Rear parallel springs for your 35 to 40 Ford Frame I did a tech on the build of my 40 Ford pickup project http://www.jalopyjournal.com/forum/showthread.php?t=527407 I have had several members ask me questions on what I used and if I would do a tech on its instillation. I have the same set up in three different 40's now and my coupe has been on the road for 35 years with no problems. I use the front springs and hangers from the 49 to 54 Chevy/GMC 1/2 or 3/4 ton pickups. The hangers are riveted to the frame and easy to remove. You have to remember that these came off of the front end so they were design to support the weight of the motor and etc. You will notice the both ends have greasable bolts and the shackle end is threaded for smooth operation. I believe they use the same ends clear back to 1938 in Chevy’s and have found that they almost never wear out. The front bolt may have a groove worn into it but the bolt and sleeve as well as the rear bolt and sleeve is available through wwwrockauto.com. Front donor springs and hangers taken off a truck like this one. Front hanger, springs and shackles Rear hanger and shackles Rear shackle bolts Front hanger bolt You will notice that the shackle end will be on the front of the Chevy pickups. The spring should have 9 leaves in it. Once removed and cleaned up I dismantle the spring and remove about every other leaf with five remaining to be used. The second spring has a loop that goes around the end and will bottom out if left stock because of the different angle it will have on the Ford frame. You can remove about a half inch or cut it off before the loop for free travel. With the main leaf being number 1 I then remove the 3rd, 5th, 7th, and 9th leaves. I like to grind the ends so the corners are round and bevel a little off the bottom edge to keep from digging into the lower leaf. I also like to use the main leaf to mock up the ride height before putting this all together. When everything has been mounted and happy with its placement I then paint the leaves and install poly spring liners before putting a new center bolt and spring clamps on to complete this step. Five leaves seem to be the best to support the weight of my coupe and both of my pickups and give it a solid ride but still have plenty of movement for smoothness. I also helped do one of these in a sedan and worked the same there also. Before I start any of these changes I like to stand back and look at the wheel placement in the wheel wells of the fenders. Rounded leaves In this picture I have listed the measurements that I used to mount mine and have moved my axle center rearward a little to adjust the for mentioned centering to the wheel wells. I have found that the stock axle location on my pickup placed the tires about 1/2” to the front of the wheel wells. By using the hole in the bottom of the frame where the factory axle snubber was gives you a center point to start from. You can use the numbers I have given you to cross reference for final drilling. This is a barrowed photo to show you how the rear wheels set a little forward. Working from the front hanger first, it can be bolted to the outside of the frame as in my photos but also can be bolted to the inside if you box that area first. Either way the spring mount will be in the same location and place the spring centered under the frame. I like to box the frame to keep any side twist from happening and adding more strength to this bracket. Use the hole in the bottom of the frame where the factory axle snubber was for a center placement of the rear axle. Using the rear side hole on the front bracket and my measurement of 20 7/8” I then clamp the front hanger in place. You can mount the main leaf in place and wire the rear end up to the bottom of the frame. From the top of the spring to the bottom of the frame should be around 10” ride height at spring center. I usually use a bar clamp from the inside to squeeze the spring to achieve the 10” measurement. Put a square from the snubber hole mark to the center hole on the spring to see if your spring is also centered to the axle location or adjust it to what you think the axle center should be to center your wheel to the opening. Remember you looked at that before you got started! If not you can adjust the front mount until it does. Once you are satisfied that you have the tires where you want them mark the two hole on the side and bottom of the frame for the front hangers. At this point I like to box the inside of the frame at the front hanger mounts. Center punch them and drill out to the size of the original rivet holes or even one size larger. That finishes the front hanger mounts. Using the measurements of 37 1/8” from front bolt mount to rear swing hanger mount, scribe a line in the frame at the rear. You can also cross reference that by measuring back from your center point 17 3/16” to see if they are at the same location and also the 12 ¾” measurement from the rear edge to check that as well. Using a 1 3/4” hole saw drill a hole closest to the bottom edge of the frame as you can without going into the lower channel. That hole size gives you plenty of room to move the hanger