Posted by JDEM on January 21, 2018 at 08:00:19 from (174.230.5.25):
I already have a post going on this issue but it is getting a little buried. I am looking for some "common sense" ideas or possible explanations.
This on my 1994 Ford diesel F250 HD truck (over 8500 lb. GVWR)
Truck had 200K miles when I got it and now has 400K miles. Brake pedal has always been soft. If I hold pressure on it steady, it will slowly go near all the way down to the floor and my low-vacuum warning light comes on. Has a vacuum booster.
Note - brakes have always worked great. Just kind of un-nerving to have a fading brake pedal and a warning light that comes on under hard use.
So - put it in my shop this winter and replaced near everything. STILL has the problem. New master-cylinder, rebuilt calipers, new wheel cylinders, new vacuum pump, rebuilt vacuum-booster.
I now find out that many Ford owners with similar trucks had or have the same complaints.
Ford Motor Co. addressed the issue with two items. #1 is a special "zero loss" brake booster only for diesels. #2 is a larger-bore master-cylinder from a F450.
I have read many posts where various people tried the Ford fixes. Some said they saw improvement and some not.
I do not like changing parts unless it at least first makes sense in my head.
How can any master-cylinder allow brake-pedal fade unless it has a bypass circuit allowing brake fluid to get past the pistons? And hey - maybe the OEM master-cylinder does?
Ford came up with what they call a "zero loss" vacuum booster only to fix problem vehicles. Loss of what? Vacuum?
One more item to enter into what so far, is a mystery to me. I have read many posts blaming the ABS valve. I just found out my truck does have rear ABS with a module in front. Before yesterday, I did not know it existed. Problem is - as I see it is this. It only has two brake line ports. An "in" and "out." So it seems all it can do is turn "on" or "off" the rear brakes. It does not dump fluid anywhere. I do not see how this can possibly permit brake pedal fade regardless of what it does.
Like many problems that get posted on Web forums - I see lots of ideas but have not found any posts were someone says - "hey, I fixed the thing."
Here is the Ford bulletin info for 1997 and older diesel trucks:
Many owners have realized a low or creeping down brake pedal on their trucks. Ford has developed a Zero-Loss Travel brake booster to correct this condition if the customer finds this condition unacceptable. This part is only for use on diesel-powered trucks P/N F5TZ-2005-CA it is not a service replacement, it must be ordered by the part number specifically, not the vehicle application.
Upload one or more videos to your post. Photo filesizes should be less than 300K and Videos, less than 2MB. Formats allowed are gif, jpg, png, ogg, mp4, mov, and avi. Be sure to use filenames without spaces or special characters, and filetypes of 3 digits lower case.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - Listening to Your Tractor - by Curtis Von Fange. Years ago there was a TV show about a talking car. Unless you are from another planet, physically or otherwise, I don’t think our internal combustion buddies will talk and tell us their problems. But, on the other hand, there is a secret language that our mechanical companions readily do speak. It is an interesting form of communication that involves all the senses of the listener. In this series we are going to investigate and learn the basic rudimentary skills of understanding this lingo.
... [Read Article]
Latest Ad:
2022 John Deere 5045E, 4wd, front end loader and 3rd function with grapple. 120 hrs, 55k new, must sell
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
