 | Home > Technical > Puma rear axle casing negative camber - factory tolerance? |
 
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| Shroppy Member Since: 25 Feb 2016 Location: Shropshire Posts: 848   
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Dinnu - Yes a very interesting video, gives me some faith that I'll be able to straighten mine! The amount of weld required on that casing was worrying, though I dare say the wall thickness is probably twice that of our LR casings.
DSC - Good spot, the base plate for the diff cover is currently only tacked in place. I've left it as such as I was hesitant to complete the welding until I was sure the casing could be straightened. The axle certainly didn't spring back, or at-least the grinder cut hasn't opened up by a discernible amount. This makes me confident that my welding for the truss didn't warp the casing and the 'bend' was probably there from factory. I think I'll be able to weld the diff cover baseplate on without warping the casing if I apply the same methodology as I did on the front - zig-zag around doing short welds being careful not to overheat one spot. 1985 127 V8 Build Thread Series 2 109" Series 1 80" |
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14th Jan 2021 4:09pm |
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| Retroanaconda Member Since: 04 Jan 2012 Location: Scotland Posts: 2547 
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Would a decent jack and some chain not allow you to just tweak the casing straight?
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14th Jan 2021 4:12pm |
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| Shroppy Member Since: 25 Feb 2016 Location: Shropshire Posts: 848
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Well that didn't go as planned;
 Click image to enlarge Plenty of weld and it moved maybe 0.5-1mm. B*under. So my options are; - Grind back and re-weld at full whack (on 270amp MIG) with 1.0mm wire (was using 0.8mm). - Grind back and borrow/hire/buy oxy-acetylene or oxy-propane equipment. - Try the jack method, though not quite sure how I'd do that effectively.... 1985 127 V8 Build Thread Series 2 109" Series 1 80" |
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14th Jan 2021 7:57pm |
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| Shroppy Member Since: 25 Feb 2016 Location: Shropshire Posts: 848
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I suppose another option is to buy another casing, I really don't want to do that given the money and time already in this one....
A consideration I have just had though, perhaps my welds were a bit short and need to wrap around the casing a little more to have a greater effect? Given the lockdown, I'll grind the welds back tomorrow, switch to 1.0mm wire and give it some beans. If that doesn't work I'll seek out some oxy-acetylene. 1985 127 V8 Build Thread Series 2 109" Series 1 80" |
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14th Jan 2021 10:04pm |
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| Dinnu Member Since: 24 Dec 2019 Location: Lija Posts: 3203  
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Not sure if it is a reasonable option, but maybe can slit it, straighten and then re weld back. I think if you v shape the cut, you can weld the whole thickness. Something I would be hesitant to do, but better than simply give up and chuck it away. 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black |
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15th Jan 2021 9:06am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16870 
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If the axle deformed as you welded the truss in place (I don't know if you welded in a single session or let it cool between welds) I wonder if you have managed to weld in a uniform bend along the length of the truss, effectively making the long side of the axle a curve. This would account for the failure of the cut in the truss to open up, and might also account for the apparent lack of success pulling it straight at a single point.
A (non-Salisbury) Landrover axle it is a fairly difficult shape to measure accurately, since generally you don't have access to the centreline of the diff carrier bearings, however the fact that you have the bolt-on cover should let you run a plumb line from side to side to side and check it passes through the centre of the diff bearings. In reality it doesn't matter if the axle tube is bent provided that there is a true centreline that passes through the exact centre of both flanges and both diff bearings, and the the two flanges and the diff bearings are exactly perpendicular in both axes to the centreline. |
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15th Jan 2021 11:01am |
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| familymad Member Since: 13 Dec 2011 Location: Bucks Posts: 3463  
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This is a great read and an area I am totally new to! 1951 80" S1 2.0
1995 110 300TDI 1995 90 300TDI |
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15th Jan 2021 11:42am |
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| Dinnu Member Since: 24 Dec 2019 Location: Lija Posts: 3203
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I think in such a situation, stub axle / hub could be at an angle and can cause the driving member and shaft splines to wear faster. Edit: I read to fast... indeed hubs need to be as perpendicular as possible on a rear axle. I think front axle is more forgiving having cv joints to compensate. 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing 2012 90 CSW, 2.2TDCI, Santorini Black |
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15th Jan 2021 1:01pm |
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| Shroppy Member Since: 25 Feb 2016 Location: Shropshire Posts: 848
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To answer a few points;
- I let everything cool between welding up the truss, I've checked the casing as best I can with a straight edge and I'm fairly confident I didn't make it banana shaped. - Agreed, the casing could in theory resemble a curly wurly providing the key points remained parallel and the casing itself didn't interfere with the halfshafts. I tried again this evening and have had no success, I even cut through the truss in a second place. I had the area up to 650-700°C so according to that BOC article should have seen something...
