Factory bolts with colored thread adhesive

Have you ever reused a factory bolt that was shown in the FSM as a non-reusable part, but you knew there was nothing physically wrong with using the bolt except the colored painted on the thread ends was worn off?

If you had any experience with thread lockers you probably figured it was a type of adhesive, to keep the bolt from backing out and loosening.Here are some torque values for factory fasteners with pre applied Dri-Lock adhesive

For example crank bolts have a pre applied coating on their threads of yellow DriLock adhesive and the torque value given has factored in the reduced stress level of the coating on the threads. If the torque value is 187 ft. lbs with the (RED) DriLock then if the threads are clean and dry. The torque value would increase to about 207 ft. lbs

Loctite thread locker should also be factored in to the torque value of a fasteners original specification if it did not require or specify in its original assembly or instructions.

The same holds true for anti-seize compounds, as it does for lubricants such as motor oil, and molybdenum based lubricants. Basically anything that changes the surface of the threads resistance towards its tensile stress.

Here is a link to the color codes of Loctite brand DriLock adhesives.

Dri-Lock 200 (yellow) 0.60

Dri-Lock 201 (yellow) 0.75

Dri-Lock 202 (green) 0.65

Dri-Lock 203 (silver) 0.55

Dri-Lock 204 (red) 0.90

To find an original value for a fastener that is used without the adhesive the torque value would be divided by the adjusted specified value.

Loctite has many different formulas and consistencies (paste,liquid, gel, stick) and strengths. They are not all entirely applicable to passenger vehicles use and I will not have all of the additional technical applications or instruction material information, if someone does please post it on this thread.

Here are some links with metric fastener torque information

http://www.torqwrench.com/Info/fasteners.php

http://www.torqwrench.com/Info/conv.php

http://www.torqwrench.com/Info/extens.php

 

Your information is....informational. However just because a bolt has colored thread locker, does not indicate that is the ONLY reason why replacement bolts are suggested. They don't say to replace the bolts just to try and get more money. There are reasons for replacing them. For instance head bolts are NEVER to be reused. They may not LOOK like there is anything wrong with them, but as a torque-to-yield bolt, they are designed to microscopically stretch when tightened to the correct torque. Once stretched, their clamping force is dramatically affected. There are other bolts, like some seat belt mounting bolts, that in some cases are a "replace only" type bolt.

 

Thanks I'm sure this thread could have used a better disclaimer.
Albeit, Toyota is thinking of a safe methodical approch
in giving instructions (torque specs) for reasembly and the options for the fasteners are narrowed down to using only OE fasteners as they are presented based on their availability durring the model specific run of production.

The question could possibly arise when the OE fastner is not feasibly
obtainable and or other custom fastners are used.

For example in the case of using an aftermarket headbolt, if not specified
as a torque to yeild design they should be measured and recorded at the time of the physical inspection.
Then those measurement can be used to compare them to the
manufactures toleraces given in the instructions, and specific to those
fasteners from that batch.
Usually included in the instructions are the torque variances with different types of friction reducing substances and a prefered substance is offten named in those instructions.

Torque to yeild bolts are from my experience noticibly different in design
compared to a reusable bolt, at least when inspected after disassembly
because there is a noticable difference from their original thread pitch.

In general this thread is to make use of other reference to or where not stated in a FSM, the interest to the reader would rely on their knowledge as well as their concern for corrected specifications or having an investgative desposition and or need for the information based on the nature of this subject.

 

I won't hash details with you, but there is no way to just LOOK at a TTY bolt and determine that is is such. Or to look at one and see that it has been "stretched". The bolt will still thread right back into the same hole it came out of. The stretching is at such a microscopic level, there is no way to determine use.

 

Your numbers aren't matching up...

187 and 207 is a factor of 0.9, which matches the chart for red, yet the example is yellow.
187 on yellow would be either 312 or 250.

 

All bolts stretch and have tensile strength that deminishes through use
You may be thinking all OE headbolts are TTY which is a common mistake.
If you are reffering to micorscopic changes in length, you're not reffering to a TTY and over time cycling a bolt will produce a small variance from it's tollerance and show a measurable difference.
That is why bolts are measured before use in critical applications to make sure they are within their specified tolerance.

TTY bolts deform notably from their original specifications after their initial use they are easily identified by a narrow shank that yeilds to stress and stretches.
http://www.hemmings.com/mus/stories/2008/05/01/hmn_feature20.html

 

You're correct, I apologize.
I write early in the morning and over edit my posts through my preoccupation to communicate efficently.
I did mean to refer to RED since it would and could be comparatively obtainable.
( I also needed to edit the red part number from 200 to 204)
I realize that BLUE is more common in application,
but because the ommission of the color by the chart and through my own experience,
RED is a safe subsitute and since the whole idea of the thread is to bring awareness to
corrected torque specifications through the use of various thread applicates.

I also like the fact that you actually used the math to figure the correct difference in torque readings,
although it wasn't in my original intention.
Thank you on both accounts.

 

I see you are interested in starting a debate here. I am far from a novice when it comes to bolts and applications of such. I am not in any way thinking all OE bolts are TTY. You are just making an assumption there. TTY bolts do stretch, but it is not of a significant amount. Many people out there make the mistake or trying to reuse head bolts for example because they can't see an obvious difference in the appearance. I am curious how you are talking about "cycling" a bolt when I am discussing single use, TTY bolts. You should NEVER cycle those bolts. Once tightened they should be discarded if ever loosened. Yes, all bolts do stretch. You can't get a good clamping force otherwise. However a standard bolt, when tightened properly, remains in it's elastic condition, and returns to it's normal shape when loosened.

