WrenchingtheWretched Posted November 17, 2023 Author Share Posted November 17, 2023 That's a good question. We have a thread called Master Cylinder Upgrade Part Numbers. But I think it only deals with F150 or Bronco brakes. For your one ton you'll be looking for one with a bigger bore. In Big Blue's parts list document I have this note: "1 5/16” bore, probably ACDELCO 18M886 from a ’99 F450 Superduty." But for your truck you will probably want to get one for another F350. Here's a search from Rock Auto's catalog for a 1990 F350, and you'll see several there. But make sure you get one with a reservoir - and the residual pressure valve, which you'll need as it adapts the threads to match your brake lines. But I didn't check to see that any of those come with the residual pressure valve, so you'll have to check that out. Speaking of the brake lines, the newer masters have the front and rear ports switched so you have to bend your lines a bit, but it is easy. So taking your advice I tried searching for the newer master cylinder weeding through RockAuto I found that the “original” MC for my F350 has a 1.063in bore. The 1990 newer style has a 1.125in bore. I did find a newer style with the 1 5/16in bore in a 1994 F350 7.5l. I may just stick with the old school bail style since it’s kind of all over the place with sizing. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 17, 2023 Share Posted November 17, 2023 Okay I’ll give it all a look do I need to do anything special with the multifunction valve? You don't need to do anything to the multifunction valve. I'm still running mine. And, by the way, the issue about the speed control that is mentioned in the RA catalog isn't an issue on a Bullnose. Our speed controls don't use the switch, so there's no need for it but it doesn't hurt to have it. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 19, 2023 Share Posted November 19, 2023 You don't need to do anything to the multifunction valve. I'm still running mine. And, by the way, the issue about the speed control that is mentioned in the RA catalog isn't an issue on a Bullnose. Our speed controls don't use the switch, so there's no need for it but it doesn't hurt to have it. Jim/ArdWrknTrk just informed me that Uhaul Truck Parts has one of the master cylinders you are looking for, and it is only $52.18 + $4.95 shipping. Plus they have 99.99% positive feedback on over 25K sales says a lot. He's working and can't post right now but wanted you to have a chance to get that one. Link to comment Share on other sites More sharing options...
WrenchingtheWretched Posted November 22, 2023 Author Share Posted November 22, 2023 Jim/ArdWrknTrk just informed me that Uhaul Truck Parts has one of the master cylinders you are looking for, and it is only $52.18 + $4.95 shipping. Plus they have 99.99% positive feedback on over 25K sales says a lot. He's working and can't post right now but wanted you to have a chance to get that one. Thanks! I too have been very busy with work! So I still haven’t cracked into the brake issue but I will return with what I find! Link to comment Share on other sites More sharing options...
WrenchingtheWretched Posted November 26, 2023 Author Share Posted November 26, 2023 Thanks! I too have been very busy with work! So I still haven’t cracked into the brake issue but I will return with what I find! Indeed air in the lines! I appreciate all the insight. I apologize for not suspecting that first! Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 26, 2023 Share Posted November 26, 2023 Indeed air in the lines! I appreciate all the insight. I apologize for not suspecting that first! So you have it fixed? Link to comment Share on other sites More sharing options...
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