bill van snorkle Posted March 11, 2014 Share Posted March 11, 2014 I need to address another piece of poor LandRover design, in that of the outer swivel housing, and was wondering how common the problem of cracking in the 4 stud section at the bottom where the steering arm attaches ? The 4 studs have to cope with tensile stress from the vehicles weight trying to push the steering arm out of the housing, in addition the coping with shear stress from steering loads. After 12 years of running portal reduction boxes on my modified series 2a, my near side outer swivel housing has cracked through from one stud hole out to the swivel seal opening. It has been many decades since series LandRovers were used extensively over long distances on heavily corrugated roads over here, so memories of their many failings have faded with time. Has anyone else, particularly the African members had similar experiences with cracked swivel housings? I have always been aware of the problem of cracked swivel balls, and reinforced mine when I originally made the portal boxes and they have been fine. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted March 11, 2014 Share Posted March 11, 2014 It's never been an issue with the several-million-odd miles experience I've had with Defenders in the UK/Europe. [Though I guess I've always been more involved in issues associated with fully-laden 90TD5s hauling 3-ton twin-axle trailers for 1500 miles at BMW-frightening Autobahn-speeds.] Portal axles are not a LR offering - it's deeply unfair to complain that LR's products fail when subjected to such off-spec usage for more than a decade! Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted March 12, 2014 Author Share Posted March 12, 2014 It's never been an issue with the several-million-odd miles experience I've had with Defenders in the UK/Europe. [Though I guess I've always been more involved in issues associated with fully-laden 90TD5s hauling 3-ton twin-axle trailers for 1500 miles at BMW-frightening Autobahn-speeds.] Portal axles are not a LR offering - it's deeply unfair to complain that LR's products fail when subjected to such off-spec usage for more than a decade! Sorry Tanuki, This is the 'Series' forum, and your Defender experience is not relevant to the question I asked, as Defender swivels are a different design to Series swivels. Defenders have an integrally cast steering arm and the bottom swivel bearing cone seats against and thrusts against the bottom of the swivel housing itself, not attempting to stretch and shear the 4 steering arm studs at the same time, as it does on Series units. Also Autobahn's at breakneck speeds are not the same as hammering over hundreds of miles of corrugated gravel roads at 50-60 mph. My portal conversion has the usual 3rd kingpin and bracing to cope with the additional leverage of the drop boxes. The mode of failure is IMO the result of the vehicles weight applying a stretching/shearing force on the studs, but instead of that occurring, the casting itself is breaking. The poor bit of design I referred to was expecting the 4 studs to cope with both shear and tensile loads. The steering arms should have been fitted to the top of the swivel housing, like on earlier series Ones / Two's ,and Toyota Landcruisers. If it turns out that my swivel failure is an isolated case, then fair enough, but I do recall a number of cases years ago where the bottom mounted steering arms on Series 2A/3's were working very loose on vehicles in north Queensland when I lived there, and that was on 6.00 /7.50 x 16" tyres, and that problem is very close to what I am now addressing. Several million miles ! ? Are you having a lend ? Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 12, 2014 Share Posted March 12, 2014 Truth is: Landrovers were conceived as a UK farm mini truck. They were successful beyond imagining, but the development money never followed the sales. Even in the last few years the Defender was given cast off engines and gearboxes, all the time the focus was cheaper, not better. Shame, but it explains a lot. G. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted March 12, 2014 Share Posted March 12, 2014 Point taken about the differences between Defender and Series swivels - but I still think it a bit mean to complain about the failure of a part which iyou're utilising in a fashion which is outside the original designer's imagining. And yes, several million miles of Defender-experience. Not all personally driven by me - there were a dozen of us working on the project for half a decade, and we had fifteen Defenders in that time so I know quite a lot about their failure-modes even when operated within original LR design-capabilities. Quote Link to comment Share on other sites More sharing options...
