First issue real issue with the 55 and some ?'s

[DaveInDenver]

BTW, AFAIK metric gradings are:

8.8 is 830 MPa ultimate and 660 MPa yield
10.9 is 1040 MPa UTS and 940 YS
12.9 is 1220 MPA UTS and 1100 YS

M12-1.25 (fine) has nominal minor area of 86.05 mm^2
M12-1.75 (course) has nominal minor area of 76.24 mm^2

So a M12-1.25 10.9 bolt will have:
Ultimate of 89,492 N, which is ~20,118 lbf
Yield of 80,887 N, which is ~18,184 lbf

 

[AndrewP]

Good reading here: http://www.rockcrawler.com/techreports/fasteners/index.asp


I would always, in every application take grade 8s over grade 5s.

 

[ntsqd]

My point was that there are better bolts that are both equal to or higher in strength and are simultaneously more Ductile than a G8. I'm not all that impressed with G8's. Their sole advantage is availability.
Using the F911 as an example:
UTS: 180,000 psi
YTS: 159,500 psi

I can't find my ref, but based on memory those numbers are roughly equal to the spec for the 1960 Series Socket Head Cap Screws.

I would not advocate using a G5 in place of a G8 unless it were considerably larger OD, and that's a klugey though sometimes necessary solution.

 

[DaveInDenver]

I dunno why you don't like grade 8, but like everything it's a trade off. Going to a grade 9 usually means the bolt is several times more expensive. For example, 1/2-20 x 3" yellow zinc bolts at Fastenal in G8 are $0.98/ea and in G9 (which Fastenal's manufacturer tests to ASTM F-606) are $2.49/ea. For reference, a G5 in regular zinc at Fastenal is $0.80/ea. Even Fastenal doesn't stock grade 9 in all their local stores (I get my critical fasteners at Fastenal just so I know they're not knockoffs and really G8). It's really a question of convenience and cost I guess. So what's wrong with grade 8? Oh, also, am I wrong in presuming that in shear a higher graded bolt is also stronger? IOW, is shear directly convertible from tension or will the brittleness of a higher UTS bolt truly be a downfall in shear? I mean, seems like the tensile strength of a bolt is based on the shear of the threads, so doing a straight rule-of-thumb to derate by 60% is valid? IOW, is 150 ksi x 0.60 = 90 ksi really true for shear?

 

[Photog]

Perspective people.

There is nothing wrong with G5, G8 or G9's. It depends on the amount of strenght the fastener needs, while in service. You would not have any need to use G8 fasteners to hold your fendes on. The fender will fail long before a G5 would fail.
Normally you want the yield strenght of the fastener to be higher than the maximum force applied during service. That way the fastener is always under only one load, the one placed on it by torquing the nut. If it never yields under max load, then the ultimate tensil strength is not a consideration.

If you think it may be a high load item use a G8. If it is a critical item; something that causes harm or death if it fails, use a G9 and LokTite (or equivelent metric).

 

[ntsqd]

FWIW I'm not aware of the SAE publishing a spec for a Grade 9. That is one or more mfg's idea of what they think is better than a G8. If that has changed I'd be interested in learning about it.

My main problem with G8's is that most everyone considers them to be some kind of miracle bolt, which they are very, very far from being. For miracle bolts you start with ARP and then look to aircraft/aerospace fastener mfg's. Coast Fabrication has a decent selection of bordering on miracle bolts. At bordering on miracle bolt prices.....

May not matter as much in Overlanding, but in racing you can be very sure that a G8 will be used where a Holo-Krome SHCS or an F911 is required. So the easy solution is to not have any G8's (much less G5's) anywhere near the prep shop.


And, None of this helps the OP. As has been stated, you've nothing to loose except some time & a little cash. I'd try Heli-Coiling the striped knuckle tab. At the very worst you'll have a junk part (I'll pay shipping here). At the best you'll have a usable part or a spare. Most likely you'll have also learned a new skill.

Now, who wants to discuss better alt's to a Heli-Coil?

 

[Photog]

You are correct, there is not actually a designation of G9. I was refering to the FXXX series of fasteners, with higher specs than the G8's.

Also true in racing world, to have simplest system that will not fail, including repair processes. Overkill on fastener strength does not increase weight of vehicle, just lightens the wallet. Sponsors don't want you to lose due to an incorrect bolt that would have cost an extra $2.00.

I was recently looking at the Honda Indy car, at a trade show. All fasteners I could see, had the same markings as the fasteners used in the aerospace industry.

 

[ChuckB]

Just figured out what Kurt was asking me to measure. I'm a visual learner :Wow1:

11mm vs. 12mm Knuckle bolt pattern

I don't have one of those fancy gadgets to measure the diameter of the bolts so hopefully I can figure out how to do it with a tape measure...

 

[dieselcruiserhead]

Excellent thread. Everything is correct here. Also your Land Cruiser disk setup is worlds worlds better than the MAF disk brake conversion. It uses noticeably stronger brifields versus the original coarse spline drum brake knuckles.

