Cutting IRS Spindeles

[Tampa33Build]

I'm installing the FFR IRS system in the 33 hot rod (no donor parts). Page 76 and 77 of the manual shows cutting the spindle for the IRS installation. Before I cute off part of the spindle, I want to make sure it is correct. Additionally,why is this cut needed?

Thank you,
Neil

[edwardb]

Yes it's correct. The FFR designed upper control arm doesn't use this connection and in fact would interfere with their setup. These pictures are from my Roadster build, but the same for all.

I cut mine using a bandsaw. Left a little more material than explained in the instructions. Still fit fine:



Then cleaned up a bit:



With the UCA attached:



FWIW, this is the stock Mustang setup, and how those two spindle connections are used. Very different from the FFR setup.

[Tampa33Build]

Thanks for the reply and photos. I was hesitant cutting them, could not understand why FFR designed a frame for the IRS and requires cutting the spindle.

Neil

[Jammer369]

Yes it's correct. The FFR designed upper control arm doesn't use this connection and in fact would interfere with their setup. These pictures are from my Roadster build, but the same for all.

I cut mine using a bandsaw. Left a little more material than explained in the instructions. Still fit fine:



Then cleaned up a bit:

Paul, would you mind sharing what you used to clean up the cut ends of the spindles. Those look really clean and finished up very nicely!

[edwardb]

Paul, would you mind sharing what you used to clean up the cut ends of the spindles. Those look really clean and finished up very nicely!

Held them against my Delta disk/belt sander until the saw marks were gone. Then sanded with several grits of paper and a sanding block including breaking the edges some.

[Jammer369]

Thanks for the info. They almost looked polished!

[j33ptj]

The current manual does not state this anymore, wonder what has changed (this thread started in 2017...)

[edwardb]

The current manual does not state this anymore, wonder what has changed (this thread started in 2017...)

Yes, post has been around. But Factory Five hasn't changed the design of the suspension. Without that area trimmed off on the knuckles, they would interfere with the upper control arm attachment and most specifically the adjustment sleeves/nuts that are on the end of the upper control arm. What instructions are you looking at? Don't have the most recent Roadster or Coupe manuals. But the IRS instructions on their website haven't changed. https://www.factoryfive.com/wp-conte...2015-REV-D.pdf

[j33ptj]

Sorry, looked at the wrong pages.... need to check better before opening my big mouth...

[32J]

I wonder if the manual should also mention, "If you are installing an IRS brake package, you may also have to cut off the top brake caliper ear on the spindles." It would be easier to do all the cutting, grinding, sanding, polishing (and in my case, Cerakoting) in one step before mounting.

[edwardb]

I wonder if the manual should also mention, "If you are installing the 2015 IRS Wilwood brake package, you will also have to cut off the top brake caliper ear on the spindles." It would be easier to do all the cutting, grinding, sanding, polishing (and in my case, Cerakoting) in one step and BEFORE I mounted the spindles to the IRS.

Would like to know more about this. I've done two IRS builds with the upgraded Wilwood package (a Roadster and a Coupe) and did not have to cut the brake caliper ear. In fact, as I remember the 249-15139/40 brackets bolted to those ears. Need to dig out the instructions to confirm since I can't find any pictures. But maybe you could provide more details? Something maybe has changed. Would hate to see someone cut and find they're needed.

[progmgr1]

FWIW, I have a '33 Hot Rod with the 2015 IRS and Wilwood brakes purchased in 2016 - 2017. I did not have to cut off the caliper ear to install the brakes. Maybe something has changed since then?
Keith HR #894

[FF33rod]

Same a Keith, IRS with Wilwood brake package, only had to cut off what Paul (edwardb) has shown, no other ear to cut off.

I didn't have a band saw but tried using a sawzall, wasn't fun but got the job done. The real pain the butt modification on that spindle was drilling out one of the holes!

Steve

[32J]

The 2015 IRS brake instructions from the FFR site mentions cutting the spindles. A tech at F5 then sent me a different set of instructions, which did not indicate cutting the spindles. They were still the wrong instructions for the brakes I was actually supplied by F5. Eventually I found the correct instructions. Not a problem for experienced builders, but being a newbie I was a bit anxious. I edited my post above, as the instructions on the F5 site (where spindles have to be cut) are intended for some combination of IRS and brakes (not mine, thankfully).

[FF33rod]

The 2015 IRS brake instructions from the FFR site mentions cutting the spindles. A tech at F5 then sent me a different set of instructions, which did not indicate cutting the spindles. They were still the wrong instructions for the brakes I was actually supplied by F5. Eventually I found the correct instructions. Not a problem for experienced builders, but being a newbie I was a bit anxious. I edited my post above, as the instructions on the F5 site (where spindles have to be cut) are intended for some combination of IRS and brakes (not mine, thankfully).

Glad you got it sorted!