Snagger Posted March 12, 2014 Share Posted March 12, 2014 Bill, in over 1/4mil miles, all I had was some slight thinning of those studs which allowed the bottom arm to rotate slightly in relation to the housing, which was resolved with new studs, but no problems with the castings themselves. To be honest, I have never heard of a failure like yours from any of the clubs, forums or mechanics I know. I suspect you have suffered from a combination of fatigue cracking due to the many miles of hammering on rough surfaces and the increased steering loads from the portals and large tyres. I suspect that once you have repaired or replaced the swivel housing, using top mounted steering arms like the older SIIs would allow the bottom studs to deal solely with the weight of the vehicle and and side forces while getting the relatively under-worked top studs to take the steering loads, evening out the forces to more tolerable amounts in the long term. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted March 12, 2014 Share Posted March 12, 2014 S1 had smaller studs than S3 railco, so it's fair to assume one problem caused another, by thinning the casting. Although a cast-in arm of the rangy saved cost, it also feeds that load direct into the swivel housing. So I think it would have been considered a design upgrade over series assemblies. But saying that, I've not heard of a casting cracking on series. Quote Link to comment Share on other sites More sharing options...
Phil Hancock Posted March 12, 2014 Share Posted March 12, 2014 The top mounted arms were also slightly thinner than the bottom mounted arms, if you were to go to top mounted IIRC you would need the opposite hand steering versions or the ball joint eyes would be in the wrong place. Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted March 12, 2014 Author Share Posted March 12, 2014 I already fitted the series 3 trackrod arms to the top years ago to deliberately reverse the Ackerman angle. That is probably why the right hand side hasn't failed. Lacking a left hand drive version of the drag link arm, I left the original on the bottom left, but braced it from the redundant rod end socket to the portal box to relieve the 4 studs of the steering shear forces. Recall reading a factory workshop manual on swivel pin studs years ago that stated " failure to fit the 2 special dowell studs to the bottom will result in PREMATURE failure. Note my emphasis on the word 'premature'. My engineering brain reads this as saying that under certain conditions the studs will fail eventually anyway, but fitting non dowell type studs will speed up their demise. Nice bit of engineering design LandRover ! Quote Link to comment Share on other sites More sharing options...
redneck Posted March 12, 2014 Share Posted March 12, 2014 Shame on Land rover for designing an axle componet that might fail when used in arduous conditions 50 years later, what were they thinking? Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted March 12, 2014 Author Share Posted March 12, 2014 Shame on Land rover for designing an axle componet that might fail when used in arduous conditions 50 years later, what were they thinking? Yes you and Tanuki are correct. They last well enough over the relatively short distances in generally soft ground conditions of jolly old Britain, and it is unkind of me to sling off at the engineering competence of LandRover designers who consistently get everything so very right ! There was a question in the title and text of the thread. ( How common are cracked swivels? ). Some of you seemed to have ignored it. So how about you ignore the thread altogether ? Quote Link to comment Share on other sites More sharing options...
redneck Posted March 12, 2014 Share Posted March 12, 2014 I'm quite happy to highlight the inadequacies of land rover engineers, and there are plenty of opportunities to do so, but in this case probably not. As requested I shall leave your thread in peace now. Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted March 13, 2014 Author Share Posted March 13, 2014 For anyone that is still interested, the swivel housing that I have cracked is from a Stage One V8, and just now when comparing it to a normal series 3 casting that I was intending to replace it with, the flange surrounding the swivel seal register,is appreciably thicker and a bit larger in diameter,and the stub axle (spindle)mounting area is also thicker, in addition to being a bit tougher to drill when opening up the bolt holes for larger bolts. For LandRover of all company's to make those changes, cynical mean old me thinks there was a likelyhood that feedback from around the world suggested the original castings weren't quite strong enough under some conditions. Quote Link to comment Share on other sites More sharing options...
Gazzar Posted March 13, 2014 Share Posted March 13, 2014 Well, I don't know about that, but the S1V8 was designed for the CV joints, which, I think, are bigger - so, being an even bigger cynic, I'd suggest LR ignored any reports from around the world and just built it bigger because they couldn't be bothered to do some engineering calculations. G. Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted March 13, 2014 Share Posted March 13, 2014 Hehe yeah Bill us Northern Europeans probably haven't got the slightest idea what sort of fatigue rough roads year after year does to things. Heck every fourth year the Danish Land Rover Club hosts a trip to Iceland for a month and even VERY well prepped and cared for vehicles has the weirdest failures that we rarely, if ever see in Denmark. Mostly around the suspension components, and seeing as all the axle components is before the suspension one would think they live an even harder life. In general I don't think anything surrounding the design of the axlecasing/swivelhousing area really leaves much to be desired on Land Rovers, for what I see they are the strongest design around. Loosing a wheel for any reason other than wheel nuts working loose are extremely uncommon in Denmark, however seen much more often on Japanese 4x4s. This is only as seen through my narrow line of sight mind you, so don't any of you get all wound up if you disagree, it's just my experience. The only problem I have had with the Series swivel housings is those four bottom studs working loose in the housing. It was on a Series II I had, and the thread was very coarse. But on the Series III housing I have on my 80" they are a fine thread, so maybe an upgrade? Quote Link to comment Share on other sites More sharing options...
