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well, as I think about it, it was east. driving down the road and the entire axle with drum just walked out of the housing. fortunately I saw what was going on in the mirror and pulled over before it left the truck altogether.
it is not really obvious how that assemble is meant to be held together or held on the truck. can't really tell if the press fit of the inner race of the bearing is supposed to do it or the c-clip or both. but got a mechanic who had messed with these before to get a new bearing and put the shaft and seals back together and i put a new seal in the axle housing as well. i'm not even really clear how oil gets to the bearing but I guess it does and there are two seals.
so it all goes together well and the spline at the differential end is OK and slid in well. no metal in the differential oil. that end looks good.
but the backing plate for the brakes that is meant to bolt to the flange on the end of the axle housing is very slightly out of flat with the flange when i hand tighten the nuts. with wrenches it would be easy to bring the surfaces flush but I'm wondering if this puts a little angular tension across the bearing or if this is standard to a have a little correction in flange alignment to be made up on the install.
Try rotating the axle shaft when it's like that, and see if the crookedness goes around with the axle shaft or stays in place. That might let you know if it's the axle shaft or the axle housing that's off.
I've certainly seen bent axle housings. Have you ever had this aligned, and if so, did that corner have some weird readings?
@Jomoka
thanks for reply. I did realize after posting that rotating the axle to several different orientations would indicate if this was bent axle and I did that and no change was detectable so i don't think it is bent axle. possibly the housing could be bent. I never had it aligned but it seemed to run true on the road and the tires wear evenly (at least for thousand miles i've had it) and I don't think they were replaced to sell it. I just don't know if the deviation of the flange is within normal expectations or should raise concern.
obviously given the problem I had with the tire, drum and axle leaving the truck maybe this was the problem all along and it was glossed over in a previous bearing service. or maybe this is within normal variation or operating range. i just can't find any threads that seem to indicate at what extent a deviation from parallel between the axle house and the axle is a problem. I saw a what looked like a tiny bit of deviation (not as much as I have) in an axle going back together in a great thread on how to replace the bearing on tacomaworld . What I have will easily close up if I torque the bolts but i'm wondering what amount of small angular force on the bearing is appropriate and if there is any sense of an acceptable limit on this alignment.
Last edited by archibaldtuttle; 12-18-2023 at 04:28 AM.
Reason: add more information
@millball it looked like the surfaces diverge quite evenly so that they both are flat but not aligned. that said I did not check them. I found a recommendation to check that the seal is riding near the center of the spacer by making a sharpie mark on the spacer and reinserting and spinning the axle and the seal will rub away the sharpie where it rides so when I pull it out for that I'll check flat with a straight edge.
The bearings have a little 'wiggle' to them even when new, that amount of a bend in the housing is probably not an immediate big deal if the bearing isn't under tension when tightened, but still within the 'wiggle' room. if the bearing gets into some tension as it tightens, you're probably looking at a really short life.
Another way to check for a bent axle housing is to bolt up the wheel and then mark a dot on both rear tires, and then measure the distance between them as far back as you can still get a straight line, and then as far forward, and at the bottom as well. Shade tree alignment check. If the axle is straight, should be the same distance regardless of where in the rotation you measure it. Mark dots and use them to make sure you're not measuring a bent wheel of an uneven tire.
Petty common to have that gap as the axle bearing can be bumped on/in the axle cup/backing plate easily. But yes a axle coming out of the tube can bend the axle housing and axle shaft, only saw that once and the entire assembly left the axle at 100km and required a complete replacement axle assembly. axle shaft run out is checked by rolling axle shaft on flat surface with flange overhanging edge. If you get it together an alignment will tell you if the axle housing is bent, 0 camber 0 toe
thanks very much for continued replies on this. I detect two possible ways in which the bearing and cup can accommodate this alignment as I tighten down. one is a little bit of angular play in the bearing. the other is that the outer race as not as tight in its cup as the inner race (i'm inferring about the inner race) and can slip a small bit to assist with alignment of bearing and axle housing.
I'm guess it might be smart to tap the outside of the axle with a 3 lb. sledge while tightening to assist that outer race in seeking its most comfortable placement. Jomoka mentions the possibility that if the difference is too much tension would be introduced across the bearing. I'm guessing that the difference I see can be accommodated by the two areas of give mentioned above, but is there a way I would detect tension once the assembly is fully bolted down if I have exceeded the tolerance for adjustment?
