Goop in the calipers

[Hook#3287]

After 15 1/2 years and 115k miles, my front calipers were sticking a little and the pads were clinking somewhat when going over ruff roads.

Time to rebuild.

Took them off and was debating whether to pull the pistons or not. 

Glad I did, inside was some goop like stuff of the consistency of GOJO in the bottom of the piston chambers,  about the size of a quarter.  Felt like it could be grease, maybe from original install?

I know these calipers have never been apart cause I bought that bike brand new.

I've had many a calipers apart before but never seen anything like that, wish I took a picture.

Anyways, rebuilt with new springs, boots, SILICONE grease, pins, seals, retainers and pads.  Swapped out the fluid.

Just like brandy new.

Good for another 15 years or so, well, except new fluid every 3 years and pads when needed.

[hubcapsc]

Good for another 15 years or so, well, except new fluid every 3 years and pads when needed.

Why wait until it goops back up?



People were saying here that the silicone lube listed in the manual was probably a
mistake and could react with the seals and make the pistons stick... I always just
lube everything up with brake fluid... anyone else remember anything about
using silicone lube?

-Mike

[michaelyoung254]

Many years ago when I was taking auto mechanics classes, both in high school, and in college, we were always taught to never use anything except brake fluid on any brake components such as master cylinders, calipers, and wheel cylinders.


Mike

[BonS]

I don't know about Honda, but Yamaha includes a packet of lubricant with their caliper seals. It's a silicone based lube that is applied to the bore, piston and seal to guard against corrosion. The silicone lube forms a protective layer for the piston and bore for when brake fluid absorbs water or water gets into the piston area from the outside through a leaky seal. It also is useful when parts will be shelved in inventory before installation, again to avoid corrosion. The nasty sludge found in brake systems that haven't been flushed is congealed brake fluid. There are more than a few manufacturers of brake cylinder assembly lubricant such as Seiken, Castrol and Permatex.

[salty1]

Time, water, brake fluid creates sludge.    Dot 4 is very hygroscopic, loves water.

[BobB]

Many years ago when I was taking auto mechanics classes, both in high school, and in college, we were always taught to never use anything except brake fluid on any brake components such as master cylinders, calipers, and wheel cylinders.

Mike

I'm with Mike.  Anytime one puts a fluid into the caliper cylinders that may have a lower evaporation temperature than DOT-4, one may get mushy brakes.  The fluid can gasify and compress...

Time, water, brake fluid creates sludge.    Dot 4 is very hygroscopic, loves water.

Not exactly...  Yes, brake fluid loves water.  It absorbs it like mad, but the water remains in suspension.  The problem is when your brake temperature reaches around 212^o F, the water in there turns to steam.  Steam is a compressible gas, and when one presses the brake, it's mush and nothing happens.  Hydraulic systems only work with incompressible fluids (liquids).

[bentwrench]

Yuck that stuff looks gross.That why I do my brake fluid every fall.One can does all three,cheap insurance.

[Hook#3287]

Yuck that stuff looks gross.That why I do my brake fluid every fall.One can does all three,cheap insurance.

My fluid was changed every three years, sometimes two.

Many years ago when I was taking auto mechanics classes, both in high school, and in college, we were always taught to never use anything except brake fluid on any brake components such as master cylinders, calipers, and wheel cylinders.


Mike

I only used the silicone grease on the pins and boots.  Although the manual states to coat the piston with grease, I use DOT 4 fluid only.

[98valk]

off the shelf brake fluid needs to be changed every two yrs.
always buy the highest DOT 4 wet boiling point (WBP), the higher more resistance to absorption of moisture. moisture is absorbed right through plastic bottles, metal cans have a longer shelf life no absorption of moisture.
Dry boiling point only maters on the track.
DOT 5.1 is higher WBP but it has a different viscosity for ABS, might not work right in a system designed for DOT 4.
Napa sells http://www.pentosin.net/f_brakefluid.asp in metal can.
higher WBP than std DOT 4

ATE is even better for WBP
http://www.amazon.com/ATE-706202-Original-Brake-Fluid/dp/B003VXRPL0%3FSubscriptionId%3DAKIAILSHYYTFIVPWUY6Q%26tag%3Dduckduckgo-d-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3DB003VXRPL0