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Discussion Starter #1
I've got a 1-1/2 bore MC from an 04 f350 super dooty that came with the hydroboost I installed recently. After researching the problem is that I have too large of a bore MC for my stock brakes (10.5 swap is in the works) and the pedal is extremely stiff only allowing about an inch of movement. I could throw on a smaller bore MC although I'd have to ghetto bolt it up to the larger hydroboost but is there any way I could solve this problem while keeping the 1-1/2 MC installed? Larger wheel cylinders? Residual valves? My knowledge of brake systems/parts/ratios etc is limited so any help is appreciated.
 

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I wouldn't "ghetto" anything as far as brakes are concerned. Your problem probably lies in the fact that you are using 1/2 ton calipers and wheel cylinders with that big MC, the calipers especially.
I would like to say put all your old stuff back on till you can do this right or until you get your 1 ton stuff on
 

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I have the same set-up as you have now, one ton master cylinder and brake booster, half ton calipers. The 10.5 sterling swap will only help your rear brakes. Front brakes are more important that rear. Are you going to install a D60 front? If so, all will be good.

You are right, your ratio right now is not good. That said, I have been running like this for a couple of years. Use two feet if you need to panic brake. It will stop the truck. Mine will lock up all of the tires and skid.

If you are not going D60 front, late 60's Thunderbird calipers have the piston diameter that you need and the matching Bronco D44 bolt spacing, but getting them installed gets messy at the banjo bolt and brake line. They are different sizes than stock Bronco. If you have a lift and extended brake lines, you have to choose between buying another set of brake lines with custom ends for the T-bird calipers which can run over $100, and follow the internet write-ups with some conversion fittings.

I went down the other path and tried modifying the T-bird calipers to accept the stock Bronco banjo bolt using a heli-coil type thread interface. I forget the brand, but Granger sells it. I drilled out the T-bird caliper to 9/16 inch but got stuck when it came time to thread the new hole. The cast iron caliper has an odd shape, so I could not hold it steady enough to get the tap started properly. I found a small custom machine shop near by that may be able to do it, but that project is low on my list since I can drive the truck as it is. If you can get this idea to work, it will probably cost more than buying new brake lines and some new fittings.
 

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Discussion Starter #4
I wouldn't "ghetto" anything as far as brakes are concerned. Your problem probably lies in the fact that you are using 1/2 ton calipers and wheel cylinders with that big MC, the calipers especially.
I would like to say put all your old stuff back on till you can do this right or until you get your 1 ton stuff on
Really the only "ghetto" part would be where the MC docks into the hydroboost. The 1-1/2 MC has a large diameter that fits like a glove into the hydroboost. With a smaller MC, the ears might need some trimming but docking into the hydro won't be flush all the way around. There will probably be a 3/16" space around the MC. I'd have to try it out to see how stable it is but you're right.

I have the same set-up as you have now, one ton master cylinder and brake booster, half ton calipers. The 10.5 sterling swap will only help your rear brakes. Front brakes are more important that rear. Are you going to install a D60 front? If so, all will be good.

You are right, your ratio right now is not good. That said, I have been running like this for a couple of years. Use two feet if you need to panic brake. It will stop the truck. Mine will lock up all of the tires and skid.

If you are not going D60 front, late 60's Thunderbird calipers have the piston diameter that you need and the matching Bronco D44 bolt spacing, but getting them installed gets messy at the banjo bolt and brake line. They are different sizes than stock Bronco. If you have a lift and extended brake lines, you have to choose between buying another set of brake lines with custom ends for the T-bird calipers which can run over $100, and follow the internet write-ups with some conversion fittings.

I went down the other path and tried modifying the T-bird calipers to accept the stock Bronco banjo bolt using a heli-coil type thread interface. I forget the brand, but Granger sells it. I drilled out the T-bird caliper to 9/16 inch but got stuck when it came time to thread the new hole. The cast iron caliper has an odd shape, so I could not hold it steady enough to get the tap started properly. I found a small custom machine shop near by that may be able to do it, but that project is low on my list since I can drive the truck as it is. If you can get this idea to work, it will probably cost more than buying new brake lines and some new fittings.
I do plan on a D60 front as soon as I can snag one from the local JY. I acquired a sterling 10.5 with rear discs from an 00 f250 souper. Sweet jesus that thing is heavy. I've throw way too much money into this stupid project that was supposed to be decently affordable as a replacement to my bad vac boost so I'll keep in mind the t-bird option but I don't want to mod it just to take it off in the next 6 months.
 

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Upgrade to the TBird calipers NOW. Do your 10.5 swap ASAP. Drive it like you stole it till it breaks then do the D60 front swap. Now you can say you got your monies worth out of the TBird calipers. You could upgrade to F350 rear wheel cylinders easily as well and with only expense being the wheel cylinders. If you are going to drive and modify at the same time you have to make some sacrifices whether it is money or abilities.

There is nothing that can be done about having too much MC volume except out on the brake end. You could play with brake pedal ratio but that opens another can of worms.
 

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Discussion Starter #6
Ok here's an update and idiot of the month award goes to me. My rear brakes were "locking up" which led me to replace the hydroboost and in turn brought me to the large bore MC issue. Problem is with the 04 superduty MC, the fittings are on the driver's side, not the passenger side. I couldn't put another smaller MC without rebuilding some of the hydraulic hoses because my reservoir is attached to the passenger side of my MC via the PSC reservoir mounting bracket on the MC. Smaller bore MC's have the fittings on the passenger side. I said screw it and threw back on the souperduty MC in hopes of finding out what was stopping me from going into reverse. IT WAS THE CHOCKS. Drove it around with no issue. Only thing noticeable is the short range of brakage and the slight humming of the hydraulics when idling with the brake pedal down. The brakes aren't touchy like some people mentioned. You just have to add a little more foot weight to the pedal instead of previously pushing the brake pedal near to the floor. Thanks for the input anyways guys.
 

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doesnt an 04 350 SD have rear discs?? that MC will be moving way to much fluid to the rear. I have a 14 B rear axle and I researched around ordered up a f350 master cylinder from an 84 since It had drum brakes and had the smaller rear resevoir
 

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you can install 1 ton slave cylinders out back temporarily till you get the new rear diff installed.
 
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