Keeping your Land Rover in a straight line
Drive Straight and True
Keeping your Land Rover in a straight line is an art, finds Neil Watterson
Ask any tyre fitter about what causes the most wear on a tyre and they’ll reply “wheel alignment”. But wheel alignment doesn’t just affect tyre life – it has an impact on how your Land Rover steers, handles and brakes.
Even the fairly crude suspension system fitted to leaf-sprung Land Rovers has loads of points where even small amounts of wear will encourage wander on the road – independent suspension is worse.
Most people understand the importance of getting their wheel alignment checked, but few will actually do anything about it, unless the tyre tread is getting scrubbed off.
But before you take your Land Rover to an alignment centre you should make sure the suspension is in good condition– spending a bit of time preparing the vehicle will give you the best results and can transform your vehicle’s handling, as well as making it easier to drive.
Most of the checks and adjustments can be done on your own driveway with basic tools – you’ll just need some string and a tape measure to do the basic checks
The Expert: Chris Clark
Chris has worked as a tyre fitter for Southam Tyres, part of the 4Site4x4 group (4site4x4.co.uk) for over a decade and has been doing wheel alignment for the last three. His pet hate is working on Land Rovers where the fixings are seized!
Safety
Any adjustments you make to the steering must be correct and bolts must be torqued correctly (figures are given in workshop manuals). If a bolt comes loose you could lose control of your Land Rover. Get any adjustments checked. Properly support the Land Rover when you are working on it
1. Camber
Camber angle is fixed on beam axles – the wheels will generally be perpendicular to the ground, or a small amount may be built-in. It is adjustable on independently-sprung models. Negative camber – where the top of the wheel leans inwards, as illustrated excessively above – can improve grip when handling, but it only needs to be a small amount. Too much negative camber will rapidly increase tyre wear and heat build-up. Beam axle vehicles often have slight positive camber. Tyres wear at an angle to the tread.
2. Steering Axis
Steering axis, or kingpin inclination is the angle formed through the top and bottom swivel pins on a lateral axis and helps with self-centering of the steering. The angle is fixed on beam-axled Land Rovers, but can be adjusted on independently-sprung models.
3. Toe Setting
Toe setting is the amount the front wheels are out from parallel. Slight toe-in increases straight line stability, though Defenders are set toe-out. The toe setting is the only steering setting that can be adjusted on all Land Rovers. Excessive setting feathers tyre edges.
4. Thrust angle
The thrust angle is the difference in the direction the rear wheels are pointing relative to the centre line of the Land Rover. If a rear axle isn’t square to the chassis it will produce a thrust angle (negative if it is pointing towards the centre of the road/driver, positive if it points towards the kerb). If the thrust angle isn’t 0º, you will have to turn the front wheels (right in the drawing above) to compensate for the wheels being out of line. The thrust angle needs to be sorted before the front wheels are aligned.
5.Caster Angle
The caster angle is the angle around which the wheel revolves when the steering is turned. This angle can be adjusted on all Land Rovers (use wedges on leaf sprung vehicles) and is affected by changes in suspension geometry. The angle is set so a line drawn through the centre of the pivots would meet the ground just in front of where the tyre’s footprint is. Too little caster angle will reduce directional stability; too much will make steering heavy. Care should be taken to get the correct caster angle on lifted vehicles to maintain steering stability.
6. Steering Damper
In an ideal world with smooth roads, properly set up steering shouldn’t require additional damping but the reality of driving fast on bumpy roads makes them necessary. They help control undesirable movement and oscillation through the steering.
All Models
1. Tyre size
Overall sizes can vary between different tread patterns from one manufacturer even though their sizes are the same. At the very least, try to match tyre size/type/brand on an axle, but a matched set of four is best. Make sure the pressures are correct.
2. Wheel offset
Few modern Land Rovers run non-matched wheels as they look ‘wrong’, but Series Land Rover owners may find the offsets on their wheels – they changed over the years. Check the part numbers and measure the offset of each on a flat surface.
