Snagger

I get the analogy - it's like a pedal cycle: while in theory, the cyclist can only apply so much torque on the crank shaft and front sprocket (input pinion), the reality is that a lower total gearing results in rapid enough acceleration that the cyclist can't keep up with the torque demand, so the forces in the crank and front sprocket are not the cyclist's maximum. It's on the velodrome cycles with the fixed high gear and painfully slow acceleration where the cyclist's maximum force is transmitted through the crank, sprocket and chain because the wheel can't keep up, so those parts get a hammering and chains often snap. It'll be a shame to lose the quieter cruise and 10% fuel saving, but what's the point in that if I keep blowing transmissions - that's more costly than 10% more fuel and a damned sight more inconvenient! It'd be nice to know if the 4.1s would work, but it seems risky. Yet again, though, it's a mod that lots of people run successfully but causes me trouble, even though the vehicle gets good maintenance and is driven sympathetically. God hates me!

Yeah - £1500 in the mid 90s, so about £2200 by current value, for a pile of scrap; it also had bent valves, an incorrectly assembled oil pump that produced almost no pressure. I rebuilt it myself a couple of years later, once all the problems had showed up and it needed a rebore and new pistons already too, probably because of the bent crank (that was only found on strip down). It ran beautifully after that, though - started instantly even afyer weeks of standing in sub zero conditions and pulled my 109 along on the flat at a little over 60mph, despite all the drag from the accessories, and never used a drop of oil or water. That's why I always tell people to build their own, not to buy recon - I had two recon gear boxes with similar quality issues, and replaced the later one with a Gen Parts factory recon which failed after just 30-odd thousand miles (3rd/4th synchro spring failure, jamming the hub unit), which showed numerous thrust washers fitted the wrong way around and a few shims and thrust components fitted in the wrong sequence, wrecking the second gear wheel and no use of the bearing seating compound on the main shaft bearing - not even LR assemble them right! If didn't have such bad luck, I'd have no luck at all!

I think some Japanese vehicles still use leaf springs too, at least on the back end. Like I said, it was an interesting book for the first half - the different manufacturer systems were quite clever, from live beam axles to independent suspension, with a curious middle ground of a scissor-like axle pivoting in its centre. A few of the mods in the second half were OK, but some were clearly risky - leaf springs with so much camber they were literally semi-circular (you can imagine how stiff they'd be, and how much aft movement of axle you'd get as the springs compress; the bushes would last no time at all and the shackles had to be over a foot long, which was highly unstable), but combined with a SOA conversion with 8" or more of raising blocks between the axle and spring and U-bolts 2' in length, and you get the general idea. Plenty of heim joints in steering components, and drag links with 45 degree bends set at 30 degrees or so to the axle. All that good stuff! I know what you and Bill mean about Heim wear - the longitudinal link between the base of the selector lever and shaft on a Roverdrive uses Heim joints, and while they take very little force, over the space of a year they became loose enough that the flange of the joint rotates on the ball easily enough to rattle against the arm of the lever pivot to which the ball is bolted. They're free of slop for actuation, so the fix was an o-ring between the arm and flange, around the outside of the pivot ball, just to sop the rattle. I wouldn't want to use them on critical parts, but figured that anti-wrap bars would be non-critical, providing an advantage but not of great consequence if they wore a bit. Of course, if one failed outright, it could rather ruin your day being so close to the steering system... Serious question, guys: am I just making my life more difficult by worrying about this? You don't hear of many front two leaf parabolics failing (not the good brands, anyway) unless used hard on triallers, so with the three leafs I have, used almost entirely for routine road driving, is it worth the effort? I can see how it's technically beneficial, but is it going to be practically beneficial to me or am I just over-analysing again?

Yes, you can just do that for inspection. I don't think the Disco servo is the same, but I stand to be corrected.

It looks like that site has been taken down. Shame - it was as entertaining as it was horrifying! That book was OK in many respects - it showed a lot of different suspension schemes used by 4wd manufacturers, (all US), some of which seemed quite bizarre but entirely reasonable. Where it went awry was in showing off-the-shelf modifications. Everything was very glossily painted in bright primary colours, looking pretty and neat on first inspection, but much of it was clearly unstable or unworkable, looking from an engineering perspective like many of the red-neck crates on that site. It was worth the read, but demonstrates that you have to be careful to get information from more than one source. By the way, I was in and out of MLA this morning, Grem - I've never seen it looking so green!