I've unearthed length of RSJ so may try jacking it as a last ditch attempt but in truth don't think ill be sufficiently happy to use it on my 127. So I'm now pondering the following; Option 1 - Find another post 2002 110/130 casing and check it a million times before doing anything. Option 2 - Find a Salisbury disc axle and use that, though to be honest I already have a ruck of new parts to suit the above. Option 3 - Find a Wolf rear axle. Its all a learnin experience and ultimately I should have checked the casing over much more thoroughly before I started welding! 1985 127 V8 Build Thread Series 2 109" Series 1 80" |
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15th Jan 2021 7:18pm |
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| DSC-off Member Since: 16 Oct 2014 Location: North East Posts: 1351 
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Regarding option 3) Wolf axle.
The Wolf XD (110/130) axle case has a truss fitted to the lower side. The truss is a single piece running the full length of the axle. Most interesting though is it wraps the front and back to within a few mm of the centre line welds, and is stitch welded very close to the centre line of the axle. This is probably the best solution for adding a truss and minimising the distortion. Best picture I could find, Click image to enlarge |
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16th Jan 2021 1:23pm |
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| Shroppy Member Since: 25 Feb 2016 Location: Shropshire Posts: 848
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Well, option 1 is now underway:
Click image to enlarge Replacement puma casing delivered today by a good friend along with a replacement set of trusses from Nige @ 4x4Xcess. The trailing arm/tie rod brackets are well and truly spannered so I have a new set of HD (6mm) ones on order and hope to make a start this weekend. The most important bit.... it seems to be straight to within about 0.5mm which I'm happy with.  1985 127 V8 Build Thread
Series 2 109" Series 1 80" |
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10th Feb 2021 11:58pm |
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| Shroppy Member Since: 25 Feb 2016 Location: Shropshire Posts: 848
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I wonder if anyone has any thoughts on trailing arm bracket placement? I'm in the process of fitting new ones, before chopping the old ones off I took a number of measurements and compared them against the bent casing. Guess what? They don't match up.
I understand that the measurement shown in green is crucial as that is what determines whether the axle is centred between the chassis rails or not. I am reasonably happy with this dimension but will do a dry assembly before final welding. Click image to enlarge The rotation indicated by the red arrow is where I'm scratching my head a bit. I understand the implications of rotating it one way or tother, but frustratingly the axles didn't match up in this respect. If I replicate the position as it is on the bent casing, the protruding edge of the bracket is hard up against the weld on the casing (as per the photograph) whereas, I'm minded to think that the weld should be broadly centred in the scalloped portion of the bracket. Of course, the replacement bracket is not quite like for like either. How much difference will it make? Well, it will impact the propshaft angle and if I run a huge lift (which I won't be) then I guess the trailing arms could foul the brackets. The amount of rotation is limited by the size of the scalloped portion but there is too much ambiguity for my liking. Any thoughts? 1985 127 V8 Build Thread Series 2 109" Series 1 80" |
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25th Feb 2021 7:36pm |
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| htb2 Member Since: 02 Nov 2018 Location: aberdeenshire Posts: 509
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Personally would rotate brackets upwards towards torch as less like to foul radius arms on articulation, just make both sides the same. Axle centralisation is mainly by the A frame, radius arms are secondry only stop axle going back and forward. Think of a Disco 2 centralisation by watts linkage.
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25th Feb 2021 8:57pm |
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| Shroppy Member Since: 25 Feb 2016 Location: Shropshire Posts: 848
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Agreed, the profile of the bracket fits the casing better if rotated towards the torch too. Will cut the tacks tomorrow, re-tack and offer it up to the chassis. 1985 127 V8 Build Thread
Series 2 109" Series 1 80" |
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25th Feb 2021 9:36pm |
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