I've been chasing a bouncy/shimmy/vibration issue on the front passenger side. I pulled the hub once again today to start looking at the knuckle as the problem. There is wear on the shoulder where the inner bearing is located when the hub installed. I have a spare knuckle I pulled from a pick your part last year, just to have one on hand just in case.... The spare doesn't have wear.

Would the wear cause an issue with the bearing functioning properly and causing bouncy/shimmy/vibration rolling down the road?
Is this normal wear for 324K miles?
Is the wear caused by the spindle nut being overtightened?


Original Knuckle with the wear on the shoulder


Spare knuckle, no wear

 

This spindle wear is VERY unlikely to cause shimmy or vibration issues if the bearings are in good condition and adjusted to the torque and resistance specs found in the FSM

Such wear is usually found after long service where the bearings were run somewhat too loose, permitting the bearing inner race to turn on the spindle
. (Spindle nut UNDER tightened.

No cause to change the spindle out though unless the wear is Extreme.
I would call extreme, anything approaching a 32nd of an inch or so.

Did you roll the whole tire/wheel rotating assembly to check for runout before disassembly??

I have run many different machines many tens of thousands of miles with substantial spindle wear.

You ought to be able to take a measurement with a decent caliper, or better yet, a micrometer to determine how much wear actually exists.

 

Here's the long story of chasing the problem...

Bought the truck 14 years ago. It did not see much love prior to me owning it.

Up to when the problem started, brakes (new calipers, pads, rotors), upper control arm bushings, ball joints upper and lower, shocks and inner bearings replaced within last 1 1/2 years. Tie rods, drag link, steering damper replaced within 4 years. Outer bearings replaced 8 yrs ago.

Mid January - Front end Alignment, was in a hurry and walked out without a printout. My screw up!
First of February - New tires installed
3rd week of February - began feeling a bounce and uneven braking passenger side front

I suspected a bad caliper because the last time was in it the piston was hard to press in. When I got in it one of the brake pads was wearing uneven. Replaced right side caliper, both side pads and rotors. I also put on a different hub with new inner and outer bearings, right side. Still had the bounce and uneven breaking.

Paid to have lower control arm bushings replaced, last thing to be done to refresh front end. I had tried to do it but I couldn't get torsion bar bolts loose. Mechanic said alignment bad and recommended rotor turn or replacement. At this point I'm not thinking rotor because problem there with old and new rotor.

Had alignment checked, it was crap. This shop didn't know where the shims were, I had to show them. They even loosened an upper control arm bushing bolt, before I could stop them. Had them stop and I left without an alignment. I don't think the first shop in January knew what they were doing because one of the left side upper control arm bushings exposed rubber is now crushed.

Two weeks ago yesterday, I had Toyota dealership do alignment cuz hard to find a shop that knows how to shim a 38 year old truck. Great alignment. My steering wheel has never been straight after an alignment until now. They suggested turning the rotors on the truck. That afternoon I had the tires rotated and rebalanced.

Two days later on a Thursday, I had toyota turn the rotors. After test driving it, the tech said braking 85% better, but that he didn't know what else could be a problem since everything tight and I'd replaced everything. When I drove it, I didn't think it was even 5% better.

On Friday afternoon, something felt really bad on the right. On that Saturday I found the 1 1/2 yr old shock blown. Replaced shocks. Still had bounce and braking issue.

This past Saturday I put a dial indicator on the rotor and hub. The hub was ok. The rotor had a high spot, so the Toyota machining was a fail. I put the old/newish rotors and the original hub back on. Braking was better but still had bounce and uneven braking. I since had gotten a spring tension gauge to measure the tension/preload. I had always done it by feel, right or wrong I don't know, wrong probably. I also rotated front tires.

When I checked the tension on the driver's side (no problems), it measured 5 lbs. Spec is 1.3 - 4 lbs. I set both sides to 4 lbs. The passenger side still had an issue, more of a shimmy and the uneven braking. I bumped it to 6 lbs. Passenger side still an issue driving/braking, but felt different like too tight. I set it to 5 lbs. Drove it yesterday. It was still an issue to start with then it got worse. Drove it home. When I took off the wheel, there was some scrubbing on the hub and wheel like I hadn't tightened the lug nuts or hub slipping. I always torque the lug nuts to spec!

So my plan yesterday was to put back on the hub with the new bearings. Before doing that I inspected the knuckle to find the wear on it.

The flat area on the knuckle is about 5mm. The wear starts about 4 mm. The wear is diagonally.