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Options for re-engineering track rod ends / heims

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Trying to get the 109 back on the road, one of the jobs is to replace a dodgy track rod end - easy peasy right? Not with Volvo portals on a RHD truck, the parts just don't exist anymore.

The Volvo setup uses offset TRE's, they have a cranked end to reach around the end casting at full lock:


Which complicates matters somewhat, but not nearly as much as the other end:


That's the drop arm joining on the nearside TRE, which has two tapered pins in one casting. The offset means you can't put LHD parts in as they're then cranked the wrong way. The offset from the cranked part is about 25.4mm

Now it's basically unpossible to find a modern off-the-shelf TRE that would match this beastie, so I'm assuming I'm going to have to get a couple of ends machined that can then accept either a different TRE or a Heim joint, and new steering links to suit.

An alternative may be to crank the ends of a steering bar but that seems like introducing a weakness.

There's also the question over what sort of joints to use: Ideally I'd track down some currently available TRE's with the correct taper and use those as I really don't want to machine the casting, but I have found after many hours of e-mails and phone calls that TRE companies simply don't know what the pin taper is on any of their parts - they don't write it down, it's not in their computer, you can't find anyone who will even admit to the idea and they certainly can't or won't give any hints on other parts which may be the same. If you could strangle someone over the phone for being unhelpful and useless there would be several dead bodies at ZF/Lemforder HQ by now :angry2:

Anyway, unless anyone has any information on TRE pin tapers that I've somehow missed I'm left with plans B and C:

Plan B is looking at the possibility of machining a tapered insert to adapt something to fit in the hole. Not an ideal solution IMHO, and frustratingly there doesn't appear to be a LR part that lends itself to the job at hand. The most popular TRE's, as fitted to all coilers, are too "short" in the taper to fill me with confidence. D2/P38 ones (QFS 000010) get much closer but leave very little room for an insert.

How LR TRE's fit in the hole:


How P38 TRE's fit in the hole:


I could start fishing round for TRE's from other vehicles but as manufacturers don't actually know the measurements it means basically trying to persuade a parts counter to let you look in all their boxes until you find one that's maybe close-enough. Sticking with LR would mean easy to buy parts and a fair chance they're up to the job at hand.

Plan C is to use heim joints and either machine a tapered pin, or a tapered sleeve for a regular bolt to pass through the original tapered hole. Now, there are a number of issues with this plan, not least of which is the fact that heim joints do not like mud and dirt and wear out in moments. I've been told that going against manufacturer's advice and adding boots & grease to them makes them last much better, but I'm still quite wary of them.

Whatever I do I'm going to need to solve the offset issue, to my mind this means machining a chunk of metal that accepts the thread of the TRE or heim and then has an offset threaded end to screw into a steering bar, plus one of them will need some way of joining up with the drag link, a tapered hole that will accept another TRE seems the obvious thing to me.

I'm taking it as a given that whatever I do, I'll be making new steering bars to suit.

So, any help, advice, horror stories, information, experience would be greatly appreciated at this point.

The big questions are:

- Can you crank the end of a steering bar and it still be strong enough?

- Could you machine a tapered sleeve to fit despite the lack of clearance at the top (as per the diagram) or would that be a bad idea?

- Can heim joints be made reliable enough for UK on & off-road use?

- If you machined a lump of metal to give the offset & joint for the drop arm, what material/grade would you use?

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WRT tapered inserts.....

Massey Ferguson TRE have a habit of working loose and turning the tapered hole oval. The solution is straight drilling/boring the hole and dropping in a tapered insert with a top-hat profile that when tightened down cannot pull through. I have an insert here on my desk... I bought the larger of 2 sizes they make when I needed the smaller one so there are at least 2 different sizes out there to buy off the shelf :-)



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Just a thought the Salisbury steering bar is cranked so might be worth a look there was one on eBay recently.