Anyway everything here is correct. There is also a distance difference between the old and new knuckle pattern, the older (76-79 I think?) is a smaller overall pattern. Either or but the best setup would be the larger pattern, which with your vented rotors makes your front axle the same as a FJ60, which is a great setup and as good as it gets until you get to FZJ80 stuff which about the best SFA Toyota stuff out there.

Anyway, if you do not use the clips again (they are really not required IMO) use a mild glue like elmers and literally glue the pads to the pistons in the caliber. The glue and the clips do the same thing -- they are supposed to stop brake squeaking, by always having the pad firmly against the brake calipers in a rust-free situation.

My speculation on why the bolt wasn't there was simply because the PO or a shop ruined it with the swap. No big deal. But the front axle rebuild is, IMO, one of the messyiest jobs out there. It is also really quick to do if you know how to do it (I've probably done over a dozen times, can get it done in an hour or maybe a hair longer with air tools) but it took me over a day per side the first time, reading the manual and looking at directions/photos online as I had questions. Again, if there is a local cruiserhead or a mini truck guy (the front axles are nearly identical) perhaps you can have one of them show you. It is less preferred but it works to have one bolt in there for now for a week or less IMO. It is a little dangerous but if its help up this long then it is great. You are getting the real organic experience of cruiser ownership.. Which honestly is priceless and goes a long way IMO, there is something very natural and powerful about it.

 

[ChuckB]

Andre,

If I read your post right, are you saying that you can tell by the pictures that I have the 12mm knuckle pattern? If so, that would be great as it sounds like this is the much better setup.

I have been driving around (unknowingly) with one caliper bolt for about 2 months. But its in the garage now and its not leaving until its fixed properly.

I figure since I had my FJ60 for about 4 years and really never did anything to it other than put gas and oil in it, my time has finally come to do some real :Mechanic: I need to de-virginize myself as far birfields are concernced!!

 

[cpg]

Andre,

If I read your post right, are you saying that you can tell by the pictures that I have the 12mm knuckle pattern? If so, that would be great as it sounds like this is the much better setup.

I have been driving around (unknowingly) with one caliper bolt for about 2 months. But its in the garage now and its not leaving until its fixed properly.

I figure since I had my FJ60 for about 4 years and really never did anything to it other than put gas and oil in it, my time has finally come to do some real :Mechanic: I need to de-virginize myself as far birfields are concernced!!

I dont think he can see from those pics if you have the larger bolt pattern knuckle or not. Just take a scale or ruler out there and measure it.

 

[ntsqd]

Just figured out what Kurt was asking me to measure. I'm a visual learner :Wow1:

11mm vs. 12mm Knuckle bolt pattern

I don't have one of those fancy gadgets to measure the diameter of the bolts so hopefully I can figure out how to do it with a tape measure...

A simple trick that MISF taught me for dealing with things like that. You probably already own the tools too.

Use open end wrenches. If both the 11mm wrench & the 12mm fits over the body of the studs, they're 11's. If only the 12mm wrench fits, they're 12's. So simple, yet never occured to me.

 

[dieselcruiserhead]

No I am not able to tell. It is just more likely than not that they are the larger size simply because they are more common. That said, the FJ60 (or mini truck) era birfields do not fit into that era housing without a little grinding on either the birfield or the axle housing. So it takes someone who knows what they are doing IE most likely a cruiserhead to sucessfully install FJ60/Mini Truck/ large pattern knuckles.

Anyway I'll stop guessing.. Even with the smaller pattern nothing wrong with that at all, the larger ones are a little more common which makes repairs and finding parts for a little easier and they are a hair stronger, as the early disks are land cruiser specific parts only for a few years. ...that's all... It took me many years and 35's and a front locker before I broke my first birfield. So really not a big deal at all, and most of these parts seldom have issues.

 

[DaveInDenver]

A simple trick that MISF taught me for dealing with things like that. You probably already own the tools too.

Use open end wrenches. If both the 11mm wrench & the 12mm fits over the body of the studs, they're 11's. If only the 12mm wrench fits, they're 12's. So simple, yet never occured to me.

Good trick. Gotta ask, what's MISF?

• Minimally Invasive Spinal Fusion
• Metal Insulator Semiconductor Field Effect Transistor (OK, that's MISF'ET, but who's keeping score?)
• Multiple Investment Sinking Fund
• Management Information Systems Facility

Also, a 12mm JIS nut takes a 17mm wrench. How about a 11mm JIS? That would take a 16mm I think. Easiest thing would be the 11mm and 12mm go/no go trick with a spanner, though.

 

[ntsqd]

Good trick. Gotta ask, what's MISF?

"My Infamous Scout Friend"
Over the years I've told too many stories about him on various lists & forums to publically identify him. Thus the acronym. Smart guy who does some the dumbest things, and then giggles about it.......