So today after driving at about 65-70 mph for about 20 miles or so when i got off the highway the brake pedal dropped to the floor, it stopped but the pedal was on the floor. After using the brakes a few more times in city traffic they were normal again. When i first got the car it did this after doing the same highway drive, and then I replaced all brake hoses. The next time i did this same drive the brake pedal was normal so i figured it was restricted brake hoses and said problem solved, then today it happend again after the same drive.

There are no fluid leaks in the system, all the pads are fine, none of the calipers are dragging.

The brake fluid is pretty dark even after i changed the hoses. So here is what I think. The brake fluid is boiling causing the pedal to drop of driving at high speed for a long time. I guess i need to flush the brakes some more.

I don't think its the master cylinder because the pedal doesn't drop down while sitting still.

So what do ya'll think about this? Thanks

__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg

I'd avoid that drive. But seriously, I think you're right about the brake fluid. I'd flush it out and put new fluid in and bleed the brakes good. I had this happen in my '75 240D and that cleared it up.

hahaha, tormorrow i'll do that and see what happens, it can't hurt.

__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg