1999 Ford XL 2x4 Extended Cab, Rear Drum Brakes w/ABS-Rear Only!
June 2018
New Brake Lines (All) Dorman
New Brake Hose (All)
New Rear Wheel Brakes, Drum Style, Drums & Shoes, Springs.
Sanded Mounting Plates and applied POR-15
New Rear Wheel Brake Cylinders.
New ABS Sensor, rear.
New Master Cylinder.
New Brake Booster.
New Proportioning Valve, Mounts under Master Cylinder, Re-Manufactured.
(Prior to replacement, Brakes would lock up on wet surface - indicating defective/bad Proportioning Valve.)
Re-used existing Proportioning Pressure Regulator Valve, attaches to Master Cylinder.
Current Problem:
Brake Pedal is still soft, will travel to floor, ABS & Brake Light will come on at this point. Restart engine and Lights will go off. No Codes Detected ZR-13 Code Reader. Looking for Solutions. Either Vacuum issue or Proportioning valve. Not sure!

 

Im going to bump this for visibility. One of the guys that knows brakes should be by soon.

 

There were some recent threads about screwing up the ABS pump by pushing fluid back in to them when changing pads. Similar pedal to floor problem afterward.

You might clear up some confusion. You seem to be saying that you bought a new valve but used the old valve.

 

Here's the one I was thinking of - https://www.f150forum.com/f12/replac...-floor-419946/

 

Did you bench bleed the MC? Air in the system of the baffle in the booster is leaking, any hissing?

 

I purchased a Re-manufactured Proportioning Valve. Kelsey-Hayes is the name on the label. I reinstalled the existing Pressure Regulator which mounts on the Master Cylinder. Seems to be two parts to the ABS Proportioning System. The Pressure Regulator can be seen in the Photo I posted. About the size of a large lug nut on the side of MC. Brake line attaches to it.
I can't be sure of both parts the make up Proportioning Valve system. Not sure how to test their functionality. Engine races at start up, so I am considering Vacuum issue. The Brakes will work in stopping the truck. However, I can still push the pedal all the way to the floor board and the ABS & Brake Light indicators will come on. The lights will go off after Engine restart. I am just trying to cover all bases before I let some local spend too much of my money chasing stupid around. Not much more I can replace. I do not have a good Mechanic around to reference. Thanks

 

Yep, I bench bled the Master. First (NEW) one leaked from the rear seal. This one (NEW) seems to be fine; no leaks. The Booster is new. All function tests indicate it is good. The only thing I notice is a bit of engine racing at start-up, before it goes to normal idle. I have an AIR-AID intake filter, so I can't tell if I here that making noise or a vacuum sound. I tested around old-school way for vacuum issue. None found. I will not rule out anything at this point. I have bled the brakes all around every time I replaced a part or removed a line from Master Cylinder. I am going to loosen the the output line on the proportioning Valve while pushing pedal down, to see if any air is trapped. Just one more bleed!!!!!!

 

The standard test for air in the system is to pump the pedal. If there's an air bubble it will compress and the pedal will stop going to the floor.

 

OK, let's get a little more detail. Engine Running? etc....? Step by step instructions. I have watched many a video about testing Booster/Brakes etc. It would be nice to have an established test method to identify functionality with "Pass" or "fail" results, 'no doubt' about anything. If you have the time for instruction, please respond. Many Thanks for the reply!

 

You have to know a little bit about hydraulic systems, and why air bubbles are a problem. Air is compressible, brake fluid is not (essentially, for the purpose of the system). When you pump the pedal you push fluid in to the bubble, squishing it down until it's tiny. Might be easier if you just went and pumped the pedal to see what happens. Key off, all valves closed, just pump the pedal to the floor about ten times quickly and see if the pedal rises.

With all of that new hardware though, it might be that you just need to do a lot of bleeding. There's probably a special process for a new system. Some trucks have an automated system run by the ECM. It's described in that link I provided. I don't know if 1999 has it. Rnlcomp called it the "service bleed" and talks about it in Post #17. Find out if your 99 model has a service bleed procedure.