ArdWrknTrk Posted January 23, 2021 Share Posted January 23, 2021 Ford doesn't call it a proportioning valve, because that's not what it does. But yes, that thing... Actually, Ford calls it a proportioning valve, at least part of it. I know there's been a lot of debate over this, same as Stepside vs. Flareside, and the starter "solenoid" and Start Relay, etc, but it is what it is I guess. That's interesting Cory. All the documentation I've seen calls it a multifunction valve. But as I've been wrong before, I'll be wrong again. But what they're calling a "proportioning valve" obviously isn't functioning as a brake bias control, but a residual pressure check valve. I guess it's just my autistic literalism, but (to me) a "proportioning valve" effects pressure bias, and this as shown can't do that. Link to comment Share on other sites More sharing options...
85lebaront2 Posted January 24, 2021 Share Posted January 24, 2021 That's interesting Cory. All the documentation I've seen calls it a multifunction valve. But as I've been wrong before, I'll be wrong again. But what they're calling a "proportioning valve" obviously isn't functioning as a brake bias control, but a residual pressure check valve. I guess it's just my autistic literalism, but (to me) a "proportioning valve" effects pressure bias, and this as shown can't do that. Jim. it is also interesting that it was done away with after 1986. The newer master cylinders still have the residual pressure valve for the rear brakes, but no longer have the proportioning function. I removed the valve on Darth when I went to the newer booster and master cylinder. I used an inverted flare union where the RWAL actuator went on the 1990 and gave it and the electronic box to my boss as cores for his 1987 F150 2WD. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted January 24, 2021 Share Posted January 24, 2021 Jim. it is also interesting that it was done away with after 1986. The newer master cylinders still have the residual pressure valve for the rear brakes, but no longer have the proportioning function. I removed the valve on Darth when I went to the newer booster and master cylinder. I used an inverted flare union where the RWAL actuator went on the 1990 and gave it and the electronic box to my boss as cores for his 1987 F150 2WD. Yes, I don't think the multifunction valve would fare well with the hammering it would get from the RABS. With the warning light moved to the reservoir and the residual pressure check valve moved to the MC there's no reason for it on the Bricknose and later trucks. Link to comment Share on other sites More sharing options...
Rembrant Posted January 24, 2021 Share Posted January 24, 2021 With the warning light moved to the reservoir and the residual pressure check valve moved to the MC there's no reason for it on the Bricknose and later trucks. That’s how my ‘84 is set up, with the lower valve removed. I’m doing the same thing on the ‘80 as well. I cleaned up the old MC from the ‘95 I pulled the frame out of. Link to comment Share on other sites More sharing options...
Vic Roma Posted May 19, 2021 Share Posted May 19, 2021 With the warning light moved to the reservoir and the residual pressure check valve moved to the MC there's no reason for it on the Bricknose and later trucks. That’s how my ‘84 is set up, with the lower valve removed. I’m doing the same thing on the ‘80 as well. I cleaned up the old MC from the ‘95 I pulled the frame out of. Is there an "idiots guide" to the master cylinder upgrade? I would like to do this on the 84 Bronco, but even with two hands and a flashlight, I'll get lost. Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 19, 2021 Share Posted May 19, 2021 Is there an "idiots guide" to the master cylinder upgrade? I would like to do this on the 84 Bronco, but even with two hands and a flashlight, I'll get lost. Not yet, but John/Machspeed said he would do one. However, if you've read the whole of the thread you've seen that he gave the part number of the one he bought and said it came with the residual pressure valve that is needed. So it should be a straight master cylinder R&R with the exception that the lines have to be swapped. And the factory shop manual section on that is at Documentation/Driveline/Brakes and then the Master Cyl's & Boosters tab, the Factory Shop Manual Sections tab, then the Pedal & Master tab. Link to comment Share on other sites More sharing options...
Machspeed Posted May 20, 2021 Author Share Posted May 20, 2021 Not yet, but John/Machspeed said he would do one. However, if you've read the whole of the thread you've seen that he gave the part number of the one he bought and said it came with the residual pressure valve that is needed. So it should be a straight master cylinder R&R with the exception that the lines have to be swapped. And the factory shop manual section on that is at Documentation/Driveline/Brakes and then the Master Cyl's & Boosters tab, the Factory Shop Manual Sections tab, then the Pedal & Master tab. I can't speak for your this swap into your Bronco, but this was a direct swap into my 86 F150. If your brake lines look like mine, it shouldn't be a problem. From my previous posts in this tread, you will find all the information needed to make the swap, including the part number for the Master Cylinder. You may have to adjust the power booster rod, which you can glean from Youtube. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted May 20, 2021 Share Posted May 20, 2021 I can't speak for your this swap into your Bronco, but this was a direct swap into my 86 F150. If your brake lines look like mine, it shouldn't be a problem. From my previous posts in this tread, you will find all the information needed to make the swap, including the part number for the Master Cylinder. You may have to adjust the power booster rod, which you can glean from Youtube. Do note that you should get the later reservoir pigtail to indicate fluid loss. The wiring from the combination valve can be repurposed for this. Link to comment Share on other sites More sharing options...
Rembrant Posted May 20, 2021 Share Posted May 20, 2021 Do note that you should get the later reservoir pigtail to indicate fluid loss. The wiring from the combination valve can be repurposed for this. Yup. I have mine wired in this way since I removed the combination valve. You could wire them both in if you wanted to. The float switch in the new master has 3 wires...a common, and then N/O and N/C. Link to comment Share on other sites More sharing options...
Vic Roma Posted July 20, 2021 Share Posted July 20, 2021 Do note that you should get the later reservoir pigtail to indicate fluid loss. The wiring from the combination valve can be repurposed for this. Which pigtail fits the BRMC63? Link to comment Share on other sites More sharing options...
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