Jump to content
SAU Community

Disk Warping Issues

hetman
 Share

Recommended Posts

hetman Apprentice

hetman

Posted
Posted

Hi guys. I'm after a bit of input on your experience with warped disks, I can't seem to get a straight story out of any mechanics (though most are usually keen for a dollar). Any suggestions or recommendations for a mechanic that might be equipped to deal with this would be awesome.

I have an R33 GTS-t with the standard 4 pot calipers. Haven't had an opportunity to track it, so while there are some nice roads out of the city for spirited driving, obviously there's only so hard you can push it. Until recently I've probably braked pretty hard even in normal traffic because of annoying squeel from the fronts.

Originally my disk warping problems started with a set of slotted RDA's together with some PBR performance pads. Warped after a couple months. From then on these would hold on for maybe 2 weeks if machined, and then the shudder would slowly creep back. During this time I had a problem in the steering rack fixed which had a bit of play when warm, a wheel bearing and stub axle bearing replaced, all on the right side. Since then no one has been able to fault the suspension since I presume what remains is a brake heating issue.

Eventually I had the disks replaced with original Nissan rotors and pads downgraded to Bendix Heavy Duty. Of course, it didn't fix the problem. After a while these rotors started to go as well, the killing blow being a nice drive through some mountains... the disks badly warped as a result (in retrospect those Bendix pads probably weren't so good for those rotors... there didn't seem to be any fade when hot).

Anyway, no amount of machining seems to get these disks good now. At best it reduces the shudder which then returns in full force over the next few days!! I've downgraded to a Maxi pad but that seems to make no difference (at least this guy managed to finally shut the squeel up with some shims & grease).

I understand cast iron disks if seriously stressed tend to result in patches hardening due to uneven carbon content so it's likely these disks are fubared now anyway. This is consistent with the uneven grabbing I get from the at low speeds (30km/h and below) which doesn't seem to be coming from the back given that's been recently worked on.

I presume if I upgrade to some DBA 5000 this might finally make my issues go away, but I'd like some advice before I pour more money into this.

Cheers

Link to comment
https://www.sau.com.au/forums/topic/239126-disk-warping-issues/
Share on other sites
MrStabby Grand Master

MrStabby

Posted
Posted

I have the same problem.. as yet unresolved. Not bad on the street but its a jackhammer on the track.

Make sure the mating surfaces between the rotor and the hub are completely clean - no rust or other gunk at all. Even a tiny spec here will cause shudder.

I cant see any point in you changing the rotors again - BTDT and it didnt help me.

Roy Grand Master

Roy

Posted
Posted

Remove the rotor and check the face colour of the rotor, is the inner different to the outer. Its possible that you have trailing pistons in your caliper meaning that there is always pad contact and in turn heat input. When you get up it and give it some stick the rotor distorts due to the uneven heat distribution.

But also, is it just simply a case of the use? I doubt it, but remember brakes like engines, gearobxes etc all like to be warmed up with a bit of heat put through them before you really get stuck into the braking.

When you say the rotors are warped is anybody actually checking the runout of the rotor? Is it both fronts, only rears, only one particular rotor....which rotor/s is warping?

hetman Apprentice

hetman

Posted
  • Author
Posted

I've bedded them my self on a few occasions (no stopping until cool again and all that), let the mechanic bed them other times, etc etc. Never seems to make a difference either way.

The calipers have been checked by a couple mechs who reckon pressure is even on all of them. The runout's been checked, although on the last two occasions the first time the runout was apparently within tolerance, and the second time it was not. Shudder seemed just as bad in both cases. And strangely the shuddering seems to randomly get better and worse (which if my damaged disk theory was true I would've attributed to the angular displacement between the two front wheels, i.e. how the carbon hardened blobs lign up... I know seriously stretching for any kind of explanation here).

Good question with which rotor is warping, I forgot to mention that last time I had it checked although I can only assume if it was only one they would've told me (or not).

