As I'm starting to put my front end back together I was wondering if there's a general rule of thumb as to what to apply anti-seize to and what to leave alone..... Shock mount bolts, caliper bolts... any definitive list of things NOT to put it on?
I use copper based anti-seize on every exposed-to-the-elements nut and bolt and screw that doesn't require thread sealer. (Didn't use it on my flywheel or pressure plate bolts. Used Loctite there instead.)
Someone down the line will be thankful. Usually that "someone" years later is me.
[This message has been edited by Patrick (edited 12-02-2013).]
Any lube, including Anti-seize, then forget torque spec on bolts etc. Most spec's are dry threads. Any lube and torque to spec's are often major over tight.
Make sure you check them after driving.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Any lube, including Anti-seize, then forget torque spec on bolts etc. Most spec's are dry threads. Any lube and torque to spec's are often major over tight.
Make sure you check them after driving.
That makes sense. Seeing as I was able to get all of them off with the exception of a rusted lower shock bolt, I'll skip the anti-seize and go with factory torque specs.
That makes sense. Seeing as I was able to get all of them off with the exception of a rusted lower shock bolt, I'll skip the anti-seize and go with factory torque specs.
After seeing your images in the other thread, your decision makes no sense to me.
After seeing your images in the other thread, your decision makes no sense to me.
So if I were to use anti-seize, how would I compensate for the change in torque? They do use a lot of salt here, but I don't drive the car in the winter, which I'm guessing wasn't the case for the previous owners.
And I was thinking at the very least of putting some on the shaft of the bolts that go through the bottom of the shocks.
[This message has been edited by NetCam (edited 12-03-2013).]
So if I were to use anti-seize, how would I compensate for the change in torque?
What are you worried about? Seriously, what is your fear?
Ogre's post was valid, but I think he's scared the bejesus out of you with his comments about torque settings.
If you're really worried about it, there are ways of compensating when torquing fasteners with "wet" threads. Marvin has posted about this in the past.
I might add though that I put plenty of anti-seize on the lug-nut studs on my Fiero which I autocross... and I've never had an issue with correctly torqued lug-nuts being too tight or coming loose or whatever it is that we're occasionally warned about.
Worrying about the compensation required when anti-seize is used on bolts to mount your shocks is a little over the top IMO.
I used copper based anti seize on all my 88 cradle bolts and suspesion bolts in hopes it would prevent future rusting...the car is starting to show its rust and its usually exponential in growth. All were torqued to spec and oddly only 2 were still tight after a year of driving. One of the rear cradle bolts actually backed out 5 full turns! Caused a mysterious clunking for some time under hard accelleration and a mis-alignment of the exhaust pipes. Not sure how I feel about anti-seize anymore. I'll probably use it where i feel necessary and monitor those fasteners.
One of the rear cradle bolts actually backed out 5 full turns!
I suspect you've got an infestation of gremlins.
That's really weird. I've slathered anti-seize on everything I've taken apart (including swapping the tranny) on my '84 which has been autocrossed for three years, and I haven't seen any evidence of nuts or bolts backing off.
I've done the same thing to my '88 Formula which I acquired this past summer. I'll be watching it closely.
What are you worried about? Seriously, what is your fear?
Ogre's post was valid, but I think he's scared the bejesus out of you with his comments about torque settings.
If you're really worried about it, there are ways of compensating when torquing fasteners with "wet" threads. Marvin has posted about this in the past.
Breaking bolts, cracking bolts, straining binding bushings, striping,etc. Torque setting can be important though, what I have heard is use 25% less torque if you anti sieze them. This leaves out data like which brand and type of anti seize, and does how much you use matter? Do you need to retorque later? Anyway just saying his concern makes sense in my opinion.
[This message has been edited by 2.5 (edited 12-05-2013).]
