Brake caliper swap dana70 SF to Dana70 FF

bajadave · 02-16-2021, 10:50 AM

New to the sportsmobile forum but hopefully someone has an answer. Have a 2015 E350 van with a Dana 70 semi floating axle. Doing the axle swap to Dana70 full floating so i can install ARB air locker. Closest thing i could find in local salvage yard is a 2008 Dana 70 FF. Now that i have it home looks like flanges on ends of axles are different. Was hoping my 2015 brake calipers and mounting plates would swap over as they are much larger units. Any information on this issue would be appreciated. Is this because of the year difference between 2008 and 2015 or is it because one axle is semi floating and other is full floating?

carringb · 02-16-2021, 12:45 PM

2008 brakes are the same as 2015. But 2014 was the last year for the semi-float axle (and vans in general for that matter). 2015 should be full-float only.

If the salvage yard axle has smaller brakes, it's probably a 2007 or older.

bajadave · 02-16-2021, 02:54 PM

Sorry i stand corrected, my van is a 2014 E350 and it definitely has a semi floating Dana 70. It is very possible salvage yard gave me bad info on the year . Was told it was out of a 2008 year van but the flanges on the ends of axle housing have a different orientation than the flanges on my 2014 housing. The calipers are definitely smaller on the axle I purchased from salvage yard. The caliper mounting plates on my 2014 axle housing are 11" center to center. Just trying to figure out a way to adapt my newer 2014 brakes and calipers to the 2008 axle. Was not sure reason the for different axle flanges, was it a change made between years or because one is semi floating and other is full floating. 2014 SF axle on the left and 2008 FF axle on right.

carringb · 02-16-2021, 04:14 PM

Yeah that looks like the '05-'07 axle. Or possibly a diesel.... They did not get the same upgrades at the same time. You do want an '08 however. It was the ONLY year with big-brakes, RSC, and a full float. Make sure it is from a 5.4L Wagon, because those have RSC. Some cargo vans did get RSC, but you'd have to verify the outboard wheel-speed-sensors. Diesel vans, even the wagons, did not get RSC and do not have outboard speed sensors.

The other option is a SRW cutaway axle equipped with the a rear-fuel-tank, which is 5" wider. Again, you'll need to verify outboard speed sensors, but all the '09+ gassers should be compatible.

bajadave · 02-16-2021, 05:19 PM

Well you are definitely correct.after calling the salvage yard they confirmed it was from a 2006 and not a 2008. I was hoping this would be a straight forward swap. Probably easier to take back and keep looking for a later model

bajadave · 02-17-2021, 11:14 AM

Looks like i am most likely stuck with this 2006 Dana 70 FF axles. What i can find out so far i might have issues with in swapping into my 2014 van is the ABS ring has a different tooth count. I saw another post where the they took and swapped out the rings so newer 2014 ABS system could read . Any thoughts on other potential issues would be appreciated?

carringb · 02-17-2021, 02:05 PM

Assuming the 2006 is an RSC axle, then the tooth count issue is probably the biggest. Then of course the smaller brakes.

You should be able to swap the brake backing plate over if it isn’t seized. The bolt pattern on the end of the axle tube should be the same.

bajadave · 02-17-2021, 02:44 PM

I was reading up on the details of what makes the RSC work on Ford Van. Sounded like there were many different factors that could affect the system including lift kits. I am hoping by moving the tone ring and ABS sensor from my 2014 it will keep van from throwing a code. As for the brakes, hoping my caliper plates will swap over. The 2006 axle flanges are definitely clocked at a different orientation than my 2014. Not sure if that's going to affect brake setup or swapablity. Worst case scenario i will go to a larger aftermaket caliper/rotor. I will keep everyone posted as my project progresses. Appreciate all the feedback.

ShuttlePilot · 02-17-2021, 03:01 PM

Greetings bajadave, With your handle being bajadave I'm assuming you, and the 2006 FF axle that your stuck with, aren't close to Colorado? I was just baking an idea of a possible option to relieve you of it, if you were interested. My SMB is a 2005, Semi Float, antiloc tone ring in the differential, small brakes. Wondering if an axle like yours would get me to FF with minimal changes.

P.S I'm kind of hoping you say your in San Diego so I don't start a new project.

- Eric

bajadave · 02-17-2021, 03:38 PM

I have made numerous calls to shops that specialize in building rear ends including the guys at Yukon gear. I have been told by all that the semi floating axle Dana housing could not be converted to full floating without extensive and costly modifications. Basically cutting the ends off the housing to convert. Probably why you can find semi floating Dana 70 axles stacked up in about any junkyard. Seems the full floating were not used much in later model Ford vans from what i can see.