Brake Caliper mounting bolts! Replace them when removed. Alert Alert Alert (1 Viewer)

[2001LC]

Okay here I go again with Alert Alert Alert.

We had some discussion in and unrelated thread RTH Timing belt on torquing bolts, and the caliper bolt came up. I feel and alert is called for, to bring attention to the brakes caliper bolts walking out.

Based on info gather here in mud, and that fact Toyota change recommendation for the 200 series, to non reusable and add thread sealer. These are non re-usable bolt IMHO. I not saying run and replace before driving, just when removed. 99% of all 100 series have had, brake caliper bolts removed and re-torque more than once. Many are rusty. All have stressed by use.

Also worth note:
Australian Safety Recall for LX470 and LC100 - Front Disc Brake Rotor Retaining Bolt

Toyota—Land Cruiser and Lexus—Front Disc Brake Rotor Retaining Bolt
PRA number: 2007/9087 Date created: 1st March 2007

Land Cruiser 7#. Model Code FZJ78, FZJ79, HZJ78, HZJ79, HDJ78, HDJ79. Land Cruiser 10#. Model Code FZJ105, HZJ105, UZJ100, HDJ100. Lexus LX470. Model Code UZJ100. Production period 30 September 1997 through 5 December 2005.

When vehicle is operated under severe conditions with repetitive high "G" brake application forward and backward, excessive forces applied to the brake rotor may loosen the front brake rotor bolt/s. If vehicle operation continues in this condition, one or more bolts may loosen further (unwind) and eventually rattle free.

What should consumers do? All owners of affected vehicles will be contacted individually by letter.
Other regulator reference numbers: 7531A

 

[2001LC]

Brake Caliper mounting bolts:

Factory Service Manual (FSM)
I've been rooting around FSMs from 2000 thru 2010. From 00-07 they do not recommend thread sealer on or replacement of caliper mounting bolts anywhere I've seen. They simple give a torque spec. Every bolt on the 100 series has a torque spec. Some bolts and nuts have diameter spec to check before reuse, like head bolt as they stretch. Some are non reusable, pre-coated or call for a thread sealer.

I'm a big stickler for following the FSM to the letter. But I've found many misprints, some wrong procedures and some stuff we need to do that is not in the FSM or that Toyota subsequently change their position on..

In 2008 (200 series) is first mention of caliper bolt being non reusable.

I've not been adding thread locker to brake caliper mounting bolts. Some may say; "we'll why not". Well whenever a thread is lubed, be it thread locker/sealer, anti seize, oil, grease, wax, etc torque should be reduced. I get that info from Denso dealing with spark plugs.
________________________
Denso:
TORQUE RECOMMENDATION
The table on this page gives the recommended torque for proper spark plug installation. Improper installation may cause poor performance, and even result in engine damage.

Note: The installation torque values shown above apply to new spark plugs without lubricating the threads. If threads are lubricated, the torque value should be reduced by approximate 1/3 to avoid over-tightening.

*1N•m=0.1020kgf•m

Spark Plug Installation

Spark Plug Installation

densoautoparts.com

___________________________________________

I was also given, by mud member, a very cool document on fastening system from aircraft industry. Talking about the difference performances of fastening systems. He first brought to my attention when he saw me greasing some trailer hitch parts for rust mitigation. Like I said I learn so much from mud and it's great people. That doc also has section dealing with nuts & bolts. Bottom line, if you lube the threads it alters torque.

Most everyone feels Toyota uses very lite torque spec, as it is!. So if were going to replace the caliper bolt. Over torquing, due to lubing threads with sealer, should not matter. But I did see a lower torque in the 200 series of 73ft-lbf vs our 90ft-lbf in the 100 series for front caliper bolts.

Caliper Bolt for 200 series looks pre-coated, see the red:

The coating, which effectively lubes the thread, may be why Toyota reduced the torque in the 200 series to 73ft-lbf.
The 100 series don't look like pre-coated. But I'll know soon, as I'm ordering some this week.
Here's another pic I pulled from Partsouq.
100 series caliper bolt does not look pre-coated.

