Lighter = Faster (N/A build thread #2)

[infernosg]

Originally Posted by Pete_89T2

How much play does it have, and how did you measure/test for it?

I didn't measure. I just grab at 12 and 6 o' clock on the tire and try to move the assembly. The FSM says play should be 0 in. so if I can feel any movement I think something's up. That being said the driver's side definitely has a few thousandths. The next time I have the car in the air I'll try to get a dial indicator in it to measure.

I took a ~10 mile drive today to bed in the bearings. When I got back the passenger's side had a little bit of play that it didn't before. This time I removed the brake caliper and dust cap but put the rotor and wheel back on and gradually snugged up the axle nut until the play was gone. I didn't even bother measuring the force required to turn the hub. The final torque on the nut was less than 5 ft-lb. By comparison, the driver's side still had play with 22 ft-lb.

[Pete_89T2]

Originally Posted by infernosg

I didn't measure. I just grab at 12 and 6 o' clock on the tire and try to move the assembly. The FSM says play should be 0 in. so if I can feel any movement I think something's up. That being said the driver's side definitely has a few thousandths. The next time I have the car in the air I'll try to get a dial indicator in it to measure.

That's what I thought; when you think about it, that FSM procedure really doesn't isolate slop/play to just the bearings, though that would be the most likely source of play when tested like that. Any slop you have in the ball joints, or even LCA bushings (unlikely, but possible) would be felt as play by your muscle micrometers (anything > 0") if tested that way.

Originally Posted by infernosg

I took a ~10 mile drive today to bed in the bearings. When I got back the passenger's side had a little bit of play that it didn't before. This time I removed the brake caliper and dust cap but put the rotor and wheel back on and gradually snugged up the axle nut until the play was gone. I didn't even bother measuring the force required to turn the hub. The final torque on the nut was less than 5 ft-lb. By comparison, the driver's side still had play with 22 ft-lb.

Could just be a slightly worn driver's side spindle, and DJ may be on to something with the hubs. Heating the hub & cooling the races should not be necessary; a new race (assuming correct part) should just press into the hub using a decent hydraulic press without any drama. I think the real question is how much play is too much play here?

[infernosg]

Originally Posted by Pete_89T2

That's what I thought; when you think about it, that FSM procedure really doesn't isolate slop/play to just the bearings, though that would be the most likely source of play when tested like that. Any slop you have in the ball joints, or even LCA bushings (unlikely, but possible) would be felt as play by your muscle micrometers (anything > 0") if tested that way.

The ball joint on the lower control arm is the only other possible source of play I can think of. I've tried to watch for movement as I shook the tire but a few thousandths is hard to notice. I'm going to test this by incrementally increasing the torque on the spindle nut. If the play is reduced or goes away it isn't the ball joint. This is how I know the passenger's side ball joints are okay.

In the long term I've got a set of S4 LCA's on the way I'm going to rebuild with new ball joints and delrin bushings.

Originally Posted by Pete_89T2

Could just be a slightly worn driver's side spindle, and DJ may be on to something with the hubs. Heating the hub & cooling the races should not be necessary; a new race (assuming correct part) should just press into the hub using a decent hydraulic press without any drama. I think the real question is how much play is too much play here?

I'm trying to find some used spindles with less mileage than my current ones to test this theory. I'm considering the PBM Knuckles for the future, though. Not because I need extra steering angle but because they have built-in bump steer and roll center correction for lowered vehicles. At $400 they're a steal compared to OEM.

I should clarify I didn't need to heat the hubs and freeze the bushings. I don't have easy access to a hydraulic press and I had already heated the hubs to remove the old outer bearing races. I froze the new outer races to make installation easier. The smaller outer bearing outer races dropped right into place in the hot hubs. The inner bearing outer races needed some extra force so I used the old races and tapped them in place with a plastic hammer.