'77 doors onto an '84 GMC cab

[Marcoman]

Hello, is anyone familiar with "older" square body doors? I just picked up a pair for $50 and plan on using them on my 1984 GMC truck. It seems like these might be from a K5 Blazer? I hear that these came with thicker glass than those from the 1980s. True? I'm guessing if the wiring works with these I can just integrate them into the factory harness? Thoughts? Oh and I haven't tested them yet. Here's a couple of photos of what I got going on.

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[45tt]

In the LMC Truck Catalog it has the doors in two groups, 73-76 & 77-87.

If they are 77 doors, they should work on your 84.

im sure the difference in years has something to do with power windows?

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[Marcoman]

In the LMC Truck Catalog it has the doors in two groups, 73-76 & 77-87.

If they are 77 doors, they should work on your 84.

im sure the difference in years has something to do with power windows?

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Cool, I appreciate the reply! I'm still needing to measure them, it's just too hot and smokey outside right now.

 

[TubeTruck]

The 73-76 doors also came with smaller door panels. So the mounting holes will be different. '77 up doors with 73-76 panels have all the mounting holes exposed (see pic) and vice versa, the holes for the '77 up door panels won't be there on 73-76 doors.

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[Marcoman]

The 73-76 doors also came with smaller door panels. So the mounting holes will be different. '77 up doors with 73-76 panels have all the mounting holes exposed (see pic) and vice versa, the holes for the '77 up door panels won't be there on 73-76 doors.

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Thanks for the reply. I'm more concerned with the exterior fitting into the cab opening where the door goes. I understand that tolerances vary from year to year if not week to week. Hopefully it'll line up. I'm recovering from an accident so I'm limited to movements in my upper body. It's sucks growing old, lol.

 

[Snoots]

They'll fit with no problems.
BTW, 73-76 door glass is thicker than 77-up.

 

[Marcoman]

They'll fit with no problems.
BTW, 73-76 door glass is thicker than 77-up.

Promise? lol Thanks for the comment, I'll post the outcome when I get to it.

 

[Snoots]

I've got '78's on my '73. Love the PDL and PW's!
And no rust too!
As @TubeTruck said, the interior panels are different.

Hint: Take the hinges with your replacement doors.
Take the shims too and mark where they went.
Do the same with your old doors.

I'd use the newer hinges with the shims that were on them.
You can make any needed adjustments after that.
NEVER throw away shims!

 

[Marcoman]

I've got '78's on my '73. Love the PDL and PW's!
And no rust too!
As @TubeTruck said, the interior panels are different.

Hint: Take the hinges with your replacement doors.
Take the shims too and mark where they went.
Do the same with your old doors.

I'd use the newer hinges with the shims that were on them.
You can make any needed adjustments after that.
NEVER throw away shims!

Hey, unfortunately the doors didn't come with the hinges, I do have the hinges on the cab still. Hopefully they'll line up okay.

 

[Snoots]

For 50 bucks I wouldn't complain either, just sayin'.

You'll find a floor jack and some short pieces of 4x4 handy. It's not really a 1 person job, especially since your accident.

 

[gmachinz]

Window wiring is not the same-you need a correct 77-81 window crossover harness-assuming you got complete door wiring with them-if not you will need an entire harness for 77-81. The 77-81 motors arent as efficient as the 82-up reverse polarity motors.

 

[idahovette]

Window wiring is not the same-you need a correct 77-81 window crossover harness-assuming you got complete door wiring with them-if not you will need an entire harness for 77-81. The 77-81 motors arent as efficient as the 82-up reverse polarity motors.

Can you use the 82 up motors in the earlier doors without a lot of modification?

 

[gmachinz]

That I have not tried to do myself.