It would appear you solved the problem. I've never actually run into that, but given all the stuff that's in that assembly, it's understandable that it could cause that problem.
You aren't going to find this valve at the dealership, partly because if its age, and partly because there's too many variations. Because they DO have such a low failure rate, you'll have a real good chance of finding a good one in a salvage yard. Keep in mind though that the proportioning valve, which sends brake fluid to the rear and limits fluid pressure to reduce rear-wheel lockup, was carefully-calibrated to your specific truck's weight distribution and weight transfer during braking. If you can find a part number on your valve, and you find one in a salvage yard with the same number, you're home free. If there's no number on them, look for one on a truck that is the same as yours. That means the same year, same engine family, same wheel base, and same options. That valve will be different between a truck with air conditioning and one without because of the difference in weight on the front. A truck with a V-8 engine will have a different valve than one with a V-6. A dually rear axle or extended cab will be different too.
Monday, February 24th, 2014 AT 10:15 PM