Originally Posted by dshealey
There is no way to check pre-load with the housing cover in place. I had thought that if the housing cover would slip over the bearing easily enough one could put in an extra shim, push the cover down until everything was settled in place, then measure the gap between housing and cover. Then you could put in a shim 0.002-0.004" thicker than the extra one used for testing.
(Disclaimer: I have never stayed in a Holiday Inn Express, but I have done 3 crown gear bearing replacements.)
Well, actually there is, or should I say that it worked for me? The method is to remove the preload shims and then measure the movement. With just a "little" heat on the housing cover the bearing will slip in the bore fairly easy.
Let me explain:
See Pic 1.
Tools: Dial indicator w/ magnetic base, two small pry bars, SMALL soft face hammer, two small wood blocks to use as pry points, and a heat gun and a non contact temp reading device (not shown)
Setup: Drive unit assembled without housing O ring, hub seal, and preload shim(s), with or without pinion installed, parts lightly oiled is OK but CLEAN, CLEAN, CLEAN! Flat piece of steel bolted to the caliper mount holes to land the magnetic base on, two bolts screwed into the hub to use as pry points. Optional: Large "old" bath towel to place the assembly on to protect the finish.
The Prep: On the three I have done I've found that it didn't require much heat on the housing cover to allow the bearing to slip in its bore. Above 105 deg. F seemed to be sufficient . YMMV. Warm the housing cover. Take your time. Too hot to touch is way too much. Just enough to allow the bearing to slip in the bore and then just a little more.
See Pic 2.
The Deed: Put the magnetic base on the bolted on platform, place the dial indicator spindle on the center of the hub. Pry the hub assembly up in the bore.
1. Now take the SMALL soft faced hammer and "thump" the hub to seat it back down, 2. zero the indicator and pry up again. Read the indicator.
Do 1 and 2 numerous times to find the consistent reading. You will be able to feel the bearing slip in the bore and pull up tight against the housing when things are correct. Add some heat if deemed necessary. You will find that the consistent reading is the largest one. That is the end play. Add .002 to .004 in. to the dial indicator reading and that is the shim thickness to install. (And remember that the shims are metric dimensioned!)
A couple of notes:
When prying remember that we aren't trying to pull the bolts out of the hub. The pry bars used in the picture are short. Large screwdrivers would work fine.
When "thumping" the hub to seat the bearings we aren't trying to beat the $%!t out of it. (Did I mention SMALL soft face hammer?) Watch the dial indicator, it will show you when things are seated.
OK, so what about the heat? (I wondered too.) Took the assembly as seen in the picture and hung it above my little space heater in my workshop for an overnight "roast." The idea was to make sure that the internal componets were up to temp. When checked with the assembly heated (147 deg. F) the reading was less than .001 different. Not enough to worry about.
I think the reason for such a small change when heated is that the crown gear assembly is two pieces and one of them is aluminum (and expands more than if it were steel. (See Pic 3) The crown gear and hub are the same piece and made of steel.) The tapered roller bearing support (the cone shaped part) is made of said aluminum and is pressed into the hub portion of the crown gear as can be seen through the wheel bolt holes. (See pic 4)
On the last one I did (actually, the one shown in the pictures) has a few other issues dealing with possible reasons for failure. But that's another post!
HTH YMMV and Good Luck