Is it smart to apply grease to this cylinder before putting it back in??

[TownsendsFJR1300]

Just reading this thread and wanted to add an FYI:

Permatex makes a brake caliber grease designed to be used on caliber pistons, seals, sliders, etc. I've used it on my my FZ and FJR (same style caliber) front 4 pot calibers, works great. Eases installation and helps protect parts. Here's the link and spec's:

[ame=http://www.amazon.com/Permatex-24110-Caliper-Brush-Top-Bottle/dp/B000HBNV6W]Amazon.com: Permatex 24110 Ultra Disc Brake Caliper Lube, 8 oz Brush-Top Bottle: Automotive[/ame]

Its also available in most automotive parts stores...

BTW, if you purchase a new brake seal kit from Yamaha, they include a small package a grease for the installation. When I rebuilt my FJR brakes (they were dragging some) and picked up the kit, I asked the head mechanic (whom I trust, they race bikes and work on race bikes as well) was this for the sliders? He told me it was for the seals themselves and pistons... I always just used brake fluid previously. Not any more...

 

[FinalImpact]

Is it smart to apply grease to this cylinder before putting it back in?? << NO!!!!!!!!!

If we're going to do a thread revival, I'll add that you should have the service manual in hand as the FIRST STEP if you ever end up with the pistons laying in the caliper or have any doubt about proper assembly!! There should be NO Doubt about how the parts of a caliper, pads, clips, banjo fitting, washers etc are to be reassembled!!!

IT's your life! Brake failure is not an option and you will die if it fails to operate as intended! Frankly this whole thread scares me - petroleum grease on brake rubber is a no no. All the rubber should have been replaced and the proper lubricants used for reassembly. Not to mention just shoving the piston back in the bore could easily compromise the seal and trap abrasive particles inside that compromise the seals and piston.

I'm not going to go into detail but read the manual on how to rebuild a caliper and use the right tools for the job. That includes the lubricants and fluids. DOT 4 fluid is a glycol-ether mix and is not compatible with petroleum based products. If for a moment you feel you're in over your head on the brakes, get help, or take it to someone who can do it right.

Please this is not a dig on anyone. Its a heads up to play it safe, read lots, and fully understand what you are doing!

This is straight from the manual and I advise everyone heed the warning!

Regards

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Disc brake components rarely require disassembly.
Therefore, always follow these preventive measures:
• Never disassemble brake components unless absolutely necessary.
• If any connection on the hydraulic brake system is disconnected, the entire brake system must be disassembled, drained, cleaned, properly filled, and bled after reassembly.
• Never use solvents on internal brake components. (OR PETROLEUM GREASE)
• Use only clean or new brake fluid for cleaning brake components.
• Before installation, all internal brake components should be cleaned and lubricated with clean or new brake fluid.
• Never use solvents on internal brake components as they will cause the piston seals to swell and distort. (OR PETROLEUM GREASE)
• Whenever a brake caliper is disassembled, replace the brake caliper piston
seals.