You can use anti-sieze on anything that doesn't touch critical system lubrication (engine oil, trans oil, power steering etc..). The whole idea is to make it easier to service the next time without struggling with bolts (who would want to do that anyway). The original GM fasteners typically were either black oxide or cad/zinc plated. The Cad plating has its own lubrication value when new. I don't think the anti-seize effects that very much (my opinion). There is a way to compensate for lubricated vs non lubricated bolts but I've never bothered to unless it is an extremely critical safety part where the bolts are non redundant.
Personally I recommend not putting it under the head of bolts (obvious right). I also personally use them on lug stud threads but am very careful not to get it on the taper of the lug nuts. The taper of the lugs helps lock the lugs from backing off. I've had one car backlogs off but I'm not sure if it was because of anti-sieze or improper tightening in the first place. I torque to 100 ftlbs with a click type torque wrench. I've need had a problem with lug nuts since putting anti-sieze only on the threads, and I've never struggled to get them lose or broken any bolts.
When I torqued my suspension bolts I torque by feel with either a 3/8" Craftsman standard or Pro series. I use a 1/2" drive on the cradle bolts. Generally you can feel when a bolt is tight enough. I'd say most of the parts you are asking about are over engineered enough to not worry that much about it. I'm sure others on this post can agree or disagree.
Breaking bolts, cracking bolts, straining binding bushings, striping,etc. Torque setting can be important though, what I have heard is use 25% less torque if you anti sieze them. This leaves out data like which brand and type of anti seize, and does how much you use matter? Do you need to retorque later? Anyway just saying his concern makes sense in my opinion.
There are a few ways to do this. 1) lookup the recommended vales in a Machinery's Handbook, 2) if you have a Bending Beam Torque Wrench you can us a super heavy duty spring, bolt, washer(s), and nut. You can then assemble them with the washers on either side of the spring, Tighten to a given compressed length (use a caliper to measure) as you tighten and the bolt is turning you can note the reading on the torque wrench. Repeat with anti-sieze and you'll see a difference in the torque drag. That SHOULD give you a rough, measurable difference that you can use to calculate a percentage torque difference. If you do this with 3 different diameter fasteners in the thread pitch you need it'll give a pretty good idea how much friction there is.
[This message has been edited by FieroNate (edited 12-05-2013).]
As I'm starting to put my front end back together I was wondering if there's a general rule of thumb as to what to apply anti-seize to and what to leave alone..... Shock mount bolts, caliper bolts... any definitive list of things NOT to put it on?
I use it on EVERY SUSPENSION BOLT.
And I use factory torque specs on every one of them. No problems. (Bending beam torque wrench)
I even use anti-seize instead of loctite on '88 brake caliper slider bolts. As long as I hit the required torque on the bolt, again, no problems.
One thing to be aware of... Bushing sleeves are simply rolled pieces of flat steel which have butted seams on one side. You can tighten bolts tightly enough on these bushings to open those seams up.
[This message has been edited by Will (edited 12-05-2013).]
"I decided to clear off a corner of my workbench for a quasi-scientific investigation! I cleaned a new bolt, washer and nut to make them “dry”, clamped the nut in a vise and marked the position of the bolt head at points between 25 to 65 ft. lbs. of applied torque (34 to 88 Nm). Then I put anti-seize compound on the bolt and measured the torque necessary to bring the bolt head back to the dry positions.
With the anti-seize compound, I found that 31% to 44% less torque was needed to turn the bolt head to the dry position. For example, 45 ft. lbs. of torque on the anti-seize coated bolt turned the bolt head as far as 65 ft. lbs. of torque on the dry bolt. The dry/anti-seize conversion ratio became very non-linear when I put 65 ft. lbs. (88 Nm) of torque on the anti-seize covered bolt. The bolt head turned far past (remember this is quasi-scientific!) the dry 65 ft. lb. mark indicating that the bolt head was probably now cutting into the washer and/or the bolt was stretching.
