Problems replacing the right side IRS spindle

[lgordon]

I’m not happy with how I drilled the hole at the top of the passenger side IRS spindle and would like to buy a replacement matching the one that came with my MK4 complete kit.

I called Factory Five and learned that they get the spindle and hub as a kit from Ford Performance, M-5970-M. I then called Ford Performance who said they only sell the kit which includes both the IRS spindles and hubs. They suggested I order a replacement spindle through my local Ford Dealership. I did some on line research and found at least three part numbers for the 2015-2017 right side spindle (knuckle). The ones I found were FR3Z-5B758- with either a B, C or E after the last dash. I called Ford Performance back to ask which version was in their M-5970-M kit. The person I spoke with said it was the FR3Z-5B758-B. I ordered the spindle through a local Ford Dealership, using the FR3Z-5B758-B part number and paid for express shipping. (By now I had zero patience.)

The part Ford sold me was not an acceptable match for the spindle FFR supplied in my MK4 kit! While both pressed in bearings on the spindles FFR supplied are identical Ford parts those in the spindle supplied by my Ford dealer were not. One of the bearings in the spindle supplied by Ford was identical to those in the FFR spindle while the other was a poor quality unbranded bearing. I refused the spindle supplied by Ford and was able to get my money back. I’ll try to attach photos of the bearings in the FFR / FP spindles and the one in the spindle I purchased/refused.

Can anyone help me identify the correct part number for a right side knuckle matching the one in your M-5970-M kit? I understandB1B0A89A-EDBA-4356-A675-5F34B57E8CBB.jpg68B7C1EC-0FF0-4978-A632-77E339BE9535.jpgA81B97A7-69D9-481E-885A-1E04CEA06374.jpg the suffix codes B, C or E designate different models of 2015-2017 Mustang. The E one may come with a Shelby logo on it.

[edwardb]

I'm looking at the RH spindle on my Coupe build. Purchased as Ford Performance part number M-5970-M. The spindle part number is visible as FR3Z-5B758-B. There appears to be another character after the last "B" but it's not legible. Unlike your description though, the two bearings are different. The back one where the LCA is attached is marked DG9C-3C270-CA. Same as one of your pictures. The front one where the toe arm is attached is marked FR3C-3C270-BA. As I recall, the toe arm attachment bearing pivots through a pretty wide angle range. The LCA bearing does not.

According to on-line part breakdowns I could find, FR3Z-5B758-B is the correct part number for the RH spindle on all 2015 - 2017 Mustangs except the GT350. 2018 might be the same too, but the usual places I looked (Tasca, etc.) don't have that much detail on-line for the 2018 yet.

It's a little surprising that the replacement spindle had a bearing installed that didn't have the Ford part number marking. But those mfg's change suppliers quite frequently. If the FR3Z-5B758-B was a genuine Ford service part, and it fits properly, I'd be surprised if it's actually inferior to the part you received before. Keep in mind, as well, our cars are 1000 lbs or more lighter than the Mustang they were designed for.

[CraigS]

When I did my 2015 IRS retrofit, I think I remember replacing that no-name bushing w/ another one more like the one w/ the part number on it. I 'think' it was this one
https://www.americanmuscle.com/frpp-...ring-1516.html
Sorry that apparently I didn't keep any records but I think this was a fairly well known upgrade. Why your FFR spindles have it and the other doesn't I have no idea. I did notice that I was asked which year and which model, V6, GT, GT350, Gt350R, I had to see if it would fit. I wonder if Ford maybe puts this upgrade into their aftermarket spindles but not their OEM parts.

[lgordon]

Paul, Thanks for looking at your spindle! I stand happily corrected on some of what I originally described. I was calling them bushings but then watched a CH Pony Parts video where they called them bearings. (How could a YouTube video be wrong?) Ok, you are correct, the bushings in my original spindles are different but other than part number and size very similar high quality Ford branded bushings. On the side, stamped on as if by a dot matrix printer is “FR3C-5B758-BD”. Difficult to read but with the aid of side lighting and a magnifying glass that’s what it says. I’ll see if Ford recognizes that part number.

[edwardb]

Paul, Thanks for looking at your spindle! I stand happily corrected on some of what I originally described. I was calling them bushings but then watched a CH Pony Parts video where they called them bearings. (How could a YouTube video be wrong?) Ok, you are correct, the bushings in my original spindles are different but other than part number and size very similar high quality Ford branded bushings. On the side, stamped on as if by a dot matrix printer is “FR3C-5B758-BD”. Difficult to read but with the aid of side lighting and a magnifying glass that’s what it says. I’ll see if Ford recognizes that part number.

I've heard those called bushings for years. But after looking at the info CraigS provided, saw that they're apparently referred to as bearings this case. Who knew? (Well, not me anyway...). I changed my post. Doesn't matter...

Probably that character I can't read on my spindles is a "D" also. Looks like mine are exactly the same part number. I really don't think the parts Ford Performance has are any different than Ford is currently using or has in their service channel. They all come from the same place. Been there done that. But Ford Performance does stock parts at their distribution center, as does Ford service. In both cases they're stocking to forecast sales volumes, so who knows how long they've been sitting around. I'm betting we're dealing with different age parts here. But that's only a guess. Good luck sorting it out.

[lgordon]

Thanks for the upgraded bearing link CraigS! If I strike out on getting a direct replacement for the FFR supplied spindle I’ll probably order a set.