PICS Hi Dave, Pics(not all that great, as wheels still on ATM). Right Front Left Front Left Front(2) Left Rear Right Rear Rear brake discs have not been skimmed(only fronts done so far).
Hey, Chili, that all looks so 'new-ish' and in good condition that I'd still refer you to my PM. Perhaps only one side of disc was machined (?), or disc machined to different tolerance either side, causing the disc to not be centralised within the caliper (as found with mine).I know it seems almost too simple, as I said in my PM, but it worked for mine with the simple addition of a washer top and bottom of mounting points to centre the disc within the caliper.... no more vibration - and exceptional braking with the bigger kit!
Wouldn't the caliper self adjust to wherever the rotor chooses to sit? You have four largely independant cylinders, I can't get my mind around how this causes trouble. Many times I have removed brake pads (Z and other cars) where one side has worn more than the other without any shudder present I supose if they only machined one side of the rotor then the other side could be out of flat and causing the trouble.
Who replaced ur front wheel bearings? is there any chance that one of them maybee isn't seated properly ? this would push ur disk out by a few mill thus causing shuddering when brakes are applied. i read the start of this thread and u state "This issue has only become obvious since fitting new front wheel bearings a few months ago " Something to look at Regards Trev BTW ur disks look fine no hard spots
Hi Trev, Yes, it did start immediately after the new front bearings were fitted. As far as not being seated properly, the front bearings are pressed into the knuckle, and locked in place by a circlip. This pretty much precludes any possibility of the bearing not being seated correctly. This has been re-checked when the new hub was fitted a couple of weeks ago. None the less, thanks for your input....the search goes on:help:
Do u still have the old bearings around? compare them with the new ones width wise (calipers) maybee u got one that wasn't manufactured to the right spec's or the wrong part number . I guess were all clutching at straws now Regards Trev
my shudder story you may have already fixed it? by the way I see all the usual high (tech)level members on this one (which is the greatest thing about the forum) so I'm probably way off the track but this (my) was a sequence that doesn't seem to different to yours. Had wheel bearing replaced. at same time Nissan changed front Pads. Shudder soon after. returned for Machining. shudder soon after. Nissan replaced rotors. shudder soon after. review of bearing ? nothing. ended up with two re-machine sessions and then realised the lowest common denominator was the OEM Nissan Pads (who would have thought? yeah really Nissan can't make a pad for their own cars, it seems). replaced with Bendix and never a shudder since. If you've recently replaced the Pads with green stuff and had a re-machine and its still there .. try a different pad and re-machine. it may just be that simple? intended to be constructive comment only. I understand I'm no techie. good luck.
I wonder if ... ... any damage has ocurred during r&r of the knuckles; especially when removing tie-rod ends? Minor mis-re-alignment may not have been picked up in a wheel alignment. Long shot, but ....???
The caliper on the G4s bolts directly to the mounting bar.... all solid mount. The fitting instructions declare: "..... 6) Bolt the brake caliper to the caliper mounting bracket. 7) Measure the distance on all sides between the two brake pads and the brake disc.... 8)Due to the fact that location points on the OE caliper mounting bracket have tolerance, please check whether the brake disc is central in the caliper pathway. If not, realign the brake caliper and the brake disc to the optimum position by putting the washer that is 0.25mm between the the caliper and the caliper mounting bracket, or between the caliper mounting bracket and the hub.... 9)The brake disc should be flush with the brake disc mounting before the measurement of the relative distances between the brake caliper, the brake disc and the caliper mounting bracket are taken." Reasonably explicit compared with most Japanese instructions, and after experiencing extreme shudder under braking after simply bolting up the first time and then doing as the instructions said, I measured, found a slight variation in spacing, and added one washer at each of the caliper mounting points. Vibration completely disappeared... (taught me to read the instructions even if (usually) hard to understand. Although, being me, I probably won't until I bugger up something else!!
