I have changed the clutch master cylinder, slave cylinder,the rubber line, and the steel line about 8 months ago. I used DOT 4 fluid.
The fluid now seems black and crudy. I am replacing the clutch and am wondering if I should tear the hydraulic back apart and flush or rebuild.
When I replaced them before I took these cylinders apart for fun and they were full of a black gooey stuff, like the fluid reacted with the rubber parts or something.
Anyone got any ideas
W
I use Castrol LMA brake fluid and try to change it out every year. It seems to be less hard on the seals and is compatible with the sensitive seals of older UK automotive products. Girling and others recommend it. Mercedes uses ATE, Lucas Girling, Bendix and others interchangeably on their brake systems. I think the Castrol will work fine in the G hydraulic brakes, difflocks, and clutch systems. Some brake fluid brands are tough on rubber parts. This could be contributing to the gack you are finding in your system. I try to change out my fluid in the lowest humidity summertime because it is so hygroscopic and I live in wetland winter Oregon.
The seals are probably being worn by the machined surfaces of the new master and slave cylinders. This should slow down with time. Flush the fluid if you don't like how it looks, and flush it once a year anyway. Minimise the system's exposure to cruddy fluid by suctioning the gunky fluid out of the reservoir and filling the reservoir with clean fluid before you start your flush.
I also use Castrol GTLMA, as does my trusted local MB mechanic wh says he's used it in all kinds of MBs for 20+ years with no ill effects.
There's a hydraulic systems service (flush) article on the G-tech pages at http://www.clubgwagen.com
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