Topic: High Vacuum grease on calliper parts?

[Ewan 500K1]

For the caliper cylinder seals , red rubber grease can be used.  Tech data sheet here:

http://www.bp.com/assets/bp_internet/castrol/castrol_south_africa/STAGING/local_assets/downloads/t/Red_Rubber_Grease_TDS.pdf

  You could use this in place of the assembly lube.  But, it does not have  high enough temperature stability to be used in place of the Dow corning silicone grease.

yep TT that's right ...red rubber grease only for the seal in the caliper cylinder. Carlube Silicon Grease for for brake pad back & sides etc .... both are stock in UK

[70CB750]

I found the name - Sil-Glyde.

[TwoTired]

I found the name - Sil-Glyde.

I can say from awful experience that this stuff is terrible for this application on SOHC4 calipers.  While it has some silicone in it, it is not based on silicone.  And, in my oven tests turned to tar at about 150-200F.
The base of the compound is NOT stable even at room temp, separates, bleeds, and flows outward along any surface it is placed upon.

It flowed outward and contaminated the caliper pads after the first hard stop I made with the bike.  The new pads had to be replaced.

The best use I found for Sil-Gyde was for lubing auto door hinges and those multi-position stop devices that hold the door in place when open.

Please don't EVER use Sil-Glyde on the SOHC4 caliper components.  The package labeling is very misleading, imo.

[70CB750]

Hmmm. I would never expected that.  Thanks!

[Harsh]

  Lets' review.
There are four products needed to restore a caliper.
1. Brake cleaner
2. Brake parts assembly lube for the caliper seal only.
3. Dow corning High vacuum grease.
4. Brake fluid

Each has it own specific application and needs for the task to be performed.

#1 is used to get everything clean.  (given the confusion, it had to be said)
#2 is used ONLY on the seal and must be compatible with #4, as some of it will invade the brake fluid chamber.
#3 is NOT used on the seal, as that would put silicone inside the brake fluid chamber.  This is a bad thing as the compounds are incompatible.  It is used behind the brake pads and a thin coat is used on the parts of the calipers and piston that are exposed to the elements and subject to water ingression.  The Dow Grease will not mix with ANYTHING.  It is a simple barrier with the very important property that it will NOT melt when the parts get hot and then run/creep into the brake pad friction material and provide lubrication between pad and disk rotor.
#4 is what makes the hydraulic part of the brake function. (I hope that part is clear.)

Cheers,

TT I have a question for yah.

You say that #3 is not used on the seal, but my manual says to use it on the seal and piston.  My front brake setup is a '75 GL1000.  Here is a copy of the manual.  I have some Dow HVG, but not sure what the best course of action is.

[TwoTired]

I don't want any silcone inside the pressure vessel.  It is compressible and very tenacious at hanging around, making complete removal very difficult.  If you want to use it anyway, I'd recommend limiting to a very thin coat.

The guideline I posted was for the SOHC4 caliper.

I just did an '81 GL1100I brake system.  I used brake assembly lube on the seals, and used a bit of HVG on the piston but only on opposite side the brake fluid side of the seal.  So far, it seems to work pretty good.  Ask me again in 10-15 years. 

  Maybe Honda is trying to reduce piston caliper pitting with a coating overall.  I mean water is going to get in there one way or the other.  Perhaps the plating just isn't enough.

Cheers,

[Harsh]

Thanks.  However, now I wonder about using DOT 5 fluid which is silicone based and non hygroscopic to boot.

[TwoTired]

Thanks.  However, now I wonder about using DOT 5 fluid which is silicone based and non hygroscopic to boot.

I won't save you from regular changes.  DOT 5 doesn't absorb water, but it still collects in low points of the system.  The calipers we are talking about don't have a low point drain, so getting the water out means dissassembly.  Whereas, with DOT 3, 4, and 5.1, the water comes out of the system with a biannual flush.

Also, some have reported a spongy feel to DOT5.   It's a one way conversion, as nothing combines/dilutes with silicone to flush it out, it can only be moved or pushed around by mechanical means, so some will always be inside the system unless all the parts of the system are replaced at the same time.  This is why the US military is stuck with using DOT5, as it really didn't save then any money after they began to use it.  Service procedures are the same and they can't covert back without replacing all the parts.

Best thing about DOT5 appears to be its property of not eating paint when spilled.  If you need extreme temperature ability, 5.1 is the better choice, imo.

Cheers,