When I bought a "recon" 12J from a well known Leeds based specialist with a keen interest in rallying, , I soon found they tried something like that - the slot had presumably been damaged and they'd welded it up, filing the key to fit the mishapen slot. In the process, they ovalised the end of the shaft, so they drilled an offset grub screw halfway in the pulley, half in the crank, to stabilise the crank. Unfortunately, they had the pulley pressed the wrong way at the time and secured it off centre. No matter, the crank was bent in the middle anyway!

When I first did the conversion, I did have problems with 4th, but the spigot bush hadn't been replaced, as was specified, by the engineering shop when they did the rebore and grind. Replacing it sorted it out and I haven't had even a twitch from the gear stick since, just in third. My engine is a Discovery 200, modified with Defender manifolds and mounts to fit the 109, and the flywheel housing is a pretty snug fit into the bell housing. I think its alignment is alright, though I haven't gone to the lengths you describe - I figured that any significant misalignment would prevent the primary pinion sliding through the splines and into the new spigot bush without a hell of a lot of force to slide the clutch plates while engaged, and they didn't need much pressure at all to mate up. Conveniently, the Tdis and Series engines share the same spigot bush! You see what I mean about my luck, though - loads of people run a Tdi and coiler axles on leafs or 3.54s in Series axles, but I seem to be the only one coming a cropper! A couple of friends, one who is a REME mechanic and the other a very experienced LR mechanic, reckon the gear may have had a metalurgical fault exacerbated by the oilway cross drilling. Maybe... It still seems a little too coincidental with being six months after the axle swap for me to dismiss it, and I can't help but feel you're right about it being the diff ratios.

Good plan. Use the blue semi-permanent locktite, not the red permanent one, so that you can remove the key in the future should you need to.

Thanks, Bill. The car is pretty heavy, but is rarely used as an exped vehicle and more for my commute. That means it's usually empty and the front tanks (I have the standard rear tank and twin underseat front tanks) are rarely used. Even the 20l water can in the locker is kept empty unless on a trip. The rack, winch, underbody protection and empty tanks all add up, though, and throw in the bonnet spare, a load of sound proofing and a thicker than standard tub floor and I reckon it comes to a few hundred kgs extra over a standard 109 hard top. The trips I like aren't really into dangerously remote areas - so far I have only done the Alps trip and some camping holidays around the UK and France, and I don't fancy desert driving, but I am concerned about the strain on the transmission - the gear box is probably the weakest link, whereas I'd prefer it to be the hub drive flanges. I've been looking at the prices of 4.1 diffs, which would be the best for driving, but it still puts more strain on the gear box than the original 4.71s. I got about 10% fuel saving with the 3.54s (not to be ignored at current prices), and it's much more comfortable to drive at 60-70mph, but is overgeared as much as 4.71 was undergeared. The thing is, 4.1s will cost about £750 for the gear sets alone, and if it still results in broken boxes, it'll be an expensive mistake. On the other hand, I have a mint condition 4.71 Salisbury axle centre sitting on my garage floor, kept for its innards, and getting a good second hand front 4.71 costs no more than a round in a pub. I want the comfort and estimated 15% fuel saving of the 4.1s, but the reliability of the 4.7s... Never simple, is it! I do wonder, though, if the cause of the gear breaking had another factor - for a while before it broke, the gear lever was moving fore and aft on pressing or lifting the accelerator, suggesting the third gear wheel had excess end float, while none of the other gears did this. I read (on here somewhere, not a book, US or otherwise ) that excess end float can result in stripped teeth, and I have also heard from many sources that it's usually second which tends to strip on Series units. With the unit stripped, I found a tiny amount of float - something in the order of .25mm, as a guess. What do you think? It does all make fitting a short nosed LT77 or R380 and LT230, (probably a Discovery version) more tempting, both to sort the gear box weakness and the overall gearing out. But that then involves chassis chopping and a lot of work around the cab floor and seat base, and makes the vehicle less of a SIII and more a leaf sprung Defender. The long term plan is to restore my RRC and use that daily, with the 109 become a trips vehicle, in which case 4.71s make even more sense.

They are tight, or at least should be, but not astonishingly so - it's more a matter of gaining access to press with a small tool it in than needing room for a huge pressing tool. If the key is not an interference fit, then it'll fret and wear the key and the slot, wrecking the shaft - it has to be that tight to guarantee it won't damage the shaft, but has to be looser on the pulley otherwise you'd never get the pulley off, and so it's the exposed part of the key which wears because of that looseness.

