New M35A2 home and on the jack stands looking for the wheel issue

[kenn]

I finally got some of my supplies in from various online vendors and decided to start tearing down my new to me M35A2. I tried to drive this home and about 400 miles in, the truck started oozing a LOT of grease from the boots. The driver hub was also getting hot very quickly. I started with just jacking it up and checking for wheel spin. It spins pretty easy! There isn't anything that feels like metal on metal other than there IS a slight scrape noise happening for short durations while the wheel is spinning. It sounds rather hollow so perhaps brakes? I have attached a picture with the hub removed as I get started and the bearing appears to be rolling smoothly and it certainly didn't get hot enough to melt the original brown grease in there and the grease is still very "greasy". I also removed the axle vent and it breaths freely.

Both boots are shot for sure. They are cracked/torn in several places. As soon as my breaker bar and budd socket get here, I'll pull the wheel and check the brake spacing.

When driving around the parking lot, the hub was reading 185ish on a short drive on the driver side but about 120 on the passenger side. It seems like a longshot but maybe the IR gun wasn't giving an accurate reading due to too much sunlight or something. It seems hard to imagine how a hub could be that hot and not melt that grease in the outer hub. Also of note there is zero liquid in hub. Just grease.

Regardless, I'll post more details once I get the wheel off. I might as well do a full hub service. I got the parts (silicone boots instead of zippered) so it's all coming off regardless.

 

[kenn]

Side note - I assume the mild clacking when spinning the passenger wheel (hubs installed vs. not installed) is backlash. Removing the hubs ends that, of course, because the axle shafts aren't moving at that point.

I fear this is going to be a money pit. The drive shaft is clearly bent and has a good 1" of movement around what should be a center line.

 

[kenn]

Inside the hub. I didn't check brake clearance before pulling it. Doh! I'll put it back on and snug the outer bolt and check. Bearing doesn't look/feel damaged. Some of the yellow factory grease is still in between the rollers. It's missing there about 2 o'clock as I spun the bearing there. Again, I'm not sure how the hub could have shown close to 200 degrees and NOT burned off all that grease. Other than the brakes is there anything else that could have heated up the hub only on the driver's side? And wouldn't that level of heat torch that grease to almost nothing?

 

[cbrTodd]

The only other thing I can think of in that area that has relative motion with wheel rotation and could cause heat build up (beyond the brakes and the wheel bearings like you mentioned) is the fit of the axle shaft inside the spindle. I would have expected that to show up as heat damage to the spindle and wheel bearings if it got hot enough to read 200 F on the drive flange. To me it's really looking like you either had a brake dragging or an IR gun playing tricks on you. You should be able to confirm once you pull the spindles and axle shafts.

You said the drive shaft appears bent. Are the pinion bearings still tight and smooth rotating? If you have significant damage to the center section, it might be cheaper to buy a good rear axle (from someone who bobbed or parted out a truck) and swap it over. Front axles cost significantly more but the center sections interchange.

 

[williamh]

Most wheel bearing grease doesn't melt till well over 350deg. , excessive heat on the hub could be just the breaks dragging , but you also posted that the boots are cracked and leaking oil , there shouldn't be oil leaking from the boots unless the seals are bad allowing the diff oil to contaminate the grease and break it down enough to cause the grease to fail and bearing to slip on the shaft ?

Only a guess on the bearings without looking at them

 

[kenn]

Not sure how to check the pinion bearings so I'll research that. Seems I'll have to remove the driveshaft to check for movement? I'm going to try to tear down all the way tomorrow morning and see what I find. I'll take a short video of the driveshaft rotating "out of center" or whatever it's called. It is quite significant.

 

[kenn]

Most wheel bearing grease doesn't melt till well over 350deg. , excessive heat on the hub could be just the breaks dragging , but you also posted that the boots are cracked and leaking oil , there shouldn't be oil leaking from the boots unless the seals are bad allowing the diff oil to contaminate the grease and break it down enough to cause the grease to fail and bearing to slip on the shaft ?

Only a guess on the bearings without looking at them

Thanks for the data on the temp. I'll post good pictures of the mess around the boots tomorrow morning. I'm not sure if there's oil mixed in or not just yet. It is flung around the inside of the tire/wheel but could just be grease I suppose and no gear oil.

 

[davidb56]

maybe check the oil level in the pumpkin to see if its coming out the boot area (bad seal ?)

 

[ToddJK]

If the drive shaft was bent or bad pinion bearing, wouldn't there be a lot of excessive vibration?
Maybe it's just my lack of knowledge on different types of wheel bearing grease on the market, but I haven't seen that type of grease look like a rusty brown type of color.

