Dielectric grease

[chuck hahn]

I was told today that I shouldnt use dielectric grease on the connections on the wiring harness..bullet connectors or the plastic connectors. Was told it is non conductive and will make heat which in turn melts them.

But they come lubed from the factory with something, and I have used dielectric grease on cars and bikes for 30+ years and havent had any adverse effects that i have ever found.

So, all you guys that regularly work in the electronics fields, whats the truth here??? If the factory didnt use dielectric grease they what kind do they use??? I havent ever seen tubes of electrical "connector" grease!!!

[JTGS850GL]

No issues with using dielectric grease. The grease is non conductive but is displaced by the mechanical connection and block moisture without bridging the contacts. It should never increase the individual connection resistance.

[chuck hahn]

Yes it has silicone which repels water..which is what I thought the general idea was all about. The pins in the plastic connectors and the bullet connections are a solid metal to metal contact which should allow the current to flow normally..least thats the way i had it explained decades ago.

[JTGS850GL]

Yep, pretty much the way you understand it.

[londonboards]

Make the connections - then put the grease on.

[posplayr]

unless the crimps have dielectric grease in them the grease is only protecting the contact surfaces and nothing else. It is crimps that usually get hot.

Personally I have moved on from using dielectric grease except for maybe something that needs some lube like a ignition switch housing. Deoxit is much easier to apply and coats the parts as well and probably can even penetrate into crimps if they start clean.

I do:
1.) Naval jelly to clean out the old oxidation and green stuff ,
2.)rinse with water and dry,
3.) solder crimps (flux help a lot here) by keep heat down and minimizes solder wicking up the wire beyond the crimp. Even use a heat block on the crimp to slow wicking.
4.) Spray DeOxit for all exposed contact/metal.
5.) heat shrink as required.


From this picture as an example, it is clear that heat was concentrated mid point between the crimps. But you have to understand that the wires act as heat syncs and so the coldest spots are away from the connection and the hottest mid way between the hot test spots.

Anyway the crimp workmanship and connections look to be of generally high quality(certainly better than most we see here) and yet this happened. Why? Oxidation of untreated surfaces. So for those proponents of "proper crimping" based on aerospace experience, it just "doesn't fly" with motorcycle electronics.

And by the way, it appears that someone came in after the initial crimp replacement with the electrical tape as if that was going to solve anything.

[bwringer]

I think it's all about what's appropriate for the application.

The connections we're talking about (old motorcycles) are low voltage and low current in a very harsh environment, and most of the connectors are unsealed. Dielectric grease is an EXCELLENT idea in this case.

Another issue is that you just can't slop some dielectric grease on a corroded or failed connection and expect good results. You have to do whatever cleaning, repair, and/or replacement is necessary first to ensure a solid electrical connection, then protect it with dielectric grease to keep water out. This may be why you received this advice -- many people don't do a proper inspection first.

You also may have to correct design issues along the way. For example, every GS has the stupid unused loop of stator wire that goes up to the headlight shell and back. And Suzuki is still at it -- on V-Stroms, there's a badly undersized headlight connection under the left fairing that eventually fails on every bike.

[Buffalo Bill]

Overheats the connection? HA! Does your source also believe "Helmets will snap your neck", or "Loud pipes save lives"?
Anyway, the first place I heard of it recommended was HEI spark plug and distributor connector covers.
I use it on connectors.

[JEEPRUSTY]

I have used dielectric grease in the past that has caused verdigris to form on the surfaces. I forget the brand. It was a bad experience.

[Fjbj40]

IMOP, based on a aviation background and cars, boats and motorcycles from my experience products such as ACF50 http://learchem.com/industry/motorcycle.html are a better choice. They isolate moisture away from the contacts and also wick up into the wire to further prevent corrosion. Protecting the wires from vibrations via strain relief type installations also prevent premature failures.

On my boat, which operates in salt water all the time, I have zero corrosion on any of the electrical connections installed 9 years ago which receives annual ACF50 applications.

[posplayr]

IMOP, based on a aviation background and cars, boats and motorcycles from my experience products such as ACF50 http://learchem.com/industry/motorcycle.html are a better choice. They isolate moisture away from the contacts and also wick up into the wire to further prevent corrosion. Protecting the wires from vibrations via strain relief type installations also prevent premature failures.

On my boat, which operates in salt water all the time, I have zero corrosion on any of the electrical connections installed 9 years ago which receives annual ACF50 applications.

Unless you have some heavy MIL-SPEC salt fog applications the low viscosity treatments would seem preferable in most cases. I assume this ACF50 is similar to DeOxit or perhaps better?

[chuck hahn]

What about just some plain axle grease like we used to do on car battery posts?? Idea is really to keep the moisture from making oxidation in the connections so wouldnt grease be an acceptable option if he doesnt want to use the dielectric???

I myself would just use the dielectric and never have a second thought about it but its not my harness.

[JJ]

I have never had a problem using dielectric grease, and have been using it for years.

[chuck hahn]

I had to pose the question because i had never heard that claim ever about dielectric grease and harness connections....on bikes or cars.

[Fjbj40]

Unless you have some heavy MIL-SPEC salt fog applications the low viscosity treatments would seem preferable in most cases. I assume this ACF50 is similar to DeOxit or perhaps better?

I have never used or seen DeOxit. The ACF, in my experience, will slow down and/or sometimes arrest corrosion. As for cleaning contacts I use contact cleaner, IPA 90% minimum, naptha and an acid brush or tooth brush followed by ACF.

ACF has very good results in the aerospace industry.