After my experiment, I looked at bolt manufacturer data and found they generally recommend roughly 25% less torque (compared to dry) on fasteners lubricated with anything (oil, grease, etc.) and roughly 40% less torque on fasteners coated in anti-seize compound.
I am still a big fan of anti-seize, but I am going to more carefully consider the torque specifications for each bolt. Many, if not most, of the bolts I install are hard to access and impossible to get a torque wrench on. Most fasteners have likely been inadvertently lubed by the penetrating oil I used to help remove them, transmission fluid, the grease on my gloves, etc. With those hard to get to bolts, I can only use the manufacturer torque specification as a ball park figure to calibrate the pressure I feel in my hand and wrist when I turn the wrench. Manufacturer torque specs in the repair manuals are usually a range rather than an exact number so now at least I know to usually aim for the low end of the torque range." originally from RockAuto http://forum.ih8mud.com/80-...-torquing-bolts.html
Maybe 40% less torque with Anti seize?
[This message has been edited by 2.5 (edited 12-05-2013).]
A guy on that same thread I posted (but page 2) who works for loc tite says:
"..there is only one reason bolts that are properly installed become difficult to remove later on and that is rust. I know it's hard for most people to believe, but in a typical threaded assembly, there is only about 15% metal to metal contact. (flights of the male thread touching flights of the female thread) The other 85% is air. Air which contains water and different amounts of salt depending on where you live. This is why we get bolts that are rusted shut.
There is a way to prevent water from entering the threads without leaving a lubricant behind. Using a medium strength threadlocker does lubricate the assembly process but it chemically changes into a hard plastic when it cures. Now you have a hard plastic filling up that 85% space. This does two things for you. It prevents unwanted loosening and also prevents rusting. So a thread locker is also an anti seize in the sense that it will take the same amount of torque to remove that fastener tomorrow as it will 10 years from now. Remember that the medium strength (blue) Loctite is removable with the same hand tools you installed with. However, if you're concerned about rounding over the heads of smaller bolts and screws, you can use the low strength (purple) Loctite. Same rust preventing benefits with lower removal torque needed.
Now, about the second topic. Torque vs clamp load for lubricated vs dry fasteners. FJ4068 is absolutely correct. It's too complicated to explain so I'll sum it up.
Torque is related to clamp load via a factor called "K" The impossible part is that the "K" factor for any threaded assembly depends on the following: 1. diameter of the bolt 2. pitch of the flights 3. engagement of the flights 4. metallurgy of the male threads 5. metallurgy of the female threads 6. friction coefficient of the two metals describe above working against each other 7. quality of the fastener (i.e. how consistent are all the above from one end of the fastener to the other) 8. which particular lubricant? (by name and number)
If we want to get really technical you have to look at more than just the rotational displacement of the head. You need to look for elongation.
There is a really good reason high end connecting rod bolts are torqued to a stretch limit or a torque value and then an angle for GM OEM bolts.
There is actually a formula in Machinery's Handbook for calculating bolt torquing requirements. There is a variable for lubricated vs non lubricated bolts. But in reality remember torque is designed to get you a stretch amount (or a certain place on the stress-strain curve of the bolt). For example 'torque to yield' head bolts are not really torqued to yield but they are torqued roughly to the end of the linear portion of the stress-strain curve.
Also keep in mind your bench test needs to take into account kinetic vs dynamic friction. You can't stop and restart without first backing off and then retesting.
With all this discussion I'm pretty sure the risk of over torquing will damage the chassis and bushings before the bolts themselves.
What are you worried about? Seriously, what is your fear?
quote
Originally posted by 2.5:
Breaking bolts, cracking bolts, straining binding bushings, striping, etc.
I'm aware of what the potential risks are (minimal IMO), and it appears you are as well... but I was asking NetCam what his concerns were so I could possibly address them.
It seemed to me he was unduly afraid of applying anti-seize to anything.
