Hi can anyone help me? I am wanting to install speakers in the rear deck of my 1978 Oldsmobile delta 88 thanks

 

Hi can anyone help me? I am wanting to install speakers in the rear deck of my 1978 Oldsmobile delta 88 thanks

 

If factory speakers are still there, I think those have an insulated cardboard enclosure around them and are held in with a spring tension wire. You have to lay in the trunk to get at them and taking the spare tire out makes it easier.

The enclosure and wire retainer are useless for anything other than factory speakers due to magnet size. To retain the new speakers you'll need either small carriage bolts or what are called "T-nuts". Hopefully the speaker openings in the shelf already have the slotted screw holes to mount those.

 

Yes what Rocketraider said. Some years use these covers. Take a picture to teach us all.

 

You should be able to carefully drill holes from inside the trunk and slip the screws that came with your speaker in without removing or hacking the package tray. Just push it up from underneath and prop it up a little.

Hopefully your car has previously been wired for rear stereo or you'll need to run additional wires for the second channel all the way from the radio. You'll also need to splice new connectors,. Just cut off the factory connectors and crimp some spade connectors on, assuming that the speaker has spade prongs. It's been awhile since I bought new car speakers.

 

This is exactly how mine looks. And I do not have any speakers in mine.

 

How about pictures from under the rear in the trunk. Most GM cars in that era had these funky slide in holes shaped like a cul de sac. The studs snapped in those slots. They sucked for a couple reasons. One they could only mount a factory super thin speaker. Two there was no metal to mount to. We would shift the speaker so we could hit metal. Make sense?

 

Since there are no factory speakers, but you have the holes in the package tray, you just have to fill in between preparations the factory made for rear speakers and some options the original buyer didn’t pay for.

First figure out the wiring from your head unit. There should be a + and - wire for left rear and right rear channels. In my mid-60’s cars, there was only a + wire, the negative was grounding the speaker to the body. To figure this out, get a cheap speaker and set it up as though it were mounted in the package tray, but leave it loose probably with the rear seat and rear seat back removed. Once you have signal to it from both rear channels, you can move onto physically locating & mount the speakers.

If you have relatively small / quiet speakers in front, don’t buy the biggest, loudest 6X9’s you can find - it’ll be so loud in the back that you’ll struggle to hear the fronts. You’ll figure out the mounting. If the T-nuts are there, you can probably use them. If not, you’ll need to pop the package tray fabric away from the metal and drive your own. Use a sharpie and cardboard to make a template of your speaker mounting holes so you can locate them in the package tray metal shelf. If/when you drill the package tray, look out for damaging the rear window. Drill down, not up.

Label your wires + and -; Left & Right for future reference. Repeat these labels at the head end while you know which is which. While you’re at it, might be smart to label the front channel wires too.

Lastly, get some of the the foam backing enclosure boxes from eBay or Crutchfield. For $10 or $20. They cheaply & efficiently direct the sound into the cabin where you want, instead of dissipating it into the mounting void of the speaker. Super cheap additional decibels out of a given set of components.

Hope that helps
cf

 

There will not be factory wires run to the trunk if the car didn't come factory with rear speakers. You will need to run wires.