bb83 Posted October 1, 2014 Share Posted October 1, 2014 Hi All, I've searched the forum but can't find a definitive answer to this: I got my UK 350z GT (.03) on monday. Well happy with it, couldn't stop smiling on the drive home! I purchased the car knowing that it has a few issues (helped me drive the price down ALOT). Now the car is mine - need to fix those issues! ISSUES 1) The brakes rumble/vibrate/shudder when braking from over 40mph. Suspect needs new discs but I'm not sure how to diagnose if its the front or the back. There's no vibration or movement in the steering wheel when braking so I think its the back, but want to be sure before I splash out on a new pair. Any body know how I could diagnose this? I had the wheels off this morning and can't see any signs of deposits on either the front or the back discs so not sure what else I can check. 2) A 'clunk' sound on full right steering lock. The car has had two new suspension arms fitted to the front, and feels solid and very quiet when driving. But clunks once per turning circle when on full right lock. I suspect its either an anti-roll bar link with play in it, or perhaps the top right mount point. Anybody got any other idea what it might be? I'll jack up the car at the weekend and give everything a good shake to see what moves that shouldn't. Could this loose suspension part be the cause of the brakes shuddering. 3) Left hand speakers cut out every now and then (I found the answer to this on the forum thanks). Bit of a bugger to fix by the sounds of it so I'll see how annoyed I get before trying to sort this. 4) Airbag light flashes: Tried the ECU reboot method (turning on and off again 4 times) and it stopped flashing for a bit. But its back on this morning so suspect its one of the under-seat sensors/connectors. Not too fussed about that. Any help/advice on diagnosing this brake shudder would be much appreciated. I have searched the forum I promise, but couldn't find any definitive answer. Cheers Quote Link to comment Share on other sites More sharing options...
GIXXERUK Posted October 1, 2014 Share Posted October 1, 2014 (edited) to be 100% you would need to check the run out on the discs, a general check is......if its the front the, steering will shake, if its the rear then you feel it in the seat you could try the bedding in procedure for the brakes best to get someone to move the steering left/right slightly while you check the bushes/joints on the steering/suspension, could be anything tbh, track rod, bush etc Edited October 1, 2014 by GIXXERUK 1 Quote Link to comment Share on other sites More sharing options...
GIXXERUK Posted October 1, 2014 Share Posted October 1, 2014 (edited) bedding in procedure, it's worth a go as it costs nothing........ http://www.350z-uk.c...showtopic=18649 ps. when you check discs, it's much more important that you check the rear of the disc Edited October 1, 2014 by GIXXERUK 1 Quote Link to comment Share on other sites More sharing options...
bb83 Posted October 1, 2014 Author Share Posted October 1, 2014 Excellent - sound advice. Will try the bedding in procedure tonight - gives me another excuse to go out in it And I didn't actually check the rear surface of the discs..nice one, will have a look at those later, and also spin the wheels to listen for rubbing. The previous owner had only done 3000k miles in it in the 10 months that he'd had it, so perhaps that's a factor. Though the discs are very clean and rust free. I'll keep tinkering. Thanks Quote Link to comment Share on other sites More sharing options...
GIXXERUK Posted October 1, 2014 Share Posted October 1, 2014 Excellent - sound advice. Will try the bedding in procedure tonight - gives me another excuse to go out in it And I didn't actually check the rear surface of the discs..nice one, will have a look at those later, and also spin the wheels to listen for rubbing. The previous owner had only done 3000k miles in it in the 10 months that he'd had it, so perhaps that's a factor. Though the discs are very clean and rust free. I'll keep tinkering. Thanks did you check the rear of the discs ? the often look good from the front but can rust on the backs, especially if the car is not used a lot Quote Link to comment Share on other sites More sharing options...
bb83 Posted October 1, 2014 Author Share Posted October 1, 2014 Had another look at the brakes.. Can feel ridges on the face of the front discs when running my fingers accross them. Must of missed that when I checked before. Will order new discs n pads tomorrow. Quote Link to comment Share on other sites More sharing options...
bb83 Posted December 5, 2014 Author Share Posted December 5, 2014 An update on this: Replaced Rear and Front discs and pads, but the vibration is still happening when braking above 40 mph (and the vibration is very severe when braking at speed (70mph+). New pads have been bedded in nicely. I gave front and rear suspension a really good inspection when doing the discs and couldn't find anything suspect. All joints were solid, can't find any movement anywhere. All bushes are intact, no splits anywhere. The car brakes in a straight line, not pulling to either side. The callipers are all sound, not sticking and not overheating. This is starting to do my head in! The vibration almost feels like the ABS is kicking in. You can feel it in the pedal. I wonder if there's a way I can switch the ABS off just to rule that out? Any idea's anyone? Could it be something really silly like the tracking or wheel balance perhaps? I'm not getting any un-even tyre wear but haven't had the tracking looked at since owning the car (3 months). Urrrrgh. I just want smooth braking. HELP!!! Quote Link to comment Share on other sites More sharing options...
PageyUK Posted December 5, 2014 Share Posted December 5, 2014 Hi, When you replaced the discs and pads, did you check the calipers to see if and of the pistons or sliders were seized? Not sure on the 350, but on other cars I've had you can disable the ABS by pulling the fuse for it... Quote Link to comment Share on other sites More sharing options...
GT4 Zed Posted December 5, 2014 Share Posted December 5, 2014 (edited) If you still have this shaking on braking after changing both front and rear pads and discs I would take a close look at the runout on all the hubs. Where the faces cleaned thoroughly? Do you have OEM or after market wheels? If after market check you've got the right spigot in each wheel centre bore it it's not crack and missing some bits. Also check you wheels are not bent or unbalanced. As mentioned above check for seized pistons but that should be obvious as the disc from the affected calliper would be rusted or extremely worn. This is unlikely but worth checking. On the suspension side of things. Which one was replaced? I suspect it was the compresion arms but the lower control arm bushes are often mised and get tend to go when the compresion arm have been neglected for long. This would clunk and could even be the cause of your symptoms. You just need to be thorough in your trouble shooting. Goodluck. Edited December 5, 2014 by GT4 Zed Quote Link to comment Share on other sites More sharing options...
bb83 Posted December 5, 2014 Author Share Posted December 5, 2014 Thanks for the replies folks. I did clean the hub faces, but having spent 3 hours scouring the web, I'm beginning to think that I didn't clean them up well enough. It seems even the smallest amount of rust on the hub face can cause this exact problem. Will take the wheels/discs off again soon and do a really thorough cleaning job on the hubs. Quote Link to comment Share on other sites More sharing options...
harryjackson Posted December 12, 2014 Share Posted December 12, 2014 Commenting for updates. Sent from my iPad using Tapatalk Quote Link to comment Share on other sites More sharing options...
harryjackson Posted December 14, 2014 Share Posted December 14, 2014 Thanks for the replies folks.I did clean the hub faces, but having spent 3 hours scouring the web, I'm beginning to think that I didn't clean them up well enough. It seems even the smallest amount of rust on the hub face can cause this exact problem. Will take the wheels/discs off again soon and do a really thorough cleaning job on the hubs. Did you manage to solve your problem? Sent from my iPad using Tapatalk Quote Link to comment Share on other sites More sharing options...
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