As stated, Toyota in the 2008 200 series FSM changed recommendation to non reusable for Caliper mounting bolt. Given that, and the statements we've seen in the 100 series tech section of mud, on them coming loose. I feel and alert to mud is called for.

So bottom line replace the caliper mounting bolt and or seal the threads when removed, would be best practice!

 

[nukegoat]

So the FSM doesn't say to, and on a different vehicle, it does, so we need to? What makes caliper bolts different than every other fastener?

 

[Matt Phelps]

Hey Paul,

I lost a driver side front caliper either due to not torquing upon re-installation, (I seem to recall tourquing everything down), or the caliper bolt walk itself out. Either way the result was caliper fell out of position and ground on the rim for sometime.

It happened while flat-towing my LC, so I'm not sure how long it was scraping for.

Interested to see other's experiences.

 

[CanadianRockyCruiser]

I've never had a problem reusing my original bolts without thread locker. Perhaps I've been blessed with natures loctite (rust) in Canada's winters. Is it possible that the issues are isolated to a failure to torque?

 

[FxFormat]

We don't use loctite in the North East, rust is our loctite, and is 10x stronger.

 

[FarmTruckLX]

Thanks for sharing this. I had a rear caliper bolt come all the way out once. The other bolt on the same caliper worked lose, but wasn’t quite out when I heard the noise. The caliper would bounce up and rotate down on the rotor when I went over a bump. Fortunately, I was able to get a bolt locally and go on. I assumed that I had missed torquing them, but now I wonder.

Could someone please confirm, are the part numbers for bolts and washers the same for front and back?

 

[2001LC]

When I first saw Toyota change the recommendation. I though possible it was due to rusty bolts concern. They are weaker if rusted. But now I feel it has to do with bolt stretching more than rust. If rusty, the bolt will be compromised and should be replaced.

@JunkCrzr89 in the RTH Timing belt thread agrees. He stated he thinks they stretch!
Is this why they walk out, who knows. Need and engineer to come forward.

 

[nukegoat]

When I first saw Toyota change the recommendation. I though possible it was due to rusty bolts concern. They are weaker if rusted. But now I feel it has to do with both stretching more than rust. If rusty the bolt will be compromised. @JunkCrzr89 in the RTH Timing belt thread agrees. He stated he thinks they stretch. Is this why they walk out, who knows. Need and engine to come forward.

You could calculate if the bolts are at a yield point based on thread pitch, size, and grade. They're m12 bolts, right? Even a 10.9 m12 fine thread typically gets torqued to 90ish ft lbs in a non TTY scenario

 

[2001LC]

	Caliper mounting bolt	90105-12175 BOLT, HEXAGON(FOR FRONT DISC BRAKE CALIPER)
	Caliper mt bolt washer	90201-12452 WASHER

We may not need washer for fronts as picture looks like they're part of bolt.

Bolt/washer cali mt rear

90105-08304 BOLT(FOR REAR DISC BRAKE CYLINDER MOUTING)

You could calculate if the bolts are at a yield point based on thread pitch, size, and grade. They're m12 bolts, right?

Have at it Nukegoat.

I don't have any of these bolts in shop at the moment, so don't know size. But that sound right. FSM gives type bolt and torque by markings on the head.

But If we're changing them out, I'm not overly concerned with over-torquing due to lubing threads with a sealer.

 

[kruisinkid]

all bolts stretch when torque'd properly. thats why they in theory they do not loosen because they are acting as their own lock/spring washer. once that new bolt is torqued and thus stretched, a percentage of that will not unstretch. in wire rope it is construction stretch and is typically about 10%. i can certainly imagine that with a caliper bolt, once torqued and then hundred or thousands of temperature cycles, that bolt will unstretch even less. im sure they are strengthened bolts like a head bolt and i thought more often than not (like the 80 series?) when you do a head gasket job, you are supposed to use new head bolts. certainly if you are reusing a caliper bolt, i would up the torque spec maybe 10%. sure some blue loctite will certainly help, i cant imagine it hurting. and I cant imagine we are all using $500 torque wrenchs that are recertified every year and whatever number we think we are torqueing to, it is some small amount off.

so i would agree that it is a good recommendation to either use new caliper bolts or loctite them, and i would up the torque spec a few percentage points to cover for the not-amazing torque wrenches most of us are using.

