Bigj66
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Posts posted by Bigj66
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38 minutes ago, lo-fi said:
No, that would be pointless.
If they look outboard, there's an optical illusion going on - have a look over the drawings again. I don't think this one is tractable, there is literally no way to do it that'll provide a satisfactory result in terms of steering geometry or without resorting to nasty bodges like chopping the arms and welding.
Interesting discussion, but the Haystee conversion kit is probably the best way to go.
An optical illusion it was 🙈
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I got impatient waiting so I popped a front wheel off the 110 to take a looksee.
The wheels are set straight ahead and from what I can see, the TCA taper hole is definitely inboard of the top swivel pin and looks to be in line with the centre line of the axle as discussed earlier. In other words, slightly inboard of the kingpin line as it should be 👍
I placed a long bolt on the centre of the top swivel pin to try and give a visual reference point between the various positions.
Again, it’s no big drama if the track rod has to remain at the rear.
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41 minutes ago, lo-fi said:
I have to apologise, for some reason I thought the coiler swivels had bolt on arms like the series. Ignore my idea about swapping left to right, it won't help.
Can’t the complete housing be swapped? I am a bit confused though because when I looked at the 110 yesterday, it looks like the TCAs are outboard of the kingpin pivot point and not inside it as the Ackermann principal suggests it should be for a rear track rod.🤷♂️
We’re going to have some fun when I get this axle delivered that’s for sure 🤣
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1 hour ago, Snagger said:
You could use the existing housings and swap them from side to side as Big66 asked previously. The only I’ll effects of that are having the callipers in a different place that may interfere with where the track rod needs to be and the filler plug will be on the other side, mildly affecting fill level accuracy.
If the callipers do end up in the way doing this, then you would need the left housing from an RHD vehicle and the right housing from a LHD vehicle to have the drag link arms up front, but if you’re going to be cutting and welding, you could just work with what you have and cut the track rod ends off the back and weld them to the front of their respective housings. Again, I’m not in favour of this as I think it’s a severe safety and legal issue.
For me personally, I will only go with a bolt on solution and if there isn’t one then so be it. The track rod at the front is a nice to have not a need to have but I’m finding the discussion very interesting and learning a lot so that’s win 👍. There’s been some good suggestions thrown up and lots of useful contributions but now I think the next step is to get an axle on the workshop floor and try to see what works and what doesn’t.
On the subject of the calliper position, am I correct in thinking that the coil sprung caster angle is somewhere in the region of 12 degrees and that the leaf sprung caster is 3 degrees? My plan is to rotate the swivel ball to achieve a caster closer to that of the leaf sprung axle although if I end up with a few degrees of additional angle (5-6) then I don’t think that will have any major adverse effects on steering.
If the swivel housings are swapped over to get the track rod to the front of the axle then I’m guesstimating that the callipers will be sitting in the 1-2 o’clock position and that rotating the swivel clockwise to correct the caster angle will move the calliper closer to the 3 o’clock position where conflict with the TCA is more likely? All this on the current assumption that there is no change in spring shackle length or wedging of the axle pad.
This in itself may end up as a show stopper.
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56 minutes ago, lo-fi said:
For sure. My measurements are approximate, but hit the geometry right where it was expected to be, give or take.
Now... Purely as a point of discussion: is it possible to mount the defender arms facing forwards, but swapped left to right and use the longer series track rod? I know it's possible on a Series, not that you'd want to ordinarily. Arrangements for the drop arm from the steering box would need to be looked at. Possible clearance issues again - I'm just throwing the idea up.
Interesting....🤔
So (theoretically 😉) swap them left to right and then use the coiler TCA ball joint mounts up front? Then use a kit like the Steve Parker one to connect the drag link to the track rod? Clearance wise, the coiler swivel ball will need to be rotated anyway to get it to the correct 3 degrees of caster that the series axle runs at so that may or may not help.
What is it that makes a coiler swivel housing handed? Is it just the position of the arms or anything to do with the position the pins are located in the casting? On a coiler isn’t the arm cast into the housing?
