Sometimes you need your car to be level, like when aiming headlights or adding essential fluids. Generally you’re supposed to make sure the surface you’re parked on is level, the tires are properly inflated, there’s a certain amount of fuel in the tank, and somebody sitting in the driver’s seat.
But what if your suspension was damaged and sagging? How could you know? How do body shops fix damaged cars back to the correct reference?
Is there a universal place on a vehicle that ought to be used to measure with a bubble level? Like a door sill, shock mount, floor pan? Or is it like everything else in the automotive world, “depends on the car”?
It depends on the damage you’re asking about, but there are two ways (other than visual inspection to find damaged parts). One is a frame rack. If a vehicle is hit hard enough that they suspect the frame or other structural components are damaged, it is put on a frame rack which has sensors and a computer with the precise dimensions of every vehicle on the road. It is measured and, if the measurements are not what the should be, something structural is damaged and can then be repaired/replaced to get the correct measurements.
Second, for suspension damage, any vehicle that might have suspension damage will get a wheel alignment and if a suspension component is bent, it will not align properly.
When it comes to being level, the short answer is that the frame rack and alignment rack are installed to be level to begin with. With frame racks, the car is clamped in certain places from the bottom then lifted up so it really doesn’t matter if the vehicle sits level on it’s own or not. Here is a pic of a vehicle on a frame rack. As you can see, it doesn’t even have wheels. Or an engine, or windows, or seats or anything.
It depends on what you are trying to do. Check your oil? Your garage is probably plenty level enough.
Aim your headlights? Best advice is take it to an shop that does headlight alignment and they will set them.
Measuring to see if a spring have sagged? Absolutely level piece of real estate, (I use an alignment rack), car just driven, wheels straight ahead, no driver, no passengers fuel level doesn’t matter. You measure from the ground up through the center of each wheel to the fender. Look up the spec. Toyota for example says if it is within 20mm side to side it is normal.
For Oil, and other engine fluids, the engine is a part used in an number of vehicles.
The engine may be at various angles in those vehicles but its a tiny angle in any… in most vehicles, if its parked on the flat, the engine is quite level… if you were scientifically measuring fluid levels, you would use the block 's plane surfaces to level it.
For leveling lights, its when the wheels are on the level.
For suspension, the shell has a design… obviously the heights on various parts of the shell (the box or I girder like features of the shell, the reinforced bits where attachments are placed… should be the same left to right, but not necessarily front to back…there is a spec for those heights when using manufacturers suspension parts. (its may be that an aftermarket suspension is meant to change the height.)
This makes no sense and is incorrect. The engine is not necessarily level when the car is parked on flat ground. There is no reason for it to be level. By inclining the engine cars can be built with a lower hood line. An example of this would be 5 cylinder Volvos (S60, S80, V70 etc) the engine is inclined at about 20-25 degrees toward the front of the car.
Regardless of what orientation the engine is installed at the engineers have given it a dipstick that reads correctly when the car is on flat ground.
correct but I still maintain the average person is better off leaving this one to someone that has the equipment to set them to the correct level. I’ve been blinded by too many oncoming cars with mal adjusted headlights.
I’ll be damned if I know what you mean by I girder. I think you will find it is a lot easier to measure the way I described up thread.
For alignments and frame straightening, you need to be level to a degree of precision. For checking fluids and aligning headlights not so much. If it looks like you are parked on a level surface, you are close enough.
Ok, here’s the real world example. I will need to change the transmission (manual) gear oil and rear differential oil at some point in the future. These are typically drained out one plug on the bottom of the housing and refilled from another plug somewhere on the side of the housing. You need to refill until oil just begins to dribble out the fill plug. If the car is not level the fill amount will be incorrect. I don’t know how far out of proper spec matters to a transmission or differential, and I don’t know how much out of level it would take to under or over fill by a serious amount.
To do this fluid change professionals would put the car on a hydraulic lift and raise it over their head and not think anything of it because hydraulic lifts probably lift cars as close to perfectly as possible. The lifting pads are put positioned on jacking points under the car provided by the manufacturer.
I don’t have a lift. I have a gravel patch sloped away from the house for drainage. The car is high enough to use a little hand pump that pulls the oil from the container and squirts it into the fill hole without jacking it up. I could park two of the wheels on plywood to level it, but I don’t know where to measure to see how close I am.
If I ran a string line from two jacking points under the car and measured the string, would that work?
