Holy crap! I'm working on the CrewCab today and pull the tires off the front and find that there is a HUGE hole in the rotor! It's in the corner of the top-hat section and measures about 1.5 inches long by .75 inches wide. It goes completely through the rotor and I can stick my finger in it and touch the inner hub.

:eek: :eek: :eek:

This is a genuine LR vented rotor that's been on the truck from new (approx. 2 years now). I see that there are not any impact marks on the inside of the rim where it may have had contact with a rock or something getting jammed in there, and there isn't any obvious deflection of the rotor itself around the hole.

Pics to follow, but I wanted to throw this out there to see if anyone had heard/seen it before. Wow, it was a total shocker!

That's not right!!!
Does the vehicle sit for long periods of time?

Long periods of time? No, not really. If you're thinking a rust puddle eating the bottom of the rotor out, I don't think that's it. It looks to me like it's just a weak spot in the metal (but I'm not a metallurgist, obviously).

:confused:

This thread is worthless without pics :flipoff2:

(yeah, I know I have lots of room to talk about pics)

You have a problem with mice in the garage? :flipoff2:

Here are some pics. The first one is of the entire rotor. This is a genuine rotor that had the green cad plating on it when new. The spacer you are seeing between the rotor and the hub is a custom spacer to allow us to use some late series III hubs on the coil-sprung knuckle. This gave the freedom to use freewheling hubs on the front axle. Kind of complicated and expensive, but I wanted to let you guys know what you were looking at.

http://tawayama.com/gear/randompics/hole-in-rotor.jpg

The next shot is a detail of the hole in the rotor.

http://tawayama.com/gear/randompics/holedetail.jpg

It looks to me like the bolt on the inside has been rubbing against the ID of the rotor? I have noticed squeaking in the past, but have always attributed it to the pads, never seeing anything weird upon inspection. It looks as if it's been wearing for a while by the look of that bolt head. Thinking that is has caused a weak spot in the rotor by the wearing against the bolt, and it finally gave way and chunked off like it did. Not having the rotor off yet, I can't confirm my theory, but from the looks of the bolt head, and the way that rotor chunked off, that's what I'm leaning towards.

The truck is in the garage (no small feat BTW...), and I will take off the rotors in the next few days to see what they look like on the inside. I wonder if I am using bolts with a head that is too tall? Are there bolts with shorter heads for the hub?

Anyway, if you REALLY want to see the whole pic that is un-resized and really big, you can download it here:

http://tawayama.com/gear/randompics/DSC_0879.JPG

Any ideas?

Something with some force pushed that piece from the inside...out. I wouldn't be suprised if you find something inside the hub when you remove the brake disc. Might have caught between the disc and that marred bolt head and broke it out.

Billster

That looks like a design flaw created by your spacer off the hub to me. I agree that something got inside and pushed from the inside out. So how can you keep anything from ingressing that area? That could have been more serious a problem. Mud sheild?


JP

seen exactly the same when one of the bolts that hold the rotor on had come out and spun around inside till it made a break for freedom.

I concur.

Something wedged inside and popped that peice from the inside out.

Like the battleship maine.

If you could only find the piece. A little JB weld and it would be good as new :flipoff2:

That looks like a design flaw created by your spacer off the hub to me.
JP

You are talented at yanking the chain aren't you? :D I don't think that the spacer let anything in there. The relationship of the hub to the rotor doesn't matter in this case. Something would have had to come in from the inside, and the spacer is completely sealed off. So, I disagree that the spacer had anything to do with it.

But, it does seem reasonable that something was bouncing around in there until it made it's own escape route.

seen exactly the same when one of the bolts that hold the rotor on had come out and spun around inside till it made a break for freedom.

Maybe I'll find one of my bolts from the rotor is missing when I take it all apart? Kind of blows Pendy's theory out of the water now doesn't it? :flipoff2:

You are talented at yanking the chain aren't you? :D

Don't worry Mike, I did all I could to dispel Pendy's rep at the SEMA show. Shopgrrl helped by telling everybody what a pussycat Pendy really is :flipoff2:

If you could only find the piece. A little JB weld and it would be good as new :flipoff2:

Couldn't you just fill the hole in with JB Weld. Or if you didnt' have any, maybe some caulking??? :confused:








:flipoff2:

-Jeff

Couldn't you just fill the hole in with JB Weld. Or if you didnt' have any, maybe some caulking??? :confused:








:flipoff2:

-Jeff

Duct tape?

toothpaste worked on the dorm walls when I was in college.....maybe it work on the rotor :D
Make sure you use tartar control.