Snagger Posted March 13, 2014 Share Posted March 13, 2014 I know you disagree with me over the Ackerman issue on steering feel, forces and turn radius, but do you thing reversing the angle could have caused side loads on the castings that contributed, in addition to the leverage from the portals, to their failure? My mental picture of the forces makes me think that they are major contributors. I don't think there was anything wrong with the housing design - I have never heard of any other failure, and many engineering companies have disc brake conversions that require removal or material from these castings without any reported failures. I think this is an issue related to modifications, like I have suffered on other issues, rather than a design flaw. Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted March 13, 2014 Author Share Posted March 13, 2014 Well, I don't know about that, but the S1V8 was designed for the CV joints, which, I think, are bigger - so, being an even bigger cynic, I'd suggest LR ignored any reports from around the world and just built it bigger because they couldn't be bothered to do some engineering calculations. G. Well they mainly built them thicker in places, but more or less interchangeable with earlier ones. On inspecting an undamaged casting there is a noticeable lack of detail finishing work that can really only be done by hand, to reduce stress concentrators that IMO certainly didn't help to prevent cracks from starting at the exit of the threaded stud holes and out to the sharpish corner of the swivel seal abutment. The little 1/4'' bsf drain plug hole drilled almost through to one of the steering arm stud holes doesn't help either. The Stage Ones, having slightly wider spaced swivel bearings also required metal to be removed from the bottom of the casting to provide clearance for the bearing cone, but counter boring this area has removed far more metal than necessary and left another sharp edge between the threaded stud holes and the swivel pin bore. If I use a normal series 3 casting I think I can sort most of those issues by dressing all the stress concentrators with a die grinder, like I successfully do with CV joints to improve their durability. I will also make a thicker swivel seal retaining plate to make that area more rigid, and re tap the stud holes out to M10 and use 4 dowelled bolts in place of the 7/16" BSF studs. BtW, My earlier posts may have mistakenly given the impression that I regularly "hammer my vehicle over hudreds of miles on corrugated roads at 50-60 mph. That isn't so. I gave that example to Tenuki to illustrate the difference between driving at speed on autobahns verses what 4wds are expected to do on outback Australian roads. My vehicle in the past 12 years has almost exclusively been operated at relatively low speeds in extremely twisty terrain, or used as a substitute tractor around my bush property. In fact I can't recall ever severely bottoming the front suspension on its bump stops. About the only time the bump stop come into play is during articulation. The extra leverage that the portal boxes would apply to the casting has been compensated for with a 2nd botton king pin bearing on an adjustable strut running to the axle housing and various other bolt on bracing to prevent relative movement between the portals and the casting, in addition to fitting the steering arms to the top and having heavily back spaced wheel rims. The reversed steering arms Snagger, actually gives very close to parallel steering on my truck, so I don't see an influence there either. Quote Link to comment Share on other sites More sharing options...
aaronledwidge Posted March 14, 2014 Share Posted March 14, 2014 Bill do you want to pop some pice up of your setup? It sounds interesting and would remove a lot of the speculation. In relation to your failure mode it's not one that I have heard of before. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted March 14, 2014 Share Posted March 14, 2014 When you get down to it, you have to say that the Dana style D2 axel rectifies most of problems of a 1948 landy by being a lot simpler at the king pin. But having a 1958 S1 and a 1972 RRC buggy I'd say it's the coil suspension that is the biggest stress reliever on the swivel housings. Although the unsprung weight is about the same, it seems to fight the terrain less on the coiler? Either way up, I'm thinking that the extended third bearing must have some flex in it, as the original lower bearing should now be the neutral piggy-in-the-middle? The lions share being on the OE top bearing and your new lower portal box one? Quote Link to comment Share on other sites More sharing options...
