Anit-seize or locktite blue?

[redstack]

Rebuilding my rear brakes and had an easy time so far getting the calipers off and the rubber flex lines replaced.
I'm starting to put things back together and I'm wondering if I should use a dab of anti-seize on the caliper bolts for next time, or maybe locktite blue to keep any vibration worries at bay?

Opinions? I'm leaning towards anti-seize.

[Hendog]

Anti-seize and torque them to spec.

[Drymartiniwi]

Anti seize and torque it


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[Tremelune]

You'll get plenty of answers and little science. Unfortunately, I don't have much else to offer besides my research leading to more people who preferred threadlock over anti-seize on their brake components.

The thing that will keep the bolt in is proper torque. Both anti-seize and threadlock will facilitate future removal, because they both take up the space of air between the threads, and that's what causes corrosion and seizure. Torque values are assumed to be "dry" torque values unless otherwise specified. Anti-seize and threadlock can both affect the torque reading, as they lubricate the threads to some degree. Loctite claims their threadlockers do not affect the torque value...sometimes. There is some mystery to it, and there's no flat "percent mark down" that is considered optimal, becuase there are too many variables for a given fastener.

The more I look into it, the more inclined I am to use Loctite 242 on most bolts, and anti-size only on serious bolts, such as exhaust bolts, and even then I try and use a high-temp compound that leaves behind lubricant bits after the anti-seize dries up (anti-seize dries up). I wish I had better science, but after much research, there is more conclusive advice than conclusive evidence.

Are the caliper bolts one-time use? For my Cayman, I bought new bolts, used Loctite 242, and torqued them to the spec value listed in the factory service manual. The original bolts that came on the car had a green threadlock on them while the new ones came dry.

http://www.planet-9.com/987-cayman-and-boxster-service-and-tech/184098-987-1-s-front-caliper-rebuild-post1686817.html#post1686817

[sugarwood]

You're on a DIY forum. You will probably have those rotors replaced sooner or later. Plus, your car is probably garaged. I think you're fine.

Next time you deal with the caliper bolts, just an impact wrench. If not that, then a box wrench with no offset to minimise stripping the bolt head. (like a crooked socket) That should make the discussion moot.

If you're worried, do a Google search for "Caliper fell off". I bet you don't find much.

[redstack]

I went with anti-seize but I do realize it might effect torque values. Of course the big question is how would you ever get a torque wrench on the lower 19mm bol, the one everyone has so much trouble with? I know the value is 70ft/lb as per something I read on PP. So that's not overly tight and I torqued the top and tried to match the bottom.

As is said above, I have rarely heard of a caliper falling off, but they are always a bear to get apart. So we shall see in a hand full of years when I redo the calipers again.

[ClickClickBoom]

I use antiseize, torque to spec. Use the wavy washers no more than a couple of times. I had a wave washer fail and the bolt worked out, caliper schwacked the backing shield. The caliper was trashed, bolt hole on the caliper was ripped open/off. The bolts operate under tremendous shear with a loose bolt and scrubbing off speed. Remember to clean off the mating surfaces of the caliper and strut, I use Brake Clean or the equivalent. In 35 years of wrenching, split washers fail with alarming regularity, never had a wave take a dump!

[Pazuzu]

Originally Posted by ClickClickBoom

I had a wave washer fail

never had a wave take a dump!

Wait just one minute here...

[redstack]

Well there you go then, a case of a caliper trying to leave the scene. Grass roots did a good article on Bolts and Washers and they did say that split washers are pretty much useless. I'll have to check on some Wavy washers to fit. I can always replace them any time the wheels are off.

[Tremelune]

Well then...Today I learned that lockwashers are useless.

https://www.reddit.com/r/AskEngineers/comments/5n0hes/lock_washers_useless/

http://hillcountryengineering.com/wp-content/uploads/2011/10/Split-Lockwashers-Separating-Myth-from-Truth.pdf

Studies on the use of lock washers? - Mechanical engineering other topics - Eng-Tips

[Bob Kontak]

Originally Posted by Tremelune

You'll get plenty of answers and little science. Unfortunately, I don't have much else to offer besides my research leading to more people who preferred threadlock over anti-seize on their brake components.

The thing that will keep the bolt in is proper torque. Both anti-seize and threadlock will facilitate future removal, because they both take up the space of air between the threads, and that's what causes corrosion and seizure. Torque values are assumed to be "dry" torque values unless otherwise specified. Anti-seize and threadlock can both affect the torque reading, as they lubricate the threads to some degree. Loctite claims their threadlockers do not affect the torque value...sometimes. There is some mystery to it, and there's no flat "percent mark down" that is considered optimal, becuase there are too many variables for a given fastener.

The more I look into it, the more inclined I am to use Loctite 242 on most bolts, and anti-size only on serious bolts, such as exhaust bolts, and even then I try and use a high-temp compound that leaves behind lubricant bits after the anti-seize dries up (anti-seize dries up). I wish I had better science, but after much research, there is more conclusive advice than conclusive evidence.

Are the caliper bolts one-time use? For my Cayman, I bought new bolts, used Loctite 242, and torqued them to the spec value listed in the factory service manual. The original bolts that came on the car had a green threadlock on them while the new ones came dry.

987.1 S front caliper rebuild - Page 2

Nice write up.

I see little risk in the blue 242 for most anything.

I will mention that I have had the red 271 set in a matter of a minute with a small tube installing flywheel bolts. Assuming "old" Get the $20 bottle of the stuff, 271 or 242.

[sugarwood]

Is there any correlation between the size of the bolt and the need for LockTite?
It feels like mainly small bolts are the ones that require lockTite.

[Bob Kontak]

Originally Posted by sugarwood

Is there any correlation between the size of the bolt and the need for LockTite?
It feels like mainly small bolts are the ones that require lockTite.

Probably has more to do with the duty they will serve. Flywheel bolts are not that big but it is required. The little bolts holding the pressure plate to the flywheel require nothing. They all spin the same speed. Where must the stress be?

Clarification: I see my products above are Permatex.

I did a quick scan. Most say use the Locktite over the Permatex but another guy said Locktite makes the stuff for Permatex. HOWEVER, Zymol sold at Wallmart is made by Turtle Wax. Who knows what marketers are up to.

Loctite vs Permatex equivalency

[db_cooper]

A torque wrench and new hardware tightened to spec is a good idea. The original bolts are old enough to vote.

Most threadlockers will go soft when hot anyways..and the calipers get hot.

[Tremelune]

Brake grease on the springs, pads, and stuff, but not on the threads of the caliper bolts.

[Bob Kontak]

Originally Posted by db_cooper

A torque wrench and new hardware tightened to spec is a good idea. The original bolts are old enough to vote.

Most threadlockers will go soft when hot anyways..and the calipers get hot.

That makes a good deal of sense.

[redstack]

Some great tech info from you guys.

Good point about the Loctite and heat from the calipers, especially on a race car.

Add check caliper bolts to the regular maintenance

[Tremelune]

Rather comprehensive Loctite guide I stumbled upon:

http://www.wdarc.org/Loctite%20Guide.pdf

Most Loctite is specced to 300°F.