Oh, that's a normal, stock inspection port that LR designed into the rotor. Just run it and quit worrying.

Yeah, you guys are a lot of help.

:shaking:

Yeah, you guys are a lot of help.

:shaking:

You're welcome :flipoff2:

Meow.


But the spacer puts the rotor closer to the spindle flange. And that is where something decided to break out. Of course if something came loose inside then that is a different problem.

Whatever happened I hope I can help you jump to conclusions. Why else would you ask for insight?

JP

But the spacer puts the rotor closer to the spindle flange.

YOU ARE WRONG! :D The spacer actually puts the rotor back into the factory position. The late SIII hub is dimensionally different from the stock coiler hub. In order to use the free-wheeling hubs, SIII hubs needed to be used, and we needed to have the spacer built to place the stock rotor precicely into the stock position, so that the factory calipers could be used. (still with me?)

I *suppose* a mud shield would have worked, but the rotor and caliper are in their stock locations.

And that is where something decided to break out. Of course if something came loose inside then that is a different problem.

Whatever happened I hope I can help you jump to conclusions. Why else would you ask for insight?

JP

You are right about that. This is a great place to get people to jump to conclusions. :flipoff2:

You are right about that. This is a great place to get people to jump to conclusions. :flipoff2:

While trying to withhold my laughter at the BB comment, if you don't like what you learn here, Dweb might be back up soon and you can ask these questions there :D

That's just mean PT! You go to Dweb for arguments, not information!

"You malodorus toffee nosed twit!"
"What? I came here for an argument!"
"Sorry sir this is insults, arguments are down the hall."

If you bought spacers from EE and not made them yourself the only thing left after a nuclear war would be cockroaches and those spacers.
Did I help?

YOU ARE WRONG! :D The spacer actually puts the rotor back into the factory position. The late SIII hub is dimensionally different from the stock coiler hub. In order to use the free-wheeling hubs, SIII hubs needed to be used, and we needed to have the spacer built to place the stock rotor precicely into the stock position, so that the factory calipers could be used. (still with me?)
I *suppose* a mud shield would have worked, but the rotor and caliper are in their stock locations.
You are right about that. This is a great place to get people to jump to conclusions. :flipoff2:

Don't make me pay you a visit as well.

JP :grinpimp:

Don't make me pay you a visit as well.

JP :grinpimp:

Bring it! :D

Don't make me pay you a visit as well.

JP :grinpimp:

Don't you have work to be doing? If you have all this free time, come back out here and give me a hand. I have trucks stored outside as the shop is full. If something doesn't happen soon (trucks finished and paid), there will be five trucks outside waiting for room inside. A high-class problem, but a problem all the same. Two more head jobs once this one is done.

Get 'er done!

Took the hub off and looky looky what I found! Not one, not two but three, count 'em THREE missing bolts that hold the rotor onto the spacer.

I dunno what happened, maybe used too short of bolts, maybe didn't use loc-tite, maybe a combination of the two, but whatever I did wrong, it certainly didn't hold. Wow, what a shock. No wonder the hole blew out, there was a lot of shrapnel floating around in there. Interesting thing is, I dunno when it happened! I don't remember hearing any rattling, clanking, tinkling, or any other noise coming from that hub. OCCASIONALLY I would hear squeaking which I thought was a brake rotor/pad/rock combo, but now looking back I'm thinking that it must have been the bolts backing out and squeaking against each other. I *never* would have thought to take apart the entire hub to check for this.

Anyway, enough prattling on...here's a pic. :eek:

The stub axle didn't fare too well either. All of the bolt heads have been polished by the shrapnel bouncing around in there. The upper bolt has already been removed BY ME. I took it out to get the specs for it so that I can replace all of the remaining bolts. I don't want to leave any of the original bolts for the stub axle or the rotor. I'll be checking the other side too and replacing both rotors with DBA vented cross-drilled and slotted rotors.

Updates to follow....

Well I don't see any lockwashers on there or anthing else to hold them in and the stock bolts are stretch bolts so I want to say that indirectly it was the fault of the spacer because it caused you to use those bolts without anything to hold them in.