 

[nukegoat]

all bolts stretch when torque'd properly. thats why they in theory they do not loosen because they are acting as their own lock/spring washer. once that new bolt is torqued and thus stretched, a percentage of that will not unstretch. in wire rope it is construction stretch and is typically about 10%. i can certainly imagine that with a caliper bolt, once torqued and then hundred or thousands of temperature cycles, that bolt will unstretch even less. im sure they are strengthened bolts like a head bolt and i thought more often than not (like the 80 series?) when you do a head gasket job, you are supposed to use new head bolts. certainly if you are reusing a caliper bolt, i would up the torque spec maybe 10%. sure some blue loctite will certainly help, i cant imagine it hurting. and I cant imagine we are all using $500 torque wrenchs that are recertified every year and whatever number we think we are torqueing to, it is some small amount off.

so i would agree that it is a good recommendation to either use new caliper bolts or loctite them, and i would up the torque spec a few percentage points to cover for the not-amazing torque wrenches most of us are using.

Stretch doesn't mean plastic deformation, though. For critical fasteners near their ultimate strength, they are employed in a torque to yield approach which definitely plastically deforms them.

This is a simple thing to test, though. Measure a caliper bolt, torque to 90 ft lbs, remove. If stretched, then yes, they are TTY. But I highly doubt it's a concern here.

 

[ClassyJalopy]

Hey Paul,

I lost a driver side front caliper either due to not torquing upon re-installation, (I seem to recall tourquing everything down), or the caliper bolt walk itself out. Either way the result was caliper fell out of position and ground on the rim for sometime.

It happened while flat-towing my LC, so I'm not sure how long it was scraping for.

Interested to see other's experiences.

One bolt on my driver side caliper backed off and caused the caliper to rotate and lock up the wheel. Lucking it happened in my driveway after I had returned from a 250 mile trip. Needless to say I used the red thread locker on it upon reassembly with new bolts.

 

[gregnash]

FYI... just happened to see this thread while I was perusing the Wits End site (@NLXTACY ) and he has both bolts (front and rear) OEM in stock under the 100 series section. Once again making it super easy to find things you need.

 

[abuck99]

Blue locktite is fine- red will make it very tough to remove with out heat. Match mark the bolts and give periodic inspection movement- at oil changes would be good timing.

 

[nissanh]

Here is my experience with toyota:
I fix my dad's hilux LN 106 made in 1990 and it still has same caliper bolts and never used any thread lockers.

When I took the truck to get front leafs springs done, you won't believe what the guy did to the front brake hoses. He NEVER disconnected the brakes (hoses or caliper from mounting) and simply raised the truck to release the tension on the leafs springs. That made the hose to stretch almost 100% percent. I was small and had no idea, but nothing happened to hoses and it got replaced after 12 years due to being old.

Newer toyota's are not as good as the ones made back then I guess.

 

[katit]

I always replace those Toyota or not. It's like $5 to brake job, just a small piece of mind. Don't care what manual says!

 

[Kofoed]

I see a lot of wash board roads......I use a lot of loctite, nylock nuts, etc

 

[2001LC]

I'm not saying everyone need to run out buy new caliper mounting bolts before driving. Just be aware.

From this day froward, I'm doing like @JunkCrzr89. First reuse seal the threads, next time replace the bolts.
I'm also marking/painting bolts once torqued as visual aid.

The extra $10 and 10 minutes is worth it in my shop.

Is this over kill. I do not think so.

Here's why:

Toyota made the change to recommendation, for a reason. IMHO it because they found issue with caliper bolts after repeated re-torque.
In the 200 series:
They now say don't reuse!
They now pre coat bolts with a thread sealer!.
They reduce torque to compensate (IMHO) for coating on threads.

Given Toyota made this change and the small sampling we see reported in mud falling out. Why not consider.

There's a number of change in the 200 series FSM. As I spot them I adopt them, provided they make sense. Replacing these caliper bolts makes sense to me!

You make up your own mind.

 

[JunkCrzr89]

Needless to say I used the red thread locker on it upon reassembly with new bolts.

Have fun getting those off again! As @abuck99 noted, BLUE loctite is what you want.