It took me a while to find threads and generate feedback on this question. I'm hoping it doesn't really come up that much as this sure seems like a troublesome design to get right in terms of spacers and seal alignment, this flange alignment I'm dealing with, as well as special tools and complexity for R&R. Malcolm99 says he's only seen one instance of this resulting in damage to axle housing. I don't know, have you seen more that were able to be reassembled. To say I was shocked at the failure in which the axle started to walk of the housing would put it mildly. I always used to think doing the bearings and brakes on bigger trucks was a PIA because you had to unbolt the axle from the drum and hum assembly, but the bearings were integral to the drum and hub, not the axle. and never had a chance of losing the wheel. Suddenly, those designs look pretty damn good by comparison (actually IIRC, the toyota duallys are similar to my GMC 5500s.)
I'm fairly sure that all of the bent axle housings I've seen were probably the result of accidents. The first was an e-locker axle my wife got to upgrade her '96. Seemed OK, the axle shafts would go in and out without undue effort. But if you looked down the side of the car you could see some angle difference between the front and rear tires on the driver side. Bad camber on the front? No, it would align to specs, I forget, maybe the alignment shop wasn't checking the rear? Anyhow, after a bunch of years and some shorter than expected rear wheel bearing lifespans, culminating in a broken side gear in the diff (possibly unrelated, since it happened on the passenger side) she decided the axle housing was just bad juju and bought a replacement housing. When that arrive, we did some careful measuring with a flat edge on the housing ends (where the axle bearing bolts on) and discovered it was bent as well. the eBay seller was nice enough to just send us another one when they saw the pics. That one showed up and was straight.
I guess all of the axle housings came from wrecked/totalled vehicles in junkyards. So odds are a couple of them had taken a hit of some sort on a rear wheel. On one of them you could actually see (with a straight edge) where it was bent - in the tube between the outer flange and the center housing, closer to the outer edge. I'm not sure how much of a hit it takes to bend, but with a big wheel/tire on it, there's a lot of leverage. Getting bumped by another car is probably a lot more likely to bend one than some wrenching on it.
And yeah, the non-floating axle design isn't great. One single bearing holding the whole wheel on. No disc brake to act as a failsafe and give you a chance to pull over. No c-clip on the inner end of the axle like some US cars with similar bearing setups. If the bearing gets bad enough, the whole wheel/drum can just walk on out. That happened once to my Dad while we were driving in his 1952(ish) Ford 3/4 ton pickup. One of the rear wheel bearings left the chat and the wheel wandered out about a foot or so from the housing going along a twisty moderately hill country highway. This was bad because it had single circuit brakes, so when the drum on that wheel was out of place, no hydraulic brakes. It was 2WD, so with the axle out of the open diff, no engine braking either. And last but not least, the parking brake on that era of Ford was another mechanical drum brake on the rear of the trans that braked the driveshaft, but like the engine braking, with the rear diff freewheeling, no braking there either. So just coasting along, no way to slow down. Just random chance we weren't at the top of a steep hill or it would have gotten way more exciting.
But at the same time, these rarely ever fail on a 4Runner. They eventually wear out, but they give you plenty of warning, usually. it's only if you persist in ignoring the rumbles will they finally get loose enough to come apart.
If you're really worried about it, open up the wallet and do a full floating axle disc brake conversion on it: https://frontrangeoffroadfab.com/ful...er-conversion/
$739 plus a bunch of stock solid front axle parts you supply yourself.
@Jomoka I guess the c clip on outside end these axles is supposed to be the fail safe if the pressfit on the inside bearing race fails. as you say, you should be reasonably aware before the bearing would fail to the point that the two races part. and i guess the bearings are made to take some side load when cornering. I would imagine that, in general operation driving straight, there shouldn't be much force exerted in or out on the bearing; but, as you say, the 16" wheels aren't light and the higher profile tires you gotta a lot of leverage by the time you get to the outside of the whole setup so I doubt even on an unbent axle that there isn't enough vaguery that these is always a little side tension on the bearing albeit this would increase with toe or camber problem of slightly bent axle. I don't think there is a way with that o-ring seal on the outside end of the axle housing to align the rear tires if they are just a little out of camber or toe. Is there even an alignment procedure for the rear really?
assume your checking of the used housing you bought was putting a straight edge across the two faces on the drivers and passengers side and measuring between the straight edges? and you could do that both in the fore and aft check and flip the axle housing up and check alignment top and bottom as well? My axle housing sure doesn't look like it has been molested. Toyota did the frame replacement a couple years ago and it hasnt' had lots of miles since then. don't know if that gets a check during frame replacement. No sign of accident damage. Mystery to me.