I would check the otherside too.

I still don't want to blame the spacer. I'd rather blame myself...for either using the wrong bolts, no lock-washers or loc-tite. Don't be a hater! :D

The other side will be changed to all new bolts for both spindle and rotor (as well as changing the rotor too).

I even think I have some extra brake pads around here somewhere...

I will agree it is definately your fault :flipoff2:

It seems to me that if you put regular bolts back in they will fail again. I don't think you can use lockwashers now that I think about it because there is not enough clearance (you would have to check), so that leaves loctite, little sketchy for me, YMMV, maybe take a stock bolt to a real bolt warehouse and get a longer one that is of exactly the same spec. Might be $20 for all 10 but it would probably be worth it.

Now that I've done a head gasket job on the engine and have learned about stretch bolts and how they work, I'm wondering about using them here. Couldn't I use stretch bolts for both the spacer and the rotor?

If so, how would I know which stretch bolts to get, and what to torque them at?

If you look at the original pictures you will be able to see if there is clearance for lock-washers. I'm not sure there is, I might try to put it together with them just to see.

Might I suggest that you look at the condition on the other side of the axle? If this side had problems, the other end might as well be about to :nuke: .

I mean, you have everything apart, and you are getting parts. I mean, think about it, if you screwed that side up, might have screwed up the other side too :flipoff2: .

"Now that I've done a head gasket job on the engine and have learned about stretch bolts and how they work, I'm wondering about using them here. Couldn't I use stretch bolts for both the spacer and the rotor? If so, how would I know which stretch bolts to get, and what to torque them at?"

How exactly does the spacer work? Do the bolts that hold the rotor to the hub go through the spacer?

If so I would take stock bolts that bolt the rotor to the hub to your local friendly bolt place (there is one in every major town whether you know about it or not) and be like I would like these only X longer (X being width of spacer) and then torque them down to whatever stock is or whatever the bolt guy recommened (well that is a lie, I would crank them down pretty hard and not bother with torque settings).

It looks like you might be able to squeeze a lock washer in there but I would be concered that it will be so tight that a mininal misallignment (from say a worn wheel bearing) would cause the bolts to catch on the spindle bolt head.

YMMV

Most loctites let go around 100C. Maybe that part of your hub would stay below that, but I wouldn't put money on it.

Just do them up tighter.

They do make high temp loctite (which makes removal interesting to say the least) but what dougal says is why I said "sketchy" on that solution.

Might I suggest that you look at the condition on the other side of the axle? If this side had problems, the other end might as well be about to :nuke: .

I mean, you have everything apart, and you are getting parts. I mean, think about it, if you screwed that side up, might have screwed up the other side too :flipoff2: .

Hey Max, scroll up and re-read post #29. If you read it SLOWLY you might notice that I said something about checking the other side.

Thanks for the reminder though. :rolleyes:

How exactly does the spacer work? Do the bolts that hold the rotor to the hub go through the spacer?

No. The spacer bolts to the rotor on the back side, and the front side bolts to the hub. There is no bolt that goes through the spacer from the hub to the rotor. Think of it like stacking Legos instead of making a shish-ka-bob.

:D

When I get it all taken apart, I'm actually considering having the hub and spacer beadblasted and cad-plated. If I don't get them cad-plated I'll at least paint them and will do a fancy two-tone paint job and photograph all of the parts apart from each other so you guys can see how it works a little better. I don't think I shot them when they were originally assembled.

I think I will be able to get some factory rotor stretch bolts and use them for the rotor to spacer and spacer to hub, needing 4 complete sets (2 for each side). That would let me use stretch bolts I think.

Humm . . .

How short are the bolts that hold the rotor onto the spacer? If they are too short stretch won't work. IIRC the stock bolts are fairly long and go in to the hub quite a ways. I could not see the stock bolts working to hold the rotor to the spacer.

The other solution would be avaition bolts (ie the one you wire shut).

EDIT: why did you not make it a shish-ka-bob, it would seem to be easier . . .

All bolts stretch if you do them up tight enough.

Well actually, some strip but most will stretch. :D

It would be best if you used longer bolts that went though the spacer and screwed into the hub.

If you do this and tension the bolts correctly the spacer will be preloaded in compression and will reduce the magnitude of the cyclic fluctuation of the tensile load in the bolts, thus improving the fatique capacity of the bolts.

