Ford Power Stroke Nation banner

OBS Superduty Axle Swap

14K views 15 replies 7 participants last post by  Anchorism 
#1 ·
After a very long time of gathering parts, I finally got my axle swap done. It's only been about 10 months since I purchased the axles, but I had to wait to unbury them from the snow to start the process. I began by cleaning them up and painting them, then finding rims and tires that suited me. After a large amount of deliberation I decided to attempt the swap without a RSK kit. Much to my surprise it worked out wonderfully. The axles I swapped in are a 3.73 vs the 4.10 I had. (I am hoping for better mileage on the highway.) The rear axle, although very time consuming due to not having much help or a lift, was pretty much straight forward. I did end up using the superduty springs which were setup for an oilfield rig so they are pretty stout. On the front I used the standard obs f250 springs but added a 2inch block to help level it, which allowed everything to fall right in place. For the brakes, I had to redo the ends of the lines at the union so I just fitted the right sizes vs having to adapt anything. The front brakes from the OBS actually bolted right on to the superduty axle so there was no need to adapt lines. I ended up fabbing a panhard bar which made a world of difference with the steering. To do so, I just used the pivot point bracket from the old ttb setup. It worked like a charm. All I have left is to adapt my front driveline for the correct ujoint size, and get an alignment. After it's all said and done, I'm damn sure feeling it... after all, I did it on a sloped driveway with Jack stands and bottle jacks.
 

Attachments

See less See more
5
#3 ·
Just realized my pictures turned out like crap.....
ll repost them here.




































Here is my panhard bar... used the rear bracket for the old ttb pivot point, then went to the back of the sway bar mount.

Still need to clean up the passenger side brake line a little bit.
 
#4 ·
Cool! I wouldn’t mind getting rid of my ifs when it starts giving me trouble. Only thing that I woulda done differently (with what I’ve been told over the years) is don’t put a lift block in the front. Take that with a grain of salt because I could be full of crap but I’ve always thought it made sense
 
#5 ·
Yeah I would buy new front springs. 1) blocks on the front are a no no. Under heavy braking you can spit the block and pretty much have the axle fall out. 2) the spring rate for the ttb is super stuff compared to the f350 springs, so you can fix two problems with one stone and have a better riding truck.
Your other pics didnt show either.
 
#6 ·
Yeah I would like to buy new springs eventually, but considering after all is said and done I'm in about $1500 my wife said it'll have to wait. That being said, I actually used the front blocks that came off of the old ttb but I get what you're saying about them. I did end up using it to haul the rv to the lake on labor day. Other than riding like a brick she did quite well! Very little squat in the rear and pulled down the road well.

<img>https://lh3.googleusercontent.com/wb8D9WbBV-oMd25MuRCenDfjOrMyN8xVmGVFxTeZ4nLODkDJvx-9tUR9SI-2Cq0i5acVzGIH2LVH_vtjt-cc09fRmRA_nxbmpIRnDsOZSxEG9hpx4Zj4FzRAxgXb0pLX89Siv-ofjHWlPNxB51olk6fsXFQEXZmBj2fMG65STwssFWhFI9WZPb1RdzXWxj_SZF7t5hZt3KxNQnhp2IsyuDt8w6-hr1lqgjYiDQO39N8i46TX2Pvr8KWIKkkqdAL0xTLAc_bh_TWxtUsWk-8L8tv7SOsxZZxQTFR_hzSWh0yQKYyp0Xkj0e6RPu7QEeYXex-n-JVWSfBqelN-VeEV8H7uJtWFXD2gUcTXUsH3yA2NeIOwVjhBkJ24O8TWrYrt7H7KP-NumXz2_E6siWGpExWkoSI8se-UIz_4bvMo8lqUmU_OhXU1FDb3X3-SKo-Za4o7409mYWqWBzyvO-mkzvfhymFaZWIUGAzjyflfP1326SjgFA8NygeA40nySG3D7UdBF1cDbnmTlX5RUNr_FG9blGArWgU3qx0L_4DeMvNhQxu45iP4Mi1WlQKt89z3lq3k83YpEjenHBKoYvMfoqhrjK3uQpQasKpl5U1ZY4fq4a5aWQSKULMuxCRH6EVwQTsb2MFmLCKeG8Dcbmx-VCuVk1GW4FEEOCGVpxmMis1DSAvhheH6KOY=w1082-h528-no</img>
 
#9 ·
I AM PUTTING A 2002 FRAME UNDER A 94 obs
maybe not as easy?

but get the best setup efuel and disks
upgraded engine with all 2002 stuff
180 injectors
terminator
hydro boost
1991 5 speed zf 42
made new cab mounts..
will run air to air cooler also too
will repin out connectors for 2002 computer
 
#12 ·
Ok so now that it has been a year I have decided the ride is WAY too stiff. Now I'm chalking it up to the F350 rear springs from an oil field rig with utility bed, but am not sure what to do about it. Clearly in my last photo the truck doesn't even squat to level (or at all) with my 10k fifth wheel. So should I remove a leaf or two from the rear? Or should I get smaller rear blocks then replace shocking? I'm sure my shocks are shot. I'm just not sure which route to take. I know I'm going to replace front springs eventually but I need to address the rear first.
 
#14 ·
Looks like all your pics are gone. Shoot a pic of the pack again and repost it
 
#16 ·
Its been a while since I updated this thread. I ended up removing the extra springs in the rear and that did the trick. Also I had to replace the center pins while I was in there. All in all its riding much better now. Next up would probably be new shocks. Earlier this year I installed all new calipers pads and rotors from Powerstop, updating to the 2002 pad assembly.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top