It seems the last mechanic I had look at this decided he couldn't make any more money out of me and lost interest in actually troubleshooting this any further. That's why recommendations for someone with decent persistence and experience with this sort of thing would be great.

Cheers guys

blind_elk Grand Master

blind_elk

Posted
Posted

Maybe a stupid question, but it's not the ABS working is it.

If you are warping disks at that rate, then you must be really nailing the brakes all the time.

Have you discussed it with the manufacturer (RDA)?

  • 1 month later...
hetman Apprentice

hetman

Posted
  • Author
Posted (edited)

So I thought I'd do a bit of an update.

I've had this looked at by a vehicle inspection joint. They seem to have found the problem: runout on the axle flange (wheel flange? I thought there were no axles on the front). I've had the car for a few weeks now and had a chance to push it a bit and there has been no recurrance of the shudder.

You'd think 4 other mechanics would be able to figure this out :-/

Thanks again for the feedback!

Edited by hetman
  • 3 weeks later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Duncan
      7 Speed Auto transmission fluid change (Skyline, Q50, Q60, Fuga, Q70, A62 Titan and probably heaps of others including Navara...)

      By Duncan · Posted

      So, that is it! It is a pretty expensive process with the ATF costing 50-100 per 5 litres, and a mechanic will probably charge plenty because they don't want to do it. Still, considering how dirty my fluid was at 120,000klm I think it would be worth doing more like every 80,000 to keep the trans happy, they are very expensive to replace. The job is not that hard if you have the specialist tools so you can save a bit of money and do it yourself!
    • Duncan
      7 Speed Auto transmission fluid change (Skyline, Q50, Q60, Fuga, Q70, A62 Titan and probably heaps of others including Navara...)

      By Duncan · Posted

      OK, onto filling. So I don't really have any pics, but will describe the process as best I can. The USDM workshop manual also covers it from TM-285 onwards. First, make sure the drain plug (17mm) is snug. Not too tight yet because it is coming off again. Note it does have a copper washer that you could replace or anneal (heat up with a blow torch) to seal nicely. Remove the fill plug, which has an inhex (I think it was 6mm but didn't check). Then, screw in the fill fitting, making sure it has a suitable o-ring (mine came without but I think it is meant to be supplied). It is important that you only screw it in hand tight. I didn't get a good pic of it, but the fill plug leads to a tube about 70mm long inside the transmission. This sets the factory level for fluid in the trans (above the join line for the pan!) and will take about 3l to fill. You then need to connect your fluid pump to the fitting via a hose, and pump in whatever amount of fluid you removed (maybe 3 litres, in my case 7 litres). If you put in more than 3l, it will spill out when you remove the fitting, so do quickly and with a drain pan underneath. Once you have pumped in the required amount of clean ATF, you start the engine and run it for 3 minutes to let the fluid circulate. Don't run it longer and if possible check the fluid temp is under 40oC (Ecutek shows Auto Trans Fluid temp now, or you could use an infrared temp gun on the bottom of the pan). The manual stresses the bit about fluid temperature because it expands when hot an might result in an underfil. So from here, the factory manual says to do the "spill and fill" again, and I did. That is, put an oil pan under the drain plug and undo it with a 17mm spanner, then watch your expensive fluid fall back out again, you should get about 3 litres.  Then, put the drain plug back in, pump 3 litres back in through the fill plug with the fitting and pump, disconnect the fill fitting and replace the fill plug, start the car and run for another 3 minutes (making sure the temp is still under 40oC). The manual then asks for a 3rd "spill and fill" just like above. I also did that and so had put 13l in by now.  This time they want you to keep the engine running and run the transmission through R and D (I hope the wheels are still off the ground!) for a while, and allow the trans temp to get to 40oC, then engine off. Finally, back under the car and undo the fill plug to let the overfill drain out; it will stop running when fluid is at the top of the levelling tube. According to the factory, that is job done! Post that, I reconnected the fill fitting and pumped in an extra 0.5l. AMS says 1.5l overfill is safe, but I started with less to see how it goes, I will add another 1.0 litres later if I'm still not happy with the hot shifts.
    • Duncan
      7 Speed Auto transmission fluid change (Skyline, Q50, Q60, Fuga, Q70, A62 Titan and probably heaps of others including Navara...)