The calliper mounting points would also change wouldn’t they? Maybe not a bad thing though if it helped avoid the shock absorber.
My two series ones seem identical except for the drain plug location.
I think the only way to find out for sure with all of this would be to get an axle on the workshop floor and play about with different configurations taking measurements as you go.
I have two coil axles on order so when they arrive I’ll do just that.
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1 hour ago, Bowie69 said:
Hopefully it is still a Saturday morning
It might only be 10mm, by extrapolate that to the rear axle and it is quite a lot.
On a cooler, the Ackerman is based on a 100" wheelbase anyways, and no adjusted for the shorter or longer wheelbases options.
However, it is not reverse
As to the reference for swivel pin axis, it will end up being the mid point between top and bottom swivel pins.
As above, ackerma is never perfect, but it is at least something to strive for, at least somewhere in the ballpark anyways.
Interesting as to how that affects a 90 and 110. Presumably the Landrover engineers settled for a happy medium between the two?
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4 minutes ago, lo-fi said:
I still don't think you're quite grasping this. I did some rough measuring of a Series setup, extrapolated to the Defender setup, and finally mocked up the reverse setup. The dashed lines represent how the wheels steer in a turn. Hopefully this makes things a little clearer? I not only for you, but for people who will no-doubt read the thread in the future when exploring the same ideas.
Great illustration, thanks for taking the time to do it.👍
I knew there was a difference but this shows just how much it would likely be.
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39 minutes ago, Bowie69 said:
Hopefully it is still a Saturday morning
You see? Ackermann is the last thing I need to be worried about 🙈🤯
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25 minutes ago, lo-fi said:
Probably neither. The wiki shows a very crude approximation. The imaginary point where the lines meet could be ahead or behind the rear axle, and it's up to the designer to choose the angles to suit the application. Or if you draw the lines from the centre of the rear axle, they won't cross directly through the kingpin pivot point - depends how you want to look at it. It's never perfect over the full range of steering travel anyway, so there's leeway for adjusting it to suit where the designer wants the most correct effect and to tune the handling.
With that in mind then how critical would the 10mm difference in the position of the front drag link arm be on the coil axle compared to the rear track control arm? If the hole centre of the drag link arm is at the very worst, in line with the upper swivel pin and, if anything when looking at it from under the vehicle, probably slightly outboard, then as long as it isn’t inboard at any point then theoretically at least, it should still meet the general requirements of the Ackermann principle shouldn’t it?
Not wishing to sound complacent or blasé about safety in any way, as I’m not, but when you take into account the manufacturing tolerances on vehicles of this age along with general wear and tear of related suspension and steering components, I do wonder whether differences like this would even be noticeable when the vehicle is driven? Maybe they would be very obvious 🤷♂️
I confess that I don’t know enough detail on the subject to say for certain myself and it would probably take an engineering boffin to work it all out but it’s an interesting discussion nevertheless. It does help to understand better the criticality of tracking settings on a vehicle though and their impact on the handling characteristics.
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Just out of interest I clambered under the 110 and measured the centre of the TCA ball joint hole to the wheel rim and the centre of the drag link ball joint hole to the wheel rim. The difference is that the drag link hole is set inboard by 10 mm each side to the track rod hole.
I wish my series axle was still assembled now so I could do the same exercise but comparing both assembled axles whilst sat on the workshop floor would be more interesting.
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1 hour ago, missingsid said:
So as I get older I start to realise that like my parents before me I am no longer understanding current language or concepts.
For instance (and not passing judgement or comment just demonstrating change), There was Straight and Gay, then there was LBG, LBGT now but possibly out of date allready, LBGTIQCAPGNGFNBA.
But this is the one that really supprised me today.
I was watching a bit of SUV Supercar Build, not something I am interested at all but it was about the current G-Wagon (see there is 4x4 relevance) so I caught a bit until.
The G-Wagon is hand built,
So to me a hand built car is you take a flat sheet of ali and craftsmen run it through an English Wheel and assemble the body from nothing. Think Aston Martin in the 50's and Morgan still. Or Carbon Fibre parts hand formed and compiled to make a monocoque.
