Brake Proportion Valve, and slow reation from the brakes.

Change the inlet lines and cap the extra line, plug the old inlet.

 

Those were how the first systems were made. I’m not exactly sure, but I’ve read about it on Merritor or Wabco website. I think it was Merritor. The fronts default to 50% bobtailing. If I remember correctly it’s the relay valve in front that controls it. 99 Freightliner A10466

 

Regular pressure to the steers, 50% to the rear. Supposed to keep from locking up the rear. Was easy enough to by pass on all that i had.

 

Mine is a 95 Freightliner I had the same problem.

I went to FleetPride and I took the valve with me and I bought a regular relay valve. I suggest taking it with you because those valves are set up differently some have different size fittings some of the fittings are in a different spot, but if you get the same exact valve but it's just a regular Bendix valve that will do it.

My truck stops much nicer now and it even works better in conjunction with the trailer.

 

You have two lines coming in to the top of the valve. One is hot when you release the trailer brakes. Cap it or trace back to trailer valve and plug it. Move the other line to that port and plug the proportioning port. Couple of dollars in parts and you're done. Had to do quite a few of them because the drivers cried about it.

 

You want full air into the control port. (Just a generic picture)

 

I’m not sure if my 99 is the 50% type or not. I was thinking it isn’t, but could be used instead, and still have abs on fronts. I do know I had to stand on them, to stop. An adjustment in driving habits. First Truck I had with abs. Current 2000 is the same way. I’ve barely stopped a few times, had to stand on them, felt like I wasn’t going to stop. I don’t like that. I may be confused on the 50% steer valve. The more I think about it, I think that was for pre abs systems. I know I used to back them off twice the drives with manual adjustment slacks. @Dino soar seems to have it all figured out.