Loctite 7649 Cleaner/Primer

[krhnh]

Anyone use this? The instructions for the TC hybrid cam plate install specifically call this stuff out. It's about 30 bucks a bottle, money's tight this week and I was hoping to get the cam chest together this weekend.

Wondering how essential it really is.

[FSG]

I've used it at work in the oil patch but never on the bike, I use brake cleaner then dry off with compressed air before applying loctite.

[barny7655]

use it every day at work on captiva cars ,VE holden front timing covers,sumps ,will work on cast as well, this ensures that the surface is clean so the sealant can adhere to the surface,eliminates that film of oil that is on the covers , great stuff,but must let the sealant cure before you refill with oil and heat, 12 hrs at least,over night ,ill post the PN# tomorrow as i dont have any at home ,this is a primer used for surfaces to be sealed with a sealant like engine cases etc , no so much as a primer for threadlockers etc , cheers Barny

[krhnh]

Hmm. Seems to be a cleaner but also an activator where Loctite red is an anaerobic. I found this in a Loctite Q & A...

Q1: How do you define anaerobic in relation to your products?

A: Anaerobics, that include many of our threadlockers, pipe sealants, retaining compounds and flange sealants, are products that cure in the absence of air. These are products that are designed for metal-to-metal assemblies although they are sometimes used for other materials as well. The presence of metal (ions) accelerates the cure of these products. When you assemble parts with an anaerobic and you have excess squeeze out, outside the joint, this will not harden due to the anaerobic nature of the product. Simply wipe the excess away with a common solvent like acetone or isopropyl alcohol. Typically anaerobics fully cure in 24 hours at room temperature under normal ambient conditions when properly used.

Q8: Do I need to use a primer with anaerobics?

A: We recommend the use of primers such as LOCTITE 7649 & 7471 with most anaerobics where both parts are classified as "inactive" metals. These metals lack the presence of iron or copper content and thus, lack the "active" metal ions required to fully cure the product in 24 hours. These metals include plated parts, stainless steel, galvanized steel and anodized aluminum, to name a few. If, on the other hand, both or at least one part is an "active" metal, such as plain steel, brass, bronze, copper or iron, there is no need to use a primer to ensure full cure in what is typically 24 hours at room temperature.

The MoCo is saying to use it on the bolts holding the crankshaft and primary cam drive sprockets. Would have to think the bolts, crank and cams are hardened steel. Have to wonder if they mean the Loctite just won't cure in 24 hours or never cure right at all.

Looks like I'd have to send away for the stuff. Have to wonder how many people have actually used the stuff on all the cam plates sold.

Maybe I'm just nitpicking.

[PoorUB]

Maybe I'm just nitpicking.

There is your answer.

[truck]

I bought a similar product at NAPA. I don't remember the price but I'm sure it wasn't $30.00.  http://www.napaonline.com/Catalog/Result.aspx?Ntt%3d765-1154%26Ntk%3dKeyword%26Nty%3d1%26Dn%3d0%26D%3d765-1154%26Dk%3d1%26Dp%3d3%26N%3d0

[krhnh]

Thanks truck. That would be a lot easier to get.

The MoCo throws a curve ball once in a while. Last time they had me looking for Hylomar, which seems only slightly less difficult to find these days than uranium.

[krhnh]

Ok. So I've done a bunch of reading and I'll add the stuff I didn't and never wanted to know about Loctite in case anyone in the future winds up with a similar question and searches the board.

• Loctite does not dry like a normal adhesive since there's not going to be enough air in the threads of a tightened nut or bolt to dry it.
• Threadlocker works with certain kinds of metal to create enough heat to set through a chemical reaction.
• Cleaner/Primer like Loctite 7649 cleans like an acetone but the "primer" property is because it has little bits of copper suspended in it. If the metal you're applying the threadlock to is not the kind it can react with then it will react with the copper in the primer.

Any source I've been able to find says that parts like the crankshaft, cams and bolts are made of hardened steel. The threadlock will not react with stainless but hardened steel is basically just heat treated steel so I'm making the assumption that the type of metal isn't the issue.

This is just logical deduction but obviously oil could interfere with the chemical reaction of threadlocker by creating a barrier between the chemical and the metal. I'm assuming where the factory calls out Loctite Cleaner/Primer it's more about getting the oil out of the threads. I've noticed that Harley seems to use certain products at the factory and the dealerships seem to have the same stuff. My guess is that since it's what they have it's what they've tried and since it works they cover their backside by specifically calling it out. If you don't use what they called out then they can say you didn't follow the instructions. If I had to make a bet, my bet would be that as long as you use something that breaks up the oil and removes it the threadlocker will cure normally.

Yeah, I know. I'm sure this seems like overanalyzing things to a lot of people but I've been an electro-mechanical tech working in engineering for years. If I don't understand the technical background then deviating from a spec will nag at me. It's about peace of mind. Everyone has to make their own call on this but there's some food for thought.

[PoorUB]

You are nit picking!

Use some brake cleaner, blow out the holes with compressed air and apply the Locktite. Trust me, I have been bending wrenches since I learned to walk, the Locktite will set up just fine without the primer.

[FXDBI]

You are nit picking!

Use some brake cleaner, blow out the holes with compressed air and apply the Locktite. Trust me, I have been bending wrenches since I learned to walk, the Locktite will set up just fine without the primer.

   Bob

[rbabos]

While the stuff works great, it really isn't needed if parts are cleaned. I made the mistake once using it with 680. Loctite instantly set up before I could assemble the parts. Other grades, it didn't have this undesirable effect and the loctite behaved like a normal anaerobic epoxy. There seems to be an increased bond with LOCTITE 7649 & 7471 use possibly from etching and cleaning effects. Don't see the need for any part on a Harley though.
Ron

[krhnh]

Thanks for the input all. Makes me feel a lot better. I was having images of bolts backing out and wobbling sprockets.