Just when you thought all was going smoothly, something comes up to spoil your day. Yesterday, while the operator was working, all of a sudden a creaking sound started coming off the machine. (volvo Bl71) At first I thought some serious greasing needs to be done although it's just been greased 5 days ago but the operator stopped the machine when he got down the slope, lowered the stabilizers and crawled under the machine. I was still a few good metres away and I thought either his lunch pack is under the wheel arch or he's found a gold nugget. By the time I got next to the volvo, he asked me to get under there to check something out. As you can see on the photos, the wheel hub is leaking. I took the wheel out and tried to get the hub off to have a look inside what's happening. I'm hoping it's just the seal and not the bearing that's gone bad. The allen bolt won't budge. Allen key even snapped. Any suggestions how to get it off and what do you think is the cause of the leakage? The hub felt very hot and won't turn by hand when i took off the wheel. Please tell me the great squeaky noise was not the bearing going square inside.:Banghead As usual, thanks for your advice and opinions Spangles
Couple three choices here, you can use a sharp narrow chisel to try turning the head of that flathead bolt, if you have a torch handy a bit of heat on the bolt head and then the chisel may loosen it, or with a carbide drill bit or the like drill a small hole all the way through the bolt, then heat it through the center with a torch. Or, you can use a larger drill bit and just drill the head off, the bit just needs to be a hair larger than the thread diameter. Does seem to indicate a bearing let go, sorry.
I'd try a hand impact driver before taking a chisel to it. Might just get lucky. Greyson
Excellent suggestion. :notworthy I keep one right next to the hex drivers in my tool chest, but use it so seldom I clean forgot about it. Of course not everybody has one handy, but they're relatively inexpensive.
Yair . . . I know nothing of this machine but I'll poke my nose in anyway. Unfortunately for the poster there may be something more than "a bearing going square" behind that housing . . . it could be a basic planetary hub maybe? The little socket headed capscrew (I think) is a locator to ensure the hub goes on in the correct orientation and I am sure would succumb to heating cherry red with a welding tip and then allowed to cool out. The whole concept of the poster's operation seems strange with the operational/compaction issues discussed and now his mention of greasing "just five days ago" being adequate . . . I would put it to him that he should try greasing a few pumps every shift. Just some thoughts from an outsider looking in. Cheers.
Yep, gotta be outboard planetary hub, there should be two of those little flat head bolts to hold it together until you tighten all the wheel nuts/bolts. Could be just a bearing, could look like a grenade went off inside, place yer bets....
Since you're going to take it apart... Remove the oil fill plug on the front. Drain the hub. If you see a bunch of metal particles ... You're fore warned
Heat "around" that bolt, not on it, and it should turn out.
:iagree Had the same problem with flat headed allen bolts on old Dresser finals. Put them in just nice and snug and then when needing to remove them they would not budge. Like Scrub says heat up red and let cool then they come out easy. Also as I have often said I like to see a machine greased at the end of shift each day to flush out the crap that gets in during the day. Also make the grease flow better when things are warm when running in cold weather.
From past experience with these kind of bolts, flat headed Allens, I would respectfully disagree. I have found that heating just the head allows the head to deform slightly releasing the tension on the bolt. It actually will sometimes cause the hole in the head for the Allen wrench to close up enough that you have to tap the wrench in it. I suggest the poster try it on just one bolt and report back how it worked.
Indeed, a sharp narrow chisel did the job and took quite a few blows on both bolts to move them out enough to be able to use the allen key.
Well done. Now.... don't keep us on pins and needles man, what did you find in there? :cool2
well it's not pretty from the photos, you can see the damage done. I was not able to pinpoint how or why it happened.
Second set of photos The hub was very difficult to remove.
The worst situation possible. Hub, gears, seals, bearings etc would have been fine to order new but the axle casing being damaged that much leaves me speechless. I've checked the price for a new one and at 2000 Euros alone for the axle casing, it's way out of my budget. Scrub Puller The machine is pressure washed and greased every Saturday. We're not working in a quarry, nor using the hammer. Greasing once a week should be adequate for what we're doing at the moment, i.e, trenching, moving materials, levelling, grading and laying down rocks as a base for a new road that goes up the mountain slope. lantraxco Spot on mate. A grenade indeed went off inside. Came across this kind of damage before? hosspuller More than an inch and half of metal filings clinging to the drain plug when I got it out. thanks for your advice and opinions Spangles
Hub, gears, seals, bearings etc would have been fine to order new but the axle casing being damaged that much leaves me speechless. I've checked the price for a new one and at 2000 Euros alone for the axle casing, it's way out of my budget.
