2003 Chevy Tahoe V8 Four Wheel Drive Automatic 102000 miles
My brake fluid/system was ruined due to a faulty resevoir cap and condensation build up. The brake fluid was drained yet the rear fluid would not drain, since then the master cylinder(refurb) has been replaced yet the brake fluid is still not reaching the rear. I've done some research and I've been told it is the air lock in the proportion valve. Does that sound right and what is that? How would you replace? Also the resevoir had a green build up around it it has since been cleaned- Do you recommended replacing that altogether?
As long as the reservoir is clean and the cap fits well, I wouldn't worry about it. The proportioning valve won't block the fluid flow to the rear brakes. It meters the fluid between the front and rear brakes. If for some reason the front or rear brakes take more fluid than the metered amount because of a bypassing master cylinder, or a broken hose or line, the valves goes out of it's preset range and triggers the " brake" light on the dash. Air in the brake system will have the same effect. Most times you can't pump the brake pedal fast enough to force out the air. It keeps moving up in the lines. I would recommend taking the truck in and having the system " pressure bled". This moves the fluid through the brake system fast enough to remove the air. You may find you have a problem with the master cylinder caused by the contamination, but you won't be able to tell until the air is out. Hope this helps.