Warped disc rotors ?

[Hodge]

For a while now, I noticed what I'd call a pulsating feel through the brake pedal when coming to a halt. I'm unsure, but I feel like the issue is exacerbated when coming to a halt from higher speed ,e.g. coming off a freeway.
For ages I disregarded it and put it down to bad vibration off the road and the vibration I had from a bad engine mount (which is now replaced).

Over the past week I've sort of felt it worsen after a high country trip. So, I figured I'd pay some attention to it.

I'm super naive with brakes and have refused to tinker with them my self. I had the front on stands today , wheels off & I had a look without taking much off and to me everything spins "ok". The sound of rotors ever so gently rubbing against the pads is even and no noticeable differences round the clock.
This is without taking the calipers or anything else off ( as i don't know how to). I also checked the wheel bearings and all seems good. Even with the wheel on, 12 to 6 o'clock shake had NO movement. Pads are ok, as I had that and fluids replaced a few months ago.


Is there any way I can somehow confirm it is the rotor/s my self or is it off to mechanics for a rotor off to have a proper look ???


PS. If it is the rotors, this could smell like one of those 4.8 upgrades. Possibly. Maybe. I don't know .

[Yeti's Beast]

Sounds like rotors to me,depending on the thickness they could do with a skim.
Get an on-site on car disc machine done.


Proud BTrol Owner
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[0-TJ-0]

I've got the same symptoms mate. Only very minor. I assume mine is the rotors.

Far as I'm aware you won't necessarily be able to "see" any defects. Might be able to check them with a dial indicator but I wouldn't bother. Last time I had a set machined it wasn't expensive.. like $20 or something. Try that and troubleshoot if you're still having dramas after.

[Bidja]

Hodge

When my rotors were suss, I would get a slight pulsating feel in the pedal while solid descending into hard corner on sealed surface up the mnts. My bearings were good / pads were 70% left.

I changed them out with DBA slotted rotor and new pads. Pretty cheap these days. Could have used the old pads but put in shed in case.

Machining is fine, but if rotors have hot spots, which may not necessarily be evident and can cause problem again after machining.
Can check rotors for run out with a dial indicator but the time involved will cost. Depends what suits you and the cost will give you a direction.

May be worth checking wheel bearing end play (nipping up) but most likely be the rotors mate.

[jack]

Had exactly the same symptoms. Needed new pads so decided to replace the rotors as well, issue gone and greatly improved stopping.
Be very careful before electing to have the rotors machined on car, have a look a previous post by Cuppa. Pearcey provided some excellent advice on this and he’s speaking from experience.
http://www.nissanpatrol.com.au/forums/showthread.php?44636-Disc-Machining

[Hodge]

Thanks for the heads up folks! Some good reading in Cuppas thread.

Spoke to one of the blokes from out high country trip, and he brought up a good point which could explain why my issue got worse after that weekend.
One of the track descends we done, was super steep and super long. My 1st gear 4L motor braking just didn't cut it, so I did ride the brakes a fair bit. I completely forgot about this!

Hmmm. Now, to look at new rotors while its all apart or just get it machined. Decisions.

[mudski]

Thanks for the heads up folks! Some good reading in Cuppas thread.

Spoke to one of the blokes from out high country trip, and he brought up a good point which could explain why my issue got worse after that weekend.
One of the track descends we done, was super steep and super long. My 1st gear 4L motor braking just didn't cut it, so I did ride the brakes a fair bit. I completely forgot about this

Hmmm. Now, to look at new rotors while its all apart or just get it machined. Decisions.

Especially when you are riding the brakes and then hit a puddle or do a river crossing. The cold against the hot metal can warp things. I got my discs machined pre TB upgrade and from memory it cost $70 an end, and he came to me and did it in the driveway. He smoked about 30 ciggies per wheel too. Lol.

[threedogs]

Hodge also check your wheel bearings , if loose a little
bit will give you that warped brake feeling

[MudRunnerTD]

Hodge mate the front disks are pretty easy but have a wheel bearing internally. Look at my CV rebuild thread ans ther are great pics from go to getting the disk off. It might be viable to take the opportunity to do a swivel hub rebuild and new wheel bearings while doing the disks IMO.

[MudRunnerTD]

Have a look at the first page of this thread for the diagram.

http://www.nissanpatrol.com.au/forums/showthread.php?28969-DIY-CV-and-Swivel-Hub-Rebuild-Thread

You could take it all off and unbolt the disk from the hub without touching the bearing carrier if you thought your front end was still OK. But it does have to come 0ff.

[0-TJ-0]

Give us an update when you get it sorted out mate. I'll have to do mine eventually and would be happy to learn from your mistakes haha.

[threedogs]

Hodge I brought 4 x dimple drilled and slotted rotors with pads for $100
a corner delivered

[drgtr]

Probably late to the party but pulsating especially on the patrols tend to be from the rear.

I had it and was annoying as hell.

Both patrols from the rear.

Actually even my prado from the rear.

New rotors and its been great

[Hodge]

Probably late to the party but pulsating especially on the patrols tend to be from the rear.

I had it and was annoying as hell.

Both patrols from the rear.

Actually even my prado from the rear.

New rotors and its been greatYou're not the first to suggest that. Something I never even thought about. Might have a look later.

I also assumed, it possibly may have something to do with the death wobbles I've been having...
I don't know, brain storming, a disc off balance sending a wheel out of whack at certain speeds.

But my wobbles now entirely gone away, without me touching a thing. so can't even diagnose that now...

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[drgtr]

Hey Hodge.

Was it death wobbles or more vibration shimmying?

I had vibrations shimmy when I bought the cheapr COmforser CF3000 35 inch tyres.

They looked great but I couldnt balance them.

Was scratching my head and losing hope.
I swapped over to Kumho 35 inch and its been great ever since.

This especially I double checked all the bushes from a suspension place too.
Engine mounts for engine and transmission mounts are new

All bushes double checked. Even had new bushes ready to go in!

Damn tyres.

[Hodge]

Hey Hodge.

Was it death wobbles or more vibration shimmying?



Hmmm unsure of the difference there mate. lol

(when it does happen)
85-90km/h the steering wheel starts a rhythmic shake. Well, not just the steering wheel, it's more like the whole front of the car. It's not SUPER bad, but it is very annoying and forces me to get out of that speed range ASAP.
First things I checked were missing weights, and took wheels off and looked for clumps of dirt/mud stuck somewhere which may send it out of balance but found nothing obvious.

But before I even got to inspecting further like bushers etc, it just stopped doing it.. So bugger me , I don't know what the hell is going on. I sincerely hope it does not return. lol

[drgtr]

lol

What you describe sounds like shimmy. Death wobbles you would know. Whole car will be so violent that you must stop! Its like you going on massive pot holes or corrugations

Probably was a balance issue with wheel so when you place it back on properly it went away.
I noticed with 35 inch tyres for me. A wrong cheap brand or something slightly out. It will definitely show on 35 inch tyres while smaller tyres you can get away with
faults or imperfections more.


I learnt this by running cheap 35 inch comforsers. Brand new. I was so doubting myself and thinking maybe all 35 inch are hard to balance.
Then switch to KUMHO mt51. Smooth as.