GT Driver Posted June 23, 2014 Share Posted June 23, 2014 Need some advice folks... Replaced my front discs about two months due to a noticeable wobble / vibration under braking... I ordered new mtec discs... when fitting myself, I inspected each wheel to check that the calipers were not sticking. Both front wheels rotated freely. When the old discs were removed, I gave the hub flange a quick clean. With the news discs fitted the disc warp / wobble was no longer there. Now within 500 miles of completely normal driving, city and motorway, the wobble / shudder has returned and is even more noticeable than the old discs. Any ideas what is causing this? (At high speed braking it is a pulse through the pedal and at slow speeds it's like a mild kangaroo / wavy effect when slowing down. Sometimes the pads squeal at very slow speed and I can hear the sound come and go as the discs rotates so it seems like they are warped. I'm out of ideas as to what's causing it.. Quote Link to comment Share on other sites More sharing options...
Neilp Posted June 23, 2014 Share Posted June 23, 2014 Did you check the disc run outs when fitting? Quote Link to comment Share on other sites More sharing options...
GT Driver Posted June 23, 2014 Author Share Posted June 23, 2014 Not on the new discs Neil - I rotated the wheel on the old discs just to check for any resistance. What are you suggesting - that the new disc might not have been true? Quote Link to comment Share on other sites More sharing options...
Neilp Posted June 23, 2014 Share Posted June 23, 2014 (edited) Hi Mate, No, if the hub has any sort of dirt on it etc it can cause the disc to run out. Ultimately it ends up with DTV. The tolerances on the 350z are pretty small. Do you run spacers? Spacers have been known to cause this issue on some cars also. Edited June 23, 2014 by Neilp Quote Link to comment Share on other sites More sharing options...
GT Driver Posted June 23, 2014 Author Share Posted June 23, 2014 No spacers mate - completely standard. Like I said when I removed the old disc I cleaned around the hub flange - it seemed pretty clean. I'm just wondering if one of the pads are sticking slightly causing heat build up and uneven deposits. It's quite bad now so I want to get to the source of the issue before I get new discs or resurface my existing ones. Quote Link to comment Share on other sites More sharing options...
Ewen@Clark Motorsport Posted June 23, 2014 Share Posted June 23, 2014 As Neil says it sounds like you have DTV. In 500 miles for it to return it has to be that. I have seen it quite a few times on Z's and Evo's in the workshop Quote Link to comment Share on other sites More sharing options...
M13KYF Posted June 23, 2014 Share Posted June 23, 2014 get in touch with disc scimmers on here, That will sort it http://www.350z-uk.com/forum/162-disc-skimmers/ Quote Link to comment Share on other sites More sharing options...
GT Driver Posted June 23, 2014 Author Share Posted June 23, 2014 What is the likely cause of DTV folks? Quote Link to comment Share on other sites More sharing options...
CrustyCrab Posted June 23, 2014 Share Posted June 23, 2014 I had the same thing. Your hub faces aren't clean enough. I made the exact same mistake and disc skimmers sorted me right out. Just get in touch with him and he'll ou sort you right out. Quote Link to comment Share on other sites More sharing options...
CrustyCrab Posted June 23, 2014 Share Posted June 23, 2014 Oh and I can almost guarantee its not DTV Quote Link to comment Share on other sites More sharing options...
GT Driver Posted June 23, 2014 Author Share Posted June 23, 2014 Well if brand new discs need to be skimmed after 500 miles then surely the skimming is only a temporary solution? Quote Link to comment Share on other sites More sharing options...
Ebized Posted June 23, 2014 Share Posted June 23, 2014 What is the likely cause of DTV folks? It could be one or more of several different issues - having used Tophooker (Marcus) myself as recommended by Mike ^^^ I can't recommend him highly enough to get to the bottom of what is causing the problem. Your experience with the problem coming back after 500 miles was very similar to mine - changed what seemed to be the obvious problem but it wasn't! Hopefully you are not too far from him in Cambridge, but he does also work remotely in the South East. Quote Link to comment Share on other sites More sharing options...
eatonm90 Posted June 23, 2014 Share Posted June 23, 2014 DTV (disc thickness variation) are the peaks and troughs in the surface of the disc. Usual cause is heavy breaking whilst bedding in new discs and pads causing overheating. The cast structure of the disc needs to go through gentle heat cycles to relax the structure of the disc. Quote Link to comment Share on other sites More sharing options...
CrustyCrab Posted June 23, 2014 Share Posted June 23, 2014 When I went to disc skimmers he cleaned the hub faces (properly) and to quote Marcus they need to be 'clean enough to eat your dinner off' Quote Link to comment Share on other sites More sharing options...
GT Driver Posted June 23, 2014 Author Share Posted June 23, 2014 I can imagine that heavy braking and overheating can cause this but I've been driving like a granny for the past 500 miles! Quote Link to comment Share on other sites More sharing options...
Neilp Posted June 23, 2014 Share Posted June 23, 2014 Its not heavy breaking that causes it. its down to the fact that if the disc runout isn't spot on the disc touches the brake pad more, or constantly, in one area 1 Quote Link to comment Share on other sites More sharing options...
Vlad Posted June 25, 2014 Share Posted June 25, 2014 I got that same problem. Anyone got any good tips on cleaning hub before putting new brakes on? When I changed mine last time - I just gave it a wipe.... Obviously that wasn't enough lol Quote Link to comment Share on other sites More sharing options...
addisj Posted June 26, 2014 Share Posted June 26, 2014 I got that same problem. Anyone got any good tips on cleaning hub before putting new brakes on? When I changed mine last time - I just gave it a wipe.... Obviously that wasn't enough lol Me too. Makes it hard to come to a stop smoothly. What with this and a high clutch I feel like a right novice when stopping and pulling away lol brakes squeal too so everyone on the street turns to look Quote Link to comment Share on other sites More sharing options...
KUGT4 Posted June 26, 2014 Share Posted June 26, 2014 disk run out - ie brake pad material unevenly transferred onto the disk surface put up with it until the next disk/pad change or buy/fit a new set of disks and have the current ones skimmed (around £60 incl delivery) Quote Link to comment Share on other sites More sharing options...
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