You have to realize that not every person on this forum is an engineer, or professional automotive technician. Those of us that are, do our best to make sure that everyone gets the information that they need, to do a proper repair on their own. Yes, TTY bolts are easily identifiable to those of us that know, but many people out there who may be attempting their first head gasket replacement do not know this, so we try to give them what they need to know. Your every-day layman out there does not have a micrometer that can be used to measure a bolt to see if it is stretched too far, or if this one or that one has been over stretched. So we always recommend that they replace EVERY head bolt that is a TTY type whenever removing them. TTY bolts are not the type that you can just eyeball and say "yeah, these have been stretched." Any attempt to claim otherwise is ludicrous.

 

Like I stated before,

Sometimes if emotions are riding high written word does not communicate
efficently the idea that the writter is attempting to convey.

I can not directly confront this since the nature of the thread has already taken on a form of personal insult from a mis-interpretation of content.

If anyone wants to complain about the content of this thread ,
that it might be presenting mis-information to novice reader
(vehicle owner) please do so through personal message system here or redirect your concerns to administrative or moderating members of this website.

 

.
. . . Sub'd
.

 

Not emotional at all on MY end. You must be talking about your end. Apologies if I ruffled a little feathers there. I am confused on where you feel I have personally insulted you. Never an intention. Simply making sure, like I normally do in every thread I respond in, that people have all of the information that can be of assistance, and that it is the correct information. Nothing personal towards you in any way. You are new here obviously, and if you will look around, there are threads all over where people post corrections to other people's post all the time. It is never meant to offend, or criticize the poster, but to be sure that correct information is passed on. If you feel offended, then I apologize. If you get your feelings hurt this easily however, you will find more than me doing so, because this forum is not the high-brow status that you evidently try to portray here. This is a true-life conversation forum to help people, and to socialize. By the way, I made a few corrections in your above quote.

 

Oh in that case, if it's alright with you ,
you won't mind if you're corrected is that right?
You might what to brush up on your reading comprehension skills.

The basic premise of ASE testing is the ability to read and comprehend.

Because your not getting it, and your going around screwing up perfectly good threads with your nonsense.

If you don't like the way I write then no one is forcing you to read it,
but going around and looking for my post to find something wrong, where it's a matter of personal opinion and using your own inflamitory deligation that you're some trained professional,
it's about time some one called you on your b.s.

So if you want to learn something go back to school take a corespondence course, or stop being insinuary and scarastic and read more,
(perhaps several times) and post less.

 

Well it seems that I am being called out. Well I have no problems at all with my knowledge, and my certifications. I will post in this, and the other thread our interesting PM that you initiated, and let us see which one of us has the proper qualifications.

The following is a copy of the PM, and my reply. I decided to leave the spelling mistakes since it appears you, Lagunito, are saying I need to brush up on my reading skills. I think YOU need to brush up on your spelling skills.

Feel free to post my quoted reply Mr Lagunito. You are barking up the wrong tree if you think I am not a qualified technician. I have tried to be polite and civil, but you sir, have fired the first shot. The gloves are now off. You WILL loose this battle.



By the way, to be fair, and give you a chance Lagunito, I have also posted here:

http://www.tacomaworld.com/forum/off-topic-discussion/262951-being-called-out-tw-member.html

 

Want a little cheese to go with that... nvm

You wouldn't get it anyways.

 

I dont get it. Sorry not certified mechanic. What does thread locker have to do with specified numbers in FSM which are always for new part clean? Threadlocker does not increase friction until it dries out. So 187 ft is still 187 ft. It will be much more when you try to unscrew it after a day.
Now if drilock increases friction when I am tightening bolt its a $hity product and I will not use it. To my knowledge liquid loctite does not.

 

The problem is that IF the FSM specifies a torque value for clean, dry threads, then anything on those threads... be it thread locker, anti-seize, or lubricant, will impact the torque reading.

Lubricant and anti-seize, as well as liquid thread lockers, require that the applied torque be adjusted down to avoid overtorquing because the reduction in friction allows more clamping force to be applied for a given torque application.

Dry type thread lockers increase friction, so torque values need to be adjusted up to compensate and still maintain the proper clamping force.


The problem is, the FSM gives one spec. If that spec is for the factory supplied bolt, then that spec applies to that bolt and thread locker and not something else, nor does it apply to the re-use of the factory bolt with the thread locker cleaned off. Unless you know what locker was used by the factory, you can't properly calculate the "clean/dry" value, and without the clean/dry value, you can't go to the dry-locker table.

The OP has offered some good information, but it is for the most part useless other than making people aware of the issue.

 

Correct on all accounts, except I would make clear a couple of points .

Thread locker even the dry type decreases initial torque value
.
The confusion on the values (numbers) can be explained like this:

Any value multiplied in the negative side of a decimal point,
decreases (takes away) from the original value.

Any value divided by the negative side increases (adds)
to the original value.

(negative means is in a sense less than a whole number or a percentage value)

If factory parts are bought new and the colored dry thread locker is required in the factory line assembly,
it will be present on the replacement fastener.
And the information on the torque values that is supplied in the FSM includes this corrected value.

But what the FSM doesn't give is what the torque value is if by some chance you use a replacement bolt that doesn't have the dry thread locker.
Or you use a different type of thread locker.

There was some concern about reusing cerntain critical bolts or fasteners that are required by the FSM to be out right replaced for safety reasons.
This is a legitimate concern, and should be taken seriously.

 

Then why does the correction factor call for an increased torque to be applied for the dry lockers as given in the original example?

 

Probably because my punctuation of the partial sentence above,
is confusing...?

Does it still not make sense?