3. Chassis Sitting Level
You’ll never get your Land Rover wheel alignment right if it doesn’t sit level. If it is squatting down on one corner, resolve that issue before delving any further – it could be that the spring has failed or is simply incorrectly rated for the load it’s carrying.
4. Chassis ‘Squareness’
You’ll never get your steering correct if your chassis is out of line – something that is a real possibility on accidently damaged or badly repaired vehicles. To check your chassis correctly you will have to get the chassis on parallel with the ground (support it at each corner if needs be), then drop a plumb line from the suspension pick-up points and make chalk marks on the ground. Wheel the Land Rover out of the way then measure the diagonals between the points. If there is any discrepancy between the measurements the chassis may be out of square.
5. Loading
Ideally loads should be spread evenly around vehicle. If the loading is imbalanced it will affect the how the suspension deals with bumps. If your Land Rover is normally run fully laden, get the alignment checked when it is loaded, not at kerb weight.
6. Wheel and Swivel Bearings
Even a small amount of play in a wheel bearing will affect the wheel. 0.1mm of play in a bearing gives over 0.7mm of play at the wheel rim and as toe-in is as little as 1.2mm (Series Land Rovers) it can easily throw the readings out. Get them sorted.
7. Steering Lock Stops
Lock stops prevent the wheels from exceeding their designed movement and are adjustable for different wheel/tyre combinations. They must be correctly adjusted to prevent damage and tyres catching the chassis and suspension components.
8. Wheel Balance
Apart from causing irregular wear and an irritating vibration through the steering, an out of balance wheel will put undue stress on the other steering components, shaking bolts loose. Tyres should be balanced routinely – they can creep on the rim.
Rough Checks
1. String Gauge
On flat ground run a length of string round the wheels at axle height with the straight. If there is a gap between the string and front of rear tyres, you have toe in, rear of front tyres you have toe out. If there’s a gap on one side only, the rear toe is out.
2. Measuring Wheelbase
Measure the wheelbase at kerb weight with wheels straight – and be aware that some wheelbases aren’t the same as model name (a 90 actually has a 92.9 inch wheelbase). Take a further measurement from a fixed point on the chassis.
3. Measure the Track
The distance between the wheel rim, front and rear, gives you the toe setting. Older, beam axled vehicles have a figure given as a linear measurement. Land Rovers with independent suspension have it as an angle as well as a linear measurement.
Independent Suspension
1. Proper Alignment
Vehicles with independent suspension need to be aligned properly, but you can still do a basic check using string (as shown above) to see whether it’s worth taking in for a full check. Always get a four wheel alignment check after doing suspension work.
2. Eccentric Bolts on Discovery 3
The lower arms on all vehicles L322-on are located using eccentric bolts in a factory-set position. If they have come loose, or the lower arm has been replaced by someone who didn’t mark the position correctly, the camber and caster will be wrong.
3. Rear Toe Adjustment
Rear toe setting is adjusted by loosening the lock nuts on the adjuster arm and rotating the rod, using the flatted area along the length. The rod has a significant amount of adjustment built in, so you can get it very badly wrong if you try!
4. Front Adjustment
The front toe setting on most independent wheel models is adjusted towards the front. Loosen the lock nut on the track rod and rotate the bar to increase or reduce the toe setting. Make sure the steering is straight ahead before adjusting it.
5. Freelander 1 Rear Toe Setting
The toe setting can be altered using the adjuster rods on the rear wheels suspension. Loosen the lock nuts and rotate the adjuster rod to alter the toe setting. These will invariably be rusty, so use plenty of WD40.
6. Freelander 1 Front Toe Setting
Toe setting is varied using the adjustable track rod behind the spring. Set the steering wheel central then loosen the two clamp bolts to the side of the adjuster and turn the adjuster. When the setting is correct, tighten the lock nuts to 66lb ft.
Leaf Sprung Land Rovers
1. Check Bushes
Worn bushes in the spring eyes or chassis will allow the axle to shuttle backwards and forwards as you drive, skewing the axle every time you hit a bump or pothole. As the axle moves, the thrust angle moves, so you could end up crabbing along.