      By Duncan · Posted

      OK, so regardless of whether you did Step 1 - Spill Step 2 - Trans pan removal Step 3 - TCM removal we are on to the clean and refill. First, have a good look at the oil pan. While you might see dirty oil and some carbony build up (I did), what you don't want to see is any metal particles on the magnets, or sparkles in the oil (thankfully not). Give it all a good clean, particularly the magnets, and put the new gasket on if you have one (or, just cross your fingers) Replacement of the Valve body (if you removed it) is the "reverse of assembly". Thread the electrical socket back up through the trans case, hold the valve body up and put in the bolts you removed, with the correct lengths in the correct locations Torque for the bolts in 8Nm only so I hope you have that torque wrench handy (it feels really loose). Plug the output speed sensor back in and clip the wiring into the 2 clips, replace the spring clip on the TCM socket and plug it back into the car loom. For the pan, the workshop manual states the following order: Again, the torque is 8Nm only.
    • Duncan
      7 Speed Auto transmission fluid change (Skyline, Q50, Q60, Fuga, Q70, A62 Titan and probably heaps of others including Navara...)

      By Duncan · Posted

      One other thing to mention from my car before we reassemble and refill. Per that earlier diagram,   There should be 2x B length (40mm) and 6x C length (54mm). So I had incorrectly removed one extra bolt, which I assume was 40mm, but even so I have 4x B and 5x C.  Either, the factory made an assembly error (very unlikely), or someone had been in there before me. I vote for the latter because the TCM part number doesn't match my build date, I suspect the TCM was changed under warranty. This indeed led to much unbolting, rebolting, checking, measuring and swearing under the car.... In the end I left out 1x B bolt and put in a 54mm M6 bolt I already had to make sure it was all correct
    • Duncan
      7 Speed Auto transmission fluid change (Skyline, Q50, Q60, Fuga, Q70, A62 Titan and probably heaps of others including Navara...)

      By Duncan · Posted

      A couple of notes about the TCM. Firstly, it is integrated into the valve body. If you need to replace the TCM for any reason you are following the procedure above The seppos say these fail all the time. I haven't seen or heard of one on here or locally, but that doesn't mean it can't happen. Finally, Ecutek are now offering tuning for the 7 speed TCM. It is basically like ECU tuning in that you have to buy a license for the computer, and then known parameters can be reset. This is all very new and at the moment they are focussing on more aggressive gear holding in sports or sports+ mode, 2 gear launches for drag racing etc. It doesn't seem to affect shift speed like you can on some transmissions. Importantly for me, by having controllable shift points you can now raise the shift point as well as the ECU rev limit, together allowing it to rev a little higher when that is useful. In manual mode, my car shifts up automatically regardless of what I do which is good (because I don't have to worry about it) but bad (because I can't choose to rev a little higher when convenient).  TCMs can only be tuned from late 2016 onwards, and mine is apparently not one of those although the car build date was August 2016 (presumably a batch of ADM cars were done together, so this will probably be the situation for most ADM cars). No idea about JDM cars, and I'm looking into importing a later model valve body I can swap in. This is the top of my TCM A couple of numbers but no part number. Amayama can't find my specific car but it does say the following for Asia-RHD (interestingly, all out of stock....): So it looks like programable TCM are probably post September 2018 for "Asia RHD". When I read my part number out from Ecutek it was 31705-75X6D which did not match Amayama for my build date (Aug-2016)
×
×
  • Create New...