One way to check the bearings is to clean it so it's virtually grease free and then run your fingers over the bearings. There should be easy rotation of each bearing but no excessive rattling or flat spots. The wheel may spin easily with no sounds done by hand, but there's no load on the wheel and it's not spun at the rate of speed as if driving. I could be way off as I'm just mostly self taught and advised by others, so take what I say with a grain of salt. Hopefully it's just a case of a bad wheel bearing.

 

[kenn]

Ok, I'm stuck at the top king pin/arm. It seems fused to the knuckle. I put a 4x4 cedar block up against it and beat the hell out of it from below and it didn't even crack the bond between the two. I banged on the corner of it rather carefully with a rounded hammer so I wouldn't mar it up but still no dice. Any suggestions on getting this king pin/arm assembly broken free without damaging it?

I've pulled everything else out that I can to this point. The bearings are now clean and I don't feel any flat spots. The races aren't grooved. The inner and outer rings of the bearing do have some play, though. I don't know how much one should be able to move "in/out" relative to each other along the center axis but it's at least a 1/16th. Here are a couple more pictures inside the tube and the boot. It is a zipper type and it completely gone with a flap hanging. There doesn't appear to be any diff oil in the tube and the grease inside the knuckle is just a bit thinner than outside. Some greases are hygroscopic so I suspect it has absorbed humidity over time with cracked boots that weren't well sealed and thinned a bit. Still not runny though but not vaseline-like. That brown color is what the original military grease looks like from what I understand.. There is a video on youtube by tactical repair with that exact color of goo in it.

Interestingly, the axle seal pulled right out with the axle shaft. It doesn't look damaged. Attached are 2 pics. If any of you would like additional pics, please ask and I'll upload. Note there is a bit of rust on the axle shaft and some inside the square axle tube so there hasn't been any seepage of diff fluid that I can see or evidence thereof.

 

[kenn]

If the drive shaft was bent or bad pinion bearing, wouldn't there be a lot of excessive vibration?
Maybe it's just my lack of knowledge on different types of wheel bearing grease on the market, but I haven't seen that type of grease look like a rusty brown type of color.

One way to check the bearings is to clean it so it's virtually grease free and then run your fingers over the bearings. There should be easy rotation of each bearing but no excessive rattling or flat spots. The wheel may spin easily with no sounds done by hand, but there's no load on the wheel and it's not spun at the rate of speed as if driving. I could be way off as I'm just mostly self taught and advised by others, so take what I say with a grain of salt. Hopefully it's just a case of a bad wheel bearing.

Thanks, Todd! I would think there would be excessive vibration -- there doesn't seem to be but it's hard to tell, lol, because the whole thing is a vibrating beast. I'll deal with this issue after I get the wheel issue solved. I may just remove the driveshaft completely for now, check the bearings, and then go on from there.

 

[kenn]

I went back and watched tactical repair's video and he just beats it to get those little pressed in cones so I did the same and eventually they worked loose. I have it all off now. I cleaned up both bearings and they seem fine. I'm going to go to Napa and compare mine to a new set and see how much play they have. There doesn't appear to be any scoring, flat spots, etc. The only part that looks to have abnormal wear on it is the axle shaft seal. Pics below but it is very scratched up and appears to have some rotational wear as well like it was spinning some. Maybe this explains why it just popped out without any effort.

Anyway, pics attached. I think I'll net a new set of axle tube seals before I reassemble. Money. Pit. Lol.

 

[ToddJK]

I know the deuces vibrate a lot, but a drive shaft out of balance, bad bearing, sometimes bad U-joints, will cause severe vibrations as if your tires are so out of balance. It's definitely not a steady or typical vibration one expects in a deuce. I had a bad U-joint that caused that issue with my old one shortly after I bought it.

 

[kenn]

Quick update. I stopped at the auto parts store and compared new bearings to my existing bearings. There was a little difference in that then new ones didn't have quite as much play and seemed to roll a bit smoother but not by much on either account. Since I have the whole thing apart I'm going to go ahead and replace them just so I don't leave that question mark so that if the hub heats up again I'll have narrowed it down further. I think everything other than the axle seal carrier look like nothing has gone wrong, though. I ordered a pair of the billet "new style" ones from rockwell and as soon as those get here, I'll reassemble, adjust the brakes, and get it on the road for testing. I have the boot on the inner knuckle and just waiting for the parts to wrap it up.

