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Today I was servicing my front brakes and one slide pin on each side was frozen in the bracket.

After removing and cleaning everything I went to grease the pins but realized I ran out of silicone paste that I normally use.

I did however have some left over dielectric grease from a tune up and used some of that. Then I got wondering about the differences as I believe dielectric grease has or is a form of silicone?

This brings me here inquiring. Can they be used I interchangeably? Like silicone paste on spark plugs or dielectric grease on slide pins etc

Btw my brakes felt better so for now all seems well with the dielectric substitute on the slide pins

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  • Dielectric grease dies not conduct electricity and does not cure (stays pliable), silicone does not conduct electricity and cures to a hard form. Neither should be used on brakes. Slide pins should use synthetic grease for that purpose.
    – Moab
    Aug 8, 2016 at 0:55
  • Oh interesting I've always heard of silicone being used on slide pins forever from various people? Now I'm confused lol
    – user58423
    Aug 8, 2016 at 0:58
  • Its better to use synthetic grease on slide pins, labeled for disc brakes.
    – Moab
    Aug 8, 2016 at 1:08
  • Ok is this synthetic grease specific only to brakes or can it also be used for things like ball joints, tie rods?
    – user58423
    Aug 8, 2016 at 1:09
  • Synthetic grease is superior to non synthetic in all applications.
    – Moab
    Aug 8, 2016 at 22:22

3 Answers 3

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Brakes become hot. Very hot. 300°C (600°F) and more is easily achieved at the disks after a hard braking from high speed.

Most greases become quite thin at a higher temperature, and start to creep away from where they previously have been applied to. And the last thing you want is a grease which creeps onto the surface of the braking pad.

Further more, the rubber used at the brake system is made to resist brake fluid, but often doesn't resist mineral oils and greases.

Silicone grease is said to withstand high temperatures, but since every grease has its very own behavior when hot, I would not expect that each silicone grease stays thick enough for the temperatures of a brake. At least, it should not harm the rubber.

Dielectric grease seems to be a kind of silicone grease, which is explicitly made for higher temperatures like at the spark plugs. So I don't have any objection of using dielectric grease vs. normal silicon grease.

But I would strongly recommend to use a special grease for this purpose like PlastiLube for exactly this purpose, because you never know how a random grease behaves at the brakes, even if it's made for high temperatures.

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  • Thank you for that reply. I'll look into PlastiLube. Do you know if normal silicone grease can be used on spark plug boots and/or electrical connections or you need the specific silicone assigned grease for different applications?
    – user58423
    Aug 8, 2016 at 12:34
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    @user58423 Such information is kept in the hands of the manufacturer. The fact is, it's hard to know what you're buying (without good chemistry equipment... and even then). But for what it's worth, I'm pretty sure that dielectric grease can be used as disc brake lube but the opposite may or may not be true. The reason would be purity of the grease. You can be reasonably certain that the dielectric grease will be free from conductive contaminants... whereas lubricant can tolerate more dissolved stuff. But, I wouldn't be surprised if they were exactly the same (depending on the manufacturer). Aug 8, 2016 at 16:55
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So I cant say for sure I'm no expert and I actually made this "mistake" already I thought they were the same when I did my breaks last. Well that was about a year ago and my wheel bearing went bad and I had to take the breaks off to replace it. Well when I had it off I decided to check my guide pins and they still were sliding smooth, so I'm not sure about the long run but so far for me I haven't had a issue.

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Are silicon and dielectric grease interchangeable? NO They are designed differently for different purposes. Dielectric Grease is is non-conductive. Great for keeping electrical connections free from corrosion, while protecting rubber, such as spark plug boots. So slather dielectric grease on every bulb and fuse.. Silicone grease has petroleum distilates. Real nasty on plastics and especially rubber based seals. And silicon grease cures and goes tough, while being great for the backside of disc brake pads,good to 1000' F Another 3rd is Synthetic Grease. 3M is pricey but the gold standard.This is excellent for inside disc brake slide pins. And lubricating door seal rubbers. It does not cure. And is good for high heat, like 400'to 800'F, depending on the manufacturer. So your wheel bearing grease has more metals,lead, lithium,and graphite .. so better for wheel bearings, and high friction loads like ball bearings. Be very ccareful to not cross contaminate.

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  • You seem to be using silicon and silicone to mean the same thing. They are not. While silicon grease may cure as you say, silicone grease does not. Could you clarify your answer to eliminate potential confusion.
    – Chenmunka
    Oct 20, 2021 at 14:04

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