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MG MGA - Black hydraulic fluid

Bleeding the hydraulics on my TR6. The fluid in the system is milky black. The hydraulic fluid is Dot 4. Stupid kid added Dot 3 (After being told to only use Dot 4. Now its mt problem. Any ideas? HELP
R Egge

Suck out what you can from the main reservoir then bleed it backwards, ie, push replacement fluid from the bleeders back to the reservoir. That should get 98-99% of it which will probably be enough. Then you start over on bleeding out any air.

JM Morris

Don't blame the kid for adding DOT 3 fluid - Real DOT 3 brake fluid will not cause that, it is the predecessor of and is compatible with DOT 4. OTOH, there are some really crappy fluids that are supposed to be DOTx, and are in fact something else.

Bad fluid aside, it is more likely that something else was added to the system - oil, ATF, paint thinner, etc. In 50 years of doing this, I've had one case of a sealed can US made brake fluid causing catastrophic system failure in a week. The owner topped off the system with this stuff, after I told him to use nothing but GTLMA - ate an entire brand new Jag MKII brake system - all cylinders, servo, all hoses. I assume that the substance in the can was an error in production - it was a widely sold US brand. Open cans of fluid are a bad thing for several reasons, the most serious being that somebody puts something else in the can. But, I have observed that various fluids do cause seal deterioration in varying amounts of time. It's why I always use Castrol GTLMA.

O am assuming that the system was checked and not like this when the clutch was replaced.

You have no choice but to thoroughly flush everything and rebuild/replace the entire system, including the flex hose if your car has one. Anything violent enough to cause this kind of condition will penetrate into the rubber and come out to eat new bits.

Fletcher R Millmore

This thread was discussed on 05/06/2010

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