Disc Brake Conversions

I'm rebuilding my 67 M715, with lift, bigger tires, paint job, skid plates, winch, heavy bumpers, rock sliders and all the other good parts that go along with that stuff. I'm using 42" tires on Stazworks custom two piece beadlock steel wheels. That tire - wheel combination is pretty heavy and along with all of the other weight that I'm adding to the truck, I'm afraid that the stock drum brakes will no longer be adequate for highway speed stops. Axle swaps are out of the question since I've already invested so much in the stock axles, such as lockers, custom wheels, new front spindles, etc. My plan was to order disc brake conversion kits for both axles from Uglytruckling. Well apparently I waited too long to order that part of my project because when I went to their website, which is still up, and contacted them, I got an email back telling me that he has retired and has no kits left. A real "Oh crap" moment. I wrote back telling him that I would be more than happy to pay him to send me some blue prints and any other information so that I could build my own disc brake kits for my truck, but I never heard back from him. Does anybody know of any other options for disc brakes for the M715, or does anybody have one or both of the kits, new or used, that would like to sell them? I would definitely appreciate any helpful info. Thank you.

I am of the axle swap crowd, but I keep hearing how well the very large stock drum brakes can work. I bet putting a large vacuum booster or hydroboost would make things much better for you.

Until I can come up with discs, I will probably put in a vacuum booster and dual pot master cylinder. I was planning on hydro boost with the discs, but I believe that a hydro would put out too much pressure for the wheel cylinders. The other problems with the drums is that they don't work very well when full of water and mud and the drum system weighs a lot more than discs. Thanks for the input.

I used a hydro boost with stock axles. My set up came from a '90's Astro van. I got the hydro boost with master cylinder from the same vehicle. I also did the Ford wheel cylinder conversion and chevy brake shoe conversion. Once adjusted I could easily stop as well as my 2002 Duramax that has 4 wheel disc brakes.

I could be wrong here but the vacuum or the hydro booster both do the same thing. They only make it easier to push the brake pedal. Neither one can "create" any more pressure than the master cylinder itself is capable of producing.

I do understand the desire for disc brakes but I was quite happy with my modified "stock" brakes.

there are pics of uglytruckling brakes in open discussion rar disc key. first pic is of ring that is pressed on and welded to stock hub. second set is front hubs.

I guess you never saw this ad from the 60's. Pretty well covers the brake situation.

https://s-media-cache-ak0.pinimg.com...a1bfdbaf37.jpg

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Originally Posted by kwai

I guess you never saw this ad from the 60's. Pretty well covers the brake situation.

https://s-media-cache-ak0.pinimg.com...a1bfdbaf37.jpg

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This was the laugh of my day!....Thanks!

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Originally Posted by kwai

I guess you never saw this ad from the 60's. Pretty well covers the brake situation.

https://s-media-cache-ak0.pinimg.com...a1bfdbaf37.jpg

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That is too funny...

The vacuum will increase the psi at each wheel cylinder considerably and the hydro boost will increase the psi at each cylinder by more than a thousand psi over the vacuum booster. That's why the pedal pressure is so much easier.
Could you tell me a little more about the Ford cylinders and the Chevy shoes? What vehicles are they from? Do you have to do any modifications for the swap?
Are you running the stock size tires? Thanks a lot for your input.

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Originally Posted by JimmieM725

there are pics of uglytruckling brakes in open discussion rar disc key. first pic is of ring that is pressed on and welded to stock hub. second set is front hubs.

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I saw that. Thanks.

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Originally Posted by kwai

I guess you never saw this ad from the 60's. Pretty well covers the brake situation.

https://s-media-cache-ak0.pinimg.com...a1bfdbaf37.jpg

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That's really good. I like that. Thanks.

Particularly when combined with "non directional" tires :)

You guys are too cruel ;)

I still have a stock braking system, in good working condition, NDT tires and it stops just fine. I think maybe some of us (myself included) are just accustomed to easy to drive large vehicles. Yes, it does require more than toe pressure on the pedal. But it will lock all four wheels when requested.

Call this guy...

http://hartford.craigslist.org/pts/5565335413.html

Dang...there it is...nice find.

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Originally Posted by Mikel

Call this guy...

http://hartford.craigslist.org/pts/5565335413.html

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For the sake of leverage, know that these have been on Craigslist forever, so hopefully the seller is flexible and willing to ship.

Thank you very much. I will contact him first thing tomorrow.

How did it go?

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Originally Posted by Mikel

How did it go?

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I called and talked to him Thursday evening and he said that he was going to text me pictures of everything he has that evening. He hasn't texted me anything yet. I sent him a quick text Saturday letting him know that if he sent pictures, I didn't get them and could he please try again. I'm going to try calling him again tomorrow or Wednesday. I'm going to see if he would be willing to just sell me the conversion kits. He told me that he won't ship because it's too big, heavy and bulky. I can understand that, but it's over 900 miles from me. Maybe he wouldn't mind shipping just the kits. I'll let you know when I find something out.

