Alignment Checking - Underbody. Pontiac Grand Am 1998

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 1998 🢒 Grand Am 🢒 Body and Accessories 🢒 Frame and Underbody 🢒 Alignment Checking - Underbody

Horizontal and Vertical Dimensions


(1)	Datum Line
(2)	Upper Hinge
(3)	1972 mm (77.6")
(4)	1972 mm (77.6")
(5)	1126 mm (44.3")
(6)	1296 mm (51.0")
(7)	880 mm (34.7")
(8)	1296 mm (51.0")
(9)	816 mm (32.1")
(10)	704 mm (27.7")
(11)	700 mm (27.5")
(12)	554 mm (21.8")
(13)	1156 mm (45.5")
(14)	907 mm (35.7")
(15)	440 mm (17.3")
(16)	1144 mm (45.0")
(17)	666 mm (26.2")
(18)	523 mm (20.6")
(19)	190 mm (7.5")
(20)	640 mm (25.2")
(21)	800 mm (31.5")
(22)	208 mm (8.2")
(23)	212 mm (8.3")
(24)	376 mm (14.8")
(25)	364 mm (14.3")

•	All of the control points are symmetrical from side to side unless it is otherwise noted.

•	All of the measurements have a tolerance of ±3 mm.

•	The right side gauge hole is relative to the left side gauge hole.

The gauge hole should be at the following location relative to the center of the vehicle:

-	13 mm (0.5 in) above

-	23 mm (0.9 in) rearward

-	10 mm (0.4 in) outboard

Use a measuring tram gauge in order to accurately determine if the underbody is aligned. Ensure that the tram gauge set that includes a vertical pointer. The pointer must be capable of reaching 457 mm (18 in).

A tram gauge can make the following types of measurements:

•	Direct point-to-point measurements

•	Datum measurements

The datum is a horizontal plane that is parallel to the underbody.

Take point-to-point measurements on the following components:

•	Steering components

•	Suspension components

•	Engine compartment components

Set the vertical pointers equally when you take point-to-point measurements.

Unless otherwise specified, measure the dimensions to gauge holes within the following guidelines:

•	To the center of the holes

•	Flush to the adjacent metal surface

Measure the diagonal dimensions on both sides of the vehicle in order to verify the dimensional accuracy.