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Hey guys,

Here are some photos I just took of the wheel cylinders. The one that seems to have a very rusty orange fluid coming out of it is on the drivers side. The fluid that was in the system before I bled it was fairly brown, so I guess a lot of moisture was getting in at the reservoir.

-Garrett

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Is the bore pitted on that cylinder? That rusty fluid is no bueno. If that was fresh fluid from a new bottle, it shouldn't be rusty in that short of a time. It should last like two years or more.

Time to flush out the entire system if there as that amount of moisture in the syste.

You need to find out where that water is getting in the system.
Brake fluid(regular DOT 3) is slightly hygroscopic, (picks up moisture from air) but it's in a closed system so NO water should be in there. Always use fresh fluid from a sealed cotainer. Check you're master cap and gasket. These were mounted "down low" and subject to splashing. Caps and gaskets are available.

....but it's in a closed system

Not quite, the filler cap is vented so that each time the brakes are applied and the fluid level drops, some air (probably with some moisture) is drawn in, and then expelled again when the pedal is released and the fluid level returns to normal. Enough repetitive cycles combined especially with use in high humidity conditions will eventually work it's evil. That's why it's best to change fluid at some interval.

Hey guys,

Kev, I went out to check the bore on that cylinder and those spots didn't wipe off, so it is most certainly pitted. The location of my reservoir takes a lot of the blame here. I have it mounted on my inner fender where it is directly under the crack of the hood/fender. I'm sure some water found its way into the vent hole on the cap. I'm going to relocate the reservoir somewhere "better". I am so glad this problem reared its ugly head on my routine check-up and not on the road. This should be a warning to any of you all to make sure your brake system is in good working order, even if it seems to be working fine.

Question: If I have bled the brakes to where I am only getting clean-golden fluid, do I still need flush out the system?

-Garrett

Quote:
Flushing is more thorough than just simply bleeding - even if you're getting what appears to be clean fluid.

Essentially, you need to push enough fresh fluid through the system to completely replace all of the old fluid. Technically, that would require you to ascertain the system capacity, but that may not be practical. Capacities vary widely, but a quart is a good starting point - though you may not use all of it.

What I've done with vehicles of more recent manufacture is siphon all the existing fluid out of the master cylinder reservoir, and then blot the reservoir, repeatedly, with some Q-tips to get rid of any sediment. By doing so, I'm actually (and purposely) gonna introduce some air into the system.

Then, I refill the master cylinder reservoir and start bleeding (either manually or with a MityVac and bleeding kit), being mindful not to run the reservoir dry during that process. That way, when there's no more air in the stream of exiting fluid, I feel confident that I've pushed all the old fluid out of the system.

However, that may not be so easy to accomplish - depending on the location and style of your master cylinder. If mounted low or underneath the car, you might have to remove the master cylinder for cleaning. If you have a remote reservoir, be sure to drain, clean, and refill it, as well.

Yet, the only way to be 100% sure that you've removed all contamination is to completely disassemble and clean (or repair) ALL cylinders and (as previously noted in this thread) flush out the lines and hoses with a compatible solvent; then refill, and bleed.

I would like to add one cautionary statement: Replace the cap on the reservoir each time you add fluid and before pumping the brake pedal. If you don't some fluid could be squirted out of the reservoir and damage paint. This was an expensive lesson for me with this oversight. But, you already knew this, right?

(o{}o)

Re-Inspect all the cylinders and master cylinder bore. Hone/Replace any cylinders that are pitted, or you will be leaking fluid.

I replaced all the wheel cylinders for my Patrician for $36.00 at NAPA. Not worth the labor to hone them.

Hey guys,

I've got the master cylinder out and I'm in the process of cleaning it out. What solvent do you all recommend to clean everything out? Isopropyl alcohol, or something else?

Thank you,

-Garrett