Wednesday, June 24, 2009

Bearing good tidings

We are at the Wal-Mart in West Valley (map), just outside Salt Lake. Careful readers might recognize that this is actually ten miles beyond where we need to be, which is the Salt Lake KOA just down the street from the Salt Palace Convention Center.

There's a good reason for that -- we rolled in to the greater Salt Lake area on the dregs of our fuel tank, which we last filled over a month ago back in St. Helens, Oregon. The gas station attached to the Smith's Grocery store in this town, just another couple blocks south, had diesel for an incredible $2.459, less with purchase in the store on your rewards card. Even Flying-J here in Utah is running upwards of $2.65, and the nearest local competitor came in at $2.57 or so. We jumped on it, driving straight to Smith's after pulling into town, and putting 225 gallons in. The clerk in the booth was incredulous.

That made this Wal-Mart the nearest overnight spot, and we had a nice dinner across the street at Copper Creek Pub, for which Louise was able to dig up a $25-off coupon on Given our general distaste for KOA (this will be only our fifth KOA stay in as many years), we had no desire to show up there a day early. We'll roll up there around mid day today, in time to get squared away before we need to show up at the Salt Palace.

Our original plan had not been to arrive in the area until this morning, but once I found out about the cheap fuel I wanted to get it out of the way, and also did not want to take the chance that the generally rising fuel prices would make the deal disappear before we got there. Also, we've been nervous enough about the fan drive that we wanted to have a safety margin.

Speaking of the fan drive, I got up extra early yesterday to start making calls around Twin Falls. No one answered my 7:37am call at Kaman, the bearing distributor, even though their posted hours ran from 7:30 to 5. Fortunately, the first truck shop I called, Van Dyk Truck Repair, had a pair of 6503's in stock for $14.50 apiece, and agreed to pull the cantankerous race off the spindle for me. I asked them to set the bearings aside for me, finished my breakfast, and pulled a scooter out.

All the repair shops were at the other end of town from us, so it ended up being about a 15-minute ride each way. They had the right bearings, but two different brands, which seemed fine to me. The trouble started, though, when they tried to get the old race off -- something I had failed to do with an engineer hammer and a pry bar.

It turns out that the race had spin-welded itself to the spindle. The guy from Van Dyk tried three different bearing pullers (driven with an impact wrench) to no avail. Then he tried to break it off with a cold chisel -- also ineffective. Finally, the acetylene torch had to come out, and the combination of torching it and chiseling at it finaly got it off. That left some additional metal on the spindle that had to be removed with a grinder, and the whole spindle had to be sanded and polished up. It's a good thing I had made no further effort (such as buying a bearing puller) to remove it myself, as clearly it was beyond my capacity to do so -- it took a professionally equipped shop over 40 minutes to do the job.

So choosing to go straight to the truck repair was the right move; in addition to the $29 for the bearings, it cost me $49 in labor (at $70 per hour) to have the old race removed and the new bearings pressed in. Money well spent, and $80 and a full hour later I was ready to put the fan back together.

That proved something of a challenge in itself. Getting the pulley assembly back in and the belts on was the easy part; much harder, however, was adjusting the belt tension. First off, I have no specification for the tension, so I am just guessing at it. Secondly, the single pulley which we just repaired serves as the sole tensioning mechanism for both belts. Getting the tension right for both belts simultaneously is nearly impossible -- one needs to first adjust an offset angle for the pulley carriage, then tension the whole assembly with a jack screw.

If the tension between the belts is not even, the jack screw needs to be backed off completely, the offset angle re-adjusted, and the jack screw tensioned again. Since the jack nut is recessed in a channel and can only be moved about 60° at at time, this is a tedious process. I probably spent half an hour just trying to get the belt tension to an acceptable setting for travel, and I remembered the last shop to have adjusted the belts complaining about the same thing.

All this got me thinking that perhaps the difficulty in tensioning the belts is what led to the bearing failure in the first place, and the lack of proper adjustment information had me nervous about the setup for the rest of the day. When we finally got rolling, we stopped every hour to check belt tension and bearing temperatures, and I loosened the adjustment at the first such stop.

By the time we got everything back together and buttoned up, and the tools put away, it was lunch time. We had our lunch there with the Snake gorge as a backdrop, and were back on the road just past noon. Given our concerns about the fans, we decided to stay close to the Interstate, although we did make the scenic detour to old highway 81 across the state line.

Now that we are safely in Salt Lake, I'm researching proper belt tension, starting with a call to good friend Jim Shepherd, of RV Safety Systems. Jim used to work for Gates, the belt company, and I knew he could give me an answer. As I suspected, it's not a simple matter, and he will have to do some engineering analysis based on my pulley and belt sizes and expected fan HP. We'll try to get that done before we leave town, so I can re-adjust the belts before we get back on the road.

In a few minutes, we should be rolling over to the KOA. This evening we will begin our conference, the annual General Assembly of the Unitarian Universalist Association. I expect that we will not blog here much during the conference; for one thing, we'll be pretty busy, and for another, this is a secular blog (whatever that means). However, as part of our commitment as official voting delegates for our congregation, we keep a separate blog for that purpose, and you can follow us over there if you are interested. Also, I will likely be tweeting from my BlackBerry during the event.

I should resume a normal posting schedule next week, when we are done with General Assembly.

1 comment:

  1. Great timing to lose the bearing in "civilization." That would have been a nightmare had you been way out in the boonies and lost the whole pulley assembly. Luck was running with you. I lost a trailer wheel bearing once and got lucky to stop before it wrecked the entire spinle/axle assembly. Those belt tension issues can be tricky. Years back I ruined an alternator and a water pump by over tightening belts. You folks must be living right! Take care and enjoy your assembly. Doug S.


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