Squeaky Wheel Redux
Even after years the results of poor workmanship continue to float to the surface. A sudden loss of brakes on the right led me to take off the right rear wheel, expecting to find that the worn old linkage had finally slipped out. To my consternation, if not horror, it was oil. Again. There are two seals, one to keep the oil in the rear end and one to keep the grease in the bearing and the dirt out. For the oil to get to the brakes it has to get by both. We've been down this road before. The brakes were drenched in oil when Old Stoney got here. His first trip to the dealer, to get a new rear main oil seal, clutch and all new bearings in his water-filled transmission, he also got new seals and brakes. Ten years later the seals were starting to seep again, but by then I thought I could replace them myself. After all, I have a service manual.
When I encountered the axle bearing retaining nut I realized I was out of my depth. It's a two and three-quarter inch nylon insert self-locking nut, tightened to 230-250 ft/lbs. It's down inside the hub far enough that it can't be reached with a box-end or open end wrench and it's on the axle so a socket can't slide down to it. I offered to let the dealer do that part for me, and they said they could get to it in a week or two. I took them to the machine shop behind my favorite auto parts store and they said, "Sure. Pick 'm up day after tomorrow."
When I got them home and saw that they had used a cold chisel and a punch to remove and put back the the nuts I said........well, one of the things I said was,"I could have done that."
So when, a few months later, it turned out that they had also failed to pack the bearing on the left (see Hip Replacement) I did.
Getting back to this time - I resolved to do better. I went to the dealer to get seals. They were out of one, had to order it, take a few days. They weren't really interested in lending out the special tool that the manual requires
While I waited I finished tearing it down.Once I had the axle out I closed up the hole to keep the wrens from building a nest in there while I was away. They're quick. I also hung the shims on the end so I wouldn't forget to put them back.
I went ahead and used the punch method to remove the nut. I figured if it was too messed up to reuse they'd have one in stock. As it turns out I was able to clean it up well enough with the Dremel.
That went as well as could be hoped, and I was able to get the two seals out without much trouble, and I thought to take the bearing out and repack it, as the oil had washed all the grease away. Here's more trouble.
Scratches and gouges from the metal chunks the jacklegs had cut off the nut. And -
It just is visible in the photo, but it's easy to feel. I thought it to be spalling, maybe a side effect of the debris damage, but when I showed it to Leon, the maintenance manager at work, he immediately said,"False Brinelling." It's caused by vibration in a stationary bearing, for instance in the rear axle of a back hoe that spends a lot of time running without rolling, and can be aggravated by insufficient preload, for instance by trying to get 250 ft/lbs with a punch.
On the way to pick up the seals I stopped at Bearing Distributors and got a new one. I also had stopped by a couple of other places looking for ideas on the tool. The counter guy at the bearing place suggested the NAPA out Bluff Road, where all the big truck dealers and repair places are. They had one of these in my size, shown here after I started modifications.
Home with all my parts and equipments, I set about tool fabrication. First, set up the welding shop.
Then add a handle to the socket
and let it cool. This is why we're called "shade tree mechanics."
Then all that remains is, as the manual has it, reassemble in reverse order. The counter guy at the dealer said it took two men to apply the proper torque, one to turn the wrench and a big one to hold the hub. The book shows a substantial vise. Having neither, of course I did it the easy way.
Put a few lug nuts on it and let the wheel hold it. And when it was time to be sure it was tight enough, let gravity help.
Lotsa chocks and blocks. I've since had it pointed out that for my arithmetic to work out the wrench handle should have been at three o'clock. For now I'm going to rest assured that the hard tug I added ("for good measure" means something) put it closer to spec than it's been in many years. And modify my tool with a torque wrench attaching point (see manual image above) for next time.
To do the calculation for the increase in torque with the longer handle I went to Norbar's website and used their calculator applet. www.norbar.com
But their drawing makes it easy to do the math in your head. Really.
It makes even more sense (to me, anyway) if you read it as "M2 is the desired torque..."
So, if my torque wrench is 16" from the head to the center of the handle and I weld a large nut to the extension centered 48" from the center of the socket (makes the "Extended Length" 64 inches) and I want 250 ft/lbs actual torque on the bearing retainer, I should set the torque wrench for 62.5 ft/lbs. Check me out on that.