FAQ suggestion to add to birfield repack

IdahoDoug · 10-17-06, 12:55 AM

I took some extra time on this repack to consider two of the most common failures people have experienced after repacking their birfields:

- loosening of the 4 nuts/studs on the bottom of the knuckle
- wheel bearings coming loose

First, the 4 knuckle bolts. I have done this 3 times and have always had to fiddle with reinstalling the steering arm on the knuckle - which is attached by the 4 nuts. The fit of the arm is extremely precise and will often bind while you are tightening the bolts before it is all the way on. This will leave a gap of only a few thousands of an inch, but the arm is definitely NOT on. I verified this today by playing with it a few times and it sis easy to do. So I used a hammer to tap the arm upward every few turns of the nuts, preventing it from binding. It worked perfectly. Considering the fastening system is quite bombproof, I think these failures are simply due to the steering arm binding up just before seating all the way. Many have bought the newer torx head bolts (including me!) in fear of this loosening phenomenon, but I think tapping it with a hammer continuously until it is all the way home solves the problem. I did not use the new bolts, and am not sure what I'll do with them.

So, I'm suggesting that the FAQ birfield repack instructions should be amended to add light tapping with a hammer as the nuts are tightened on to prevent this bind.

Next, the wheel bearings. In the past, and on this job today I had to really struggle getting one of my newly repacked wheel bearings to fully seat. When you're putting the disc rotor back on with the new grease seal on the back, it feels like you've solidly thunked it all the way on, but you may not have. I thought I had, but having done this many, many times it did not look quite all the way on and a light went on. I wondered if some are putting the thrust washer and nuts on at this point and then having problems with preload or simply getting the preload even though the assembly has not been pushed fully home. In my case, I was reluctant to grab the rotor and seriously heave on it because I'd degreased the rotors and my hands were greasy. With less experience in this exact situation, I might have continued with assembly and later the bearing would pop on and be loose. I don't know what it is that catches back there but I think it's simply the precise fit of the inner bearing on the spindle. At any rate, feeling suspicious I grabbed a couple fresh rags and really got aggressive with pushing it on. I was rewarded with a thunk and thought I'd bring this to everyone's attention.

So, I'm suggesting that the front wheel bearing installation be amended to include extremely close attention to making sure the rotor is all the way seated before setting up the bearings - up to and including some hammer blows with a brass or plastic hammer to seat it.

Just a couple observations today as I buttoned 'er up.

DougM