Ford Performance Rear Hub w/ ARP Studs Issue?

[Anviltester]

So put a new set of fp hubs on a 2020 mustang road race car (M-1104-B) and after 1 race weekend (in the rain no less with too many fcy's) I was prepping for our next race at vir and noticed what I think is excessive play in the bearing. I called FP and they sent me another set under warrantee. we pulled the 2 new ones from the box and decided to bench test them for play (I have a cnc machine shop so have all the cool measuring tools and fixture plates) and the new ones have the same play as the one we took off (driver rear). Funny thing is the pass rear used one has no play at all. So I now have 3 with play and 1 with no play. Does anyone know what the deflection measurement should be (if any) or is all this normal?

 

[JAJ]

So put a new set of fp hubs on a 2020 mustang road race car (M-1104-B) and after 1 race weekend (in the rain no less with too many fcy's) I was prepping for our next race at vir and noticed what I think is excessive play in the bearing. I called FP and they sent me another set under warrantee. we pulled the 2 new ones from the box and decided to bench test them for play (I have a cnc machine shop so have all the cool measuring tools and fixture plates) and the new ones have the same play as the one we took off (driver rear). Funny thing is the pass rear used one has no play at all. So I now have 3 with play and 1 with no play. Does anyone know what the deflection measurement should be (if any) or is all this normal?

Depending on your schedule, contact FP again and show them pictures of the play. They may have a defective batch.

I had this problem once on a set of replacement OEM rear hubs (with longer studs installed) on my GT350 and it was caused by the machine shop that swapped the studs catching the corner of the mounting flange with one of the studs when they pressed the original studs out of the hub. The interference just barely pushed the mounting flanges out enough to create a touch of play, but the bearings were junk. If you're in a hurry, take the one that has no play, carefully tap the studs out with a hammer and replace them with a set of loose ARP studs (or someone else's studs). That hub is sound and useable and it's good for a while yet.

 

[Anviltester]

I'll have to get the deflection measurement from my machinist as he did the testing. All 4 hubs are the same fp ones - just have one that has no play (too tight or just right) and 3 that have about the same play within a couple thou. One set I just got today and the other was back in December. Same batch? I don't know how I would tell. When I called they said to shoot an email which I did. Just waiting on a response. Didn't know if anyone else had this issue before and/or had what was acceptable play (if any). if the bearing fails is it one of those things where the wheel just locks up or something else or can the wheel physically leave the car? We race next weekend at vir and 130+ up the esses or 150+ down the back straight either would be a bad place to have a failure lol. Walls are close but thankfully not Sebring close lol.

 

[JAJ]

I'll have to get the deflection measurement from my machinist as he did the testing. All 4 hubs are the same fp ones - just have one that has no play (too tight or just right) and 3 that have about the same play within a couple thou. One set I just got today and the other was back in December. Same batch? I don't know how I would tell. When I called they said to shoot an email which I did. Just waiting on a response. Didn't know if anyone else had this issue before and/or had what was acceptable play (if any). if the bearing fails is it one of those things where the wheel just locks up or something else or can the wheel physically leave the car? We race next weekend at vir and 130+ up the esses or 150+ down the back straight either would be a bad place to have a failure lol. Walls are close but thankfully not Sebring close lol.

I have the set on the car and a spare set and there's no human-detectable play in any of the four. If the bearing separates under a high lateral g load, the only thing that can keep the wheel on is the brake caliper.

 

[Anviltester]

Fun! So now I have to go deal with ford performance people. Ugh. Wonder how many sets of hubs its going to take to get a good pair lol