ArdWrknTrk Posted February 15 Share Posted February 15 Multifunction valve..... At least, that's what Ford calls it. 🤷♂️ You can just get a fitting that adapts it, much like the fitting you need to put a normal brake line onto the rear axle splitter on the driver side. 💡 It's metric! I've always gone for an inch of stick out. Never had any idea there was an official dimension. I'm tagging Cory. He's done this a bunch of times to a 150. Link to comment Share on other sites More sharing options...
Rembrant Posted February 15 Share Posted February 15 I'm tagging Cory. He's done this a bunch of times to a 150. Did somebody call me??...lol. Thanks Jim! Are you referring to the later brake master cylinder swap? I have done that a couple times, yes sir. In both cases, I ran all new brake lines on the trucks, and I removed that factory prop-valve (or whatever it is called) and chucked it. I'm sure they were a good idea 45 years ago, but I don't know how effective they are 40+ years later when they're all rusted out and gunked up...jmtcw;). The later master cylinder DO require that residual pressure valve for the rear port, if for no other reason that to connect the brake line...the valve has the correct size and flare for a brake line fitting. I'm not sure how you'd connect a brake like without it. As for gutting it...I can't answer...I never did that personally. I don't even know if you can. Some new master cylinders come with that residual pressure valve, and some do not. I went to the junkyard and grabbed one (a couple actually, to have a spare). PS: Lastly...if you DO chuck the factory prop valve(s) like I did, you can take the original wire and connect it to the float in the later master cylinder. That way your BRAKE light will illuminate if your brake fluid gets low, which is kinda neat...and more "modern"...at least 1990's modern. I forget which terminals on the float switch are which...there are three. Common, and NO, and NC. You'll have to run a ground wire to the common, and then connect the original prop valve wire to the normally open terminal (I think). Hope that helps?.. PS: I also ran into same issue Gary mentions with the booster push rod...better for there to be a tiny gap than any pressure on the MC at all. I have always checked and adjusted them though. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted February 15 Share Posted February 15 I'm tagging Cory. He's done this a bunch of times to a 150. Did somebody call me??...lol. Thanks Jim! Are you referring to the later brake master cylinder swap? I have done that a couple times, yes sir. In both cases, I ran all new brake lines on the trucks, and I removed that factory prop-valve (or whatever it is called) and chucked it. I'm sure they were a good idea 45 years ago, but I don't know how effective they are 40+ years later when they're all rusted out and gunked up...jmtcw;). The later master cylinder DO require that residual pressure valve for the rear port, if for no other reason that to connect the brake line...the valve has the correct size and flare for a brake line fitting. I'm not sure how you'd connect a brake like without it. As for gutting it...I can't answer...I never did that personally. I don't even know if you can. Some new master cylinders come with that residual pressure valve, and some do not. I went to the junkyard and grabbed one (a couple actually, to have a spare). PS: Lastly...if you DO chuck the factory prop valve(s) like I did, you can take the original wire and connect it to the float in the later master cylinder. That way your BRAKE light will illuminate if your brake fluid gets low, which is kinda neat...and more "modern"...at least 1990's modern. I forget which terminals on the float switch are which...there are three. Common, and NO, and NC. You'll have to run a ground wire to the common, and then connect the original prop valve wire to the normally open terminal (I think). Hope that helps?.. PS: I also ran into same issue Gary mentions with the booster push rod...better for there to be a tiny gap than any pressure on the MC at all. I have always checked and adjusted them though. "The Dr is in...". 😄 (Appreciate your insight, Cory!) Link to comment Share on other sites More sharing options...