I did try to shock the bearing cup to get better natural alignment given @Malcolm99 pointing out the, in this design, it is actually the outer bearing race that is a little loose vs. inner races that you can just insert through close fit but without pressing on typical dually axles. It was pretty cold out, right around freezing and of course you can't see the bearing with all the spacers and crap but as best I can tell I didn't move it. I did have a stud out of the hub and I put a half inch bolt through the hole and was able to solidly strike the end of the assembly studs after tightening the high nuts a thread and a half at time. when i got it all the way made up and let off it went back to how it was so I don't think I really gained anything as far as moving the outer bearing race. Wheel turns nicely when flange and hub are tightened to one another. might detect just a little more tension/resistance than turning the axle in the finger tight position. I need to take it back anyway and get the spacer reversed apparently it is a military secret that you have to reverse the spacer to hit the new seal design, so the garage didn't reverse it and the seal just barely rides on the spacer (as delineated by the drawing a perpendicular line across the spacer and then bringing the axle in. tightening down and turning it several dozen times and seeing where the seal wipes away the sharpie. it might have sealed but I don't want to risk it. enough friggin trouble already!) so I'm going to ask when he has the spacer popped off to reverse if he could drive the bearing a little deeper if it is not already at the bottom of the cup on the rear side of the axle.
The spacer stack on those rear wheel bearings is a PITA. I can't think of another situation where there are air gaps between the various pressed on items (bearing, ABS tone ring, seal collar). Every other stack like that has spacers where needed, and it all sits tight on the item next to it.
I think it's a recurring thing to have a machine shop replace the bearings (if you don't have a big press at home to do it), and then put them on, and it leaks oil because the seal collar isn't in enough to engage the seal.
I don't know that the collar has to be reversed so much as it just needs to ride far enough in on the shaft. Magic marker works, also some grease, smear that on it and dry fit it, pull it back out and see where the seal got to.
I really don't think there should be any room to seat a bearing any alternative slightly crooked way either on the axle shaft or in the bearing housing. If yours isn't snug, that could be the cause of the issues. Inner shell should be tight on the axle, outer shell should be tight in that bearing housing.
And PS - yes, that was how we tested the new bare axle housing that arrive. Straight edges, held flat against the outer flanges of the axle housing on both sides, measure the gap front vs. rear, top vs. bottom. Should be the same in all directions, and it wasn't. We redid the measurements several times to make sure we were getting consistent reading. There are a few places where you can hold a short straight edge against the axle tubes as well, but the amount of bend there is pretty small and harder to detect. It only takes a little bend in the tube itself.
@Jomoka so i didn't have the other side broken down so couldn't do straight edges off the axle housing flange but with the tires on measuring between I show about 7/8" toe out in the front between the tires and that is coordinate with the 3/32 or so I was seeing putting the axle in at about a 3" radius vs. 12" radius where i'm measure between the tires. deosn't change as i rotate the tire. I'm assuming this is too much for any kind of standard operation. my measuring is rudimentary but accurate enough I think to leads me to suspect there is a small bend here. don't know if it was preexisting and undetected or happened when the axle came apart. it didn't seem that violent when it happened but obviously put some stresses on happening at highway spped.
assume what that means for me right away is i'm going to park the truck where i plow and not drive it too fast or hard anywhere while i look for a new axle housing to throw in in the spring.
the rear end is fine, insofar as I can tell. its high ratio 4WD standard was like 4.55 or more iirc. i'll have to get the code and look again at axle tables. i suppose I could shift the workings over from the axle I have as long as I get the housing for 8". and I either need to source locally so I can go measure or ask anyone i'm buying from to do a demo measure before I go getting the thing.
damn.
Last edited by archibaldtuttle; 12-20-2023 at 10:40 AM.
I'm actually having an easier time finding complete axles at least internet searches, e.g. car-parts.com
So my axle code is B07A which is supposed to be 4:30s and when I do the turn the wheel test, one turn yields ab out 2 and 1/6 turns of the drive shaft. for reason I don't fully comprehend, I think half the motion goes into rotating against the non-turning axle so that does correspond to 4:30.
It is definitely not an e-locker and by the code it is not an auto locker either.
I am finding a lot of standard locker axles available complete at that gear ratio and since I plow, might be a useful upgrade. I assume the OEMs are 'auto'lock. (and I only just mounted the plow. It hasn't been plowed before and has recent frame replacement so I'm not looking to plow service as being responsible for any vagaries in alignment, not to mention that I plow slow with 700 lbs of weight in the back so as not to hit any curbs or obstacles at any kind of speed. Been doing this for years with the older 80s pickups and never had a problem.
wouldn't mind actually an elocker. If that is an upgrade that is available aftermarket. Sounds like it would need a compatible (aftermarket?) housing. On account of the stories of bent housings, that is the one other thought I have. Differential lock or now differential lock, is there a heavier aftermarket axle to consider? OF course all of this will only solve the rear axle and I'll have to take care of the front axle or think about that sometime. I could run smaller wheels and tires on this to try to limit leverage on the axles. It's got big tires (265/75 16s) whereas my old fleet of 80s units has 235/75 15s. The center hole and bolt pattern are the same on my 15 and 16 inch rims.
12-16-2023, 11:06 AM