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Originally Posted by Overkill

I called and talked to him Thursday evening and he said that he was going to text me pictures of everything he has that evening. He hasn't texted me anything yet. I sent him a quick text Saturday letting him know that if he sent pictures, I didn't get them and could he please try again. I'm going to try calling him again tomorrow or Wednesday. I'm going to see if he would be willing to just sell me the conversion kits. He told me that he won't ship because it's too big, heavy and bulky. I can understand that, but it's over 900 miles from me. Maybe he wouldn't mind shipping just the kits. I'll let you know when I find something out.

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You can use Fastenal for shipping. They are very reasonable.

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Originally Posted by Mikel

How did it go?

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Well, after almost four weeks of trying to talk to the guy who posted the add for the axles on Craigs List, I can finally answer your question on how it went. The short version, not good. The longer version, I don't think that he really wants to be bothered selling them. He doesn't like to answer his phone or his texts and won't return calls. The first time that I managed to talk to him, he told me that he had both front and rear disc brake conversion kits, all new bearings, races, seals and everything needed to completely rebuild the axles. It turns out that he only has the conversion for the rear axle. There are no new bearings, races or seals. He refused to ship and I would have to make the 1900 mile round trip to pick them up. I asked if he would sell me just the rear conversion kit and offered him $350 plus $50 for shipping. Nope. He paid $1000 for everything and that's the only way that he would sell it. Oh well. I'll just have to start the search again. Thanks for the heads up on the add. I'll let you know if something else comes up.

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Originally Posted by Overkill

Well, after almost four weeks of trying to talk to the guy who posted the add for the axles on Craigs List, I can finally answer your question on how it went. The short version, not good. The longer version, I don't think that he really wants to be bothered selling them. He doesn't like to answer his phone or his texts and won't return calls. The first time that I managed to talk to him, he told me that he had both front and rear disc brake conversion kits, all new bearings, races, seals and everything needed to completely rebuild the axles. It turns out that he only has the conversion for the rear axle. There are no new bearings, races or seals. He refused to ship and I would have to make the 1900 mile round trip to pick them up. I asked if he would sell me just the rear conversion kit and offered him $350 plus $50 for shipping. Nope. He paid $1000 for everything and that's the only way that he would sell it. Oh well. I'll just have to start the search again. Thanks for the heads up on the add. I'll let you know if something else comes up.

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Sorry to hear. The guy has had those for sale for a long time and looks like it will remain that way.

If at some point shipping is the only thing in the way, I can drop the parts off at a Fastenal. Clinton is 20 minutes from where I live.

I can give you photos and measurements when I get home I have front and rear on my truck but I'm keeping them.

Look up rar disc key (I misspelled it in post) it has pic and dimensions of rear ring that disc brake bolts to. Its from a heli conversion

I'm Sorry I haven't replied to your offer until now but this is the first time that I have been on the site since my last post. That is really a very generous offer you made. The problem is that I don't know where I would keep three extra axles. I really don't have a whole lot of room here. Once again, thank you very much for the offer of your time and efforts.

I'm very sorry that I haven't answered your offer until now but I haven't been on this site since the beginning of July. I want to thank you for your very generous offer. The problem is that I just don't have the room to store three axles that I don't have any use for. All I need are the disc brakes. Once again, I really appreciate you offering your time and effort. Thank you.

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Originally Posted by Overkill

I'm very sorry that I haven't answered your offer until now but I haven't been on this site since the beginning of July. I want to thank you for your very generous offer. The problem is that I just don't have the room to store three axles that I don't have any use for. All I need are the disc brakes. Once again, I really appreciate you offering your time and effort. Thank you.

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Yeah, I know Mikel, I responded to you twice. I thought that I lost the first one so I wrote it again and then both of them popped up. Sorry.

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Originally Posted by JimmieM725

I can give you photos and measurements when I get home I have front and rear on my truck but I'm keeping them.

Look up rar disc key (I misspelled it in post) it has pic and dimensions of rear ring that disc brake bolts to. Its from a heli conversion

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Hey Jimmie, like I told Mikel, I haven't been on the site. If the offer still stands, photos and measurements would be great. During the last month I pulled the bed off the frame and have been doing some customizing on it and prepping it for paint. I've also been working on my motor getting it ready to bring it in to be dynode. I'm sorry that it has taken so long to get back to you.

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Originally Posted by Mikel

I am of the axle swap crowd, but I keep hearing how well the very large stock drum brakes can work. I bet putting a large vacuum booster or hydroboost would make things much better for you.

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Next time your heading down the road take a look at almost any tractor trailer or dump truck, 100,000 lbs and drum brakes all around

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Originally Posted by Overkill

The vacuum will increase the psi at each wheel cylinder considerably and the hydro boost will increase the psi at each cylinder by more than a thousand psi over the vacuum booster. That's why the pedal pressure is so much easier.
Could you tell me a little more about the Ford cylinders and the Chevy shoes? What vehicles are they from? Do you have to do any modifications for the swap?
Are you running the stock size tires? Thanks a lot for your input.