Defender servos can suffer fatigue cracks near the master cylinder mountings, so take a close look around those studs - you might need to take the master cylinder off the servo to do it properly, though you shouldn't need to disconnect the plumbing. A cracked servo could split all the way, which would cause the master cylinder to break loose completely, resulting in total brake failure, so check it carefully.

How long until someone suggests filing the key down? (DON'T!)

I wasn't trying to thumb my nose at anyone's solutions - there would be little point is asking for others' input if that was the plan, and it certainly wouldn't help get a response next time I need advice. I didn't understand the fitting of the ladder bar system properly, and that book was partly responsible having shown them fitted horizontally, hence why I thought they'd cause wrap from articulation while stopping it from torque reaction. Like I said, there was a lot of carp being pedalled in that book, like leaf springs with over 18" camber, shackles nearly 12" long and spacer blocks under the springs up to 6" with SOA conversions - a lot was of it was real red-neck stuff and I'm disinclined to do most of what I saw in there and prefer to learn from you lot. But, at the same time, I want to retain the standard LR attributes where I can, minimising the alterations from standard. I'm not en engineer, but I have had plenty of technical training and can easily visualise where stresses act and how they affect components, which is why I have been less keen on some solutions than others; while most people will get away with certain things, they have a way of biting me in the arse - it always seems to be me that gets the problems, even when doing exactly the same mod a hundred others have done before without issue! Maybe I perceive the tone of some posts incorrectly, but I think Soren took some stick too for his 88, but while his bar may not be pretty, I still think it was a smart solution - he found it works well, and hasn't caused any problems despite his concern that it might wear the rear bushes. I thought it unfortunate that his idea was so readily dismissed. I did get some very useful information, including photos, by PM, and I can only guess at the reason it was sent that way.

The point I was making about the book was apparently unclear - I was making the point that not everything in print is accurate and that not everything on sale works. Sorry that point wasn't clear. I was also trying to point out that I did try to carefully look into how to do my axle swap, looking closely at what others who had already done it, both on here and other forums, in the club I'm a member of, and by reading a couple of books about it, including said inaccurate US book. Part of my problem was not realising how much the diffs move on leaf springs through axle wrap and overlooking the fact that I had already fitted a Defender engine, which means that rhs mount is much lower than normal for a SIII. This was not an issue for others as those I had seen didn't have that combination, so didn't come up in my research. I don't object to what other people have done, but I do object to Dan jumping down my throat for no reason, regardless of his experience. A reversed Ackerman is clearly be little problem for what you use your vehicle for - off road, on relatively straight roads or at speed, I'd agree that it probably makes little difference, but with the roads in this little island being so twisty, the the towns having so many tight corners, and using the 109 to commute, parking in tight car parks, the Ackerman angle becomes a little more important; a large part of the reasons for swapping axles in the first place was to improve the turning circle, and it frequently gets used at full lock. While the angles aren't adjustable, they are at least a close approximation, which not only reduced loads on the wheel bearings and swivel pins, but also reduces loads on my arms! I'm probably one of the few people who has such a widely modified and heavy 109 and still retained the original steering...

The spring plates are slightly lower than before, but still higher than they would be with standard leaf springs - parabolics are much thinner in the middle. As for notching the axle, I really didn't fancy weakening it like that. Given that my 109 is mostly used as a family runabout and camping vehicle with the ability to do expedition work, but is not set up for rock climbing or deep mud pay and play site use, losing about 1/2 clearance under the springs compared to before makes little difference - the diffs are still by far the lowest points. As for the Ackerman issue, it's basic physics. On a mostly road going vehicle, it's a benefit to have it, otherwise it wouldn't be incorporated in the design of cars. I don't need to experience neutral Ackerman to know it's not a good idea, just like I don't need to experience jumping off a cliff to know that's a bad idea too. You still haven't explained your attitude.

The Ackerman angle is pretty significant on RR axles at full lock, and given almost all of my driving is on road, I'm not willing to have it reversed. As for the argument that because the Series axle had it track rod in front, that the coiler axle can be set up the same way, that's not right - the angle between the axle and steering arms has to be set up correctly; if I remember rightly, they have to be convergent in front of and divergent behind the axle, so swapping the swivels from side to side won't work, and nor will using a lhd swivel on the rhs. As for your comments, dirtydiesel, my ground clearance has not been lost - the third leaf has given it a very small rise of about 1/2" despite the taller saddles. I also had no choice about the saddle height as the diff sits further outboard on coiler axles, with the neck over the spring - this means the saddle has to be taller. The diff housing is actually touching the top of the spring with the saddle formed around it; the saddle height is the absolute minimum for the axle case to fit, regardless of steering systems. The contact problem is more because of the overlooked lower engine mounting, not directly because of the axle mounting solution. You don't know the vehicle and haven't read my posts properly, so, why the attitude?

