Dana 25 disc brake swap with dana 30 parts |
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Millennium falcon
Member Joined: 20 Sep. 2016 Location: Central PA Status: Offline Points: 1521 |
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Posted: 24 July 2022 at 12:21pm |
Here is a documentation of my disc brake conversion for a dana 25. This swap uses parts from a jeep dana 30. Below I will include pictures part numbers and years of the parts I used. While you could order all the parts separately I recommend buying a whole axle. I found a guy selling them for $75 each. I bought 2 of them. There are many different options for disc swaps.. This is just the one I happen to like. It uses cheap "jeep" parts and has 11.750" diameter vented discs and really large piston calipers what work great with the stock single reservoir master cylinder. My other jeep with this conversion can lock up the wheels on pavement without too much difficulty. Calipers and rotors for this swap are around $30 each
Step 1) locate a dana 30 front axle. You want a 77-79 cj5/7/8 axle that has the thicker 1.125 thick rotors. the 7/8 rotor axles will not work for this swap. The thick rotor axles use a 6 bolt caliper mount that works with the dana 25 knuckles. A quick measure of the rotor thickness will help you out at the junk yard. *****YOU WANT 1-1/8" ROTOR ALXES. Step 2) Strip them down.. This is pretty basic start at the hub and work your way in until you remove the 6 bolts that hold the caliper mount on. Save all the parts and hardware you remove. The parts needed from the dana 30 are.... rotors calipers caliper mount spindles hoses hub bearings seal wheel studs. Here are the parts i removed. I sand blasted my caliper mounts, and rotors. As long as they aren't warped or completely wore out you can reuse them. Here's everything cleaned up and ready to go! Step 3) remove all the drum brake stuff from your dana 25 Strip it all the way down to the knuckle. Its a good time to check and replace your kingpin bearings and re pack your pudding! This is where you should end up. Step 4) This is the only "custom" part needed for this conversion. You must use the dana 30 spindle and they have a larger bearing to support the axle whereas the dana 25 uses a smaller bushing. Drive out the bearing and press in the bushing. The picture below shows the bearing after its removed and the custom bushing I pressed back in. Here are the dana 30 spindles. (left) on the right you can see the smaller dana 25 spindle with the small bushing. Parting the new bushings.... Ready to roll! Here are the dimensions so you can make your own. It may be something McMaster Carr carries.. I didn't look since i was able to make them. Pop quiz... where did that note paper come from? haha! Step 5) Install the spindle and then the caliper bracket in this orientation. The clocking is important for everything to clear properly. You will need a total of twelve 3/8-24 bolts 1-1/4 long with lock washers for this install. I would use grade 5 or 8. Step 6) clean up your dana 30 hubs and install new bearings & seal. (part numbers will be at the end) Step 7) press your studs back in. The rotor goes behind the hub. Dana 30 studs are not swaged and can 100% be reused if you want to. I re-use mine as long as they are not damaged. If you dont replace your rotor you will be able to skip this step. Step 8) install the hub on the spindle just as you would the dana 25. You can use the big nuts and washers from the dana 30 or 25. they are the same. You will also be able to reuse what ever hubs or drive flanges, gasket and hardware you were using on your dana 25. You cannot use the hubs from the dana 30. (Part II) Coming in the next post. Edited by Millennium falcon - 24 July 2022 at 5:45pm |
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Millennium falcon
Member Joined: 20 Sep. 2016 Location: Central PA Status: Offline Points: 1521 |
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Step 9)
Pat yourself on the back, look at your awesome disc brakes and have a beer... you're doing great! Step 10) throw these things out... you wont need them anymore. A question I get alot is about the wheels and spacers. I run 1" spacers to clear my 7.50-16's so its a non issue for me. 3 of my original 16x4.5 wheels fit fine without spacers but 1 of them needed at least a 1/4" spacer to clear the rivets. If you run 15" wheels from a scout or an amc cj5/7 they will not require spacers. but if you want to run 16x4.5 willys wheels I would plan to just slap some 1" spacers on just to be safe. ive run them on both my jeeps with no issues I get them on amazon for around $90 for all 4. I can share a link if anyone is interested. heres my blue jeep with this conversion and 1" spacers. clears everything with lots of room. 1" aren't really that noticeable. but I totally understand that some people are anti-spacer. Here they are with larger 1.5" spacers I used to clear the big SxS tires you may have seen on my jeep some times. Step 11) Flex hoses. Stock CJ5 hoses work perfectly. (Part numbers at the end) they even lock into the factory tabs without any problems. The banjo bolt looks like it will hit the kingpin cap but it doesnt. You can use the same hose for both sides. I used the little clip from the stubby drum brake hose to retain the new longer hoses. Step 12) remove the residual valve. this is located inside your Master cylinder all the way at the front clipped into the main spring. This is an important step because it keeps too much pressure on the system for disc brakes to function properly. You can poke holes in it but I like to just remove the whole thing. If you dont your disc brakes will drag really bad..... Step 13) bleed the system... Im sure you can handle that on your own. Step 14) Put it all back together. I think that is basically all... please ask questions. I hope this helps someone out. I will be doing a rear conversion this week if anyone else is interested I will gladly share. Thank for reading! Part numbers. napa bearing pbr35 napa bearing pbr50 Wheel seal Napa 23035 Brake pads napa pf-7013m Flex hoses rock auto 150.67015 Rotors rock auto 3550R Caliper advanced auto 184095 & 184096 Cheers!!!! have fun be safe! Edited by Millennium falcon - 24 July 2022 at 8:29pm |
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Bob W
Member Sponsor Member x 4 Joined: 08 Aug. 2005 Location: Monticello, NY Status: Offline Points: 1693 |
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Cool upgrade writeup. The Willys Reunion of course!