Don't despair yet. Take the axle casting around to a few shops. Welding & remachining or sleeves may be able to repair the damage. I've see greater damage on shafts repaired. The key is the break point between the repair and a new or "used" axle.
I feel for you, that is indeed a sad sight. My experience is mostly excavators and track dumps, but I have seen very similar cases. You'll probably never know for sure what the cause was, was there any oil left in it? It looks to me like the inner bearing let go and started throwing metal out through the outer bearing and into the gears, along with the cage from the outer bearing. Is that a seal on the inside of the housing that seals the stub shaft or are my eyes deceiving me? If it is, then the hub seal probably started seeping and the hub ran out of oil a while back? Doesn't really matter, it's all knackered save the outer case. That axle housing should be repairable in place, I have had truck drive axle housing spindles that broke off and we had a company machine cut what was left square and true, made a new spindle tube, welded it onto the old housing and then machined the inside and outside back to original spec. Machine it down, weld it back, machine it to finished size. When you pull the other side off to inspect it and the hub bearings the repair company can get the measurements they need off of it. Sort of a reverse line bore setup. Company over here is a franchise called Axlemaster. I have actually seen cases like this ground down, built up with bronze rod and filed until the bearings fit, poor folks, as they say, have poor ways, we do what we must. Not like it's going round the racing track.
Spangles, All I can say is ouch!:OMG Have you looked to see if there might be any used parts available???
I've contacted a two shops here and awaiting a quote. A sleeve would have been ideal as it would be so much faster and probably cost less but I doubt they offer this here. Anyhow, when the quotes come back, I'll ask if it can be sleeved instead of welding and machining.
It is indeed a sad sight. My heart sank when I saw what sort of damages the bearings did on that drive axle. I'm still pissed off how that sort of thing could have happened. The hub seal was seeping very little oil and it dripped from the back. There was plenty of oil left when the plug was removed. Approx 0.4 litres was collected. If you don't mind me asking, would bronze rod be the best material to use to build it up?
I've emailed a company in South Africa where they break up volvo BL 71 and waiting for a quote from them.
I hope you have made plans to remove the other wheel !!!!!! Is the operator you have on it the only one that runs it ? That damage didn`t happen overnight. If he is the only operator, you problem goes further than what you now have. You may also want to service the rest of the machine oil compartments not checked on a regulr basis, like the trns, hydraulic.
If it's going to be machined back to spec then more likely weld up with steel. Some machine shops will use a bronze alloy, it's not as strong as steel but works well when the exact material spec of the housing is not known and requires less heat to apply. Judgement call.
I have to agree with GregD1, everything that shares oil with this compartment needs to be disassembled, cleaned and inspected. To try to save a few coins now will only cost you more down the road. And like lantraxco says there are a few ways to go with the repair. Hopefully one of the shops can give you some options. Might even pay to check with dealer to see if factory has a repair option. I recall having a similar failure on a 35 ton off road truck and back then we were able to purchase the end of the axle and AirArc the old one off then push the new one in and clamp with long piece of all-thread and weld it up, just like new.
Gentlemen The parts have arrive and it's lego time. I'm trying to fit as much as possible before calling in expert help for the final assembly. As you can see, I'm putting together the planetary gears. There are 62 bearings per gear. Not as hard as I thought it would be to drop the bearings into place. Sorry if it's a stupid question but should I apply some grease to the bearings? Also I've noticed all the gears have a shiny part. Should the shiny part face up and is it used as a guide to make it easy to fit the shaft? Many thanks for your help Spangles
I always use a thick grease with needles or rollers, helps keep them in line while you're pushing them in. I believe the shiny part of the gear is supposed to ride against #5 which is a thrust washer? Just a guess.
Ahh I see...indeed that would have made much more sense and take less time than try to drop each bearing in carefully. Hmm the shiny part of the gear is not levelled....it feels like an angle grinder been applied to it as it's a slight dip towards the centre of the gear. Number 5 is a thrust washer. The gears are the same either side except for the shiny part on one side. I've tried with the shiny part facing down and it does not make any difference at all. The gear still rotates freely. Trying to look it up online and there's no mention of this at all. That's baffling! :/
I just had a look on the old set of gears. There's no marks/shiny part whatsoever on either side. So I guess it's just used as a guide to line the gear up for the shaft cause i'm guessing when it will be fitting time, that's going to be one hell of a fiddly fit.
