Cause of Brake Fluid Reservoir Sludge

[The Critic]

I had a 03 Pilot here for a front brake service. Found the reservoir filter to be clogged with sludge. After wiping away the goopy stuff, I found some harder black particles remaining.

How exactly does “sludge” form inside the reservoir?

 

[MParr]

1) Not flushing the system and changing the brake fluid
2) Deterioration of rubber brake lines
3) Adding improper brake fluids

 

[Jetronic]

yes it's rubber from the brake lines. Not uncommon but this seems to be extreme.

 

[doublebase]

Wow, I’d say at some point someone put something other than brake fluid in there. I’ve never seen anything quite that bad.

The thing I don’t get it, nothing that large should bypass that little catch screen. That’s really a very fine membrane on those reservoirs. I don’t see how rubber pieces from a brake line could get through that. I could see fluid getting through it and sludging up, but I’ve never EVER seen brake fluid look that bad, that high up in the system at the reservoir. Could someone possibly have dropped pieces of crud in there by being careless, previously?

And on an unrelated note — Is there another vehicle that gets pounded more than the family hauling Honda Pilot? My lord! Just total abuse and neglect. They’ve become the grand caravan of the modern era. Use and abuse. Rinse and repeat. Packed to the gills with vacation stuff, driven to the moon and back. Skip a few oil changes. Don’t worry about the old transmissions and other stuff. Just load’em up and go.

 

[Lubener]

I had a 03 Pilot here for a front brake service. Found the reservoir filter to be clogged with sludge. After wiping away the goopy stuff, I found some harder black particles remaining.

How exactly does “sludge” form inside the reservoir?

Old age, plain and simple.

 

[demarpaint]

Age of the fluid, not changing the fluid every two or three years, and deterioration of the brake hoses.

 

[benjy]

changing fluid every 5 years is generally recommended + even though "rubber brake lines look good outside, inside can be a different story!! being able to STOP is more important than better go power for sure!! get a Motive power bleeder for eze one person bleeding, end fittings vary for different vehicles.

 

[Greasymechtech]

Owner neglect

Flushed a brake system loaded with algae a couple times. I guess enough sunlight leaked thru to power the bugs.

I find that the best maintained vehicles are grossly negligent somewhere. So many owners are critical with their oil change intervals but completely negligent concerning the brake fluid, transmission fluid, gearbox/diff oils, and antifreeze.

 

[JHZR2]

Age will darken it, but I think it has something to do with the materials used in the Honda system. My 40yo Mercedes cars don’t get the little specs of dark fluid, and a layer of who knows what in the reservoir, that my 5yo Honda vehicles do.

My Ram had a layer of similar junk at the bottom of the reservoir when I changed the fluid, but I have no idea of the history there. The Honda vehicles seem to do it much faster. Even my hybrid thst barely wears the brakes at all.

 

[DukeOfFrontenac]

I agree with JHZR2. I had an '06 Pilot. The fluid in the reservoir would get dirty like that and I did fluid flushes every couple years on it.

 

[philipp10]

Age of the fluid, not changing the fluid every two or three years, and deterioration of the brake hoses.

I don't think it has anything to do with not changing the fluid. If it did.....well then I am in big trouble as I almost never do it. I guess my point is.....there has to be a scientific explanation for this type of thing happening and unless you know that old fluid will "sludge", it's not the answer. I suspect the true answer is your internal rubber components are breaking down and the particles are forming sludge.

 

[edyvw]

Is this that part when brake fluid discussion comes, and someone leaves comment: I drove it 15 years without changing it. No problem.

 

[demarpaint]

Is this that part when brake fluid discussion comes, and someone leaves comment: I drove it 15 years without changing it. No problem.

I'm not going to go there. It appears that's where this might be heading.

 

[miden851]

time to change it; i'd flush it twice in short time period