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DeepVeer
Member Joined: 01 May 2022 Location: brampton Status: Offline Points: 100 |
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Hi brother,
I read the whole post about this conversion. I doing disc brake conversion all around to my cj2a. According to your post, do I really need proportion valve and residual valve? I know you didn't use it but I'm running dual master cylinder.
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Millennium falcon
Member Joined: 20 Sep. 2016 Location: Central PA Status: Offline Points: 1521 |
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Thanks Bob! Yep I have lots of Bertram merch. Haha!
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Millennium falcon
Member Joined: 20 Sep. 2016 Location: Central PA Status: Offline Points: 1521 |
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The proportioning valve is optional one of my Jeeps has an adjustable one that I have biased towards the front but I haven’t found it to be very noticeable. It stopped very controllably without it as well. So that’s up to you. The residual valve is already in your master cylinder and must be removed. That is the case with stock MC’s not sure about the dual reservoir mc’s. Edited by Millennium falcon - 25 July 2022 at 12:35am |
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Barry S
Member Joined: 01 Mar. 2020 Location: Ohio Status: Offline Points: 664 |
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Very nice write up - I'm sure it's going to help a lot of folks. I too like the confidence of disk brakes on all 4 corners.
Great Job! -Barry
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1947 CJ2A 93664 "Grasshopper"
1947 CJ2A 90729 194? CJ2A 04893/194304 1946 CJ2A 46745 1946 CJ2A 36723 1945 MB 413665 1971 CJ5 8305017 375392 Drive train parts donor Bantam Trailer T3-C 25487 |
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Millennium falcon
Member Joined: 20 Sep. 2016 Location: Central PA Status: Offline Points: 1521 |
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Thanks Barry! Yeah once you drive one with 4 wheel disc it’s hard to go back. I also like how easy they are to service and clean…. And they never need adjusted. 👍
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LuzonRed47
Member Joined: 11 Apr. 2007 Location: Plymouth, MI Status: Offline Points: 842 |
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Seth, 'how-to' instructionals are your calling card. You do 'em really well and the D30 disc-to-D25 axle one is really useful.
For those of us contemplating this upgrade, any chance you would offer your jumbo custom bushings for sale?
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CJ2A #140275 "Ziggie" (purchased new by my dad in 1947)
ACM #124334 CJ3A windshield, Warn Overdrive 1953 Strick M100 trailer Serial #18253 |
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bobevans
Member Joined: 31 July 2005 Location: Pittsburgh, PA Status: Offline Points: 844 |
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Thanks Seth, awesome write up. And even us old guys can access this info now!
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'48 CJ2A
'56 DJ3A '79 CJ7 And two of them actually run! |
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Millennium falcon
Member Joined: 20 Sep. 2016 Location: Central PA Status: Offline Points: 1521 |
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Thank you! I’m glad you enjoyed it. I haven’t thought much about reproducing the bushings but it may be something I offer in the future. I’ll post updates on here if I do. Thanks!
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Millennium falcon
Member Joined: 20 Sep. 2016 Location: Central PA Status: Offline Points: 1521 |
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Thanks Bob! Im glad you have access to it… 😉 you seem like a pretty tech savvy self proclaimed “old guy” lol…
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drm101
Member Joined: 12 Dec. 2012 Location: Clarkston, MI Status: Offline Points: 1471 |
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Thanks Seth! Very nice. I'm thinking of doing this with the Dana 27 axle in this CJ5 I am working on. I'm guessing that bushing might need to be thinner for the 27, but I won't know until I get it apart.
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Dean
'47 CJ2A "Ron" '66 CJ5 "Buckie" The less the Power the More the Force |
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Millennium falcon
Member Joined: 20 Sep. 2016 Location: Central PA Status: Offline Points: 1521 |
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Cool! You’ll have to double check but I’m fairly certain the axle diameter of the 27 is the same. Perhaps someone else will chime in to confirm or deny this.
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Rick G
Member Joined: 17 May 2015 Location: Amarillo, TX Status: Offline Points: 1468 |
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There are lots of disc brake conversions out there and this is one of the easiest "bolt-on" applications.
Edited by Rick G - 29 July 2022 at 10:31am |
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Millennium falcon
Member Joined: 20 Sep. 2016 Location: Central PA Status: Offline Points: 1521 |
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The problem I encountered with the dana 25 hub and spindle is that they do not property fit the caliper bracket so there is no way to correctly center things it will rely on the the bolts themselves which is a too sloppy for my tastes. That’s why I went this route. I should have taken more pictures of what happens if you attempt to use the d25 spindles. It’s a “no bueno” in my opinion
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Rick G
Member Joined: 17 May 2015 Location: Amarillo, TX Status: Offline Points: 1468 |
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I forgot the D25 hubs are slightly different from the D30 hubs (uses thinner bearing sets). I edited my previous post. I thought the D25 spindle and the D30 spindle have the same dimensions outboard of the flange face, which means you could use the D30 hub with the D25 spindle with set 45 bearings and hub seal 8430-S? This wouldn't address the issue of centering the bracket, however. That bracket requires the larger shoulder of the larger hub seal and set 47 bearing spindle found only on the D30 with discs.
Edited by Rick G - 29 July 2022 at 10:55am |
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oldtime
Member Joined: 12 Sep. 2009 Location: Missouri Status: Online Points: 4186 |
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Nice write up Seth !
Yes the factory D27 bronze bushing is the same as the later D25’s. In fact the late D25 spindles and bushings are identical to D27’s. That said D27 uses a slightly different hub and wider wheel bearings than a D25.
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Currently building my final F-134 powered 3B .
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