Not so according to TV and Mercedes, the hand built G-Wagon means that the car is built by people on a factory assembly line as normal except there are no robots!
The parts are still foundary pressed, they are still jig located and they are still spot welded and MIG welded but by humans (shock horror awe) so hand built now means that it is built on an 1980's production line (they are known for producing quality products)! Oh and the spot welders and MIG welders are called Artisans now and are difficult to find?
Yes I have been called a grumpy old man for a few years now.
Just more marketing BS for us to contend with 😠
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13 minutes ago, Bowie69 said:
The rotational axis of the swivel, which is set by the location of the top and bottom swivel bearings/pins.
I'm not sure how rotating the swivel will overcome any of this problem.....
No, it won’t but it will allow the caster angle to be adjusted but that’s for later. 😉
The Ackermann principle refers to, and I quote from WiKi:
“A simple approximation to perfect Ackermann steering geometry may be generated by moving the steering pivot points inward so as to lie on a line drawn between the steering kingpins and the centre of the rear axle.”
If the kingpin inclination on a Landrover axle is formed by the angle between the top and bottom swivel pins and vertical, then as these upper and lower pins are not of equal distance apart, which one is used as the reference for the line between the steering kingpins and the centre of the rear axle as stated in the quote above?
Is it the pin to which the TCA is connected to as opposed to the drag link or, is it a mid point between the two at a point in line with the centre axis of the axle?
I know it’s a bit heavy for a Sunday morning but I’m a bit bored.😉
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41 minutes ago, Bowie69 said:
Essentially you are describing in perfect terms what will result in reverse Ackerman.
The front swivel arms would need to be outboard of the swivel pin, they are not at all, so can't be used as you describe without creating reverse Ackerman.
See this image, the series axle has the arms wider apart than the swivel pin centre:
And here:
Defender stuff shows the arm inboard:
I believe, amongst other things, they moved the track rod to the rear to make more room for brakes and better fitment for wheels -with a shorter track rod, the swivel arm is no longer so much in the way.
Hope that is now clear
Interesting 🤔
Out of curiosity, where is the reference point for the measurement of the angle between the centre of the ball joint and the swivel? I’m looking (with some difficulty) at the axle on the 110 and I can see that the TCA ball joint is in line with the lower swivel pin but that the drag link ball joint is in line with the top swivel pin.
With the swivel set at an angle inclining inwards this creates an obvious difference in lengths between the opposite sides front and rear of the axle casing that I might measure just for the sake of it. However, which swivel pin becomes the reference point for the angular measurement or is it the mid-point between the upper and lower pins?
Either way the outcome is that the drag link mounting points are further inboard that would be required by the sounds of it so some you win and some you lose🤷♂️
One other question - what is the outcome with a ‘neutral’ Ackerman angle where the width of the TCA is the same as the distance between swivels?
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Thanks for the discussion and good feedback gents 👍.
I should have worded my previous query in a better way to make what I was pondering a bit clearer. For the time being forget my reference to the castor angle as that relates to a separate engineering challenge to overcome.
I don’t have a coiler axle here or, my series axle assembled anymore to do a like for like comparison, but I noticed on photos of some of the coiler axles the swivel housings have both front and rear arms built in to them.
In standard setup the track rod is attached to the rear arms and the front attachment points are for the drag link with one side remaining unused depending on whether the vehicle is LHD or RHD.
I have no idea yet as to what the angle is of those front drag link arms, if I can call them that, in relation to the swivel pin but my question is whether it would be possible to utilise the unused drag link attachment point on the offside hub to connect the track control arm to and thus transfer the TCA to the front of the axle? Unlike a series axle, as there is only one attachment point on each side of the front of a coil axle, then in order to attach the drag link to the nearside hub, a modified linkage such as that used on the Suzuki in the other thread or, that used by Steve Parker, would need to be used.
The big unknown for me is whether an arrangement like that would then provide the correct Ackerman angle that is required for the series vehicle that the axle is used on? I have no idea if it can or, even if it could, what other factors would need to be considered which is why I threw the question out there.