From the viewpoint of a mechanic, your oil level was too low to get grease splashed into the hub bearing that failed. And from looking at the fill plug, it looks like it didn't get too much attention. I wish you luck on the repair. It looks expensive. Howard
Hello Howard, yes all the parts that had to be replaced did come to a shocking amount. When the oil plug was removed, the oil level was correct - it was the bearing on the axle stub that failed and the bearings chewed on the axle stub before they made their way into the planetery drive gears, shaft, causing more damage etc. I've been putting together the planetary drive gears and everything was going alright till one of the gears will simply not allow the top bearings to be fitted. Forcing a few in and spinning the drive gear only results in the gear lifting itself up or the bearings lifting themselves out partly. Got a digital vernier caliper and checked the inside diameter and it turns out there's 0.5mm less than the other gears. Should I attempt to sand it down a little or is that a bad idea? Spangles
I would talk with your part supplier first before doing your own bootleg machining, But sanding accurately might be difficult. Howard
Send it back, it's manufactured incorrectly. .5 mm would be about ten thousandths of an inch of material to remove all around, that's a lot of metal. Worst case have a machine shop correct it with an internal grinding machine.
You're right, with tolerances measured in the mm or inches depending where you're from, I don't think sanding would be a good idea or within my skills. Sending the part back and waiting for a new one to arrive will take another 15 days...Perhaps a machining shop can sort that out for me. Ever had that sort of problem before Howard? I'll speak to the supplier tomorrow and see what they say. Spangles
Hello lantraxco how are you? I'll give the machining shop a ring tomorrow and ask how much they'd charge for that sort of correction. If it's not a big deal, i'll get it done, if it is too much then i'll get the supplier to send me a new one. Spangles
I have seen parts poorly machined in every possible dimension and in every possible way. There are two buddies of mine who always drink free, my welder and my machinist! Having the part repaired locally might be fine, but what about the heat treat and surface finish? Howard
True...it's what I knew deep down but did not want to hear it. New replacement part it will be from the supplier then. Spangles
Another thing you can't guarantee regarding the reduced internal diameter of the gear is whether or not the bearing bore is actually concentric with the pitch circle of the teeth on the outside...? They got the final bore diameter wrong, what else did they get wrong..? One would expect the concentricity to be OK (just missing a few thousandths of internal diameter) but you have no way of guaranteeing it. If it was mine I'd be telling the parts supplier to "send me another one FOC, this one's fcuked" ......
:iagree
I have heard that "freezing" a bearing is sometimes needed to have them fit, just a thought.
That would be for bushings, not needle rollers.....
Well thank you for the added infos that I'll be saying to the supplier. I guess this issue illustrates and serves as an example for parts that don't 'fit' and instead of trying to 'fix', it should be replaced with a new one to avoid unnecessary headache later on.
That did cross my mind, but once it expands back to normal size, there's no way that drive gear would have spun freely, be stuck in there and most likely would have caused damage.
Nope, bearings are "frozen" also, look it up. "Spangles", as suggested by others, I wouldn't "modify" a bearing, get another one, but my guess would be that it will be the same, you need very tight tolerances there, keep that in mind also.
The needle bearings you mean? It's not the bearing that would have been modified, but the drive gear. Two of the drive gears spin freely with all the needle bearings put in place, it's only the third drive gear that's not cooperating and i agree there needs to be very tight tolerances between drive gear and needle bearings but this one is definitely too tight that it's not possible to fit the needle bearings. Freezing the needle bearings? These suckers are never going to come out again and that drive gear will not spin freely.
What we have is that the interior of the drive gear forms the OUTER race of the roller bearings, NOT needle bearings. What they did was to combine the gear component with the outer race component, and we want different surface finish and heat treat for the teeth (shock resistance and toughness), but a very hard surface for the race. I would do it with a case hardening to give both toughness to the structure and wear resistance. To machine that surface required and interior grind machine operation. To anneal, machine and reheat treat is a tough job for a small shop. They normally do not have heat treat furnaces. Howard
Got it. I must have read this wrong, and wasn't aware the needles were separate.
Actually the correct term in uncaged roller bearings. I had a Russian mechanical design professor who pounded bearings and gears into us. It is actually a pretty good design to maximize roller bearing area while keeping the planetary ratios where they want them to be. Howard
I know it's a pain, but you're not the first person to experience new parts not fitting correctly due to whatever reason and I doubt you'll be the last ....... what makes it difficult for you is the distance that separates you and your parts supplier. It's not like you can jump into the pickup and drive back to their place and ask for a replacement.
