Torque Values for Lower Balljoint Bolts - Very Important - Please Read

[mtbtim]

Hey Dudes,

I just learned something about the two different style bolts for our LBJs that is very important for you to know.

I knew there were two different style bolts already. One for the 1996-2000 models that don't have a dust cover over the boot and another for the 2001-2002 models with the dust cover. It appears that the difference in torque values many of us have seen is potentially not due to some error the technical writers of the manuals made, but it's due to a difference in tensile strength between the two different style bolts. We all know that there's mistakes in these manuals and i assumed that this was yet another incidence of them making a mistake. But, it appears there is good reason for the two different torque values printed in the manuals.

Here's the part numbers for the two different style bolts

1996-2000 use a flanged bolt, part #90080-10066

2001-2002 use a bolt with a washer (it's a little longer than the 1996-2000 bolts), part #90119-10933.


The #90080-10066 bolts are suppose to be torqued to 59 ft-lbf

The #90119-10933 bolts have a lower tensile strength and should only be torqued to 37 ft-lbf.

Torquing the #90119-10933 bolts to 59 ft-lbf causes stretching of the bolt and increases the chance of failure. This is maybe why we have heard people reporting a balljoint failure not from the joint coming apart but from the bolts shearing off.

This was brought to my attention by somebody posting the following information on our YouTube video for this job.
The different LBJ bolts and why it's important, Prado 90 Series — Mighty 90s Forum

 

[WeakSauz]

Great info. I have 02 spindles in my 2000, and have the longer 01-02 style bolts in. Of course, they're torqued to 59 ft-lb, so my OCD is now clicking off .

I'm beginning to wonder if it makes sense to move to something like an ARP bolt in the LBJ for the dramatically increased tensile strength. Surely something like an ARP bolt would take a considerable amount of torque compared to OEM. But then it becomes a game of not getting them so tight the knuckle gets stripped.


I just an hesitant to bastardize what engineers likely spent tons of time, effort and money on getting right. (but, with LBJs, I'm wondering if they really got these right?)

 

[Ryance39]

Great find Tim! I always kind of wondered why the two different bolts, but never spent much time thinking about it.

Is it still the general opinion that a little Loctite on the threads is a good piece of mind?

Will be doing my LBJs here in about two weeks.

 

[Kanoe]

Great bit of information, Thanks Tim. This should clear up some confusion for sure.

I wonder why the change? Why a weaker bolt with lower torque values for the 01/02's? What was the engineers reasoning?

 

[mtbtim]

Great bit of information, Thanks Tim. This should clear up some confusion for sure.

I wonder why the change? Why a weaker bolt with lower torque values for the 01/02's? What was the engineers reasoning?

Yeah, my thoughts as well. I know they chose a longer bolt due to the dust covers on the 01 and 02 models but why didn't they spec a bolt with the same tensile strength as the other bolts. I guess to save money?

 

[weekendclimber]

Hey Dudes,

I just learned something about the two different style bolts for our LBJs that is very important for you to know....

This is great information. I'm about to do the front bearings and have always just removed the ball joint from the LCA when removing the knuckles. Just bought a new set of ball joint bolts (90080-10066) to make sure I got these torqued to the correct number when I replaced them a few years back.

Thank you Tim!! :cheer2:arty::rockon::beer::trophy:

 

[rickmum]

This makes sense. I bought the later model bolts for my LBJ job and torqued them to 59 ftlbs about 6 months ago.
Fast forward to a couple weeks back, I was pulling the LBJ to service my CV axles and half of the bolts were stretched..
I replaced them with the older style bolts immediately.

 

[mtbtim]

This makes sense. I bought the later model bolts for my LBJ job and torqued them to 59 ftlbs about 6 months ago.
Fast forward to a couple weeks back, I was pulling the LBJ to service my CV axles and half of the bolts were stretched..
I replaced them with the older style bolts immediately.

Thanks for sharing this. This backs up what I was told by the guy commenting on our video and what was explained in that Prado 90 Series forum link I provided.

 

[3bears]

I used the older styoe ones in mine and used locktite.
but what is the advantage of the newer ones other than a dust cover ? Is the dust cover just to protect the threads that push past the lower knuckle ?( I have not seen one).
The older ones must be stronger thus the higher torque value. can a person use the old in place of the new, or was there more to the design change in 2001 nd 2002 to require those "weaker" bolts.

Again not "seeing" the difference or application myself first hand, will toyota eventually supersede to the newer ones when ordering the older ?

 

[phattyduck]

Yeah, my thoughts as well. I know they chose a longer bolt due to the dust covers on the 01 and 02 models but why didn't they spec a bolt with the same tensile strength as the other bolts. I guess to save money?

With the new longer bolts, more unthreaded length of the bolt is exposed (due to the extra space of the dust cover), so there is a different ratio of stretch to clamping force. Also, a separate washer compared to a flanged head will require a different torque value to obtain the same clamping force.

At least, that's my theory... Mechanical engineering at this level isn't always intuitively obvious.

-Charlie

 

[mtbtim]

I used the older styoe ones in mine and used locktite.
but what is the advantage of the newer ones other than a dust cover ? Is the dust cover just to protect the threads that push past the lower knuckle ?( I have not seen one).
The older ones must be stronger thus the higher torque value. can a person use the old in place of the new, or was there more to the design change in 2001 nd 2002 to require those "weaker" bolts.

