Caliper piston chrome corrosion

[JHZR2]

Our 2014 odyssey has 94k. Original brakes. Never have warped or exhibited the rotor issues that some have complained about.

But the pads were due. Not bad for 94k of mostly in town driving.

Because of the condition of the rotors, and the fact that they aren’t warped or have funky runout, which is a common complaint, I decided to do a pad slap with OE pads. The pads and the stopping is excellent, just like new. No complaints.

The system has done well for around town use.

Rears were more worn than fronts:

Fronts:

Rotors hardly show wear either.

Nothing was that rusty really. Not huge flaky rust that was concerning. Everything could be filed or wire brushed to be ok. Everything bedded and works great.

But my concern was with the front calipers. Specifically this:

The chrome is flaking off of the one, yet it’s bright. The other piston is a bit rusty.

How concerned should I be about this? Not sure if they sell replacement pistons. I know I can still get Frenkit pistons and seals for my w123 Mercedes calipers. But not sure about for Honda. Is this cosmetic? Does it make any difference? I used a little M-77 on the pad to take up the gaps. I don’t know that it’s the best product long term for that, but it works, everything is silent, so it’s fine for now.

Thanks!

 

[vavavroom]

That chrome layer is what, a few hundredths of a millimeter thin? Looks like very superficial corrosion - just enough to make the chrome come off. I can't see the sides. Once the corrosion encroaches on the brake piston near the piston seal I would replace the pistons or the caliper.

 

[vavavroom]

If that's the original brake I bet the piston boot is a little brittle by now.

 

[JHZR2]

That chrome layer is what, a few hundredths of a millimeter thin? Looks like very superficial corrosion - just enough to make the chrome come off. I can't see the sides. Once the corrosion encroaches on the brake piston near the piston seal I would replace the pistons or the caliper.

Yeah none of that. It is indeed the fractions of a mm coating chipping away. The front dual pistons have the seal and boot set back a bit and recessed.

The rears it’s all just flat. I pulled back the boots as part of cleaning and prep and saw no issues.

So yes, superficial, all the red discoloration wiped away, no big issues. But it was still delaminating…

 

[JHZR2]

If that's the original brake I bet the piston boot is a little brittle by now.

Meh. I have far older original brakes and boots in some off old Mercedes cars.

It all pressed in nicely. I was tempted to put some Toyota red rubber grease on the boots. I figured I can always do it in the future as Pm if I’m so inclined.

 

[Warstud]

The rust your showing isnt a concern IMO . Probably came from the pad . You could always place a piece wood inside the caliper and apply the brake to extend the piston out a bit to inspect .

 

[vavavroom]

Meh. I have far older original brakes and boots in some off old Mercedes cars.

I'm not familiar with the quality of Honda rubber components.

It all pressed in nicely. I was tempted to put some Toyota red rubber grease on the boots. I figured I can always do it in the future as Pm if I’m so inclined.

I would expect grease to attract dirt. I wipe the boots clean as well as I can and apply a little 303 Aerospace Protectant. I'm sure it washes off when the boots get wet.

 

[JHZR2]

The rust your showing isnt a concern IMO . Probably came from the pad . You could always place a piece wood inside the caliper and apply the brake to extend the piston out a bit to inspect .

I did just that on the rears. But they didn’t show this chrome flaking.

I did need to clean under the boot because it started like this:

The “stainless” shims do seem to show some rust.

I'm not familiar with the quality of Honda rubber components.

I would expect grease to attract dirt. I wipe the boots clean as well as I can and apply a little 303 Aerospace Protectant. I'm sure it washes off when the boots get wet.

Which is silicone in water. It probably does wash off but that may not matter. I’m not sure if dirt really matters too much either as long as it isn’t in a sliding location. It’s not like brakes are exactly “clean” to begin with. I’ll have to remember to use 303 next time.

Regarding Honda rubber, I used to be pretty harsh on Honda based upon experiences with my GF/Fiancee/Wife’s 94 integra. But these recent Honda products seem to be better.

 

[doitmyself]

apply a little 303 Aerospace Protectant. I'm sure it washes off when the boots get wet.

LOL - thought I was the only OCD one that did the 303 thing. Maybe it absorbs into the rubber just a bit to recondition it???????

 

[vavavroom]

LOL - thought I was the only OCD one that did the 303 thing. Maybe it absorbs into the rubber just a bit to recondition it???????

It seems to condition rubber a bit even though it washes off.

 

[JHZR2]

LOL - thought I was the only OCD one that did the 303 thing. Maybe it absorbs into the rubber just a bit to recondition it???????

Now you have me wanting to pull the calipers up and apply some with an acid brush or something…

 

[Donald]

If you are really concerned you can buy new seals, pull the piston, clean & inspect.. If there is rust in the seal area or below then replace the piston. Don't wire brush or anything abrasive to remove actual rust.

 

[doitmyself]

Now you have me wanting to pull the calipers up and apply some with an acid brush or something…

Mine tend to be a bit crusty from all the road salt, debris, etc.. I use Q tips dipped in 303 and clean them before I retract them in. They look brand new after cleaning. This is why I am labeled the slowest repair person in Michigan. But, I don't so for looks. I hope that I am increasing their lifespan.

 

[JHZR2]

Mine tend to be a bit crusty from all the road salt, debris, etc.. I use Q tips dipped in 303 and clean them before I retract them in. They look brand new after cleaning. This is why I am labeled the slowest repair person in Michigan. But, I don't so for looks. I hope that I am increasing their lifespan.

If only I had the time, energy, and forethought. I got the job done before my kids’ baseball pre-season warmup today by a hair. I should plan better.

 

[Carmudgeon]

LOL - thought I was the only OCD one that did the 303 thing. Maybe it absorbs into the rubber just a bit to recondition it???????

The only stuff I've ever found to have a palpable softening or reconditioning effect is the old BMW Gummi-Pflege product, which I believe was glycerin-based. I wish they still sold it.

303's strength is more UV-blocking.

 

[atikovi]

You usually put a little brake lube on piston anyway, and it will help prevent more corrosion from forming.

 

[JHZR2]

You usually put a little brake lube on piston anyway, and it will help prevent more corrosion from forming.

What brake lube do you put on it?

For Honda brakes I use M-77 and silicone paste. I do put some M-77 on the pad-piston interface. It gets silicone oil and moly there fwiw.

 

[atikovi]

I'd think silicone alone would melt if the brakes got hot. I go with,

It has silicone blended with ceramic for high temperatures. A bit pricey but how often do you use it.

 

[JHZR2]

I'd think silicone alone would melt if the brakes got hot. I go with,

It has silicone blended with ceramic for high temperatures. A bit pricey but how often do you use it.

M-77 is silicone blended with moly. Neither “ceramic” or moly will be corrosion inhibiting.

 

[atikovi]

Anything that puts a barrier between the metal and air around it will help prevent corrosion.