The supplier is in Poland. It's been a long time since the backhoe loader broke down....the axle stub got machined and is looking as good as new. Now I just need to be a little bit patient and get all the parts fit just right.
I can see that where the bearing has an external race or cage, have done it myself withed Torrington caged needles, but loose rollers if they're that tight I don't think it would end well. Just my opinion of course.
Well how strange is that....the supplier sends back email saying they've checked a few of the drive gear and all seem fine and that i should turn the drive gear while putting in the needle bearings so that they fall in place. Doh...that's how I've been doing it and I fail to see how checking a few of their stock is going to replicate a faulty drive gear sent to me :/
Yep, logic: "Ours are fine, so yours must be as well." Idgits.
Tell me about it...checking a few of theirs apparently is good enough to say what they sent over is fine. The manufacturer is Carraro. Urgh I again replied saying that the top layer of the needle bearings don't fit and what problems it's causing etc and yes I did fit the needle bearings while turning the drive gear so that they fall in place and asked them how they want to proceed next. if they insist mine should be fine, I'll get an engineer's report and send it over.
There are 3 planetary gears, two of which have a correct internal diameter for the bearings and the 3rd which is undersize, correct..? Measure the I/D of all 3 gears and send it to the supplier.
This has already been sent. I have a basic digital vernier caliper to take the internal diameter measurements at a maximum of 1 cm from the edge. The difference noted should be enough but it seems they have their own way of 'checking' things.
Sounds like it missed the finish grind, not only undersize but still out of round.
Makes me wonder how the machine missed the finish grind and I thought they'd check each and every gear they manufacture. No wonder something goes bust in heavy equipments and gets people scratching their heads wondering how the ***** that happened. At last the supplier has put a new one in the post and hopefully I should receive it within 5 days, according to the tnt tracking status. Not holding my breath though as in the past, they have not been always been on time. At least it's been sorted and I suppose they must have fitted all the needle bearings and made sure all is fine before sending it over.
Got my fingers crossed that the next one is good to go. Always sucks when you wait for parts then when you think they are all in and ready to go you find one with a problem like this one.
In my opinion, these problems are par for the course and to be expected. The parts vendor expect us to do their quality control. If I look at my experience with "rebuilt" components sold by our friendly local auto part stores, (FLAPS), I expect a 40% failure rate upon installation! Try building THAT into cost and delivery estimates. Howard
Snafu
Hello everyone, Supplier sent me a new gear and it fitted like a glove. The faulty one will serve a life of paperweight i'm afraid. Today I went with the mech to put back the axle casing and raise the axle up to bolt it to the frame. It's seriously not easy work when machine is stranded on site. After 4 hrs of struggling and making sure nothing gets damaged, it's finally up. Phew! 2 Bottle jacks and one chain block to get it into position. Planetary gear all assembled and ready to go. Next one to go in is the wheel hub but it has to be assembled first so we'll do that tomorrow. Has anyone done this ? any advice or tips to make everything fit smoothly? So close now to getting this sorted....fingers crossed!!! Many thanks for your help Spangles
Glad to hear the new gear solved at least that problem. Can not offer much advise other than take your time and think before doing anything. Is there an adjustment procedure for the hub bearings? Shims or spacer, hard to see in the picture. Well, if you and test fit the bearings on the axle before putting them in the hub, that might save a headache or two. OH! and count the fingers when done to make sure they are all still where they belong!
I did count fingers when done but a knuckle got smashed. Thanfully not mine...mechanic had grease on the hammer head and it just glanced when he struck and went straight on his left hand knuckle. That kinda shook him up a bit.... That will teach him to listen to me when I say to use a piece of wood and not hit on the metal. The fit was a bit tricky. The wheel hub went in fine, then the planetary gear. one part somehow got left out and we had to remove the axle casing again to fit that part...that kinda made us lose at least two hours. Other than that, I got to say it went quite alright. Took all day...from 10am to 17.30 Fitted both wheels and did a test while both wheel raised on 4th gear to make sure everything turns fine without any weird/funny noise. Handbrake tested & foot brake as well. I still got a few nuts to fit onto the wheels as they came out with the studs. letting them soak in wd40 a bit before removing them. As soon as i'll get these last few nuts back on, I'll get the operator to move it from site and see how things goes. Speaking of wd40, has anyone tried this? https://www.youtube.com/watch?v=2WuVBFTzoKc Automatic Transmission Fluid and Acetone and mix them together in a 50/50 ratio Many thanks to all who helped. The combined experience on this forum is more than any dealer or mech workshop can ever provide. Spangles.