L400 suspension lift - if you have it, make sure it's good
Posted: Fri May 28, 2010 8:00 am
There are some really nice lifted L400's in Canada.
Some have perfect lift kits installed, addressing critical components, while some do not.
I've repaired a few L400's for other people that came over from Japan with a suspension lift already installed.
I'm seeing more and more lifted L400's coming over from Japan and many appear to be incomplete installations with crucial components either missing or broken.
The front IFS (Independent front suspension) can be altered without problems, so long as the suspension components (balljoints/tie rods/control arm bushings/shocks/torsion bars) are all in good condition and the caster/camber alignment adjustments can be made within the correct angles. Depending on the lift height, balljoint spacers/subframe spacers/longer shocks may be required.
The rear RA (rigid axle) with 5-link suspension can be altered but certain critical components need to be addressed with the suspension modification.
If you have an L400 with a suspension lift, please check the following:
1. Rear sway bar
What it is/purpose : The rear sway bar or Anti Roll Bar (ARB) reduces the amount of body side to side roll and it used to help in the handling of the vehicle.
L400 has a suspension lift but no relocation/drop-down bracket for the rear sway bar. This will cause stress on the upper links that are bolted to the bottom of the L400 chassis frame. Out of the lifted L400's that I've seen, only two had the proper brackets in place. I had to weld/repair the chassis on one recently because the stress ripped the sway bar right out of the frame.
Without the rear sway bar attached and/or a broken sway bar, there is significant body roll which can cause the L400 to pitch/roll unless controlled properly.
Solution : Install a drop down bracket/spacer in between the frame and the rear sway bar. The typical extension should correspond with the amount of lift (ie. a 2" lift would need to have a 2" spacer to lower the sway bar to it's stock position relative to the frame/axle).
2. Rear brake proportioning valve
What it is/purpose : The rear brake proportioning valve assists in braking with varying weight loads in a vehicle.
For those who may not know , the rear axle on the L400's has a Brake Proportioning Valve fitted to it . The valve itself is rigidly mounted to the chassis. The rear brake line enters this valve and then is routed to the rear calipers. The valve has a lever on it that moves fore and aft. This lever opens and closes an orifice to limit the flow of brake fluid to the axle as the load demands . The other end of the lever attaches to the axle via a large coiled spring. When the vehicle is empty , the orifice is greatly restricted as the lever is pulled by the extended spring because the body of the vehicle is sitting high. This prevents rear wheel lock up when empty. As the load increases in the vehicle , the rear of the car lowers which takes the tension off of the spring and allows the lever to relax a little. This opens the orifice in the valve allowing more fluid pressure to reach the rear brakes giving more braking power.
I only seen one L400 with an extension. Probably because people don't know of the need to install one. The raised vehicle without an extension will have poor rear braking performance and increased front brake wear because the valve thinks the vehicle is lightly loaded due to the body sitting high, regardless of weight in relation to the axle height.
Solution : The typical extension should correspond with the amount of lift (ie. a 2" lift would need to have the spring attaching bracket moved up 2" to keep the spring at the correct angle).
3. Control arms/panhandle bar/driveshafts
What it is/purpose : The control arms provide the physical link between the body and the axle. They pivot allow flex movement of the axle relative to the body.
The pandhard bar/track bar keeps the axle centered horizontally (left/right) relative to the driveline. It is attached at the rear axle on the left side and on the body/frame at the right side. Diagonally.
The driveshafts connect the driveline/axles.
With mild suspension lifts (1-3" inches in height), these components do not required any alteration.
With larger suspension lifts (3+ over" inches in height), these components required modifications.
As the axles are moved further away from the chassis, the control arms will need to be lengthened/dropped down in the rear. The driveshaft may need to be lengthened to compensate for the extension. The panhard bar will need to be extended (adjustable one's are common - the stock one is not) to keep the track left to right centered in proportion to the driveline.
Solution : Large lifts should be installed professionally and the proper components must be installed as large lifts greatly alter the driveline geometry of the vehicle.
4. Shocks + brake lines
What it is/purpose : The shocks provide dampening and ride comfort/handling for the vehicle. Without them, your rig would be bouncing everywhere.
The front shocks are 1" longer in stroke length than necessary. Before the shock can top out (reach it's maximum extension), the upper control arm will rest on the upper bump stop, stopping down travel. The flexible brake lines have a lot of room for play when extended (suspension lift) that does not pose a problem.
The rear shocks are maxed out to their stroke length/extension point when the entire axle is suspended in air from the body (ie. raising the body on a hoist and the rear axle hanging without support).
There are a few components that keep the axle from falling to the ground and disconnecting from the vehicle completely.
1. rear sway bar (attached to the vehicle's frame and towards the center of the rear axle)
2. panhard rod/trackbar (attached to the frame and attached to the rear axle pivot point)
3. rear driveshaft (attached to the transfer case and the pinion/differential which part of the rear axle assembly)
4. rear shocks (attached to the bottom of the vehicle frame and to the side of the rear axle)
5. brake lines (attached to the frame via hanger and connected to the rear axle)
When a suspension lift is installed, the above components' distance relative to each other and the frame/axle change. With that change, extensions and spacers are required for everything to function properly.
The stock shocks travel 2 inches past the standard ride height which allow considerable rear axle flex/articulation.
With the addition of a suspension lift, the stock shocks travel will be reduced relative to the suspension lift which will limit the downtravel of the rear axle and depending on the height of the suspension lift, not be long enough to connect to the frame and the axle.
A note as well to check the flex of the rear brake lines. Depending on the amount of suspension lift, they may be over extended which can cause the line to rupture leading to poor/no braking.
Solution : The longer shock should correspond with the amount of lift (ie. a 2" lift would need a 2" longer stroke length of the shock absorber).
