A Arm Swap

[panteratron]

Hello All. Does Anyone Know If I Can Swap The A Arms From A 73-87 Half Ton To A 71-72 Half Ton,if So What Else Do I Need? I Have A Complete 78 To Scavenge Parts From. I Was Going To Use The Crossmember But Its Trashed.

[MrShelley]

Yeah, they'll swap. I did the same thing on my truck. Unbolt the upper and lower a-arms and get spindles and all. Grab everything steering related while you're at it (steering box to rod ends).

[panteratron]

Thanks Mrshelley Thats Exactly What I Wanted To Hear!! Man This Web Site Is The Best!!!!!

[arkracing]

why would you want to swap onto a '71-'72 Truck? - they already are set up for disc brakes?

or do you not have a front end in your truck?

'73-'87 Arms will bolt right up - I put them in my '69 so I could convert to Disc's

[panteratron]

The 73-87 are alot easer to find parts for.

[harleyx2]

arkracing. would it be easier to swap the arms and sterring or just swap the entire crossmember? im about to do this swap. thanks

[MrShelley]

I did this swap on my '68 to get polyurethane bushed a-arms, disc brakes, and 3" dropped spindles. It also seems easier to find parts (usually) for 73-87 trucks.

[kevncar]

Strength and/or driveablility wise, are the poly-bushed a-arms favorable over the solid steel bushing in the stock a-arms? Or is it just because the parts are cheaper or easier to come by for the later models? Just curious.

[arkracing]

You can still get the "Bushings" for the '67-'72 Arms.
You can still get all the ball joints and everything for the '71-'72 - They share alot with the later '73+ stuff.

Oh and if you are using '73+ parts - try to get them out of a truck that had the HD front rotors which were 1.25" thick instead of the 1"


Harley2x - I just swapped the A-Arms and steering etc. I didn't do the crossmember. That way i didn't have to mess around with all the hard brake lines - just got the '71 - '72 Front Brake Hoses and used them.
Is the motor in or out of your truck? - if it is out, it might be easier to swap the the whole crossmember. If you do that you will end up using the '73+ Calipers and hoses - but you'll have to plumb up the hard lines.
The other problem is the springs - if you don't have the motor in, it might be hard to get the springs in. You might have to chain the chassis down to keep it from moving up when you jack the lower control arm up into place (Unless you are using a spring compressor). Putting springs in should always be a 2 man job - and use EXTREME CAUTION!!!!!

'67-'72 Front hard lines run on the back of the main crossmember there, where the '73+ run on the front crossmember (up near the radiator)

It you search - and use my name in the "Advanced search" there is a couple of other threads about this topic.

-Andy

[arkracing]

Originally Posted by kevncar

Strength and/or driveablility wise, are the poly-bushed a-arms favorable over the solid steel bushing in the stock a-arms? Or is it just because the parts are cheaper or easier to come by for the later models? Just curious.

The factory solid steel bushings give the suspension a very "Positive" feel - not much flex, the Poly's will work similar with some give, stock rubber are stock rubber.

I didn't notice a differance between GOOD stock rubber and the factory Solid Steel

[70GMCer]

Are the lower control arm cross shafts and u-bolts from the 73+ a direct bolt on to the 67-72 cross member? They look bigger.....

[MrShelley]

The shafts swap right in perfectly. I can't remember, but I "think" you may have to open up the u-bolt holes slightly to accommodate the larger 73-87 style u-bolts.

Here's the 73-87 arms on my 68.

[kevncar]

Very good info. I got everything complete from a-arm to a-arm from a 76 with the 1.25 rotors. I got dropped spindles from ECE that will allow use the 67 ball joints and tie rods but the spindle itself is setup for the HD rotors. SO I didn't really use any of the 76 stuff except the rotors and calipers. Basically I'm all 67 until the spindle, and then 76 from there out.

Mr. Shelly--I've always like your lower arms. I think they look much better without the bumper on them. I think I may take the ones off mine.

[SCOTI]

Originally Posted by MrShelley

The shafts swap right in perfectly. I can't remember, but I "think" you may have to open up the u-bolt holes slightly to accommodate the larger 73-87 style u-bolts.

Here's the 73-87 arms on my 68.

Yep, the u-bolts are larger for the 73 & later so the holes have to be opened slightly.

You can also use the 73 & later hard lines on the 67-72's which allows you to use the 73 & later flex lines @ the caliper. I have my prop valve located in the same place on my 68 (which used '75 parts) as my 74.

[MrShelley]

I knew this topic rang a bell...

Check this thread

[arkracing]

My U-Bolts went right in - I used control arms of of a '91 Suburban (same as the '73-'87 Trucks) I used the '69 U-bolts with no problems

[panteratron]

One More Small Question. Do I Use The Shims On The Upper A-arms From The 78 Or My 71?

[arkracing]

Originally Posted by panteratron

One More Small Question. Do I Use The Shims On The Upper A-arms From The 78 Or My 71?

I would start with the ones from the '78 - your front end will need to be lined up anyway.

(I didn't have the ones from the donor truck, so I just used the '69 Shims - I had the truck lined up)

[OLDIRON69]

Can you use your factory 69 upper arms with 73-87 lowers to get away from the pressed in lower ball joint?? I'm going to swap disc brakes from a '71 frame to my '69.

[MrShelley]

The 73-87 arms also have a pressed in lower ball joint.

[OLDIRON69]

I did not think they did, my later model S truck has riveted ball joints top and bottom...see what I get for thinking

[724x4a/cchevy]

Originally Posted by MrShelley

Grab everything steering related while you're at it (steering box to rod ends).

Does this mean the power steering setup will swap?

[MrShelley]

The power steering is definitely swappable on a 2WD. But I don't know about on a 4WD. Isn't the steering set-up different?

[62chevy302]

i have a 66 frame. what all do i need from a 73-87? a-arms ball joints spindles calipers springs? what else? thanks.

[68 P.O.S.]

I'm going to do the 73+ A-arm swap on my 68. Will my 67-72 springs work with the 73+ arms?