IF the new axle seal carrier fits as loose as the old one, what then? That would mean a new axle housing! The area in the knuckle where the carrier fits is very smooth but the outer rim of the carrier is definitely "ridged" and seems like the outside diameter is short a couple thousandths so I wonder if a used one was put in place at some time in the truck's motor pool history. Since I don't have any oil in the tubes at the moment (nor does there appear to be a history of it) I can only assume the seals at the pumpkin end are doing their job so I'm not terribly concerned at least in the short run. Would it be unreasonable to put a high temp RTV in there around the rim or just put it in there knowing it will be pressed tightly once everything is torqued down?

 

[ldmack3]

I used gearbox oil resistant RTV. One of mine was really screwed up. I went ahead and replaced all bearings, races, seals and boots. Also bushings on the spindle, the RH axle and steering pin bushings.

Should be good to go for a while!

 

[ToddJK]

Quick update. I stopped at the auto parts store and compared new bearings to my existing bearings. There was a little difference in that then new ones didn't have quite as much play and seemed to roll a bit smoother but not by much on either account. Since I have the whole thing apart I'm going to go ahead and replace them just so I don't leave that question mark so that if the hub heats up again I'll have narrowed it down further. I think everything other than the axle seal carrier look like nothing has gone wrong, though. I ordered a pair of the billet "new style" ones from rockwell and as soon as those get here, I'll reassemble, adjust the brakes, and get it on the road for testing. I have the boot on the inner knuckle and just waiting for the parts to wrap it up.

IF the new axle seal carrier fits as loose as the old one, what then? That would mean a new axle housing! The area in the knuckle where the carrier fits is very smooth but the outer rim of the carrier is definitely "ridged" and seems like the outside diameter is short a couple thousandths so I wonder if a used one was put in place at some time in the truck's motor pool history. Since I don't have any oil in the tubes at the moment (nor does there appear to be a history of it) I can only assume the seals at the pumpkin end are doing their job so I'm not terribly concerned at least in the short run. Would it be unreasonable to put a high temp RTV in there around the rim or just put it in there knowing it will be pressed tightly once everything is torqued down?

I don't think some high temp silicone will hurt anything. Not sure how much one would apply though as I've never had to mess with the axle seals or anything like that, that didn't already have a seal on it.

I used gearbox oil resistant RTV. One of mine was really screwed up. I went ahead and replaced all bearings, races, seals and boots. Also bushings on the spindle, the RH axle and steering pin bushings.

Should be good to go for a while!View attachment 871816

How much silicone did you apply and how was it applied?

 

[ToddJK]

Oops, double post

 

[williamh]

I don't think some high temp silicone will hurt anything. Not sure how much one would apply though as I've never had to mess with the axle seals or anything like that, that didn't already have a seal on it.



How much silicone did you apply and how was it applied?

A nice "THIN" layer around the outside of the seal should work well to fill in any imperfection in the housing just remember Its not a toothpaste loop , use your finger to remove any access sealer. Also They make a seal installing lube but i think its more for more for pressing in a seal not filling in imperfections.

 

[kenn]

New update. I bought a pair of the billet axle seal/carrier assemblies from rockwell and they are a MUCH tighter fit. The original one can be put in and taken out easily though it has almost zero play so I suspect it would have been fine with some RTV but I'm in there and it's a money pit so... It was tight enough that I had to use a 2x2 and hammer to encourage it to seat all the way. No need for RTV now. I'm going to grease it all up, assemble, check/test the brakes then finish up the passenger side and hopefully be rolling this weekend for at least a short drive around the 'hood. Hopefully more updates tomorrow.

I still have to address the drive shaft. Once the left wheel is on and hub attached, I'll roll it and get a video for you to see.


*** Edit *** It's not seated all the way so I can't get it back together. I need a brass drift to work that billet carrier deeper into the housing. And, of course, noone sells a 3/4 brass rod locally that is still open.... and it's a holiday weekend.

 

[ToddJK]

New update. I bought a pair of the billet axle seal/carrier assemblies from rockwell and they are a MUCH tighter fit. The original one can be put in and taken out easily though it has almost zero play so I suspect it would have been fine with some RTV but I'm in there and it's a money pit so... It was tight enough that I had to use a 2x2 and hammer to encourage it to seat all the way. No need for RTV now. I'm going to grease it all up, assemble, check/test the brakes then finish up the passenger side and hopefully be rolling this weekend for at least a short drive around the 'hood. Hopefully more updates tomorrow.

I still have to address the drive shaft. Once the left wheel is on and hub attached, I'll roll it and get a video for you to see.


*** Edit *** It's not seated all the way so I can't get it back together. I need a brass drift to work that billet carrier deeper into the housing. And, of course, noone sells a 3/4 brass rod locally that is still open.... and it's a holiday weekend.

You have anything else that's 3/4" to use as a drift? If you have some steel, could wrap the end in duct tape so to not damage the seal/carrier.