Thread locker

[Bill Musarra]

Did a search and couldn't come up with much info. Would it be advisable to add thread locker to the hub studs on pin drive setups? Could we get a list of components that would benefit from the use of thread lockers. Would be benefical to those of us that aren't that knowledgable.

Bill

 

[tom pritchett]

There are several kinds of thread lockers available. Red is for parts you really don't want to take apart. Blue is for a good hold but you will want to take apart. For the parts you describe, I really don't see a need as if they were loose, they will back out a touch to the wheel. It won't leave the car and it doesn't hold the wheel on. It is only a positioning pin/drive pin.

There are so many other parts that really need it though. The list will be very long.

 

[Seymour Snerd]

Could we get a list of components that would benefit from the use of thread lockers. Would be benefical to those of us that aren't that knowledgable.

I can't think of a metal-to-metal threaded fastener that would not benefit, to answer your question over-literally, aside from a few cases where you want absolutely the highest or most-controlled clamping force possible (CV-joints bolts, head bolts, etc, or any other place with a specified fastener torque) where the threads are specified to be either lubricated or dry in order to reach the specified force. Also some cases where the locking might be destructive on removal, for example a screw going into a threaded insert that might not be properly crimped or crimped into a weak material.

That being said, I probably would not use it on a screw holding on a piece of interior trim or an access panel I remove frequently. It's a question of criticality vs. your time.... i.e. of risk management. To do it properly is time-consuming since it requires both male and female threads to be clean and dry.

The best way to get a handle on the subject in general would be to read Carroll Smith's writings on the subject, and/or the loctite documentation:

[ame]http://www.amazon.com/Fasteners-Plumbing-Handbook-Motorbooks-Workshop/dp/B004X95JOQ/ref=sr_1_1?s=books&ie=UTF8&qid=1353610909&sr=1-1&keywords=nuts+bolts+and+fasteners[/ame] (yes, it's worth that much)

View attachment 168592_LT4985_Threadlocking_Guide.pdf

View attachment LT-6540_AN_RemovableReliable_SS_v11_Final_Links.pdf

Another approach to deciding where to use it would be to peruse the service manual for a modern production car and see where they call for it. Keep in mind that on most modern cars all critical fasteners have a specified torque, so if you're going to use that logic you have to torque all the fasteners they do. And you should.

By the way as Tom says you will see there are many more than "red" and "blue" but those two grades as sold in retail stores cover most of the situations you will encounter. The more unusual ones are used for stud or sleeve installation, application after fastening by wicking, nuclear facilities, food processing, etc. There are some for use where oil is present.

Also, by the way, some are available in "stick" form as opposed to liquid. I've used both and believe I get more reliable locking with the liquid form, at the same or less effort.

 

[Cliff Beer]

Threadlock obviously has it's uses and place, and can be vital in those specific applications. Where the fastener is subjected to a lot of vibration, and/or where there's not a locking feature (split washer, cup washer, serrated, etc.) being used upon the fastener for whatever reason....such as a simple exhaust manifold stud where there's no shoulder or room for a locking feature...it definitely makes sense to use it.

However, best to consider the totality of the circumstances when deciding where to use threadlock, including the what's the environment of the fastener? I almost never use thread lock (except on brake caliper bolts and CV axle bolts) for wheels/hub/axle locations...why? Because these locations are often susceptible to corrosion over time and I'll be using a mechanical locking feature of some kind as well in many cases. Ever tried getting a really rusted wheel bolt/nut off? The moment it breaks you've just added about four hours to the job, and sometimes all the tricks of the trade (heat, penetration oil, tapping, etc.) won't budge it. When it's all going back together, adding threadlock is not going to help. In fact, adding some anti-seize is what's needed in certain applications provided an appropriate locking feature is used.

There's not a lot of hard and fast rules here in my experience - just think about what forces are going to be working on that particular fastener over time, what kind of environment it's going to be existing within, and what are the consequences of it coming loose. A brake caliper bolt coming loose? That's a problem. A CV axle bolt coming loose? That's a problem. A valve cover bolt coming loose? Not a problem....