indie Posted February 15, 2017 Report Share Posted February 15, 2017 (edited) Hello gang! I've ended up with an unfortunate situation where my GTI keeps warping its front discs. As a result I bought a DTI gauge and measured the hubs for run out. The near side runs out to 0.5mm at one point, while the off side wobbles to 0.9mm I've cleaned the hub faces to make sure that isn't the problem and am a bit confused how this might have happened! Sometimes I have to climb large curbs where I live to park, but I'm super careful. I'm also pretty damn careful when refitting the wheels, usually use a torque wrench. FWW my local VW parts specialist reckons some Polo's also use the same hubs lower strut section? Is there any truth to that? I bet Polo spares are much easier to locate.. Any ideas. Edited February 15, 2017 by indie Quote Link to comment Share on other sites More sharing options...
cj1 Posted February 15, 2017 Report Share Posted February 15, 2017 3 minutes ago, indie said: Hello gang! I've ended up with an unfortunate situation where my GTI keeps warping its front discs. As a result I bought a DTI gauge and measured the hubs for run out. The near side runs out to 0.5mm at one point, while the off side makes it to 0.9mm. I've cleaned the hub faces well and am a bit confused how this might have happened! Sometimes I have to climb large curbs where I live to park, but I'm super careful. I'm also pretty damn careful when refitting the wheels, usually use a torque wrench. FWW my local VW parts specialist reckons some Polo's also use the same hubs and carriers? Is there any truth to that? I bet Polo spares are much easier to locate.. Any ideas. The Sport also has the same hubs. As for carriers, seen quite a few on ebay, or I have some if you're running the std 256mm brakes. Quote Link to comment Share on other sites More sharing options...
indie Posted February 15, 2017 Author Report Share Posted February 15, 2017 Thanks for the reply. What I mean is the hub carrier assembly (as in the bottom part of the strut), not the brake carrier - sorry I should have been clearer What I'm not sure about currently is if changing the hubs and bearing will solve my issue. Seems bizarre that both sides run out heavily... Quote Link to comment Share on other sites More sharing options...
cj1 Posted February 15, 2017 Report Share Posted February 15, 2017 (edited) 39 minutes ago, indie said: Thanks for the reply. What I mean is the hub carrier assembly (as in the bottom part of the strut), not the brake carrier - sorry I should have been clearer What I'm not sure about currently is if changing the hubs and bearing will solve my issue. Seems bizarre that both sides run out heavily... Ah okay! My mistake All one piece isn't it. Possibility of getting the faces machined down to be level? But yes I agree it seems odd that both are sides are out. Did one side start warping discs before the other, or did you only notice all at once? Edited February 15, 2017 by cj1 Quote Link to comment Share on other sites More sharing options...
indie Posted February 15, 2017 Author Report Share Posted February 15, 2017 Not at all... I'm a self taught spanner wrangler, so probably use the wrong names for things. Facing might work, but I'm concerned why they ended up like this in the first place. Maybe when the bearings were installed? I had one done last year locally - thats the worse of the two. Genuine WW bearing too. RE brakes I've had a few problems. This is actually the third set of discs. Unfortunately it looked bearing related, then a seized caliper. The problem came back though, so now I'm at the root of it (I hope). Breaks my heart. Car has done 125k, but the engine/box seem solid. Quote Link to comment Share on other sites More sharing options...
Sausage Posted February 15, 2017 Report Share Posted February 15, 2017 (edited) You will probably have to take the hub and knuckle off the car and split the hub from the knuckle then measure the hubs for run out on a lathe or whatever you can find, assuming there's no pay in the bearings then it's either bearings were put in badly or the hubs are bent from an accident or something. Edited February 15, 2017 by Sausage Quote Link to comment Share on other sites More sharing options...
indie Posted February 15, 2017 Author Report Share Posted February 15, 2017 Thanks for the reply. Aside from pot holes and parking on kerbs around London I can't say the car has been in an accident. I guess it could be from poorly installed bearings. Do you think the hub carrier itself will be alright, because they look to be really hard to source for the GTI (unless there is a polo that uses the same)? RE hubs these look about right, but always cautious about the GTI being different and all! http://www.ebay.co.uk/itm/VW-Lupo-Polo-Seat-Arosa-95-06-Front-Wheel-Hub-ABS-6N0407613-/151999221478?fits=Model%3ALupo&hash=item2363dc0ee6:g:CewAAOSwG-1W1beG Quote Link to comment Share on other sites More sharing options...