When I looked for these The cost of a 2nd hand one was the same price as getting a new HD one from rakeway

Rakeway may be an avenue of enquiory as I know they have experience with c303s

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Mike - believe me I have been through every TRE parts catalogue, web catalogue, sales rep, mates in the industry got me the details of the technical department at ZF/Lemforder... for reasons unknown there are many many different tapers of TRE and no-one records the information in ANY catalogues. All they know, if anything, is the diameter of the top of the pin and the threads on the end. Really unhelpful! :angry2: :angry2: :angry2:

ejparrot - Same reason all track rod ends are tapered I assume ;)

Daan - that kits looks pretty good value for sure, but I'm hoping to avoid reaming out the holes or modifying the actual axle if at all possible as it's a bit of a one-way street. If I gave in & modified the axle I'd probably try to use something more readily available, from a current LR or small truck rather than something US-specific.

Orgasmic Farmer - interesting bits, kinda what I'm thinking of but without re-drilling the axle hole if it can be avoided.

Vulcan bomber - you've sussed my "Plan C" out then ;) I've got a lathe I'm slowly learning to use, plus various contacts who are easily capable of doing the work. My only real unknowns on that plan are material choice and where to find good quality heims with boots.

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lol All I was thinking was couldn't you use a plain hole and a clevis type of joint? Better engineered than the general rigging type you get if you search eBay for 'clevis' obviously, but that style of joint. It works on large turbines for control gear so I don't see why it couldn't be used on steering.

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If it was my problem to be dealing with, I'd be looking at machining a pin the fits the taper, with a shouldered shank and a threaded end to take a common size of heim joint. Moving on to the problem of the cranked parts, can you cut the very end of the current joints off, cunningly machine the end sections down and thread to go into a female thread on a heim joint (which I assume are available)? Looks like there's enough straight section on each to make a decent job with a lock nut, though hard to say for sure from photos. If not, a piece of solid bar, suitably threaded, forged hot to the right shape and tempered correctly ought to do the job, and might actually be easier!


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Nothing of major interest to add other than mog 406/416 trac rods are bent as a lots of big tractors, if it's good enough for them...,

As you can see these are crimped in to the adjusters, you could sleeve them into a bar with/without hole for drag link and thread that bar for adjustment? Do you have details of the taper you require?


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I'm pretty sure 101 track rods are cranked, though not as much as those 303 rods. But you ask if steering rods can be cranked but strong enough with one in front of you - it's just a matter of the diameter and wall thickness of the tube. If you cant use the size tubing you need for stiffness as it fouls the swivel on high lock, then you can weld on an external gusset around the outside of the bend to add stiffness while keeping clear of the swivel.

I would ream the swivel arms to take the LR rods and make up new ends on the existing rod to take them. Machining the pins is going to get boring very quickly each time they need replacing, where as reaming the arms will need doing once and you'll have an easy job thereafter.

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lo-fi: Drilling out the old TRE's doesn't appeal greatly, the double-one wouldn't work at all as far as I can see. I think I'd rather machine a solid lump than heat & hammer a bit of bar into shape TBH. The problem of tempering a part to the "right" state is a tricky one, unless anyone here can point to an actual industry standard spec for the material & treatment of a track rod end.

Ross - I've not found a spec for the taper of ANYTHING, it's either a closely guarded industry secret and/or literally no-one outside the original design team has any reason to know or care. I've called and e-mailed every b***ard I can find that makes or sells TRE's and none of them can tell you anything beyond the diameter of the top of the pin and (maybe) the threads on the end.

Muddy - Aye there's plenty of cranked/offset ones out there, what I'm wary of is bending some bit of bar or tube without understanding the implications. At least the bent/cranked TRE's have been made deliberately like that (usually cast and I'm assuming treated) to withstand the loads. The other problem is finding one that actually fits in the hole (see my other comments about no-one knowing!)

Vulcan - Getting inside the current joints means cutting them open (the back is peened over to retain the top cover) which then means modifying them to put them back together. Also, you've still got to find identical internals to rebuild them with, and if I could find those I could engineer a solution that doesn't rely on obsolete castings...