If you prepare the joint faces correctly and tension high grade bolts to yield, spring lock washers will not be needed to prevent loosening.

Don't paint the joint surfaces, because you want metal to metal contact.

If you do this and tension the bolts correctly the spacer will be preloaded in compression and will reduce the magnitude of the cyclic fluctuation of the tensile load in the bolts, thus improving the fatique capacity of the bolts.

If you prepare the joint faces correctly and tension high grade bolts to yield, spring lock washers will not be needed to prevent loosening.


Ding, ding, ding-we have a winner. While you're at it, I think I'd give the high-temp loc-tite a try. If you use high-grade bolts (10.9, or 12), the split-ring lockwashers aren't gonna do anything anyway as the bolts will be too hard for the wimpy lockwashers to bite into.

I've done many rotor jobs and have never had such a problem. Were they torqued to spec? My torque wrench is a very good friend.

(Mike-you take the nicest pictures. I wish mine were close to that good, but I'll never spend the $ on a camera I know you have/do :flipoff2: Did you really pay more for that camera than my house? :D

I agree on the use of grade 10.9 bolts (I believe thats factory spec for the swivel ball to axle housing anyway), and suitable lock-tite. The factory rotor to hub bolts, and swivel ball to axle housing bolts use hardened washers, but not lock washers. If they will fit/clear, I strongly recommend using hardened washers.
Torqueing (sp?) bolts streches all bolts, it's the amount of stretch that is important. Torque to yeild means that the bolts have permamently stretched, and are not reuseable. Ideally, you want enough stretch to compensate for differences in expansion characteristics while still holding the parts tightly together. Of course the grade of bolt will effect the amount of stretch for a given amount of torque.
That's about the limit of my engineering knowlege on bolts, torque, and bolt stretch.

My .02

Jeff C.

Minor Plug for my shop to be follows:

JC's Rover & 4x4
WWW.jcrover4x4.com

P.S. I'll be upgrading my membership as soon as shop opens.

I've done many rotor jobs and have never had such a problem. Were they torqued to spec?

Probably not.

Did you really pay more for that camera than my house? :D

Probably. :D

Yeah, you guys are a lot of help.

:shaking:

Well if you really wanna know, I was aiming for you, with the 50 cal. and I got bit by an ant just as I pulled the trigger, so I flinched... damn your lucky :flipoff2:

... Of course the grade of bolt will effect the amount of stretch for a given amount of torque...

Until yield occurs, the amount of stretch is a function of the elastic modulus, not the tensile strength. Elastic modulus is practically the same for all steels, regardless of strength.

A good rule of thumb for designing bolted connections subjected to fluctuating tensile loads is: The bolt preload tension (not torque) should be at least twice the applied tension load on the bolt.

Normally for machinery, the preload tension is 65 to 75% of the bolt proof load.

For bolted structures subjected to dynamic loads (such as floors with vibrating machinery like screens), which don't have to be pulled apart, it has been a long standing practice to tighten the bolts to yield.

With bolts loaded in shear, bolt preload tension produces friction that resists the shear load. It is common practice, to design bolted connections so that all of the shear load is resisted by friction.

How about running normal hubs and getting some of the ashcroft free-wheel hubs that come with their part time 4wd kit?

Would that give you the solution you want but without the spacer in there to cause problems?

How about running normal hubs and getting some of the ashcroft free-wheel hubs that come with their part time 4wd kit?

Would that give you the solution you want but without the spacer in there to cause problems?

I don't know how long it's going to take you to figure out that I already have a part-time t-case and already have free-wheeling hubs. The *PROBLEM* was incorrectly torqued bolts, NOT the spacer.

Now, back to that spacer...

I got the rotor off this morning and discovered that the spacer actually is the shish-ka-bob style. I think I must have had Billster's wheel spacers on the brain when I was trying to describe the hub spacer. Different design entirely. The bolts that pass through it were not matched, no lock-tite, and honestly I probably threw it together knowing that I'd need to do it again *for real*, and forgot that it wasn't done correctly the first time.

Definitely operator error. :rolleyes:

Got all new bolts for the hub and spindle. Hub bolts are grade 8 with lock-washers, spindle bolts are 10.9. I'll get them on in the next few days, do the other side and report back.

Fair enough, just thought I'd suggest it as I know people with the kits over here have trouble giving the FWH's away...