i ordered everything from directfordparts to install f-350 blocks on my 2005
f-250 harley edition. i dont have the top auxiliary spring or spacer so the
u-bolts i have are too long. .. . i pulled the bolts up to see how much more i
had to tighten and the nuts are going to run out of threads if i tighten them
snugly. my part number was 5C3Z5705AA for the u-bolts as i read that the
newer models might have a larger axle housing.

am i okay to cut these so my deep impact will be able to tighten them down and just hope they dont bottom out or do i need to get shorter ones or the supposedly useless auxiliary spring? do all trucks have this spring or did the previous owner remove it for some reason?

anyone know the correct part number for my set up or is it N803770S436 even for the newer trucks?

and thanks to riggz for the write-up and part numbers.

long post.

 

The information I have shows that being your F-250 does not have the auxillary spring the correct U bolts are N811667-S436 when installing F-350 blocks.

 

thanks, i replied to your pm too if you can send the document. when i looked that number up, it said f-250 with auxiliary spring. i assume this adds 2 inches the same as the blocks do atleast from the u-bolts standpoint.

 

When I redid my springs after the accident, I purchased u bolts from a local spring shop. At the time I bought the truck it had an aftermarket 7 spring pack in it. So it sat higher. I didn't want to put that back in b/c of ride and not needing it. I had concern for the ride height though.

The u bolts I got were threaded long enough to work with the 2 inch original blocks, and later when I put in 4 inch blocks, overall length accomodated the extra height as well.

I want to say they were 14inches long, but I do have the aux spring on my truck. I would add extra washers for now if it doesn't look like it will tighten up. It is ok to cut them but I would avoid it if possible. Perhaps you can have someone cut some extra threads on them as well. The ubolts are 5/8".

 

is N811667-S436 the correct part number for a f-250 w/o auxiliary springs and a 4" f-350 block? The TSB PowerstrokeHD sent me said f-250 that want to be raised get a 2" block and they didnt have one before. Then the service procedure says "Raise vehicles without 4" spacer"

is there a 4X4 f-350 without the auxiliary spring? if that exists, this should be the u-bolt i need and if so, what is the part number?

i think i just want to send mine back and get the correct ones so i dont have to cut and re-thread.

 

Does anyone know the part number for the rear blocks for my 2005 F-250 Super Duty V10? I would like to add the F-350 blocks to it but cant find the part number.
The F-350 blocks should lift the rear 2"?
Thanks ~Gage~

 

https://www.ford-trucks.com/forums/6...-blocks-2.html

post #22

 

I saw that and am not sure what they are talking about with the 2" block, unless it is a missprint. I do know that F81A-5598-DB is the engineering number for the 4" non- tapered blocks so N811667-S436 u-bolts should be the correct ones for your application. I suspect that you are correct in thinking that F-250's with aux spring use the same u-bolt as F-250's with out aux spring but using 4" blocks.

The 5C3Z-5705-AA u-bolts you have are the same as the 5C34-5705-AB (engineering number) bolts listed in the TSB and would be used when installing 4" blocks on a F-250 w/ aux spring.


You have to remember that riggz write up and parts list is for pre-'05 trucks so not necessarily everything is going to be the same for '05-up trucks.

 

The first page of the pdf. . .

SERVICE PROCEDURE

Rear ride height may be reduced or increased by:

• Lower - vehicles that have the 4″ (10 cm) spacer
block by installing a new 2″ (5 cm) spacer block
along with the other rear suspension hardware

• Raise - vehicles that are perceived as riding too
low (no spacer block installed) by installing a new
2″ (5 cm) spacer block along with other rear
suspension hardware

- this is where it referenced a 2" block, that is why i wasnt quite sure if ford would put a 4" block in a 250 if someone said it was too low.

It makes it sound that some vehicles dont have spacers?

Anyway, i knew he had an older truck so i ordered the u-bolts that someone else posted in that thread that was for a 2006 so it should have been the same. However, he probably had auxiliary springs so it worked for him.

I agree with you that the part number you posted should be correct for my application. Just when i checked it on directfordparts.com it said "with auxiliary spring" so i just wanted to make sure that assembly was around two inches so i wouldnt end up with the wrong part again.

Thanks again for the tsb and your help.

To gage2502: the blocks are the same in that post (i believe you need tapered blocks for a supercab short box) but make sure you get the correct u-bolts so you dont end up in my situation.