If it can’t be done then the TCA can remain at the rear but then I would just need to address the clearance to diff and spring issues. I just wanted to discuss the possibilities.
I hope I’ve explained my thought process a bit better and look forward to your comments 👍
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23 minutes ago, Snagger said:
No, that is exactly the solution I warned against earlier - reversed Ackerman is the problem, so you’re forcing a skid every time you turn the steering wheel. Any vehicle like that shouldn’t be on the road.
The axle above is a Series axle with twin leading shoe brakes, so presumably a SIII109 or modified 88. With the geometry of its arms and swivels pins, Ackerman is correct. But moving the track rod to the front of the coiler axles with their arm geometry doesn’t work. I suspect Land Rover would have done that, avoiding the very low and vulnerable position of the track rod on coiler axles, if they could have made the geometry work.
But if the axle case is the series one and the hubs are coiler ones orientated to 3 degrees castor with an appropriate spacer between the two to restore the original series WF to WF length, then the Ackerman angle should be maintained as per original series spec shouldn’t it?
As far as I’m aware from the Steve Parker website, that is a standard series axle they’ve fitted their power steering kit to.
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Just referencing this post from Gazzar in another thread.
There must be a smarter way around the steering track issue, too. I'd hate to lose the ground clearance the parabolics have gained.
An alternative is to hang both the track rod and the drag link out of the front arm, suzuki style:
http://bulletproofsteering.com/steeringsystems.html
Not entirely convinced by this approach, the loss of the taper concerns me, but I don't know why. It should work, and the change to the hole and bolt style tie rod is probably an upgrade.
Steve Parker has a drag link and track control arm adapter kit that allows the steering linkage to remain at the front of the axle in a similar way to the Suzuki kit. This looks like it could avoid the clearance issues at the rear of the axle for the TCA, diff and springs.
I also updated Discomikeys thread with this in case anyone was searching for similar information. -
On 7/15/2011 at 10:55 AM, Gazzar said:
There must be a smarter way around the steering track issue, too. I'd hate to lose the ground clearance the parabolics have gained.
The shaped disco track rod is an option - I don't quite like the idea of applying heat sufficient to allow a bend on a steering component, but could be persuaded otherwise.
I suppose that it would have to be curved up over the spring, long enough lock-to-lock clearance, and then curved under the diff. Would the bending of it make it less rigid? Or would one of the heavy duty steering bar manufacturers be able to make them up?
An alternative is to hang both the track rod and the drag link out of the front arm, suzuki style:
http://bulletproofsteering.com/steeringsystems.html
Not entirely convinced by this approach, the loss of the taper concerns me, but I don't know why. It should work, and the change to the hole and bolt style tie rod is probably an upgrade.
You'd have to use a LHD drivers side swivel, but as you'd be buying new anyway there is no additional hassle.
G.
Steve Parker has a drag link and track control arm adapter kit that allows the steering linkage to remain at the front of the axle in a similar way to the Suzuki kit. This looks like it could avoid the clearance issues at the rear of the axle for the TCA, diff and springs.
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The law only sets minimum wattage limits for motor vehicles and prohibitions on use with respect to dazzling other drivers etc. This is why drivers get prosecuted for dazzling other drivers with poorly adjusted standard headlights.
There are standards that cover the manufacture of the bulbs used in motor vehicles and these may contain maximum light output limits but I can’t find anything to specify exactly what that is for dipped and main beams.
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25 minutes ago, Bowie69 said:
Well..........
My Audi (that I have had for 20 years....) used to run a hydroboost system, it used the PAS pump to boost the brake, ran at something like 2-3000psi, so very similar to the RRC setup, albiet not electric
I converted to a vacuum set up due to cost of repair for the 'bomb' (same as the sphere you see on RRC/P38 pumps) and have felt no change in pedal from an assistance or feel perspective -it is identical.
I was just going by how my old 4 door was compared to my old mans Softdash and then later my own soft dash compared to my TD5 that has new brakes all round. There was a definite improvement in pedal firmness and brake response with the electric boost systems on the two RRCs compared to the vacuum ones that all seemed to have more travel.
