Rotors warped again (2 Viewers)

[SHIfTHEAD]

So I've been chasing brake issues for a bit now. I my new rotors warped within a few thousand miles, after I had rebuilt the front rotors which were really crusty. So thinking the calipers were still sticking I bought rebuilt calipers and had the rotors turned. Everything was good for another few thousand miles when the rotors warped again. So thinking maybe they were bad now I bought new rotors and installed them. Rinse and repeat and a few thousand miles later they are warping again. So I started wondering if the calipers aren't being allowed to retract all the way and they were dragging, so once I got into my driveway I stuck my finger through the wheel spokes and promptly burnt the shlt out of my finger, and am now nursing a big blister. I touched it for about 1 Mississippi, so it was pretty dang hot.

So, is this most likely a failing master cylinder, or could the ABS be sticking some how? I've been thinking of removing the ABS stuff anyway since it improves brake feedback and frees up some room under the hood. Any thoughts are much appreciated.

 

[SNLC]

OEM rotors or ??

Cheers

 

[mudgudgeon]

Have you measured the run out and confirmed its the rotors?

A couple of times I've had front wheel bearings lose preload, and come loose. This showed up as a pulsating feedback through the brake pedal.

Gently washing off speed at high speed would cause a pulsating pedal.
Gently coming to a stop at traffic lights and washing off the last 10-15mph to come to a stop would cause a pulse through the pedal.
Typical braking, not so noticeable.

When it first happened, I was sure it was brake rotors, but other things tipped me off to it being loose/ insufficient preload on front wheel bearings.

Its happened a couple of times with different cruisers I've had. And bearings can end up loose FAST if not torqued correctly.

I would say, also check your bearings, and read up on how to get preload correct

 

[clx16]

If your brake lines are old they can collapse and work like a check valve not letting the calipers release.

You can test this by driving a little and then when parked and wheels chocked open the bleader and see if there is pressure and or they release.

Doesn't sound like abs or master issues to me.

Also good quality rotors like oem will not warp as much. I don't think you can fully fix warping by turning them.. I think once they get hot like that they struggle to not warp more later.

 

[SHIfTHEAD]

OEM rotors or ??

Cheers

Not OEM, PowerStop (?) and Duralast. I've used Duralast on other vehicles without issue. But, sure, could be the issue.

Have you measured the run out and confirmed its the rotors?

A couple of times I've had front wheel bearings lose preload, and come loose. This showed up as a pulsating feedback through the brake pedal.

Gently washing off speed at high speed would cause a pulsating pedal.
Gently coming to a stop at traffic lights and washing off the last 10-15mph to come to a stop would cause a pulse through the pedal.
Typical braking, not so noticeable.

When it first happened, I was sure it was brake rotors, but other things tipped me off to it being loose/ insufficient preload on front wheel bearings.

Its happened a couple of times with different cruisers I've had. And bearings can end up loose FAST if not torqued correctly.

I would say, also check your bearings, and read up on how to get preload correct

I setup a dial gauge yesterday and was seeing .03-.04mm runout. so the pulsing isn't crazy yet, but it's getting worse.

If your brake lines are old they can collapse and work like a check valve not letting the calipers release.

You can test this by driving a little and then when parked and wheels chocked open the bleader and see if there is pressure and or they release.

Doesn't sound like abs or master issues to me.

Also good quality rotors like oem will not warp as much. I don't think you can fully fix warping by turning them.. I think once they get hot like that they struggle to not warp more later.

Yeah, I recall that being the case too. But good call on the brake line hypothesis, I actually had this happen on an old BMW bike I had. I think I'll go looking for some new lines now. Good call, thanks.

 

[robnicko]

you may want to check the brake booster pushrod adjustment. If its sticking out too far will be applying pressure to the master cyl constantly.
I had this same issue with my Ford Falcon and it caused the front rotors to get hot spots and warp. After resetting the pushrod (theyre adjustable like a nut/bolt setup) the issue went away. Key indicator was after driving if I jacked up the front there was a heavy brake drag happening which would be worse after driving due to heat build up and expansion.

 

[SNLC]

Not OEM, PowerStop (?) and Duralast. I've used Duralast on other vehicles without issue. But, sure, could be the issue.


I setup a dial gauge yesterday and was seeing .03-.04mm runout. so the pulsing isn't crazy yet, but it's getting worse.

