If you are experiencing a nose dive condition with your vehicle, your intuition may tell you to look for an issue with the braking system, when the problem is more likely in the suspension. Any vehicle will nose dive under heavy braking, to a certain extent and the cause of this is called weight transfer.
As you apply brakes while in motion, weight is transferred to the front of the vehicle which forces the front shocks to compress. The same amount of weight transfers away from the rear of the vehicle, which causes the rear struts to expand. The compression of the front shocks lowers the front of the vehicle and the expansion of the rear struts raises the rear. The harder you brake, the more defined this effect becomes.
If you are experiencing more nose diving than normal, you may have a suspension issue.
Part 1 of 2: Visually inspecting the brakes
- Jack Stands
- Tire Iron
Step 1: Loosen front lugs nuts on the front tires. Use the tire iron to loosen your lug nuts on both front tires.
If you do not perform this step first, you will not be able to loosen the lug nuts (also called wheel locks) with the car in the air. The tires will spin and you will have to put the car back down.
- Tip: Do not remove the lug nuts - only break them loose. You should not have to loosen them more than a half to one full turn.
Step 2: Get the front of the vehicle in the air. On a flat surface, use whatever type of jack you have available to raise the front of the vehicle.
If you cannot find a suitable location under the front bumper, you can jack each side up, one at a time.
- Tip: You only need to raise the vehicle high enough to take the front tires off. Do not raise the vehicle higher than necessary.
Step 3: Place jack stands under the vehicle. With the vehicle in the air, place jack stands under the vehicle in a location that will leave the suspension free to travel.
Under a subframe, or on the sides of the vehicle are suitable locations. Consult with your owner’s manual for your tire changing procedure if you are unsure where to place stands
Step 4: Remove tires and inspect. Use the tire iron to remove the loosened lug nuts and set the tire off to the side.
Inspect the spring and visually confirm it is not broken. Look for cracks or dents, rust or corrosion. Feel around the piston rod for oil. Finding oil on the piston rod is a sign of a worn out seal.
Step 5: Reverse the procedure and return the vehicle to the ground. Replace the tires, and tighten the lug nuts in a star pattern until the tire begins to turn.
Use the jack to raise the vehicle just enough to remove the jack-stands, and remove the jack stands from under the car.
Lower the vehicle to the ground, and finish tightening the lug nuts. It is important to remember to finish tightening the lug nuts, while the car is on the ground, so the tire won’t spin freely.
Part 2 of 2: Testing the shocks and struts
If you found oil on the shocks in previous steps, chances are very high you need to replace them, but you can try a couple other methods to confirm.
Method 1: Do a bounce test. This is a classic method that involves placing your hands on the hood, fender, or trunk of the car and using the weight of your body to “bounce” the vehicle.
This is not the best method of testing because an inexperienced person will find it challenging to tell what is good or bad. The idea is to feel for a bounce back. A good shock will be hard to compress, where a blown shock or strut will feel “spongy.”
Method 2: Do a road test Drive the vehicle over a speed bump and feel for anything that you might categorize as bouncy or spongy. If you feel excessive body roll while cornering, this is also a sign of worn out shocks and struts.
If you are unable to troubleshoot your vehicle’s nosedive condition, contact a professional mechanic, such as one from YourMechanic, to diagnose why your car nose dives for you.
This article originally appeared on YourMechanic.com as How to Troubleshoot a Car that Nose Dives When Braking and was authored by Michael France.