Snagger Posted March 14, 2014 Share Posted March 14, 2014 The thing is, Bill, that the front axles are built to one spec regardless of wheel base, which suggests the Ackerman angle is under-done on an 88" and overdone on a 109. When you increase track, the Ackerman angle should be increased. So, you have started with too small an angle, exacerbated it by having the portals and wider wheels, and then compounded it further by reversing the angle, albeit to nearly parallel. For the axle setup you have, the angles should eb quite pronounced, and any time you are steering your wheels are being pinched together at the bottom because of this. With the leverage of the portals, the forces on the swivel pins and surrounding areas will be vastly more than the side loads normally imparted. I think that is what has cause your problems. I'm no trained engineer, and I don't have your fabrication skills, but I can picture the forces incurred on highly tractive surfaces and it's not pretty... Quote Link to comment Share on other sites More sharing options...
Phil Hancock Posted March 14, 2014 Share Posted March 14, 2014 S1 = 3/8"BSF S3 = 7/16"BSF Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted March 14, 2014 Author Share Posted March 14, 2014 S1 = 3/8"BSF S3 = 7/16"BSF S1 = steering arm on top of swivel housing = studs subjected only to shear forces. S3 = steering on bottom of swivel housing = studs subjected to both shear and tensile forces. I'm afraid I can't show a pic of the broken swivel, because I have cut the swivel seal flange off it, with which to make the thicker oil seal retainer. The more I study the remains of the Stage One casting and compare it with a normal series 3 casting, the more I am becoming convinced that it was the machining to accomadate the wider spaced swivel bearings, and the slack machining tolerance, making the king pin bore 0.020" oversize that has weakened the casting, and due to the low production numbers of Stage Ones,why this kind of failure is rare. It is a truly evil piece of engineering IMO. Ten minutes work with a die grinder, and I have managed to clearance the normal series 3 casting without removing metal from the critical area around the 2 inner stud holes from where the cracks propagated from. This section is now 2mm thicker than on the Stage One casting and I've smoothed out the inner ends of the threaded holes. I think this detail work will likely do the trick and the swivels will likely outlast me. At any rate I likely won't be phaffing about with LandRovers in 12 years time at age 76. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted March 14, 2014 Share Posted March 14, 2014 ....... At any rate I likely won't be phaffing about with LandRovers in 12 years time at age 76. ...... yeah you will, just a little slower Quote Link to comment Share on other sites More sharing options...
bill van snorkle Posted March 15, 2014 Author Share Posted March 15, 2014 ....... At any rate I likely won't be phaffing about with LandRovers in 12 years time at age 76. ...... yeah you will, just a little slower I would need to fit an extra/extra crawler box to the truck to drive any slower than I have been and presently do. Snagger,when I study the complete swivel assembly and imagine the stress path from the vehicles corner weight acting upon the bottom swivel pin, due to king pin inclination alone, I see additional shear forces being applied to the steering arm studs in addition to the shear forces from steering push and pull. Further more I see the bottom swivel pin subjected to far greater loads than the top one, even without portals. In fact, when I remove my top swivel pin altogether, I can't rock the road wheel at all, due to \the extra support that the 3rd king pin provides. Additionally, the outer 2 swivel pin studs are linked to the portal box by a stiffening bracket, which also prevent the studs from stretching over time. The nature of and direction of the break certainly suggests it is the shear forces applied by the steering arm that is the cause of my issues, and that the crack had already started before I made and fitted the stiffening rod from the redundant trackrod end socket of the steering arm to the portal box. Because I am pants at posting pics here, I will ask Michele or O'teunico to transfer the photo of my assembly from my facebook page to here, so that you can see the extra bracing I fitted to compensate for the extra leverage of the portals and larger tyres. Quote Link to comment Share on other sites More sharing options...
Michele Posted March 15, 2014 Share Posted March 15, 2014 Here're four pics from Mr. Bill with his own notes From left to right: 1. View from front of portal/swivel housing assembly and showing extra kingpin strut. 2. Worms eye view of steering arm stiffening rod and stiffening bracket from portal box to bottom swivel pin. 3. At right of photo, stiffening rod from steering arm to portal box. 4. Ear welded onto swivel ball and axle housing flange to prevent torque from loosening or shearing off the 6 flange bolts. Some may notice the double thickness swivel ball flange. Quote Link to comment Share on other sites More sharing options...
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