Series disc brakes.....using TD5 Defender parts?

[LittleBlue88]

Hi all

Ive just realised that at work i have the remains of a TD5 Defender front axle still with the o/s swivel assy.

If this was used with an earlier tdi defender/RR/Disco front axle then part of the problem with the steering would be partly sorted,but the n/s would still need modifying but how?

I hope someone understands what im thinking,TD5's have a different swivel housing than others so i could use the series steering links that should clear leaf springs...............

Any ideas anyone??

Steve

[Soren Frimodt]

Sounds interresting.. I'd better keep a close eye on this thread..

[Snagger]

Sounds interresting.. I'd better keep a close eye on this thread..

If you can post some photos, it'd be inetresting to see the differences.

[Daan]

I have seen this before; it is basically a lhd rh swivel and a rhd lh swivel (if that makes sense). I have seen someone using this on a series before, where there was 1 more tapered hole in both the front steering arms to take the trackrod, so the trackrod sits in front of the axle (like a series).

There is one problem with this: your ackerman is way out of line. This means that in a corner, the outside wheel makes a sharper turn than the inside wheel, where this should be the other way round. This has not stopped people from doing it in the past, and although in theory its wrong, in practice it doesnt seem to be a problem.

Are you planning on using the TD5 axle housing too? These swivels wont fit the series housing unfortunately.

daan

[DaveSIIA]

Could the same effect not be achieved by swapping the swivel housings side to side on the axle? The track rod would end up in front of the axle, the same as on a Series vehicle. The problem with reverse ackerman remains (probably true for a Series vehicle also).

IIRC, there was a Japanese 4x4 where the drag link ball joint engaged with a socket near the end of the track rod. I'd have to do some more research to be absolutely certain though. If so, that would make a relatively simple solution to the track rod / leaf spring contact issue.

[Daan]

Could the same effect not be achieved by swapping the swivel housings side to side on the axle? The track rod would end up in front of the axle, the same as on a Series vehicle. The problem with reverse ackerman remains (probably true for a Series vehicle also).

IIRC, there was a Japanese 4x4 where the drag link ball joint engaged with a socket near the end of the track rod. I'd have to do some more research to be absolutely certain though. If so, that would make a relatively simple solution to the track rod / leaf spring contact issue.

I have looked at this option too, the problem here is that the trackrod would end up very low ( I think that was the problem), although that can be overcome with a lot off castor angle. There is also the problem of the trackrod very close to the diff cover, limiting the steering angle you will achieve. Plus the calipers are now leading rather than trailing, which is not ideal in terms of mud falling of when braking.

All these issues are not the end of the world, but the option of lhd-rhd swivel is better IMO. It can be achieved with ordinary defender or Rangerover lhd/rhd parts, this is what I did for mine to achieve LHD on a RHD axle.

Daan

[DaveSIIA]

It was sort of thinking aloud, I haven't built up a RRC/Disco/Def front axle to check. The track rod at the front would sit a bit higher than for a coil axle normally configured as the castor angle would be reversed relative to the swivwl housing. Not sure how it would fare for steering lock. I might have to borrow an axle from a scrap RRC/Disco and try.

I think my old (1999) Td5 110 had arms forwards of both hubs, ready for either LH or RH drive assembly. Out of interest, the Disco2 front axle appears similar. If these could give sufficient steering lock with a forward mounted track rod then the big issue remaining is how to connect the drag link.

[LittleBlue88]

Im gonna have a crack at dry-building the axle at the weekend just to see if all the parts marry up but my other problem is how to fit the arm from the steering relay to the n/s swivel since the defender axle has only one eye.

Im prob gonna be using a early disco tdi front axle with the o/s td5 swivel assy,its the only one my boss is gonna let me have!

As for ackerman,what is that? and is there a way of neutralising it?

I will try and post pics as i go.

Steve

[Declan303]

I too am looking at doing this using a RR axle.

The track rod is at the back of the axle that I have so my plan is to get a swivel housing of one of those axles that has the arm on both sides to suit both LHD and RHD. I was thinking that I would then cut the two rear arms off the swivel housings so they wont foul on the leaf springs.

The either weld one of those arms to the arm on the passenger side so to give me the second eye for the drag link. Other option is to use one of those track rod ends that have a built-in eye for a drag link.