Mobieus_uk Posted February 15, 2017 Report Share Posted February 15, 2017 are you sure your reading the gauge correctly, I think the increments are 0.01 making your readings 0.05 and 0.09, that not a lot in mm, Ive not used those types of gauges before so maybe someone can clarify I'm pretty sure the small needle is 1mm increments so if you had 0.9mm that would move to show nearly 1mm but it hardly moves so methinkk you have a decimal point in wrong place making you think your run out is greater that it actually is Quote Link to comment Share on other sites More sharing options...
indie Posted February 15, 2017 Author Report Share Posted February 15, 2017 Actually thats a good point... This is the front of the gauge (below) So in fact then its 0.05mm and 0.09mm out - god thats embarrassing! I wonder if those sorts of figures are within a tolerable range? Quote Link to comment Share on other sites More sharing options...
Mobieus_uk Posted February 15, 2017 Report Share Posted February 15, 2017 (edited) compare with the other side, you are out by the thickness of a human hair, maybe checks a friends car and get some reference numbers are you fitting vw discs or another brand? Edited February 15, 2017 by Mobieus_uk Quote Link to comment Share on other sites More sharing options...
indie Posted February 15, 2017 Author Report Share Posted February 15, 2017 From what I can see 0.01mm seems to be the maximum runout on other small cars. I'll try find out from VW if they have a figure for the Lupo. Each time the discs have been after market, but in no case were they the cheapest option available. I thought it might be crappy pads that are depositing material onto the discs. I suppose its time to measure the back too.. but I can't see this being the rears. Quote Link to comment Share on other sites More sharing options...
Sausage Posted February 15, 2017 Report Share Posted February 15, 2017 Yes it wont be your hubs then after all. Do the new discs solve the judder for a bit and then it comes back? I assume you have checked or moved the relevant wheels and tyres? You can test your old disks now with the dti as well. Quote Link to comment Share on other sites More sharing options...
indie Posted February 16, 2017 Author Report Share Posted February 16, 2017 9 hours ago, Sausage said: Yes it wont be your hubs then after all. Do the new discs solve the judder for a bit and then it comes back? Exactly! I get maybe 3 months and then it all goes wrong. From what I recall the rotors are within the tolerances above. I need to check again.. 9 hours ago, Sausage said: I assume you have checked or moved the relevant wheels and tyres? You can test your old disks now with the dti as well. Car pulls fine and doesn't bobble at speed. I guess I could swap the front and back wheels, could potentially be an alloy that is out of true. Anybody think rear brakes could cause this? AFAIK they don't do a great deal under normal breaking. Quote Link to comment Share on other sites More sharing options...
Sausage Posted February 16, 2017 Report Share Posted February 16, 2017 Fronts do most of the work I'm guessing around 80%. Sticky caliper sliders can cause judder / snatching but that would be usually be one wheel, as the tyre starts to wear unevenly it gets worse over time. Quote Link to comment Share on other sites More sharing options...
indie Posted February 16, 2017 Author Report Share Posted February 16, 2017 (edited) In oct it was brand new callipers, hoses, fluid, pads and discs. Sliders are really smooth. What I didn't change was the pad carriers. Also the inner pad doesn't have the little clip that plugs into the piston, never did on my car.The company that sold the new callipers said that wouldn't make a blind bit of difference. I guess it could be shitty pads depositing crap onto the disc and causing the grabbing effect. NB: My car doesn't get used much in the week. Sometimes the first hundred feet or so is squaring the rust off the discs, but generally the surface looks to be smooth and free of scoring. Edited February 16, 2017 by indie Quote Link to comment Share on other sites More sharing options...
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