Untitled Document

Power Antenna Mast Replacement

Last Updated: June 23, 2000

Applies to all cars with Power Antenna

First, you should determine for sure that it's your antenna mast that needs replacing, and not your power antenna unit! This is very easy. Turn the key to the ON or Accessory position. Turn the radio on, if it isn't already. (Note: Some aftermarket stereos will require you to be in TUNER mode.) You should be able to hear the power antenna motor run for several seconds. Then turn either the key or radio off. You should be able to hear the power antenna motor run again for several more seconds. If the power antenna motor does not run at all, then it is probably bad and you will need to replace the entire assembly because GM/Delco does not sell the individual parts of the antenna mechanism.

Ordering a Mast
You will need to order a new mast from a GM parts dealer. Here are the part numbers for the mast:

Grand Prix 88-89 10060301 (U75)
Grand Prix 90-91 10180505 (US7)
Grand Prix 92-96 10277374 (US7)
Cutlass Supreme 88-89 12512784 (U75)
Cutlass Supreme 90-91 10180505 (US7)
Cutlass Supreme 92-97 10277374 (US7)
Regal 88-89 12512784 (U75)
Regal 90 12512784 (U75) - mast fits antennas stamped with part #10063073
Regal 90 10180509 (U75) - mast fits antennas stamped with part #10136711 and 10136712
Regal 91 10180509 (U75)
Regal 92-96 10277375 (U75)

The U75 power antenna masts are chrome. The US7 power antenna masts are painted black. Be sure to order the right mast, as there is no way to interchange black & chrome because they are different diameters. If you want to change the color of your mast for some reason, you will have to replace the entire power antenna unit.

Preperation for Installing a new Mast

Part of the nylon cable from your old mast are likely to be stuck inside your power antenna unit. Usually it is not always necessary to remove the broken bits of old cable from inside the power antenna unit. A little bit of old nylon cable stuck inside the power antenna unit will not interfere with the operation of the new mast, however, if enough old cable is broken off inside the antenna or if you've replaced the antenna mast several times and there is a large quantity of broken cable inside, the antenna may have trouble retracting. If this is the case, you will have to remove the cover from the power antenna unit and pull out the remaining fragments of old nylon cable. On an 88-91, the front cover is held on by 4 phillips head screws, and one nut in the middle. On a 92-96, the front cover is held on by plastic rivets. Disassembling and reassembling the power antenna unit can be tedious, especially on a 92-96, so it would be a good idea to try installing the mast first and see if it can extend and retract without any trouble. If you do decide you need to extract the old cable bits, be sure not to lose any parts when you remove the front cover!

GM's Instructions for Replacing the Mast