Declan303

[DaveSIIA]

Ackerman explained, shows that the inner wheel has to turn at a greater angle to the outer wheel for both to follow their correct turning radii. If tyre slip can be neglected, the projections of the front stub axles should intersect on the projection of the rear axle. However, the real world isn't that simple.

Putting the track rod in front of the axle generally gives a reverse ackerman effect unless the pivot points at the ends of the track rod can be made further apart than the steering swivels. Proximity to the tyre / wheel often prevents that. Again, that is a bit of a simplistic approach.

[Daan]

Hallo Declan,

What is the steering arm off? I have looked at doing something like this, but in the end just used the defender setup. Let us know how you get on.

Daan

[DaveSIIA]

The either weld one of those arms to the arm on the passenger side so to give me the second eye for the drag link. Other option is to use one of those track rod ends that have a built-in eye for a drag link.

I understood that a welded repair to the steering gear would be a (UK) MoT failure, so welding an additional arm could be out.

That track rod end looks to be the business and a decent way forward. The length between the pin and the start of the thread looks to be in the right ball park to use a Series track rod with a RRC/Disco/Defender axle set up. There may be a size that matches the LR TRE characteristics - pin length, taper, thread, etc. Have you got any further info about it - supplier, etc?

[Declan303]

I understood that a welded repair to the steering gear would be a (UK) MoT failure, so welding an additional arm could be out.

That track rod end looks to be the business and a decent way forward. The length between the pin and the start of the thread looks to be in the right ball park to use a Series track rod with a RRC/Disco/Defender axle set up. There may be a size that matches the LR TRE characteristics - pin length, taper, thread, etc. Have you got any further info about it - supplier, etc?

Afraid I didn't take note of the website that I found the TRE on with the eye for the drag link but will keep on searching for it. With regard to welding an extra eye on the existing steering arm, I think if it were done professionally it would not even be noticed. Anyway my first piece of the puzzle is to get a swivel housing for the driver side with a forward facing steering arm that will fit those RR axles.

Declan303

[Snagger]

Afraid I didn't take note of the website that I found the TRE on with the eye for the drag link but will keep on searching for it. With regard to welding an extra eye on the existing steering arm, I think if it were done professionally it would not even be noticed. Anyway my first piece of the puzzle is to get a swivel housing for the driver side with a forward facing steering arm that will fit those RR axles.

Declan303

The problem with that idea is still the Ackerman angles - the ends of the arms need to be outboard of the swivel pins if the track rod is in front of the axle, but they're canted inwards for the aft rod position. That means that when you turn, the wheels will toe in sharply, instead of correctly toeing out to reflect the different wheel path radii.

[DaveSIIA]

I suspect the same problem exists with the Series front axle. I'd have to get underneath my IIA and have a look - won't happen till some time next week.

Out of interest, I worked out the angle that the wheels had to be turned to track a 50m radius (centre of rear axle) circle assuming no tyre scrub - 2.59(I) & 2.53(O) degrees. Given the small difference, I suspect that other effects from the vehicle dynamics - roll, tyre slip angle, flattening of leaf springs, etc - come in to play and make reverse ackerman issues quite minor in the whole handling equation. After all, Series vehicles have been driven around the world for some 60 years and wouldn't have done so if there was a serious flaw in the steering geometry.

[Snagger]

I suspect the same problem exists with the Series front axle. I'd have to get underneath my IIA and have a look - won't happen till some time next week.

Out of interest, I worked out the angle that the wheels had to be turned to track a 50m radius (centre of rear axle) circle assuming no tyre scrub - 2.59(I) & 2.53(O) degrees. Given the small difference, I suspect that other effects from the vehicle dynamics - roll, tyre slip angle, flattening of leaf springs, etc - come in to play and make reverse ackerman issues quite minor in the whole handling equation. After all, Series vehicles have been driven around the world for some 60 years and wouldn't have done so if there was a serious flaw in the steering geometry.

I think you'll find that the track rod is longer on a Series axle than the distance between the left and right swivel pins, which is why the Ackerman angles work and the inner wheel pivots much more than the outer. If you were to fit the lower pins/steering arms on the wrong swivels, then you'd get the negative Ackerman angles (as well as needing a shorter track rod). Unfortunately, as the coil sprung axle swivels have cast-in arms, rather than bolt-on ones like the leafers, we can't swap them from side to side to reverse the cant on the arms.

[jericho]

Billvansnorkle - who we haven't seen on here for some time - reported a preference for negative Ackerman angles on his off-roader.