2. Axle Height
If the gap between the axle and chassis is significantly different on each side of a vehicle, the wheelbase on one side will differ to the other. Check the heights with a driver seated as the suspension is designed to be level then.
3. Spring Location
Many alignment problems on leaf-sprung Land Rovers can be attributed to the spring dowel not locating properly in the hole in the bottom of the axle casing. Springs could have been fitted incorrectly or the dowel could have sheared following an impact.
4. Loose U-bolts
If the U-bolts haven’t been tightened sufficiently the axle will shift as power is applied and can damage the spring’s dowel. If you have been driving round with loose U-bolts don’t just tighten them – replace the U-bolts as they will have been damaged.
5. Ball Joint Condition
A worn ball joint will introduce free play into steering. Two types of ball joints are available; those with collars and those threaded along the entire length. They are not interchangeable, even though they will physically fit the steering rods.
6. Set the Steering Relay Arms
Earlier Series Land Rovers were designed to have the top and bottom steering relay arms at 90º to each other. Later (Series III) models have the angle reduced to 81º. Push the arms up and down to check for play in the relay, giving sloppy steering.
7. Track Rod Length
The track rod length adjusts how much toe-in your Land Rover has. This is the only adjustment you can make to a Series Land Rover’s wheel alignment. Check the workshop manual to find out exactly what the toe-in should be.
8. Drag Link Length
Adjust the length of the drag link so the lower relay arm points forward when the wheels do. Then centre the steering box by loosening the pinch bolts on the longitudinal rod (between steering box and relay) and rotating the bar to centre it.
9. Steering Box Adjustment
It can be easier to lift the front wheels to check for full movement/centred steering. Once the steering is centred remove any slack in the steering box by loosening the lock nut and turning the adjuster to remove free play. Make sure it is filled with oil.
Coil and Air Beam Axles
1. Caster angle
If you’ve fitted a suspension lift or lowering kit to your Land Rover you may need to fit caster correction. As a rule of thumb, if the change is an inch or so you don’t need to do anything. If it’s more, you should adjust it, using either bushes or adjusted arms.
2. Panhard Rod
The Panhard Rod locates the front axle and prevents lateral movement. If the bushes are worn, it will allow the axle to move sideways, affecting steering. If you’ve fitted a significant suspension lift, it will pull the front axle out of line.
3. Bushes
Worn bushes will cause poor axle location allow the axle to wander, especially in ruts on and tarmac roads. If the centre bushes (A-frame, Panhard Rod or Watts linkage) are sound, the axles will pivot round them, altering the thrust angle.
4. Rear Axle Location
If the A-frame and Watts Linkage bushes are worn, the rear axle won’t locate properly and allow the body to move laterally when cornering. Coupled with worn bushes it can make for a very erratic handling from the rear, especially when towing.
5. Damper Performance
Faulty dampers won’t keep the axles under control, so the tyre won’t track the ground properly. This is annoying on straight roads, but can throw steering out on corners, or when straightening back up after cornering as the axles bounce.
6. Ride Height Sensors
If an air suspension sensor is damaged or misaligned it will give incorrect readings, causing the vehicle to lean. Apart from being uncomfortable, it will alter suspension performance. Some ECUs need to be calibrated to teach the ECU the new settings.
7. Ball Joint and UJ Wear
Worn ball joints and universal joints in the steering column will reduce steering feedback and allow the wheels to move independently of the steering wheel. Rock the steering gently while holding the joints to feel for undue movement.
8.Track Rod Length
The track rod alters the toe setting of the steering and is susceptible to damage from off-roading. If the bar gets bent it will give extreme toe-out, as shown, scrubbing the tyres and making the Land Rover wander. If the bar does get bent, it is normally scrapped.
9. Centre the Steering Box
The steering box has a threaded hole to align with the drop arm when setting the drag link length. Make sure you remove the bolt before turning the steering wheel. Centre the steering wheel at the same time. Adjust the track rod length.