Yeah, I recall that being the case too. But good call on the brake line hypothesis, I actually had this happen on an old BMW bike I had. I think I'll go looking for some new lines now. Good call, thanks.

Well, we have had brand new aftermarket rotors come warped out of the box.

Cheers

 

[clx16]

Well, we have had brand new aftermarket rotors come warped out of the box.

Cheers

I've had the same experience. I have had good luck with powerstop rotors though and have found them to be more resistant to warping.

 

[SHIfTHEAD]

So in both cases after I put on the new rotors they were smooth as butter. It has taken time for them to start warping and the pulsating sensation.

I did order a set of SS brake lines, but I'm trying to figure out why it would be both front rotors that are warping. I suppose two lines could be bad, but odds are against that I think. I'm thinking of what is common between them, and master cylinder and ABS module come to mind. I think I'm going to jack up the front and rear so all 4 wheels are off the ground and then start it up. ABS cycles are 5 mph, so I will put it in gear and let that happen, then pumps the brakes real hard several times. Put it in Neutral and see if I can turn the front wheels by hand.

 

[Mark W]

Not really contributing any answer to your question... But FWIW, you can not pay me to use Duralast components. I am pretty sure they skip right over the usual cheap as s*** Chinese factories and go straight to Somalia and Uganda to source their parts.

And... I know that there are those that feel differently, but I would never purposely disable the ABS on any street driven rig that will ever see snow or ice.

I've been doing "not recommended" stuff off road for years and while I grew out of purposely doing that on the street long ago, I do consider myself a pretty good driver, knowledgeable and experienced with an excellent understanding of the physics involved in moving my rig down the road under any conditions.
That said, there are specific times/situations where there is no way in hell that I can do as good a job of doing what ABS does as ABS does it. There have been at least a couple of times when my rig would most likely been on it's top down the embankment if not for the ABS. Not even situations where I was caught off guard, just situations where I would not have been able to do what it took to keep the rig in it's intended path.

Mark...

 

[manofthewoods]

Not really contributing any answer to your question... But FWIW, you can not pay me to use Duralast components. I am pretty sure they skip right over the usual cheap as s*** Chinese factories and go straight to Somalia and Uganda to source their parts.

And... I know that there are those that feel differently, but I would never purposely disable the ABS on any street driven rig that will ever see snow or ice.

I've been doing "not recommended" stuff off road for years and while I grew out of purposely doing that on the street long ago, I do consider myself a pretty good driver, knowledgeable and experienced with an excellent understanding of the physics involved in moving my rig down the road under any conditions.
That said, there are specific times/situations where there is no way in hell that I can do as good a job of doing what ABS does as ABS does it. There have been at least a couple of times when my rig would most likely been on it's top down the embankment if not for the ABS. Not even situations where I was caught off guard, just situations where I would not have been able to do what it took to keep the rig in it's intended path.

Mark...

I join you in the ABS has saved me club.
The easy way to prove it's utility is to get on a frozen lake and stomp on the brake pedal while steering left and right. On non-ABS brakes?
Good luck.

 

[Mark W]

I join you in the ABS has saved me club.
The easy way to prove it's utility is to get on a frozen lake and stomp on the brake pedal while steering left and right. On non-ABS brakes?
Good luck.

My most memorable was a steep downhill hairpin in a mountain neighborhood with no guard rail and a hundred foot drop. I had gone uphill on the same route within the hour and while I knew it was dicey, it must have warmed up a degree or two and it was a LOT slicker on the way down. It almost immediately exceeded my ability to manually modulate the brakes and I wound up simply holding the pedal to the floor and feeling it shudder against the sole of my boot for what felt like a day and a half as I steered into, through and out of that hairpin like I was on a dry gravel road.

That was the day that really reminded me that old school ain't always better LOL.

I also like how ABS will warn that the surface is slicker than I thought with the rattle against my foot and give me time to alter my input or my choices, even when it is still within my ability to control everything.


Mark...

 

[raisinhell2]

Your LSPV is prob stuck giving you little to no rear braking

 

[gummycarbs]

When you had the rotors turned, did they measure runout first? It's pretty rare for discs to actually warp.

Google the Centric document titled "The 'Warped' Brake Disc & Other Myths of the Braking System". It's usually deposits of brake pad material.

