I've had several requests for tips installing 49-54 p***enger car INDEPENDENT suspension in AD trucks. I'm not knocking all the other conversions! I just don't want one. I wanted to keep the Straight axle and drop it 7-8 inches. that wasn't going to happen. I had a customer come into my shop for a B.S. session. got talking and he mentioned this conversion. said it was common "back in the day." I have never seen or heard on it ever being done. He just happened to have a rebuilt 49 chev unit laying in his shop. 2 hours later it was laying in my driveway. he even voluteered to install it. Simple bolt in! just weld a couple pieces of 1/4 inch angle drill some holes and bolt it in. we layed it out and I checked the Caster. it was about 10 degrees negative. I said I neeeded about 7 degrees positive. I haven't seen him since all my photos are in an old computer that I can't get on line. I'll try to explain and answer any questions later. the early cars drive better the early trucks. The p***enger car suspension bolts in as a unit. 8 bolts on each side. I didn't have a clue when I started. (that should be enough for half of you to return to the board) I knew that I had to rock it back in the frame. those 8 bolts that hold it on are two sets of 4 bolts. I cut the front plate (4 bolts) off. I left the rear half on to help line things up. I noticed something that made everything work. The stock truck (54 GMC) front crossmember had a groove that was straight across the center that cuts back and up on each end. exactly the same as the front edge of the car unit. I had to cut notches the car cross member for the truck frame rails to drop in. once that was done I was able to line the two cross members up at 7 degree positive. with the rear plates (the back 4 bolts) resting on the truck frame. squared up all points Tacked in a couple places. called in a buddy (professional ch***is builder) to double check everything. I was within 1/16 in all directions. the truck and car cross members were matched all the way from frame to frame with 1/8 inch gap. I made 1/8 inch plates to box and fill the gap on the inside of the frame rails. I ended up with 7 inch drop with stock springs and spindles. I have a pair of 54 spindles and drums that will give me another 1 1/2 inch drop if needed (probably won't use them) I will up grade the brakes and install gas shocks and radial tires
Sounds like a very practical and inexpensive way to get IFS...What about the steering gear? As I recall the truck unit puts the pitman arm outside the frame and the p*** car pitman is inside the frame with the drag link going to the center pivot bellcrank. Also curious as to your reference of 'positive' and 'negative' regarding caster. My understanding is that as viewed from the side, the top of the kingpin is tilted toward the back of the vehicle, i.e the tilt of a bicycle fork. That would be, again as I understand it, called 'positive caster' Ray
my error. yes it's 7 degree positive. the truck steering is outside the frame. mine was moved out another 2 inches for the the 331 cad. I used a mid 80's Ford Ranger box that was in my s**** pile.
Thanks for your reply and post. I studied your pictures and will start mesuring things out. Ill keep posting as it goes.
Thanks for the post. I have been wondering about doing this to mine for a while. Now I will be on the look out for this front suspension.
OK I got the thing sliced&diced tacked in and the 54 car box mount built and in. The thing is a natural fit and looks killer. Everything clears on my mock up engine just have to fab up a simple front mount. Why hasent everyone been doing this for 30 years? I will post build pics soon as im in the middle of moving to a neww house and times slim away from the shop.
I really would have used a dropped axle and car uprights if I thought I could drop it 7 inches. I have a set of 54 spindles and drums that will give 8 1/2 inches if I need it with stock uncut springs or dropped uprights. I'm going with radial tires, gas shocks, vette sway bar. and maybe power disc brakes. it should drive better than the straight axle. I'll know soon!
Yeah just like you did Noname but I pie sectioned a "flat" in the thick 1 ton frame to mount and set the caster. I got some pics. http://i131.photobucket.com/albums/p307/Unsafe6/DSCF6192.jpg http://i131.photobucket.com/albums/p307/Unsafe6/DSCF6194.jpg http://i131.photobucket.com/albums/p307/Unsafe6/DSCF6211.jpg http://i131.photobucket.com/albums/p307/Unsafe6/DSCF6191.jpg http://i131.photobucket.com/albums/p307/Unsafe6/DSCF6190.jpg Like I said why havent people been doing it for years. Its just right. http://i131.photobucket.com/albums/p307/Unsafe6/DSCF6184.jpg
Very interesting thread, nice work guys. Just FYI though, I think you could get your 7" drop and keep a straight axle. I've got a 6" drop on my '53 using a 3" dropped axle and monoleafs. I could've used a 4" dropped axle but would have been slightly below the scrub line. Yours probably rides a little better.
When I owned my first AD truck about ten years ago, I had a gentleman chat with me while I was refueling, and he had mentioned this very same idea. After I lost that truck to a drunk driver, the idea had slipped my mind. The truck I have now is very roughly sitting on a S-10 ch***is, but something about the look of it bothered me. Thanks for posting the info.
So now that you have the truck sitting nice and low where it should be, you can take the straight axle from the truck and put it in the car to build a g***er
**** Undercover Customs you got me figured out dont ya! Waldo53 I built a AD two years ago with dearced springs and it was low but didnt drive to good. I want this truck to ride and steer as good as my 54chev car.
yours looks better than mine, I should have done mine second. it does fit like it was made for it. I've added the corvette springs and am thinking vette sway bar too
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