chirkware Posted February 16 Author Share Posted February 16 I'm tagging Cory. He's done this a bunch of times to a 150. Did somebody call me??...lol. Thanks Jim! Are you referring to the later brake master cylinder swap? I have done that a couple times, yes sir. In both cases, I ran all new brake lines on the trucks, and I removed that factory prop-valve (or whatever it is called) and chucked it. I'm sure they were a good idea 45 years ago, but I don't know how effective they are 40+ years later when they're all rusted out and gunked up...jmtcw;). The later master cylinder DO require that residual pressure valve for the rear port, if for no other reason that to connect the brake line...the valve has the correct size and flare for a brake line fitting. I'm not sure how you'd connect a brake like without it. As for gutting it...I can't answer...I never did that personally. I don't even know if you can. Some new master cylinders come with that residual pressure valve, and some do not. I went to the junkyard and grabbed one (a couple actually, to have a spare). PS: Lastly...if you DO chuck the factory prop valve(s) like I did, you can take the original wire and connect it to the float in the later master cylinder. That way your BRAKE light will illuminate if your brake fluid gets low, which is kinda neat...and more "modern"...at least 1990's modern. I forget which terminals on the float switch are which...there are three. Common, and NO, and NC. You'll have to run a ground wire to the common, and then connect the original prop valve wire to the normally open terminal (I think). Hope that helps?.. PS: I also ran into same issue Gary mentions with the booster push rod...better for there to be a tiny gap than any pressure on the MC at all. I have always checked and adjusted them though. Thanks for checking in Cory! I ordered the RAYBESTOS MC39634 from Rock Auto: https://www.rockauto.com/en/moreinfo.php?pk=309797&cc=1122398&pt=1836&jsn=2507 Pictures do not show it coming with a residual pressure valve, but evidently those who ordered it in the past said theirs came with one. I’ve got a used valve on its way from a friend just in case. As of right now, I have no plans to remove the factory proportioning valve or replace any of the lines, but I’ll certainly be checking over all that. I have 25’ of NiCopp and a variety of on hand should I need to replace some lines. I’m assuming that, if you do remove the proportioning valve, you’d just use a coupler for the rear lines, and a splitter for the front lines. I do like the idea of making the fluid level indicator work. That would be a nice bonus! On the push rod length, it’s sounding like I need to measure the depth of the slot on the master cylinder that receives the rod and then adjust the rod to match that measurement. Link to comment Share on other sites More sharing options...
Rembrant Posted February 16 Share Posted February 16 Thanks for checking in Cory! I do like the idea of making the fluid level indicator work. That would be a nice bonus! You can buy the plug pigtail for the MC from Rockauto also. You can grab one at the junkyard if you have one close by with 90's pickups. https://www.rockauto.com/en/moreinfo.php?pk=50337&cc=1121971&pt=12098&jsn=519 I'm sure you're aware, but the ports are reversed front to rear on the later master cylinders. I ran all new lines at the time so it was a non-issue for me, but I think it's OK when re-using existing factory lines also...there's enough flex in them you can reverse them (others have done this). Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted February 16 Share Posted February 16 Thanks for checking in Cory! I do like the idea of making the fluid level indicator work. That would be a nice bonus! You can buy the plug pigtail for the MC from Rockauto also. You can grab one at the junkyard if you have one close by with 90's pickups. https://www.rockauto.com/en/moreinfo.php?pk=50337&cc=1121971&pt=12098&jsn=519 I'm sure you're aware, but the ports are reversed front to rear on the later master cylinders. I ran all new lines at the time so it was a non-issue for me, but I think it's OK when re-using existing factory lines also...there's enough flex in them you can reverse them (others have done this). Yes, I've done it. You just coil one service loop tighter and relax the other.... Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 16 Share Posted February 16 Yes, I've done it. You just coil one service loop tighter and relax the other.... Yep, that's what I did as well, but on Big Blue with the hydroboost and F450 master there was a bit more stretching than relaxing as everything is longer. In fact, the large master touches the A/C line if you aren't careful and puts an odd noise from the compressor into the cab. Link to comment Share on other sites More sharing options...
chirkware Posted February 17 Author Share Posted February 17 Yes, I've done it. You just coil one service loop tighter and relax the other.... Yep, that's what I did as well, but on Big Blue with the hydroboost and F450 master there was a bit more stretching than relaxing as everything is longer. In fact, the large master touches the A/C line if you aren't careful and puts an odd noise from the compressor into the cab. Good news! I can confirm that the Raybestos MC39634 does indeed come with the residual pressure valve! In other news, no turning back now! Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 17 Share Posted February 17 Good news! I can confirm that the Raybestos MC39634 does indeed come with the residual pressure valve! In other news, no turning back now! Excellent! Glad to have that confirmed. And have you thought about getting a spare cap for it and putting a hose barb in it so you can pressurize the system for bleeding? Sure makes it an easy job. On the rear axle seal, you've found the instructions on how to R&R them? Link to comment Share on other sites More sharing options...
chirkware Posted February 17 Author Share Posted February 17 Excellent! Glad to have that confirmed. And have you thought about getting a spare cap for it and putting a hose barb in it so you can pressurize the system for bleeding? Sure makes it an easy job.On the rear axle seal, you've found the instructions on how to R&R them?Funny...I just came to my laptop to try to look at the docs you referenced (I had not looked at them, but had watched a few youtube videos) while working on Larry. To get to this website, I started entering larrysgaragemahal ... Larry, Gary, what's the difference?!? LOL Oddly, my browser didn't find the site!Reviewing the docs now before I start destroying things! :)Regarding bleeding the brakes...I hadn't really looked at that up to this point, but I think I get what you are saying now. Same concept as this video, but a bit more diy? Looks SO much easier! Link to comment Share on other sites More sharing options...
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