Anyway, it sounds like you have dragging brakes. It's my understanding that the primary factor in pulling the brake pistons back is the brake piston seal. I would order caliper rebuild kits and get to work, and make sure to inspect the pistons for buildup that would interfere with retraction and pitting that would damage seals.

You wrote that you installed rebuilt calipers, so maybe that's not the issue. Personally, I'd still start by popping out the pistons and inspecting everything.

 

[mudgudgeon]

So in both cases after I put on the new rotors they were smooth as butter. It has taken time for them to start warping and the pulsating sensation.

I'm still thinking wheel bearings.

Do you feel the pulsating every single time you brake? Or only in certain scenarios?

How do you set preload on your wheel bearings?

To change rotors, you have to take the hub of the spindle, so you're disturbing bearings.

If preload isn't adequate, or you don't get bearings fully seated, it may only take a few thousand miles for them to show up loose enough to cause a pulse in the brakes.
This is my experience anyway.

If you're measuring run out with loose bearings, is the run out actually in the rotor or down to loose bearings?

 

[SHIfTHEAD]

I'm still thinking wheel bearings.

Do you feel the pulsating every single time you brake? Or only in certain scenarios?

How do you set preload on your wheel bearings?

To change rotors, you have to take the hub of the spindle, so you're disturbing bearings.

If preload isn't adequate, or you don't get bearings fully seated, it may only take a few thousand miles for them to show up loose enough to cause a pulse in the brakes.
This is my experience anyway.

If you're measuring run out with loose bearings, is the run out actually in the rotor or down to loose bearings?

So this *could* have been the winner! I pulled off the caps today and found the locking nut on one side little more than finger tight. Odd since I just replaced the rotors a few months ago...but I have been known to screw up now and again. So I went through the torquing process and got it all sorted out and locked up. Drove it home tonight and so far I couldn't detect much brake pulsing, but thought I could feel a little bit. I assume that's down to the little bit of runout I measured in the disks, which to be honest I felt as soon as I put them on the truck.

 

[mudgudgeon]

I pulled off the caps today and found the locking nut on one side little more than finger tight. Odd since I just replaced the rotors a few months ago...but I have been known to screw up now and again.

This is why I asked how you set preload on wheel bearings.

It's not necessarily that you screwed up, but more so that the typical way of setting bearings that works for the family sedan is not suitable for these trucks, also the FSM method is problematic and unreliable.

I repeatedly had issues with bearings coming loose quickly after following the Toyota method to a tee. I no longer use the Toyota FSM method.

 

[SHIfTHEAD]

This is why I asked how you set preload on wheel bearings.

It's not necessarily that you screwed up, but more so that the typical way of setting bearings that works for the family sedan is not suitable for these trucks, also the FSM method is problematic and unreliable.

I repeatedly had issues with bearings coming loose quickly after following the Toyota method to a tee. I no longer use the Toyota FSM method.

What's your process, in case I get to do this again? I torqued to 43ftlb, backed it off and torqued back to 43, backed it off and tightened till I got about 7.5lbs of pulling force before hub rotation. Basically the FSM procedure. But it sounds like I'll be doing this again soon, so I want to use your trick.

 

[bonestock]

Been down this long, expensive and irritating road myself. Only thing that put it to bed was a full OEM part replacement (calipers, pads and rotors). Trouble free since.

 

[mudgudgeon]

What's your process, in case I get to do this again? I torqued to 43ftlb, backed it off and torqued back to 43, backed it off and tightened till I got about 7.5lbs of pulling force before hub rotation. Basically the FSM procedure. But it sounds like I'll be doing this again soon, so I want to use your trick.

There's heaps written here about bearing preload.
Tried and proven method is torque the inner nut to 20-35 lbs. (Stock tyres, go 20. 35"s or bigger, go to 35lb).
Rotate the hub back and forth a few times.
Retorque to the same 20-35lbs ( whatever you chose).
Fit tab lock washer.
Torque outer nut to 45lbs.
Bend locking tabs into place.

I also use a dead blow hammer, as well as rotating the hub, smack the hub onto the spindle with dead blow hammer befire torquing the inner nut the second time.

This is all about ensuring the tapered bearings are settled/seated before you finalise the preload/torque.

The pull test from the FSM is unreliable, and has been proven to be inconsistent/unrepeatable and affected by your choice of grease.

Only takes a few minutes per side to retorqye when bearings and see if that solves your problem. It's free and a low hanging fruit that gets overlooked. BTDT