Ive never driven a vehicle with the hydroboost fitted so that would be quite interesting to try.
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16 minutes ago, Escape said:
Some cars (like old BMW 5) came with a hydraulic brake booster, but without ABS/TC. It doesn't really matter what is used to assist braking, either vacuum (engine or electric) or hydraulic pressure.
You could fit the pump, accumulator and master (with the complete valve block) of an ABS vehicle but not use the control unit. That would give you brake assist, a fail safe system but no ABS or TC. It would be a lot of work and probably not cheap unless you have a donor vehicle.
If you're not happy with the brake feel, why not use an electric vacuum pump instead of the engine vacuum? Easier to tune to your desire and independant of engine revs. You could change the master and/or add an adjustable pressure regulator to the rear for even more flexibility. This is exactly what is being done to some Lotus Esprit when the first generation ABS system starts to act up. With very good results.
Filip
To fit the P38 system without ABS enabled, you’d need the wiring diagram for the electrical circuit and I’m assuming that’s all part of the ECU?
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1 hour ago, elbekko said:
Disabling TC is just snipping a wire. ABS is a bit more difficult, without power the system only has the emergency backup braking on the front brakes.
Maybe you could rig the valves to just open with the ignition feed or something, but it sounds sketchy.
So the output valves to each corner are normally closed in a power off condition with the exception of half of the front circuit? When energised the solenoids open to allow fluid through until the ABS senses a locked wheel and shuts the supply to that wheel off?
So as long as there is power to the system the solenoids will keep the valves open and in the event of a power failure, the front secondary circuit will still operate?
Disabling the ABS input from the wheels should keep the entire system open circuit all the time then unless there is a power failure.
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28 minutes ago, Bowie69 said:
Oh, hang on: https://www.powerbrakeservice.net/newunlarohy.html
https://lrautomotive.com.au/contents/en-us/d4944_Hydroboost_kit.html
But having said all this, the RRC brakes always feel better to me than other vehicles, I am not sure this is just down to the hydroboost, but could possibly be the pedal arrangement and its proximity to the valve block/master cylinder. When there's a servo in the way, the rod becomes a lot longer and more wibbly 😛
The hydro boost uses hydraulic power From the power steering system to provide the additional pressure whereas the Landrover ones use an electric pump.
The firm pedal on the Softdash and later models is due to this improvement over a vacuum assisted version.
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22 minutes ago, Snagger said:
I think it’d work if you have the ABS release return line and ETC supply line valves locked closed (or replaced by plugs). I think the master cylinder is part of that valve block, thought I may be mistaken - I can’t go and take a look. It may be a separable module. It could be a real can of worms for legal issues, though. A simpler power brake system from an non ABS vehicle would probably be the safer way to go.
Yeah, it was just something I was mulling over.
Do you mean a similar unit but without the ABS? What model used that?
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2 minutes ago, Snagger said:
If it remember correctly, the pedal push rod and accumulator are connected directly to the valve block, so you’d have to retain it. But you could replace the valves with plugs or remove plungers as required to ensure ports are kept open or closed as appropriate. I don’t know how much of the power brake part of the system is dependant on an ECU, though - I only suspect that the pressure switch would be enough with a simple relay to control the pump; I don’t know if there is something more complex that needs more regulation.
The Ford systems just required power via a relay and the accumulator provided the reserve in case of power failure. I presume that’s how the system is designed on a P38.
Found some diagrams of a similar system on Range Rovers.net
Leaf and coil sprung axle differences
in Series Forum
Posted
I mentioned in this post that I’d read some information which stated the caster angle on a coil axle was different to that of a leaf axle, 12 degrees compared to 3 degrees. Reading up again on the subject, it seems that some people believe that the two are actually the same at 3 degrees. To avoid any further confusion for myself or anyone who may also be looking for this information, does anyone know for certain what that angle is, where I can find it documented or can recommend a way for me to measure it accurately from the axle I have?
I think, in the interests of safety, it’s important that this sort of information is unambiguous and supported with some form of evidence if possible.