Shaft resting position inside spindle (1 Viewer)

[tohox]

Hi,

I completed a knuckle rebuild about a month ago on my '91 PZJ77 along with changing all the bearings and seals in both knuckles and hubs. I just finished a 10,000km trip and during the last 1000km or so I had a light grinding noise accompanied by a high pitched squeal between 40km/h and 60km/h on the front left side. I believe it is probably coming from the left locker as when I spin it manually I can feel some resistance and hear slight grinding. I'll see if I can replace the bearing or whatever else might need love in there but I'd like to know what caused this.

Upon completing the rebuild I had realized that the majority of the threads in both knuckles' spindle mounting holes were stripped. I had only a few days before departure and didn't want to leave for a long trip fearing that one of the spindles might pull out at the worst moment so I found a pair of used knuckles through the forum here and proceeded with the replacement. The used spindles were in pretty good shape but I had no idea of the shim placement in the vehicle they were pulled from and didn't have access to a centering tool to verify it so I proceeded with the same shim arrangement I had been using previously. I managed to achieve the correct FSM bearing preload values using the fish scale method on the first try on both sides but noted that the axle shaft wasn't resting perfectly centered on the left side which has the longer shaft (see pictures below). I could center it easily though just by pushing down lightly so I gave it no further thought and completed the rebuild.

I now have the impression that this slight shaft offset may have been pushing against the locker spline causing its bearing to wear out. Sounds plausible?

I figured I should probably be adding shims to the bottom to get the shaft to move down but I already had 2 thin ones at the bottom so I tried moving one of them to the top to see if it centered the shaft in the spindle and it didn't. The shaft still rests against the top. I could try adding thicker shims to the bottom but I'm afraid I'm going to get the bearing preload out of wack if I change the overall thickness of the shim stack.

• Should both shaft ends normally appear centered in the spindle?
• Or does the weight of the longer left side shaft cause it to drop naturally to the bottom causing the other end to lift up?
• Would a bad shim arrangement cause the locker wear I've experienced or are my original lockers just in need of attention?
• I assume if the knuckle centering is wrong it should also be wearing one side of the spindle bushing and possibly the axle's inner oil seal as well? I haven't checked those yet but I will.

Is it possible to rent or borrow a centering tool from somewhere or someone to your knowledge?

Thanks!

 

[mcmarshing]

Hi

Hi,

I completed a knuckle rebuild about a month ago on my '91 PZJ77 along with changing all the bearings and seals in both knuckles and hubs. I just finished a 10,000km trip and during the last 1000km or so I had a light grinding noise accompanied by a high pitched squeal between 40km/h and 60km/h on the front left side. I believe it is probably coming from the left locker as when I spin it manually I can feel some resistance and hear slight grinding. I'll see if I can replace the bearing or whatever else might need love in there but I'd like to know what caused this.

Upon completing the rebuild I had realized that the majority of the threads in both knuckles' spindle mounting holes were stripped. I had only a few days before departure and didn't want to leave for a long trip fearing that one of the spindles might pull out at the worst moment so I found a pair of used knuckles through the forum here and proceeded with the replacement. The used spindles were in pretty good shape but I had no idea of the shim placement in the vehicle they were pulled from and didn't have access to a centering tool to verify it so I proceeded with the same shim arrangement I had been using previously. I managed to achieve the correct FSM bearing preload values using the fish scale method on the first try on both sides but noted that the axle shaft wasn't resting perfectly centered on the left side which has the longer shaft (see pictures below). I could center it easily though just by pushing down lightly so I gave it no further thought and completed the rebuild.

View attachment 2773218View attachment 2773219

I now have the impression that this slight shaft offset may have been pushing against the locker spline causing its bearing to wear out. Sounds plausible?

I figured I should probably be adding shims to the bottom to get the shaft to move down but I already had 2 thin ones at the bottom so I tried moving one of them to the top to see if it centered the shaft in the spindle and it didn't. The shaft still rests against the top. I could try adding thicker shims to the bottom but I'm afraid I'm going to get the bearing preload out of wack if I change the overall thickness of the shim stack.

• Should both shaft ends normally appear centered in the spindle?
• Or does the weight of the longer left side shaft cause it to drop naturally to the bottom causing the other end to lift up?
• Would a bad shim arrangement cause the locker wear I've experienced or are my original lockers just in need of attention?
• I assume if the knuckle centering is wrong it should also be wearing one side of the spindle bushing and possibly the axle's inner oil seal as well? I haven't checked those yet but I will.

Is it possible to rent or borrow a centering tool from somewhere or someone to

Ignore the requote of your post^ im doing this from my phone and can’t seem to quote the appropriate amount for your post.

Question: was the squealing caused while the hubs were locked? I’m also going to reference what you called “lockers” as “manual hubs/hubs” so as not to be confused with locking differentials, and i’m assuming the hubs are what you are referencing. If the hubs were free, I would imagine your issue has more to do with either sticky brake caliper pistons or hub bearings/too tight of a hub.

Typically, the part that keeps the birfield/front axle in place (to my understanding) is the C-clip that goes on after the base of the manual hub is in place (it’s sometimes a major pain to remove and install since it’s a tight fit). Maybe you potentially forgot to install the C-clip? One thing I would check is the brass fitting on the back side of the spindle - usually can be a good indicator of wear, as well as the birfield joint contacting inside the the axle tube itself.. if the brass or birf joint are jacked up, then it’s potentially an indicator the shims are out, but I personally have never dealt with shims causing that much grief if you said they were within spec. If the brass bushing is jacked up, but the birf/axle tube are OK, you can just replace the brass fitting so that the axle “rests” in the spindle a little better.

