Regarding your inquiry on the compatibility of Metal Grease with rubber components and its use around brake calipers, please find our guidance below:
[Use on Rubber Components]
Our Metal Grease is primarily designed for lubrication and extreme pressure protection on metal-to-metal contact surfaces. It does not chemically degrade common rubber materials such as NBR (nitrile rubber) or EPDM, and can generally be used safely.
However, since rubber materials vary and may react differently depending on usage environment or aging, there remains a small possibility of unexpected effects.
For this reason, we do not officially label the product as "rubber-compatible" and recommend evaluating suitability based on the specific application.
As you have noted, we also offer a dedicated silicone grease formulated for applications involving rubber or plastic contact.
In cases where contact with rubber components (e.g., dust boots) cannot be avoided, we recommend using this product instead:
https://www.suzuki-kikoh.com/bhsilicon/
[Use Around Disc Brake Calipers]
Contact surfaces of brake pads (e.g., metal shims or backing plates)
→ Metal Grease is suitable. It improves sliding performance and helps prevent brake squeal.
Slide pins (with rubber dust boots)
→ Since these involve rubber contact, we recommend using our silicone grease, which offers superior rubber compatibility and is widely trusted by users for enclosed, long-term applications.