Right Chilli I think I have the fault worked out now. Noting the Age of you car and that the fron Chassis rails have broken, I think you will find it is your front tension rods' bushes have degenerated. These take a fair amount of load and are liquid gem filled as nissan originals. And will be (or have) leaking a gel like subsance. If you have changed these to after market nylon bushes or Tie rods, look for flogging. IF there is nothing there check the two bolts the other end are tight, they may have removed it to get to your hub bearings . Then the next (and final place) is the bushes of lower wish bone, same again. Also, check to make sure that there are no cracks. in these components. The reason it think it is this is your discs are in perfect nic, even if the fault was on the inside the "shuddering" would be showing through to the outside. And, these suspension componets are the ones that do it under braking. If you don't feel like getting dirty. you can try a crude test of driving back wards at speed and applying the brakes. It does shudder its those components, If still occurs .......... wellll
Yeah.... would have guessed that, Wiz, but.....??? Seems an awful lot of checking/replacement has been carried out (in typical efficient Chili style, God bless 'im!) without success. My thinking related to the fact that after fitting BRAND NEW G4 complete brake kit I got the shudders (well, the brakes did!!). As soon as I fitted a single washer at each mounting (interestingly, on LH side only...??) to centre the rotor inside the caliper (.25mm!!) the shuddering disappeared... and, it was very strong and very disconcerting!!
had another thought Hey Chilli, have you had a look at the torsional rods? I hope it was something as simple as the bolts being loose. I note that you had an after market one fail at the threads. I was looking at the failure and it appears to be a combination of brittle and fatigue failure. I was wondering if these faults are all inter-connected. As such if the suspension mention appears to be okay, it may be worth your while to check the sub-frame bushes, and mounts for cracks, loose bolts, etc. I hope that this helps a little.
Hi Dave, Yeah, I replaced both Tension Rods with new Tune Agent items when the Cusco one snapped a couple of months ago, and they have been checked thoroughly since then. As stated earlier, all this started mid way through last year when the front wheel bearings were replaced. It then seemed to come and go for no particular reason. Matt(WOKBURNER) and I are going to do a complete brake bleed(including the ABS Control Unit) on Saturday, so as to eliminate that possibility. While we're at it we will recheck those areas you have mentioned(I had the engine mounts replaced with OEM items at the same time as the wheel bearings were done, but don't know whether the sub-frame was interfered with in any way at that time). Large cracks were found in the immediate vicinity of the front brackets of the Tension Rods(lower radiator support panel and chassis rails) and have subsequently been welded up. My better half has a typically enlightened and practical Filipina solution to this whole saga. She says I should "push it into the harbour and grow oysters on it". I'm almost certain she's referring to the Zed. We'll see....:zlove::help:
Hmmm, Chilli this is a good one. I have actually been thinking about it a bit. It makes it easier in once sense because you are so thorough, but at the same time you rule the majority of things out. It must be the bearings, it is the only thing that could do this. I know they have been replaced and checked, and checked again. But everything else has been eliminated. All your faults are related, the chassis cracking the tension rod failure,,,, It is all related. I wonder if the bearing housing is the problem. or the puright is cracked.
Lloyd, Think about it this way If you get a shudder that follows the speed it would be related to the rotation of the wheel. First suspect would be the rotor, second a wobbly wheel bearing If it does not directly follow the speed, suspension components, support or ABS. If it started when you had the bearings changed, would they not be the prime suspects. What makes you think they were done properly ? Matt loves changing wheel bearings, especially if you take the car out onto the M4 and stop at a busy spot.
Well, I have discounted the bearings simply on the basis that apart from being brand new items, they are of such a design, that I find it difficult to imagine how it would be possible to fit them incorrectly. As you know, they are two bearings in one outer case, and are pressed into the knuckle, and then located with a circlip. The axle/hub is then fitted with the tapered section of the bearing, and also pressed into position. The whole assembly is then locked in by a large, flanged locknut which is pinned after being tensioned. Added to this is the fact that my old bearings were completely shagged, and groaning like $2 hooker(who is also completely shagged). In spite of this, there was not one indication(other than the groaning) that anything was amiss. How a brand new item could be worse than that, I simply can't fathom(although my life has been filled with inexplicable, totally unheard of disasters, to the point that nothing surprises me any more). If it turns out to be a twisted windscreen wiper rubber, I will not be fazed(and I will have the pleasure of knowing that no-one will be able to say "I told you so").
I still think it is ur wheel bearings . This when ur vibration started Could be either 3 things , wrong part number, manufacturing defect (not made to specs) or incorrectly fitted (not pressed into position enough,both pieces) Have u measured to c if ur caliper and rotor setup are centered? i figure if one of ur bearings is not pressed in sufficiently it WILL cause this problem. Did u also change brake pads at the same time? if so swap these out and try others . Regards Trev
While you're bleeding the brakes, inspect the rotors thoroughly. I had a similar problem in another car that ended up being a very small (almost invisible) crack in the hat part of the rotor near to where it mounts on the hub.