They advise the use of synthetic 75w90 because they don't get EP90 out there. And it's not all EP90s that can damage the bronze-phosphor parts - it's just some of the GL5 specs, so you should still use EP90 GL4 where available.

Believe me Bill, I looked at just about every permutation before settling on leaving the axle axis alone and using taller saddles and retaining the vehicle height by fitting a third leaf to the springs to bolster their camber. There are other solutions, but this was the best fit for my parabolics and 1-ton chassis and shackles. I spent two whole years mulling it over, fiddling with this, researching that...

Thanks for the tip, Bill. I'll be fitting the two-piece bush - over enough time, the flexing will wear the broken ends and that could cause more trouble. I think the smooth joint between the ends of the two-piece bush will wear less and last longer, especially since they'll also allow oil in better.

I'd prefer to stop it, but it sounds like it'll be preferable rather than essential, and so is less urgent, and if it gets a bit difficult, then less of a worry if I have to drop it. My first job is to rebuild the gear box - I got it stripped down today, and thankfully it's just the third gear wheel on the main shaft and the big bush on which it sits that are damaged, with all the other components being unmarked, and I already had a gen parts new third gear wheel in my spares box, so once I get the new bush, I'll put all that back together. I can't sort the engine mount out, which will be the next job, until the transmission is refitted and setting the engine alignment correctly. Hopefully, barring any other disasters, I'll be able to do something about the wrap after that. I did look at the possibility of a cranked track rod and level diff, Bill, a bit like on the 101, but it wasn't possible - the diff is too close to the rhs spring, so the section of rod dropped to clear the diff on right lock would severely foul the spring on left lock. I spent two years fiddling and assessing how best to fit a RR/Def?Disco front axle before doing it, and I think I got a pretty damned good solution, but overlooked this engine mount, which is only a problem because of the previous engine conversion using the low down 12J-200Tdi mount. It probably wouldn't have been a problem with a SIII or Discovery mount. Thanks for all your input, everyone.

FAO Somethingwitty - that sounds peculiar and worrisome. I did the conversion on a 110 Salisbury axle, and Gremlin did it on a 109 Salisbury axle. In both cases, the outboard bearing needed spacer washers for the nuts to get the correct pre-load, and these on the 109 axle needed to be thicker than original. I tried using 109 spacer washers on my 109 axle and had to bevel the inner edges to get them to fit over the ends of the smooth section of stub axle, as did Grem, quite the opposite of your problem. I later found the original 110 spacer washers with the integrated rubber seals, and that made life easier. I suspect your bearing races might not be fitted correctly in the hubs. You haven't got two outer races on the outboard side of the hubs, have you? It would result in roughly the bearing spacing you describe...

You can't set the diff level, Bill - the track rod will be passing through the diff nose area. The position of the track rod causes a lot of problems when fitting later axles to leaf suspension, and I'm not willing to use a forward track rod because I really don't believe screwing up the Ackerman angles is a good idea. I got it all to work, except for this unexpected prop contact. From what you say, the wrap that I get under heavy braking is normal, regardless of which type of axle is fitted to this suspension, so won't have any worse implications for the service life of my springs or steering components, suggesting that I may have been right in my speculation that an anti-wrap system is not actually necessary, though it would be beneficial. As for slotted bolt holes in flanges - they would certainly weaken the flange, but if I was to re-orientate the swivels, I'd weld the holes up and re-drill in the new positions.

If you get a decent thickness of paint over a well prepared surface, then brush strokes or roller patterns can be polished out, unless you use metallic, but who would do that?

The DIY waxoil sold in Halfords and the like is good for cavities but useless on the chassis' exterior - it's too soft. DIY applicators are rubbish, too. It's wroth stumping up the extra money and getting it done properly by a specialist - they have the high pressure steam lances needed to get the carp and loose rust off, the lifts to get the car up to do that properly, and the professional grade waxes that will last underneath the vehicle on salty British roads. You also don't have to contend with all the mess yourself. As for the quality of Dinitrol, it's what Boeing use, and it comes in many different grades for use in specific areas and conditions, unlike the single grade Waxoil.

Better to get the prop the right length than fit spacers - the full length prop will have less UJ movement, making them last longer and reducing vibration, but the spacers will add significant tangental forces to the pinion and bearings, increasing their wear rate and chances of failure.