Hope this sheds some light on suspension lifts/what to look for if you have one.
Some have perfect lift kits installed, addressing critical components, while some do not.
I've repaired a few L400's for other people that came over from Japan with a suspension lift already installed.
I'm seeing more and more lifted L400's coming over from Japan and many appear to be incomplete installations with crucial components either missing or broken.
The front IFS (Independent front suspension) can be altered without problems, so long as the suspension components (balljoints/tie rods/control arm bushings/shocks/torsion bars) are all in good condition and the caster/camber alignment adjustments can be made within the correct angles. Depending on the lift height, balljoint spacers/subframe spacers/longer shocks may be required.
The rear RA (rigid axle) with 5-link suspension can be altered but certain critical components need to be addressed with the suspension modification.
If you have an L400 with a suspension lift, please check the following:
1. Rear sway bar
What it is/purpose : The rear sway bar or Anti Roll Bar (ARB) reduces the amount of body side to side roll and it used to help in the handling of the vehicle.
L400 has a suspension lift but no relocation/drop-down bracket for the rear sway bar. This will cause stress on the upper links that are bolted to the bottom of the L400 chassis frame. Out of the lifted L400's that I've seen, only two had the proper brackets in place. I had to weld/repair the chassis on one recently because the stress ripped the sway bar right out of the frame.
Without the rear sway bar attached and/or a broken sway bar, there is significant body roll which can cause the L400 to pitch/roll unless controlled properly.
Solution : Install a drop down bracket/spacer in between the frame and the rear sway bar. The typical extension should correspond with the amount of lift (ie. a 2" lift would need to have a 2" spacer to lower the sway bar to it's stock position relative to the frame/axle).
2. Rear brake proportioning valve
What it is/purpose : The rear brake proportioning valve assists in braking with varying weight loads in a vehicle.
For those who may not know , the rear axle on the L400's has a Brake Proportioning Valve fitted to it . The valve itself is rigidly mounted to the chassis. The rear brake line enters this valve and then is routed to the rear calipers. The valve has a lever on it that moves fore and aft. This lever opens and closes an orifice to limit the flow of brake fluid to the axle as the load demands . The other end of the lever attaches to the axle via a large coiled spring. When the vehicle is empty , the orifice is greatly restricted as the lever is pulled by the extended spring because the body of the vehicle is sitting high. This prevents rear wheel lock up when empty. As the load increases in the vehicle , the rear of the car lowers which takes the tension off of the spring and allows the lever to relax a little. This opens the orifice in the valve allowing more fluid pressure to reach the rear brakes giving more braking power.
I only seen one L400 with an extension. Probably because people don't know of the need to install one. The raised vehicle without an extension will have poor rear braking performance and increased front brake wear because the valve thinks the vehicle is lightly loaded due to the body sitting high, regardless of weight in relation to the axle height.
Solution : The typical extension should correspond with the amount of lift (ie. a 2" lift would need to have the spring attaching bracket moved up 2" to keep the spring at the correct angle).
3. Control arms/panhandle bar/driveshafts
What it is/purpose : The control arms provide the physical link between the body and the axle. They pivot allow flex movement of the axle relative to the body.
The pandhard bar/track bar keeps the axle centered horizontally (left/right) relative to the driveline. It is attached at the rear axle on the left side and on the body/frame at the right side. Diagonally.
The driveshafts connect the driveline/axles.
With mild suspension lifts (1-3" inches in height), these components do not required any alteration.
With larger suspension lifts (3+ over" inches in height), these components required modifications.
As the axles are moved further away from the chassis, the control arms will need to be lengthened/dropped down in the rear. The driveshaft may need to be lengthened to compensate for the extension. The panhard bar will need to be extended (adjustable one's are common - the stock one is not) to keep the track left to right centered in proportion to the driveline.
Solution : Large lifts should be installed professionally and the proper components must be installed as large lifts greatly alter the driveline geometry of the vehicle.
4. Shocks + brake lines
What it is/purpose : The shocks provide dampening and ride comfort/handling for the vehicle. Without them, your rig would be bouncing everywhere.
The front shocks are 1" longer in stroke length than necessary. Before the shock can top out (reach it's maximum extension), the upper control arm will rest on the upper bump stop, stopping down travel. The flexible brake lines have a lot of room for play when extended (suspension lift) that does not pose a problem.
The rear shocks are maxed out to their stroke length/extension point when the entire axle is suspended in air from the body (ie. raising the body on a hoist and the rear axle hanging without support).
There are a few components that keep the axle from falling to the ground and disconnecting from the vehicle completely.
1. rear sway bar (attached to the vehicle's frame and towards the center of the rear axle)
2. panhard rod/trackbar (attached to the frame and attached to the rear axle pivot point)
3. rear driveshaft (attached to the transfer case and the pinion/differential which part of the rear axle assembly)
4. rear shocks (attached to the bottom of the vehicle frame and to the side of the rear axle)
5. brake lines (attached to the frame via hanger and connected to the rear axle)
When a suspension lift is installed, the above components' distance relative to each other and the frame/axle change. With that change, extensions and spacers are required for everything to function properly.
The stock shocks travel 2 inches past the standard ride height which allow considerable rear axle flex/articulation.
With the addition of a suspension lift, the stock shocks travel will be reduced relative to the suspension lift which will limit the downtravel of the rear axle and depending on the height of the suspension lift, not be long enough to connect to the frame and the axle.
A note as well to check the flex of the rear brake lines. Depending on the amount of suspension lift, they may be over extended which can cause the line to rupture leading to poor/no braking.
Solution : The longer shock should correspond with the amount of lift (ie. a 2" lift would need a 2" longer stroke length of the shock absorber).
Hope this sheds some light on suspension lifts/what to look for if you have one.