My main concern was either over torquing or under torquing the bolts. I've always had a habit of going too far when I didn't have a torque wrench, a few times to the point of breaking bolts off. So, I don't want to put anti-seize on something that doesn't need it and over do it, or end up having it spin itself back out when I'm rolling down the highway.
I've always had a habit of going too far when I didn't have a torque wrench, a few times to the point of breaking bolts off.
I guess after working on cars and engines for over 40 years, I've just sort of learned how much to tighten various size fasteners safely... without a torque wrench. That doesn't mean I don't use a torque wrench in certain situations, but I'm never afraid that I'm going to break a bolt. I'm not trying to prove how manly I am.
Here's somerthing I posted in an earlier thread after another member stated he was afraid of over-tightening and breaking off valve cover bolts. I think it applies to your apprehension of over-tightening as well.
quote
Originally posted by Patrick:
The size of wrench relative to the size of the bolt will make a big difference in regards to over-tightening.
Using a 1/4" drive ratchet on a 10mm bolt, there's little chance of "stripping a bolt head off".
A larger 3/8" drive ratchet might cause some damage with a 10mm bolt if you're feeling frisky.
However, a 1/2" drive ratchet can easily break/strip something when tightening a 10mm bolt, even in the hands of Mother Teresa.
Good rule of thumb... I have all three sizes, but tend to use the 3/8" about 99% of the time. Usually only use my 1/4" drive when I'm taking apart and putting together the interior because of the size of the bolts. I'll keep that in mind and use my 1/4" on my smaller bolts/nuts.
Smaller bolts with a 3/8" drive choke down on the handle to get less leverage.
As you get older you will find yourself going for the "cheater tube" to add leverage to your ratchet
------------------ "There is no more formidable adversary than one who perceives he has nothing to lose." - Gen. George S. Patton http://www.flowbenchtech.com
"With the anti-seize compound, I found that 31% to 44% less torque was needed to turn the bolt head to the dry position."
That is consistent with the published data on K-Factor for clean and dry fasteners vs. the K-Factor specification for the anti-seize compounds I have used. Due to the many variables involved, I generally reduce torque by about 25% when using anti-seize. For the record, I routinely use anti-seize on virtually every fastener exposed to the ambient environment and I have never had a properly-torqued fastener loosen in service. (The sole exception to the last statement is poorly designed joints that are subject to potential rotation in service ... like the long bolt that attaches the lateral links to the knuckle in the '88 Fiero rear suspension.).
The one place to be really cautious with torque is where you have a steel fastener (screw or stud) mated with a threaded hole in a much weaker material (e.g. an aluminum casting). IMO, anti-seize, thread locker, or a sealant should always be used in such joints to prevent dissimilar-metal corrosion, but any such thread treatment will lower the torque required. Using the "clean & dry" torque value when using anti-seize (or grease) can pull the threads right out of an aluminum casting.
[This message has been edited by Marvin McInnis (edited 12-06-2013).]
(The sole exception to the last statement is poorly designed joints that are subject to potential rotation in service ... like the long bolt that attaches the lateral links to the knuckle in the '88 Fiero rear suspension.).
That's because the bolt is squeezing the bushing sleeves. The bushing sleeves are wrapped and butted, so they can squeeze open under the clamp force of the bolt.
If you go to rod end lateral links and put about 80 ftlbs on that bolt, it stays.
If you go to rod end lateral links and put about 80 ftlbs on that bolt, it stays.
I agree, as long as the bolt and nut are never subjected to rotary motion. In standard aircraft practice, a plain or prevailing-torque (i.e. "self-locking") nut is never allowed on a joint even potentially subject to rotation (e.g. a control linkage); a positively locked nut (e.g. cotter pin or safety wire) is required.
That's because there's a risk, not a certainty, that it could maybe possibly come loose. Barring seizure of the rod ends (which, while possible, is extremely unlikely) there just aren't any rotating forces on that bolt.
