Romel Posted December 2, 2018 Share Posted December 2, 2018 When you say "the proportioning valve", are you meaning the one on the frame under the master cylinder? That's the one I think it probably is. But, there's the ride-height sensing one in the rear. Might it be malfunctioning or improperly adjusted? That one is supposed to limit rear braking with no load. How about disconnecting the arm from the truck, not the valve as the TSB says do not do that, and tie the arm in another position and try the braking? Perhaps you can figure out from that if it is the rear valve or not. I am talking about the proportioning valve, the rear load sensing valve is out of play, it doesnt matter to it if the brakes applied quick or slowly. To my knowledge it is just a mechanical valve, partially open when empty, fully open when loaded truck. The proportioning valve is supose to let the pressure to the rear brakes untill it touches the drum, then move the pressure to the front brakes. Seems this mechanism inside is sticking or not reacting right. Once the rears are blocked u do not have much power to the front, basically sliding like on the ice, fronts not braking much, no matter how hard u push the pedal. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 2, 2018 Author Share Posted December 2, 2018 I am talking about the proportioning valve, the rear load sensing valve is out of play, it doesnt matter to it if the brakes applied quick or slowly. To my knowledge it is just a mechanical valve, partially open when empty, fully open when loaded truck. The proportioning valve is supose to let the pressure to the rear brakes untill it touches the drum, then move the pressure to the front brakes. Seems this mechanism inside is sticking or not reacting right. Once the rears are blocked u do not have much power to the front, basically sliding like on the ice, fronts not braking much, no matter how hard u push the pedal. With that description I would agree - it is the proportioning valve. What's your plan? How are you going to fix it? Link to comment Share on other sites More sharing options...
Romel Posted December 3, 2018 Share Posted December 3, 2018 With that description I would agree - it is the proportioning valve. What's your plan? How are you going to fix it? I have no clue, I cant dig into it as I need the truck every day. I might take it apart during the spring and see what is inside, some springs, seals. I am scared to open it as if something breaks I am off the road for long. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 3, 2018 Author Share Posted December 3, 2018 I have no clue, I cant dig into it as I need the truck every day. I might take it apart during the spring and see what is inside, some springs, seals. I am scared to open it as if something breaks I am off the road for long. Perhaps one of us here in the States can find one for your truck and send it to you? But, we'd need to find it specific to your truck, as shown here (Driveline/Brakes) on the Proportioning Valve tab. Can you tell us which one your truck needs? Or, maybe better, more about your truck, such as GVW and whether 2wd or 4wd? Link to comment Share on other sites More sharing options...
Ford F834 Posted December 3, 2018 Share Posted December 3, 2018 Perhaps one of us here in the States can find one for your truck and send it to you? But, we'd need to find it specific to your truck, as shown here (Driveline/Brakes) on the Proportioning Valve tab. Can you tell us which one your truck needs? Or, maybe better, more about your truck, such as GVW and whether 2wd or 4wd? Gary, according to the chart in the MPC Jan needs E4TZ-2B257–F. For F250 4wd over 8500 gvwr and 6.9/7.3 or 7.5 engine. This also happens to be the one used for ALL F150 1984 and up. This being the case, I have a used one for him from a 1985 F150. Only problem is, I’m a worthless 💩turd💩 these days when it comes to finding time to mail stuff. 😢😔. I just need to get it to him. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 4, 2018 Author Share Posted December 4, 2018 Gary, according to the chart in the MPC Jan needs E4TZ-2B257–F. For F250 4wd over 8500 gvwr and 6.9/7.3 or 7.5 engine. This also happens to be the one used for ALL F150 1984 and up. This being the case, I have a used one for him from a 1985 F150. Only problem is, I’m a worthless 💩turd💩 these days when it comes to finding time to mail stuff. 😢😔. I just need to get it to him. Cool! I was hoping he would need that one, but didn't know if he has 4wd or not so couldn't tell. Have you taken one apart? Surely there are seals involved, but can they be cleaned and re-used? Link to comment Share on other sites More sharing options...
Ford F834 Posted December 4, 2018 Share Posted December 4, 2018 Cool! I was hoping he would need that one, but didn't know if he has 4wd or not so couldn't tell. Have you taken one apart? Surely there are seals involved, but can they be cleaned and re-used? I’ve nrver opened one. But Jan’s description of rust poorige in the MC makes me think a hydraulic shuttle could be sticking in its bore if the valve works that way. I’d like to have a look in one myself. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 4, 2018 Author Share Posted December 4, 2018 I’ve nrver opened one. But Jan’s description of rust poorige in the MC makes me think a hydraulic shuttle could be sticking in its bore if the valve works that way. I’d like to have a look in one myself. There's a procedure in the shop manual to dislodge the shuttle if it sticks one way or the other, so it is obvious that bad brake fluid can cause problems. Jan's is apparently not stuck at either end, but in the middle. If he had a spare he could try cleaning it with a cleaner, or disassembling it. Link to comment Share on other sites More sharing options...
Romel Posted December 4, 2018 Share Posted December 4, 2018 There's a procedure in the shop manual to dislodge the shuttle if it sticks one way or the other, so it is obvious that bad brake fluid can cause problems. Jan's is apparently not stuck at either end, but in the middle. If he had a spare he could try cleaning it with a cleaner, or disassembling it. It is hard to do anything on the truck these days as it rains and rains and the truck does not fit in the garage. I am in the process of moving from one location to the other and I am using the truck daily, plus it gets dark at 5pm. Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 4, 2018 Author Share Posted December 4, 2018 It is hard to do anything on the truck these days as it rains and rains and the truck does not fit in the garage. I am in the process of moving from one location to the other and I am using the truck daily, plus it gets dark at 5pm. Please be careful on those wet roads! Link to comment Share on other sites More sharing options...
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