Gary Lewis Posted February 13 Share Posted February 13 Thanks guys! Definitely sounds like I need to swap in a new master cylinder. I will say my fluid level was full when I checked it so it doesn’t seem to be losing fluid. I was really expecting to find it low. All rubber hoses were new last year, as were both wheel cylinders and the drivers side caliper (passenger caliper was just a couple years old, confirmed replaced by prior owner). New pads too. Shoes aren’t new, but have lots of wear left on them. I will say that the fluid (about a year old) in the rear of the master cylinder (so for the front brakes) looked somewhat contaminated. Not sure why. I bled sufficiently to have to mostly refill it twice, and then top it off a third time. Was really surprised by the poor pedal after. Looks like I need to prep for an axle bearing swap too on that rear right. It was really wet. I’ve not yet serviced the 9” so I think I need to stop ignoring that now. 😂 Ooooooohhh! I just remembered…when I first pulled the right rear going through the brakes when I got Larry, it was soaked. I concluded it was a bad wheel cylinder. Now I realize it was probably that seal that was the bigger culprit. I better check that diff to make sure it’s still got fluid. 🙄 Seals on a 9" are "fun". You have to drill or otherwise crack the retainer and use a press to put a new one on. As for the master cylinder, would you be interested in upgrading to a later model one? The ones with an aluminum base and plastic reservoir? You won't have the rusting hulk of the cast iron one, and it won't leak like the old ones do. Plus, it makes bleeding the system a lot easier if you get a replacement cap, put an air connection on it, and then use something like a garden pump-up sprayer to put a few psi on the reservoir. You need to buy one with a residual pressure valve on it, and Rock Auto sells one. If you are interested I'll find the part number. Link to comment Share on other sites More sharing options...
chirkware Posted February 13 Author Share Posted February 13 Seals on a 9" are "fun". You have to drill or otherwise crack the retainer and use a press to put a new one on. As for the master cylinder, would you be interested in upgrading to a later model one? The ones with an aluminum base and plastic reservoir? You won't have the rusting hulk of the cast iron one, and it won't leak like the old ones do. Plus, it makes bleeding the system a lot easier if you get a replacement cap, put an air connection on it, and then use something like a garden pump-up sprayer to put a few psi on the reservoir. You need to buy one with a residual pressure valve on it, and Rock Auto sells one. If you are interested I'll find the part number. Sounds intriguing. Does it require changing the booster? Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 13 Share Posted February 13 Seals on a 9" are "fun". You have to drill or otherwise crack the retainer and use a press to put a new one on. As for the master cylinder, would you be interested in upgrading to a later model one? The ones with an aluminum base and plastic reservoir? You won't have the rusting hulk of the cast iron one, and it won't leak like the old ones do. Plus, it makes bleeding the system a lot easier if you get a replacement cap, put an air connection on it, and then use something like a garden pump-up sprayer to put a few psi on the reservoir. You need to buy one with a residual pressure valve on it, and Rock Auto sells one. If you are interested I'll find the part number. Sounds intriguing. Does it require changing the booster? No, you don't have to change the booster. You might be interested in the thread Master Cylinder Upgrade Part Numbers. Link to comment Share on other sites More sharing options...
chirkware Posted February 13 Author Share Posted February 13 Seals on a 9" are "fun". You have to drill or otherwise crack the retainer and use a press to put a new one on. As for the master cylinder, would you be interested in upgrading to a later model one? The ones with an aluminum base and plastic reservoir? You won't have the rusting hulk of the cast iron one, and it won't leak like the old ones do. Plus, it makes bleeding the system a lot easier if you get a replacement cap, put an air connection on it, and then use something like a garden pump-up sprayer to put a few psi on the reservoir. You need to buy one with a residual pressure valve on it, and Rock Auto sells one. If you are interested I'll find the part number. Sounds intriguing. Does it require changing the booster? These pictures are from January, 2023, when I was going through the brakes before: I blamed all that on a leaking wheel cylinder, which I replaced. Yet the wheel cylinder doesn’t even look wet in that last picture. It wasn’t this bad when I opened it up Saturday, but it was getting there. Gotta be the axle seal right? Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 13 Share Posted February 13 These pictures are from January, 2023, when I was going through the brakes before: I blamed all that on a leaking wheel cylinder, which I replaced. Yet the wheel cylinder doesn’t even look wet in that last picture. It wasn’t this bad when I opened it up Saturday, but it was getting there. Gotta be the axle seal right? I agree that the wheel cylinder looks dry, and those shoes don't look like ones with brake fluid on them. Brake fluid soaks in and makes them grabby. That looks like 80/90W and they look slick. Has to be the wheel bearing seal. Link to comment Share on other sites More sharing options...
chirkware Posted February 14 Author Share Posted February 14 I agree that the wheel cylinder looks dry, and those shoes don't look like ones with brake fluid on them. Brake fluid soaks in and makes them grabby. That looks like 80/90W and they look slick. Has to be the wheel bearing seal. Does this look right for an axle bearing / seal kit? https://a.co/d/5LjIGXp The listing says it’s correct for 2wd but Larry is a 4wd. Would 4wd be different? Link to comment Share on other sites More sharing options...
Gary Lewis Posted February 14 Share Posted February 14 Does this look right for an axle bearing / seal kit? https://a.co/d/5LjIGXp The listing says it’s correct for 2wd but Larry is a 4wd. Would 4wd be different? Looks right to me - if you have a 9". I dialed in Dad's truck, which has a 9", and it is right for it. Don't think there's a difference between a 2wd or 4wd 9". Link to comment Share on other sites More sharing options...
chirkware Posted February 14 Author Share Posted February 14 Looks right to me - if you have a 9". I dialed in Dad's truck, which has a 9", and it is right for it. Don't think there's a difference between a 2wd or 4wd 9". Thanks Gary! No rear cover on the housing, so I would presume that means it’s a 9”. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted February 14 Share Posted February 14 Looks right to me - if you have a 9". I dialed in Dad's truck, which has a 9", and it is right for it. Don't think there's a difference between a 2wd or 4wd 9". Thanks Gary! No rear cover on the housing, so I would presume that means it’s a 9”. In an 86 150, yes. Link to comment Share on other sites More sharing options...
chirkware Posted February 14 Author Share Posted February 14 In an 86 150, yes. Thanks again guys! I'm about to pull the trigger on a RAYBESTOS MC39634 from Rock Auto: https://www.rockauto.com/en/moreinfo.php?pk=309797&cc=1122398&pt=1836&jsn=2507 I specced a 1996 F150 and that was the number that came up, same as from the thread Gary posted. Also was going to order oil for the 9" rear. Figured I'd also change fluid in the front diff at the same time. Rockauto has Motorcraft 80W-90 (same warehouse, so one shipping charge!), which is what I used in my 70 F100, so I was going to go with that. Does that seem like the right choice? From what I'm seeing, I'd need about 3Q for the rear and 1.5Q for the front. Does that seem about right? I figured I'd order 6Q to be sure I have enough. Any other "while I'm there" items you'd suggest? I've got a three day weekend with nice weather (my driveway is my shop!), so I plan to tackle this soon. Looks like Rock Auto can have it all here Friday if I order soon. :) Link to comment Share on other sites More sharing options...
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