 
I'm doing a complete front-end suspension freshen up on mine in the next 2 weeks, which will involve the following:

New top mounts,
ARB bushes,
ARB drop links,
Lower arms,
Track rod ends

This is something I tend to do on all cars as they pass 40k, it will tighten up the car to how it was from new. I will do a guide for all this and put it on my site.

I will follow this up for the rear when I've finished fabricating some adjustable arms.
 
mwstewart said:
I'm doing a complete front-end suspension freshen up on mine in the next 2 weeks, which will involve the following:

New top mounts,
ARB bushes,
ARB drop links,
Lower arms,
Track rod ends

This is something I tend to do on all cars as they pass 40k, it will tighten up the car to how it was from new. I will do a guide for all this and put it on my site.

I will follow this up for the rear when I've finished fabricating some adjustable arms.
Click to expand...

I did exactly this as my ethos was the the same. However, at 46k, the balljoints were like new etc etc. To cut a long story short all that 'really' needed replacing were the drop links and ARB bushes.

Not a bad thing to do but some things 'may' be a waste of money unless you believe in spending money on placebo effect.
 
Stewart said:
I did exactly this as my ethos was the the same. However, at 46k, the balljoints were like new etc etc. To cut a long story short all that 'really' needed replacing were the drop links and ARB bushes.

Not a bad thing to do but some things 'may' be a waste of money unless you believe in spending money on placebo effect.
Click to expand...

For sure, but my lower arms definitely need replacing, I've not actually had a car yet that didn't need them past 40k. I'm not talking MOT pass here but the point where you can feel the handling 'sharpness' has gone off what it once was. I'm a bit of a perfectionist in that respect.

If the arms are gone then the other components will have wear too, so seeing as the parts themselves aren't expensive, it makes sense to replace everything at the same time.
 
bouncer--daz said:
yer im pretty certain I can feeling it through the steering....might have too take her out again in a sec. Just spoke too the audi workshop.... £10 for the bushes or £55 for new complete arms.... after labour charges thats £260ish for the bushes as they have to be pressed in or £270 for new arms.:crying: really dont want to be paying that sort of money. Anyone done the job themselves?
Click to expand...

AmD told me the prices would be similar for just the bushes or with new arms, so went for the latter.
 
bouncer--daz said:
I am also getting shuddering under braking which is also inconsistant but im currently gettin a knocking noise. Ive just been out and checked the shocks, they dont seem to have gone. I also jacked up both sides and put a bar through the alloy to see if there was any play in the top mounts which there doesnt seem to be. If it were my lower arm bushes gone could this cause a knocking noise? The knocking doesnt seem to happen when going over speed bumps etc... more in terms of bumps on the road surface. Best way too hear the noise is too roll down a hill in neutral. The knocking will be a continuous tapping (imagine driving over a load of cats eyes in the centre of the road - just not as harsh). Input would be welcome!
Click to expand...

The noise you describe sounds exactly like the one I had with worn front ARB bushes an/or worn ARB.

No noise over speed bumps or other big stuff, but a knocking when going over the usual broken british roads.

That's where I'd be looking first on yours.
 
Regarding the OP, I wouldn't necessarily rule out the discs being warped just because they're Porsche items. A quick search of some Porsche fora will show plenty of evidence of warped discs, even at such low mileages.

Before you start throwing cash at the suspension arms etc, any competent garage should be able to measure the run out on your discs, and also check they are centred properly.

I'd do that first, and at least then you can move on to the next thing confident it's not the brakes?
 
Now i'm just waiting for someone to come along with that article again explaining how warped discs dont actually exist :)
 
I've never seen proper warped discs, seen loads of discs with the faces themselves all bumpy, but the discs weren't actually 'warped'.

Seen any number of cracked discs where people have had drilled discs.

Drilled discs are the DEVIL.
 
I've warped discs in the past...
Trackday use...then cooled fast...ended up warped, on mounting face to rotor alignment.
It was suggested that I check the wheel bolt torque then go and get them just as hot by using them hard...and they straightened.

This was a known issue on the Integra Type-R...so it's possible it's been a factor on other cars.

In the 2 years I had my ITR I did 15-18 track days and never once warped a disc after getting into the habit of torquing the wheel bolts correctly.
 
bouncer--daz said:
yer im pretty certain I can feeling it through the steering....might have too take her out again in a sec. Just spoke too the audi workshop.... £10 for the bushes or £55 for new complete arms.... after labour charges thats £260ish for the bushes as they have to be pressed in or £270 for new arms.:crying: really dont want to be paying that sort of money. Anyone done the job themselves?
Click to expand...

ECP want £84.00 for the front wishbones!! Anyone got the correct Audi part no.s

bouncer--daz Is yours a discounted price from Audi?? Presume if you buy the complete arm it's just a case of wrestling some rusty bolts to swap out the arms and then 4wa. (which suits me TBH).
Think i'll still get the disc run out checked before i do this though :mad:
Thanks for everyone's input so far.
 
Lovegroover said:
ECP want £84.00 for the front wishbones!! Anyone got the correct Audi part no.s

bouncer--daz Is yours a discounted price from Audi?? Presume if you buy the complete arm it's just a case of wrestling some rusty bolts to swap out the arms and then 4wa. (which suits me TBH).
Think i'll still get the disc run out checked before i do this though :mad:
Thanks for everyone's input so far.
Click to expand...

It's not strictly nessecary, but personally I always fit new nuts & bolts when changing arms.
 
Dave_Bayern said:
I've never seen proper warped discs, seen loads of discs with the faces themselves all bumpy, but the discs weren't actually 'warped'.

Seen any number of cracked discs where people have had drilled discs.

Drilled discs are the DEVIL.
Click to expand...

I knew I should have took a pic of my warped Brembo disks before I threw them away, only did something like 1k miles! :sadlike:
Sitting on a flat surface, you could actually see 2 ends of the disk 3-4mm away from the surface, and I could feel the brake pedal judder at pretty much any speed from 15mph upwards!!
 
I always thought that to check if u have warpped discs u could jack the car up and rotate wheel if brakes r warpped u feel and here it catching on the pads intermittenly.
 
I've got mine booked in for a service on Saturday at local VAG specialist, so will get him to check the bushes and the run-out on discs if necessary. I'll let ya know how i get on.
Interestingly enough i'm convinced it's the bushes as i've noticed when braking going downhill (i.e. with all the weight on the front end) there's no shake (bushes compressed!). Just a thought?
 
Ive noticed sum similar symptoms... hopefully guna have my mechanic look at mine this week.
 
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