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I'm not trying to start an argument I'm trying to learn. How does a hydo boost increase the pressure in the brake line? My master cylinder still functions the same way while it is bolted to the hydro booster as it would if it were bolted to the firewall. By my thinking the only thing the booster is doing is multiplying the torque I apply to the brake pedal and transferring that to the master cylinder. The master cylinder is pushing the fluid to the brake cylinders in both cases. The only thing I can think of is maybe I can't physically push the pedal hard enough by human strength to create the same pressure?

The modifications I did are mods that are documented here on the zone.

Ford cylinder swap here:
http://www.m715zone.com/vb/showthread.php?t=9577

Chevy shoes mod here:
http://www.m715zone.com/vb/showthread.php?t=15990

Oops. Chevy shoe conversion here.

Thanks a lot. That was very interesting. I bookmarked Oilcan's post. I will definitely be getting back to it this winter when I revisit my brake situation.

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Originally Posted by jeeper

I'm not trying to start an argument I'm trying to learn. How does a hydo boost increase the pressure in the brake line? My master cylinder still functions the same way while it is bolted to the hydro booster as it would if it were bolted to the firewall. By my thinking the only thing the booster is doing is multiplying the torque I apply to the brake pedal and transferring that to the master cylinder. The master cylinder is pushing the fluid to the brake cylinders in both cases. The only thing I can think of is maybe I can't physically push the pedal hard enough by human strength to create the same pressure?

The modifications I did are mods that are documented here on the zone.

Ford cylinder swap here:
http://www.m715zone.com/vb/showthread.php?t=9577

Chevy shoes mod here:
http://www.m715zone.com/vb/showthread.php?t=15990

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I'm not very computer savy, so tomorrow I'll have my son show me how to cut and paste an item from my favorites so I can share it with you.

[QUOTE=jeeper;259289]I'm not trying to start an argument I'm trying to learn. How does a hydo boost increase the pressure in the brake line? My master cylinder still functions the same way while it is bolted to the hydro booster as it would if it were bolted to the firewall. By my thinking the only thing the booster is doing is multiplying the torque I apply to the brake pedal and transferring that to the master cylinder. The master cylinder is pushing the fluid to the brake cylinders in both cases. The only thing I can think of is maybe I can't physically push the pedal hard enough by human strength to create the same pressure?

Basically you're right when you say that you can't push the pedal hard enough. With vacuum assist, depending on how well your engine developes vacuum, it multiplies your foot pressure and it pushes the valve in the master a lot harder which creates more pressure to the brakes without you having to push very hard. With Hydo assist, you're dealing with hydraulic pressure created by the steering pump which is much greater than vacuum pressure. That creates much more pressure to the master which creates that much more line pressure. If you're interested, here are a couple of links that can explain things much more in depth than I ever could.
http://www.brakeandfrontend.com/oper...ssist-systems/
Thanks again for the links that you gave me. They will help me out since it looks like I will probably have to stick with the drums.

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Originally Posted by bigprojectm715

Next time your heading down the road take a look at almost any tractor trailer or dump truck, 100,000 lbs and drum brakes all around

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That's right, but those drum brakes are designed for those vehicles for what they do and the size tires that they run, not to mention, they're air operated, not hydraulic. If they decided to run tires that were twice the normal height and weight, to be able to safely stop, they would need bigger or better brakes. Those trucks also aren't running through two feet of mud and then getting on the highway. The M715 was designed with a 1960's brake system that could safely stop it, but you also have to remember that it ran 35" tires with a very anemic power train that wasn't supposed to be run over 50 or 55 mph. So now you add 42" tires that weigh about twice what the original ones weigh, which puts a whole lot more leverage acting against the brakes, and throw in a power train that puts out three times the power of the original, which allows you to cruise down the highway at 75 mph and your stock brake system is no longer quit adequate. Now to further the problem, you take this truck offroad and racing in mud bogs. The drums fill up with mud and silt. Now you really have an unsafe braking system. Disc brakes are pretty much self cleaning, they don't fade on you after driving through a lot of water, you don't have to adjust them and they have more stopping power than proportionally sized drum brakes. Last but not least, a disc brake set up is much lighter than a drum brake set up which makes for less unsprung weight which, in the offroad world, means fewer broken axle parts while navigating nasty terrain.

He's back!

https://hartford.craigslist.org/pts/...669672835.html

I am very interested in some blue prints or plans to convert to disc brakes . I own a Machine shop and I am going to fab a disc brake set up in the future but would make it easier to have some where to start . Grabbing plans from the air is a lot of trial and error and brakes are very important .

Not sure if Ray at uglytruckling is still doing his disc brake conversions or not. I have a couple sets of his kits for the M715 and my Dodge M37. He was pretty good to deal with. I know at one point he was looking to retire and get out of it.