Jacking Up Your Jeep - Lift LogisticsPosted in How To: Suspension Brakes on January 22, 2014 0) (
So, you want to lift your Jeep? So do we. A suspension lift provides greater ground clearance, room for larger tires, and use of quality aftermarket components provides improved traction and performance off-road. But, what may seem like a relatively simple parts swap can get complicated, escalating as the lift height goes up.
Today, we’re lucky to have a wide variety of quality lift kits available for our rigs. A good number of owners have misjudged the performance result they expected to get from a simple or budget lift. If you’re looking to increase your ability in the dirt, you’re often better off spending some more dollars up front on a quality suspension. In any case, here are a few tips to consider and items you can’t leave out when doing a suspension lift.
Proper Shock Sizing
If you buy a fully engineered kit, shock sizing is typically already done for you with shocks included. However, if you’re piecing together a suspension lift or deviate from a fully prescribed kit, you won’t get the full benefit of your new suspension if you fail to size your shocks correctly. In the best case, you simply rob yourself of valuable suspension travel. In the worst case, your shocks end up being the hard limit to your suspension travel until the bodies are hammered from excessive bottoming, or pulling apart due to over-extension. Properly engineered kits can have the right matching shocks, but in many cases it may be time well spent to crawl under your rig and make some shock travel measurements before choosing the shocks you need.
Extended Brake Lines
Any time you add a lift, it’s a good bet your factory brake lines will no longer provide sufficient length at full suspension droop. If they don’t rip apart, they’ll most likely be pulled and stressed, accelerating wear to the point of failure.
For mild lifts, it may be possible to stretch the hard line downward on the frame the same distance as the lift height. This can allow you to keep the factory rubber hoses, and even avoid bleeding the brake system. Some aftermarket kits will include brake line relocation brackets for just this purpose. However, this is really only acceptable if the lift you’re installing doesn’t increase suspension travel.
Should your new system increase travel, you will need longer brake lines to accommodate more suspension travel. We generally prefer to upgrade to quality braided steel brake hoses. These consist of a Teflon inner tube surrounded by other protective layers, one of them being braided stainless steel mesh hose. The Teflon tube offers several advantages over the stock rubber hoses. It does not expand with pressure, is unaffected by high temperature, and resists deterioration with age. The outer braid is used to protect the Teflon inner tube and is usually coated with a flexible polymer.
Whenever lift is added to a solid-axle vehicle, the driveshaft angles increase. Driveshaft joints operate in greater harmony and wear longer when the joint angles are shallow. Steeper joint angles are a fact of life when we add lift, so there are some considerations to take into account as you push skyward. This effect is also exaggerated with stubby driveshafts found on the short-wheelbase rigs. Essentially, the transfer case always sits higher than the pinion shaft, so there will always be some driveline angle between the two. There are several ways to minimize the higher angles that can cause driveshaft bind under full droop. These include lowering the transfer case, rotating the pinions upward, or using ways to add driveshaft length and reduce its operating angle.
In almost all cases, adding a lift has some effect on the steering behavior—factory linkage angles have changed and the steering may no longer reach lock-to-lock, or geometry has changed and results in inconsistent steering.
When a solid-axle vehicle is lifted and the axle moves further from the frame-mounted steering box, the track bar (on linked front suspensions) and steering drag link angles rise. For mild lifts, this may not be a concern. But at some point in lift height, the steeper angle makes the track bar and drag link effectively too short and/or tie-rod ends may start to bind under full-droop. A steep angle causes the axle to push the steering linkage to one side or the other as the axle compresses or drops out, pulling the pitman arm with it.
Track bar angles can be improved by using a drop bracket on the frame end that makes the track bar angle flatter. Pitman arms at the steering box may be flat, or they may have a drop bend. A dropped pitman can help reduce the angle of the drag link after a lift is added to help minimize the effect of bump steer. A raised steering arm on the axle can also help reduce the drag link angle, but if you use a dropped pitman arm you need to add a track bar drop bracket of a similar value. In other words, use a 4-inch dropped pitman arm with a 4-inch track bar relocation bracket to keep the linkages parallel.
Along with the high priority of working safely when installing a lift kit, there are a few basics tricks that can come in handy when you’re trying to maneuver heavy suspension components in place that may require some added muscle or ingenuity. Use of one or more pairs of jackstands will allow you to solidly secure the frame while doing your work. Combined with a high-lift rolling floor jack, you can more easily adjust axle height and position to get all the suspension pieces to come together. When installing link bolts or leaf springs, a ratchet strap may come in handy to pull the axle into place. A track bar that is close to mating to its bracket may be coaxed into position by turning the tires left/right to make small adjustments for bolt alignment if the vehicle has its tires on the ground.