Specifically,he thought negative angles were no reason not to move the track-rod to the front of a coiler axle for use on a series.

Where are you Bill?

[DaveSIIA]

I think you'll find that the track rod is longer on a Series axle than the distance between the left and right swivel pins, which is why the Ackerman angles work and the inner wheel pivots much more than the outer.

Yes, you are correct. I have been and checked an early Series III - the steering arms are such that the track rod ends are further out than the swivel axis to give proper Ackerman effect.

Unfortunately, as the coil sprung axle swivels have cast-in arms, rather than bolt-on ones like the leafers, we can't swap them from side to side to reverse the cant on the arms.

More out of the box thinking. Would it be feasible to machine the lower pin area of the swivel housing to take a Series steering arm? Remachine the profile of the pin on the steering arm to suit the swivel bearing. Move from two bolts to four studs to retain the steering arm. Cut off the Defender steering arms

Not a job for your average man in the street that tinkers with cars

[Snagger]

Yes, you are correct. I have been and checked an early Series III - the steering arms are such that the track rod ends are further out than the swivel axis to give proper Ackerman effect.

More out of the box thinking. Would it be feasible to machine the lower pin area of the swivel housing to take a Series steering arm? Remachine the profile of the pin on the steering arm to suit the swivel bearing. Move from two bolts to four studs to retain the steering arm. Cut off the Defender steering arms

Not a job for your average man in the street that tinkers with cars

It sounds possible, but the Series arms will not be at the correct angle to get the full Ackerman angle - they're a bit too close to parallel to eachother, while the wider tracked coiler axle needs them to be canted out slightly more. However, given that LR didn't make different swivels for LWBs and SWBs (or intermediate 100" in the colier instance), then it suggests the exact angle is not critical. I suspect the SII/SIII arms were set at a compromise between the 88 and 109, so using these on a coiler axle on a 109 should give close to ideal angles, but the short wheel base of an 88 in addition to the wider track of the newer axle will give a more significant deviation from the ideal, with the angle of toe-out in a turn being too small. It'd certainly be better than using the cast arms, though.

[Daan]

http://www.pirate4x4.com/forum/showthread.php?t=727104

Read this, on page 4, someone else is having a go.

[Snagger]

http://www.pirate4x4.com/forum/showthread.php?t=727104

Read this, on page 4, someone else is having a go.

I had a look, and that's truly awful. Apart from the negative Ackerman angles he'll have by putting the track rod on the front using the original steering arms (and that will pose problems with those tyres), going for a 15o castor angle instead of the factory 3o to raise the track rod is going to give such strong self centring that the car will be near-undriveable. The PAS will help, but he'll have no feel at all, and I reckon he'll be shearing rod ends or even snapping the steering arms off the swivels, such will be the combined forces of the big tyres, the bad Ackerman, the excessive straight-line stability and the rock crawling.

[-xLr8r-]

is this any help ?

series 109 chassis

90 axle with o/s td5 swivel & hub casting

2 piece front track rod with the drop arm ball joint fitting into the joining piece.

i havnt driven it yet since the conversion, i'm going to see how it feels first before i finally set the castor angle & weld on the spring seats.

[LittleBlue88]

Just a quick update

Due to heavy workload coming upto crimbo, i haven't had a chance to have a proper go at assembling the axle,but the recent pic from xL8r has given me hope that it can be done!

I shall try and get a dry-build done before the new-year

[Snagger]

is this any help ?

series 109 chassis

90 axle with o/s td5 swivel & hub casting

2 piece front track rod with the drop arm ball joint fitting into the joining piece.

i havnt driven it yet since the conversion, i'm going to see how it feels first before i finally set the castor angle & weld on the spring seats.

It all looks very neat and strong, but you still have the reversed Ackerman angle problem because the cast steering arms that you are usinga re canted inwars, so the track rod is shorter than the distance between the swivel pins.

[HoggyN]

It all looks very neat and strong, but you still have the reversed Ackerman angle problem because the cast steering arms that you are usinga re canted inwars, so the track rod is shorter than the distance between the swivel pins.

I've built several cars with parallel or reverse ackerman. It works - as long as you drive them fast. In a fast bend it's the outside tyre that does most of the work so it doesn't really matter where the inner points (a gross simplification if an involved topic). At low speeds on hard surfaces the steering feels awful.

This link has done the rounds before but it had me in stitches. SVA/IVA pass - probably not!