Can you elaborate on why EN24T would be the material of choice? The thing I'm most wary of with this project is the metallurgy of it all, it's kinda important that they don't fail spectacularly (bend rather than break for example) and I'm very aware that I know just enough to know I don't know enough! :unsure:

At the end of the day, whatever I do (or get done by an adult) I have to be able to be sure that it's up to the job - my test for any modification is to imagine ending up in front of a jury having to explain why this part broke and the truck ran someone over, you've got to be able to put your hand on your heart and say absolutely that whatever you did was unequivocally as good or better than whatever was on there originally. I know lots of folks don't ever think too much about modding their trucks or bodging bits up but I don't want anything on it (especially the steering/brakes) that I can't drive on the road with absolute confidence.

Snagger - I'm trying to avoid reaming the arms, if only for reasons of metallurgy. The LR ends are already too small for the hole anyway, only the P38 ones come close. I'm also not talking about machining TRE pins, I'd machine a tapered insert that would stay put or a pin that stays put and takes a heim joint.

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Vulcan - Getting inside the current joints means cutting them open (the back is peened over to retain the top cover) which then means modifying them to put them back together. Also, you've still got to find identical internals to rebuild them with, and if I could find those I could engineer a solution that doesn't rely on obsolete castings...

Surely the internals of a LHD one will be the same, which you hinted were slightly more available.

Failing that and other options, there is always the option of dirty and un-precise adjustment with a club hammer. :ph34r: I know, I know, TAXI!

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OK can we just assume that I'm not going to transfer internals from LHD to RHD; they're still effin' expensive and to do so requires the RHD casting to be in good condition (no wear, corrosion, damage), and results in having to modify the thing anyway to retain the internals having had to chop the top off.

I would far rather engineer something that uses a standard readily-available track rod end (or heim joint) without modification.

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Fridge, have you actually established which size taper you need? A taper angle would be a start and it follows from. There must be one that fits. The link of the reamer i gave you should allow you to work out the angle. I wouldn.t bother with adaptors as it always means you reduce the diameter from where you are now. To vulcan: anything less than en36 for a halfshaft is a bit of a waste of time as you cannot harden en24 or less. Better than what landrover uses but still not great. Maybe ok for a steering rod though.

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Vulcan - So is EN24T like "5 better" than EN19T? :P as I said I know just enough to know I don't know enough, my concerns over metallurgy are that it's easy to make something balls hard, but you don't necessarily want that in a TRE. The failure mode really wants to be bending rather than breaking. I'd consider sending a dead TRE off to a testing house to actually determine the correct metallurgy & treatment rather than guess at something that's "probably" good enough. There's also the fact that most parts like that (half shafts included) are not "base" material but are heat-treated after production, so just machining a part from the same base does not guarantee it'll actually be strong enough. We know the Volvos have some serious metallurgy in them, they didn't muck about when they made them.

The other issue with manufacturing TRE's is that there's plastic/teflon inserts and whatnot in there, not just a ball & socket.

If it were possible to work out all the specs I'd be well up for a short production run of TRE's, but as I said I'd really want to know the specs were pukka and worked out by an adult who'd be happy with the part being fitted to a vehicle used on the road.

Daan - I don't have the kit to accurately measure the taper, it's around 6.5deg angle from the centre line, top of the pin (by Lemforder's spec) is 17.55mm, same as the P38 and LR pins but obviously differing on length & taper. Sometimes they measure the tapers in inches-per-foot and other weird measurements so it's hard to be certain, what can seem like a very strange number in degrees can turn out to be a more obvious "round" number in another unit.

I have no doubt there's hundreds of other TRE's out there that fit, but short of rummaging through every box in a (very understanding) parts depot with a vernier calliper you simply can't find out which ones out of the thousands might actually work. :angry2:

At this point I'm ignoring the relatively simple task of making a steering rod if it should be required, until I've worked out the plan for the TRE's there's no point thinking about arms.

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