Again, working on a '97 K2500 7.4L 8600 GVW, 8-lug pickup.
Just finished popping eight lug studs out of my RF hub; with the intention of changing the RF brake rotor. As you know, the 8-lug GMT400 vehicles have the rotors "riveted" to the hubs with the lug studs. The hub has to come off to get the lug studs popped free; and the rotor is behind the hub flange much like some 8-lug rear drums are behind the hub flange on the rear axle.
I knew the rotor was scored, I did not know that it had already worn past the "Discard" thickness. The 8-lug rotor starts out at 1.260. The discard thickness varies depending on the source, what I found in an older manual is 30.88mm which is 1.215 inches--.045 thinner than new. Conventional wisdom is that you're allowed to machine the rotor to .030-under, which then allows another .015 wear before it's so worn as to be at it's limit. My rotor measured 1.195", so clearly it's days were over.
UNLIKE the other side, where I had a difficult time removing the four bolts that hold the hub to the steering knuckle, the hub on this side came right out with (relatively) no trouble and no drama. It did take a heap o' torque to rattle the bolts free.
The two things that were different were
1. I bought a "special tool", a very short 15mm swivel impact socket in 1/2" drive; Snap-On p/n
RIPLM15C . This provides better clearance to the CV joint than the swivels I was using on the other side; and
2. I used the full 185 psi from my compressor, bypassing the pressure regulator. Therefore, the 3/4" impact wrench had better-than-rated power.
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Between these two changes, the bolts that came out didn't have ruined heads like on the other side. It's still telling that a regular 1/2" impact wouldn't take the bolts out, given that the assembly torque is only 133 ft/lbs. Because of having the "special" swivel impact socket that allowed me to work around the outer CV joint, I even managed to get the hub free without removing the steering knuckle from the vehicle.
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I did take the knuckle off in order to get the lower ball joint squeezed out, and the new one squeezed back in.The ball joint went out/in nicely; just like the other side. No photos 'cause they'd just be repeats from my earlier post in this thread. Just like last time, the steering knuckle was cleaned-up including the grease seal for the outer CV joint, which was lubed and re-used. Also, like last time, the CV shaft did not come "out", it just laid on the control arm, disconnected on both ends. MAYBE I could have left the CV shaft bolted to the differential flange--I don't know for sure; I didn't try it that way.
Separating the rotor from the hub, on the other hand, was a disaster. I did get all eight lug studs popped out of the hub, so that the rotor could be removed. However, it took every bit of my 20-ton press to do it. I'd pump up the hydraulic jack on the press, the whole press would kinda distort under the force, and then BANG! the lug stud would pop free. As the press sprang back to "normal", it'd jiggle the whole frame, and scare the crap out of me.
This repeated about five times, each time getting the hydraulics pumped up to near-capacity, and then releasing with a bang and the press-frame and the rotor/hub moving around. The next time, my hub/rotor/press plates got jiggled far-enough out-of-position (which I didn't notice) and when I got enough pressure on the assembly, it
broke the rotor. Now, the rotor was garbage even before it broke, but I wasn't expecting to throw it away in two big pieces, with multiple cracks. This was my fault, I should have been watching my press-plates. I knew they were getting jostled.
Anyway, I re-positioned my press plates, and the rotor/hub assembly. Removed the remaining lug studs, each one letting go with the familiar "BANG!".
I had been considering trying to remove the lug studs with a 1-ton arbor press. No way in heck was that going to work.
The point of all this is:
I'm gonna buy a new hub tomorrow. I'll put the new rotor on the new hub using new lug-studs. Replacing rotors on these hubs is just too much of a pain in the asp; the old hub seems to work just fine--but it does have 180K miles, and I do expect the pair to carry a bigass Vee-Plow for months at a time. I'd be REALLY angry if I'd gone to all the work of replacing a rotor on the hub, and then had the hub fail.
Also tomorrow, I'll install inner and outer tie rod ends on this side, and a new adjuster sleeve.