8x170 Bolt Pattern in a 2wd OBS

Atlenane

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Hi guys,

I'm new to the site, this is my first post. I have a 1990 F350 2wd, with a N/A 7.3 and a ZF5, and it has recently given me a few axle issues. I've sorted it out for now, but eventually it will need a full rebuild. I'd like to swap in a S/D 10.5 to gain rear discs while keeping the E-brake, but I'd like to keep the same wheel bolt pattern on all 4 corners. The truck is primarily used as a tow rig for mine and my friend's toys, and I frequently find myself on trips far from home. I'd prefer to not have to carry two spares, and I'd like to avoid adapters, unless I don't have another option. I'm hoping there's a way this is doable without any fabrication, just mixing and matching parts. My questions are as follows;

1. Can I swap S/D front knuckles onto my beams to convert the fronts over to 8x170 and gain larger S/D brakes? If not, can I just swap a whole S/D ITB setup under my truck? I'm not sure if the mounting points are different.

2. If that's not possible, can I swap E350 ends (hubs and brakes and such) onto a S/D 10.5? The E-series kept the 8x6.5 bolt pattern native to the truck.

3. If I'm able to swap the front out, would sorting out the steering be the same as sorting it out on any S/D solid axle swap?

Unfortunately I don't have access to a 2wd S/D for reference, otherwise I could probably figure most of this out myself. I've attempted to find an answer with google, but I've had very little to no luck. I've used existing posts for reference and to help with issues tons of times, and it seems somebody on here always has an answer. I really appreciate any help. If this is in the wrong area, please let me know.

Thanks!
 

A48WillyzGuy

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I have read that PSD vans from 96-01'ish use disk brake rears with the 8x6.5 pattern. That may be an easier solution than any of your other options.

Edit:: I just reread what you put. It seems that you already knew that... lol

Why not just swap an E350 rear end into it?
 

Atlenane

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As far as I can tell the E-series axles are narrower, and the spring perches are narrower and would need to be moved. The S/D axle will bolt right into an OBS, and it maintains the existing track width.
 

83ford

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Easiest way I see it is find 05 up I think sd axles because the front are coils and it should fit right in or be close.itll sit higher but you may not mind that


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FarmerFrank

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As far as I can tell the E-series axles are narrower, and the spring perches are narrower and would need to be moved. The S/D axle will bolt right into an OBS, and it maintains the existing track width.

I just installed a 98 e350 dually axel from a shuttle bus under my 94 SRW F350. The perches and shock hangers needed moved in 2" on each side. Bus was 49" center perch to center and the truck was 45".
 

riotwarrior

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Simplest would be get van diff take to shop and have perches and shock mounts redone. Cost a bit but worth it...all wheels same

second option is SD axle/s

Swapping van outers to sd likely could be done but to what cost...exhorbatant for sure.

If you plan making a 4x from 2x then SD front solid and rear is great option too.

The single biggest brake improvement comes not from rear discs but

H Y D R B O O S T brake setup from brick nose to obs SD F450 trucks.

Read qll about hydroboost here tons info on it.

JM7.3CW
 

Atlenane

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I plan on staying 2wd, and I already have to parts to do the hydroboost conversion. I'm thinking ill just go with the S/D Sterling in the rear, but that still leaves me with mismatched bolt patterns. I guess what I really need to know is whether S/D ITB will swap into an OBS. That way I'll end up with S/D suspension/brakes/bolt pattern all the way around.
 

pastorjeep

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I just completed the SD rear swap and looked into the front swap. What I found was that the rotors from a 2wd SD/Excursion should fit on our front spindle. The issue then would be the caliper. The answer could be as you suggest that we just swap the whole 2wd knuckle and that would handle the caliper swap as well. Right now I just live with the different bolt pattern. The 3:73 gears have lowered my mileage (former 3:08 gears) but pulls the 33ft 8000lbs camper way better!
 

OLDBULL8

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Where are you at? I've got 4 center run rims off a F250 with the 8x170 bolt pattern. There free if you want them. Won't ship them tho.
 

83ford

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I just completed the SD rear swap and looked into the front swap. What I found was that the rotors from a 2wd SD/Excursion should fit on our front spindle. The issue then would be the caliper. The answer could be as you suggest that we just swap the whole 2wd knuckle and that would handle the caliper swap as well. Right now I just live with the different bolt pattern. The 3:73 gears have lowered my mileage (former 3:08 gears) but pulls the 33ft 8000lbs camper way better!

Or just buy spacers for the front. Yes I know lots of people are agianst them but if you buy good quality ones you should be fine lots of people do it with out a problem
This would also take care of your problem of the back being wider from your other post

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Atlenane

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I just completed the SD rear swap and looked into the front swap. What I found was that the rotors from a 2wd SD/Excursion should fit on our front spindle. The issue then would be the caliper. The answer could be as you suggest that we just swap the whole 2wd knuckle and that would handle the caliper swap as well. Right now I just live with the different bolt pattern. The 3:73 gears have lowered my mileage (former 3:08 gears) but pulls the 33ft 8000lbs camper way better!

That is interesting, as it lends some credibility to the posts I've seen stating that everything is (nearly) the same. However, the ball joints are different part #s for a S/D vs an OBS. I feel like this means the mounting holes on the knuckles are different, and might prevent a straightforward knuckle swap. BUT if all the beam dimensions are the same, I might be able to swap entire beam assemblies. I think I need to find a 2wd S/D and start taking measurements.
 

Atlenane

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OLDBULL8, I really appreciate the offer, but I'm north of Detroit, and I'm barely finding time to get outside and wrench on my truck. If I had more free time, I'd be more than happy to make a roadtrip to pick those up.

And 83ford, I've considered this as well, but I'll be hauling a pretty large deckover gooseneck, mainly with a pair of classic trucks or other dune toys on it, and I'm not sure if I'm willing to put that much faith in a pair of spacers/adapters.
 

83ford

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OLDBULL8, I really appreciate the offer, but I'm north of Detroit, and I'm barely finding time to get outside and wrench on my truck. If I had more free time, I'd be more than happy to make a roadtrip to pick those up.

And 83ford, I've considered this as well, but I'll be hauling a pretty large deckover gooseneck, mainly with a pair of classic trucks or other dune toys on it, and I'm not sure if I'm willing to put that much faith in a pair of spacers/adapters.

Understandable it was just an idea there are some like the eBay ones I don't think I would trust but if you think about it the dually conversations an stuff are Rollin on adapters like that I think if you got the right ones you would be fine but it's your truck lol I was a little skeptics on pullin stuff with un to but I've got acouple buddys runnin 35's on the duallys and they've got spacers inbetween so who knows lol


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