Let us know if the sqealing was caused during turns, locked or unlocked hubs, etc.

 

[tohox]

Hi

Ignore the requote of your post^ im doing this from my phone and can’t seem to quote the appropriate amount for your post.

Question: was the squealing caused while the hubs were locked? I’m also going to reference what you called “lockers” as “manual hubs/hubs” so as not to be confused with locking differentials, and i’m assuming the hubs are what you are referencing. If the hubs were free, I would imagine your issue has more to do with either sticky brake caliper pistons or hub bearings/too tight of a hub.

Typically, the part that keeps the birfield/front axle in place (to my understanding) is the C-clip that goes on after the base of the manual hub is in place (it’s sometimes a major pain to remove and install since it’s a tight fit). Maybe you potentially forgot to install the C-clip? One thing I would check is the brass fitting on the back side of the spindle - usually can be a good indicator of wear, as well as the birfield joint contacting inside the the axle tube itself.. if the brass or birf joint are jacked up, then it’s potentially an indicator the shims are out, but I personally have never dealt with shims causing that much grief if you said they were within spec. If the brass bushing is jacked up, but the birf/axle tube are OK, you can just replace the brass fitting so that the axle “rests” in the spindle a little better.

Let us know if the sqealing was caused during turns, locked or unlocked hubs, etc.

Hi @mcmarshing and thanks for the quick reply!

Yes I did mean the locking hubs and not lockers or dif locks, my bad! Although mine are in fact the factory e-hubs and not manual ones.

The brakes were also my first thought and the first thing I checked. I did find one anti rattle clip which was broken and rubbing against the side of the rotor but that wasn't the source of the grinding or the squeal as they were both still present after I removed the broken clip. I had also done a complete caliper rebuild and installed new pads when I did the knuckles. I didn't change the rotors but their thickness was still within spec and runout was around 0.001" so I left them as is. I did find that the pads were rubbing very lightly against the rotors on both sides but this only produced a very faint wooshing sound and not the grinding or squealing sounds I mentioned in my original post so I think the brakes probably aren't the culprit. Is this slight rub normal when installing new pads or should the pistons be retracting further?

I did notice that the outer hub bearing showed traces of having rubbed against the spindle (see picture below). My impression is that this was probably the source of the squeal while the e-hub was the source of the grinding sound. At first I thought I had carefully followed the FSM procedure for setting the hub bearing preload but I kept ending up with the hub being too tight when testing with the fish scale. I finally noticed that the third adjustment nut torque spec was in fact in in.-lbs. and not in ft.-lbs (see FSM excerpt below). So I backed off the adjustment nut and retightened it to a meager 48 in.lb (4 ft-lb) as specified in the manual. I'm thinking it is perhaps this initial over tightening followed by a looser adjustment nut which caused the outer bearing to come loose and start spinning freely around the spindle. I'll replace both outer bearings and seals before reassembling the knuckles/spindles/hubs/calipers and will be checking the spindle brass bushings

Oh! and yes, the C-clip was in place on both sides.

Both the grind and squeal were present when accelerating in 2WD in a straight line. I believe they were also present when turning left or right but didn't notice them when in 4WD with hubs locked as I was going very slowly when that was the case and couldn't have heard it.

Thanks!

 

[mcmarshing]

IMO, your brakes aren't the issue. If you're concerned I would just stop after driving for the next few times to feel any temperature differences between all 4 hubs. if one hub is hotter to touch, maybe look into brakes as well as the bearings.

Seems to be that an overtightened hub assembly was the issue if it happens during 2WD. Don't forget to maybe take a look at the inner bearings as well, since the "cone" design of the spindle (from what I understand) also puts pressure on the rear bearing assembly, hence why you have to tighten it to 43ftlb and loosen it a couple times so that both bearings properly seat themselves prior to the final torque. I understand that the rear seal (and brake disc) on the hub is in the way, but maybe just popping it off and without removing the rear seal looking into it would be worthwhile. Also consider repacking your bearings if at all possible, maybe use a bearing packer to ensure it's good to go.

Also, maybe it is just an E-hub issue? I know that the spindles are different, and some guys on here convert to manual Aisin hubs using various methods. It might be worth looking into some threads on here to see if some of your symptoms could be faulty E-hub related.

 

[tohox]

I checked both the spindle bushing and the axle inner oil seal and both appear fine showing no apparent wear or damage. I couldn't find any spec in the manual for evaluating the spindle bushing wear. So replacing it or not appears to be a qualitative decision and not a quantitative one.

I dismantled both e-hubs and it appears the left one is missing the spacer ring that normally goes between the free wheeling hub ring and the inner hub (see picture). I think this e-hub is probably a rebuild as it has a blue hand painted number inside of it. So someone appears to have forgotten something at some point...

I also noted that the inner surface of the dimpled bronze bushing on this e-hub has some wear marks. Despite its surface looking a bit rough the oil gap is still within spec so I might just give it a good cleaning followed by light sanding with a very fine grit.

I can see an e-hub to manual hub conversion approaching on the horizon...

 

[OGBeno]

I can see an e-hub to manual hub conversion approaching on the horizon...

Smart.

They are junk.