I think the reason for the longer bolts is to afford room for the dust covers and make sure there's full thread engagement of the bolts with the steering knuckle. The dust covers I believe are just extra protection for the rubber boots of the balljoint so it doesn't get torn possibly from road debris or trail debris.

Now, why they chose weaker bolts, who knows. Maybe they chose a lighter torque value because there were reports of people stripping the female threads on the knuckles and there was no longer a need for the higher tensile strength bolts that were used on the older models. Just a guess. But, a ton of us have achieved the 59 ft-lbf torque value with no issues so that theory might not really hold weight.

 

[JZiggy]

Guys, this is a great discussion. Can someone with parts and bolts in hand upload some reference images? It would also be great to see pictures of the bolt heads and markings... we should be able to reference the bolt class from the Toyota manual to get rated proof strength and figure out what the torque values "should be".

 

[mtbtim]

Guys, this is a great discussion. Can someone with parts and bolts in hand upload some reference images? It would also be great to see pictures of the bolt heads and markings... we should be able to reference the bolt class from the Toyota manual to get rated proof strength and figure out what the torque values "should be".

Hey Jordan, there are some pics of the bolts in the Prado 90 Series forum link I provided, if that helps.

 

[JZiggy]

Oh thanks, I missed that link. There's tons of good info in there.

The 90080-10066 bolts that the 96-00 4Runners spec appears to be a part number that supercedes the 90105-10406 part number he references as the "best" bolt in the Prado 9 0post.

The bolt head marking, four stripes and two dots, indicate it's a Toyota 11T class which is the strongest bolt noted in the FSM.

I believe these are M10-1.25 bolts about 30mm long. ARB makes a replacement that may be stronger but interestingly the torque rating is lower... might be due to lower thread friction from special bolt coating, dunno:
The Official ARP Web Site | Kits

Metric 8.8 = 110ksi
Metric 10.9 = 150ksi (probably what the Toyota bolts are equivalent to)
Metric 12.9 = 170ksi (maybe too brittle
ARP bolts 8740 chromoly = 180-210ksi

Another idea no one has mentioned yet is to replace the bolts with high strength studs and flange nuts. A stud connection is nearly always superior to a bolted connection.

 

[RS Dude]

When I replaced my LBJs about 2 yrs ago, I torqued them to 37ftlbs with blue threadlock. How important is it to torque them to 59ftlbs?

 

[WeakSauz]

Another idea no one has mentioned yet is to replace the bolts with high strength studs and flange nuts. A stud connection is nearly always superior to a bolted connection.

That is quite interesting, and I'd be very curious to see something like this tried.

I am strongly considering going with ARP 12pt hardware next go-around
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The issue with the ARP hardware becomes tightening them so much that the actual threads in the steering knuckle get compromised. The increased tensile of the ARP bolts should theoretically accept more torque-- but how much until the threads in the knuckle get pulled? hmmm

To your point, a studded setup may alleviate this!

 

[Kanoe]

Another idea no one has mentioned yet is to replace the bolts with high strength studs and flange nuts. A stud connection is nearly always superior to a bolted connection.

I could see the stud set up being a problem in rust prone areas. The upside down nut and stud end could fuse together pretty badly. At least with the bolts a person gets new hardware every LBJ change and most of the thread is protected in the knuckle.

Might work well for snow free areas though...

 

[turbodudey2]

Lubrication plays a huge factor in the torque required to achieve a given clamp load too.

For example a lubricated bolt vs a dry bolt can vary from 30 ft*lbs all the way up to 50 ft*lbs of torque to achieve the same clamp load.

In general adding a washer under the bolt head will reduce friction during tightening.

I haven't seen a specification in the FSM for a particular lubrication process for the ball joint bolts. This could account for some of the bolt failures that have occured in the past. If a person were to well lubricate the bolt and tighten to 59 ft*lbs versus using no lubricant and only torquing to 37 ft*lbs, the clamp load could vary by as much as 4,000 - 5,000 lbs.

 

[rickmum]

Adding to the discussion here.. when I pulled my 'new style' LBJ bolts a while back, one of the bolts snapped off in the knuckle. Luckily there was lots of thread sticking out the top and I backed it out with vice grips.

When I called the dealership to buy the 'old style' bolts to replace them all with, they tried giving me the 'new style' bolts, stating that the 'old style' had been replaced with the new part number. I told them no, I want the 'old style' ones.

 

[JZiggy]

For those interested in trying out studs... ARP kits are pretty pricey but Fastenal has some 10.9 rated studs and flange nuts that would be similar class to the Toyota bolts, just in a stud format.

M10-1.25 JIS - B1190 Steel Class 10 Zinc Flange Nut
| Fastenal
M10-1.25 x 48mm OAL YZ 10.9 Cylinder Head & Manifold Double End Stud
| Fastenal (not sure if this gives enough length)

I'd install the stud with loctite into the knuckle at 1/4 to 1/3 of the final torque desired so about 18 ft-lb. Then after the loctite sets you can install the balljoint using the final 59 ft-lb with the nut.

I might try this myself sometime.