placement around to adjust its final placement. This swing location is flexible because you want the shackles to angle just a little rearward with the weight off the springs so that they will naturally swing to the rear and not flip forward on you when jacking for a tire change. Laying the shackle back too far will cause the center carriage shackle bolt to bottom out on the bottom of the frame. You will notice the center shackle hole is not centered on the shackle. The longer part goes to the top so the carriage bolt is just under the frame line. Looking around wrecking yards I have found about three different lengths of these shackles. The holes have a taper to them to fit the threaded sleeves while the carriage bolt holds it all together. Place the rear hanger on the inside of the frame and clamp that in place. Hook up the shackles with your ride height set and see if the angle looks good. I like the shackle at about 10° pointing to the rear. Once done the shackles only move an inch or so when traveling. From the inside mark the holes for the bracket for drilling. You can see from these pictures that I have filled in the bottom of the frame so the two lower bolt holes can be used too. These photos were taken with the frame flipped upside down. Make sure you clearance this filler area so the shackle will travel and not hit to the rear of the filler. I also added a small section of boxing to tie the upper and lower frame rails together from the inside. If you read my other post, I have decided to add all the extra strength to this frame I can because I’m using the torque monster 401 Nailhead for power. At this point you can bolt everything together and add all the leaves to the springs and you are ready to mount your rear end. As you can see I have added a couple air bags to add a little extra support when I tow my tear drop trailer. In the last two photos you will see how my truck and car set for ride height with this set up. I did how ever add a set of two inch lowering blocks just for my tastes. The coupe was just finished and now that it has settled a little I’m going back to a one inch set in it.
With this set up I find the ride a little on the firm side but holds the car weight well and still rides smooth. Hope this all makes sense and feel free to add any advice, photos or opinions. I know there will be some that prefer the Chassis Engineering kit or the TCI kits but I’m on a budget and think that is the traditional way.
Mj40...I feel in love with this setup since i first saw you post on it awhile back. I'm currently building my 40 ford truck and I'm going to run this setup. I just finished mocking the rear up today so this post helps me out with the leaf removal. My set of springs and hangers were so wallered out that I'm going to have to buy another set from the junkyard but at 50-100 bucks a set it beats the pre-made kits. I'm going to post my updates today. Thanks for sharing your posts have got me out of the office and back on the shop floor...
As I stated before they both have 2" blocks but will be changing the ones in the coupe to 1" soon. With the MII front end and 2" lower spindles they look too low in rear for me with 2" blocks. I will wait for the project pickup to settle out a bit before any changes there.
Thanks for posting this. I have bought all the pieces after your last post and this helps bring it all together.
...great idea, and these parts should be easy to find with all those AD trucks gettin modified. They sure fit nice.
Very neat setup, I have used Chassis Enginering brackets on three of my 35-40.......................but if I do another I'll try it, it looks like its factory.
I have collected all of my parts to try this on mine and I have been wondering about the lowering blocks. I would like to try and get by without them if possible. This is something I found on Speedway's website. Posies makes a lowering spring for the front. This drops the truck 3", so I am wondering if you could get by without blocks using this setup? http://www.speedwaymotors.com/Super-Slide-1947-59-Chevy-GMC-Pickup-Drop-Front-Springs,21674.html I realize that raises the costs, but so far I only have $150 in mine.
The biggest issue that I could see, with the Posies spring, and not using the lowering blocks, is shock absorber travel. Most generally, the lower shock mount is integrated with the lower spring pad. If you have a stock style crossmember, you may have to raise the upper shock mounting point, to even find a shock that is short enough for the job. I think that I used Monroe's 32207 in both, my '40 and my '37. Both cars have 2" blocks. If you choose that route, here is a good reference tool for choosing your shocks. http://www.monroe.com/assets/downloads/english/08_MountingLengthSheet.pdf
The OP says he removes about 1/2 the leaves in the stock springs to get them to ride good when used in the rear. The Posies springs only have two leaves and are set up for front spring use (engine weight, etc), they may be too stiff on the rear, without any options to adjust the number of leaves for tuning the ride.
Rich, I was thinking about that. I have the original springs that came with the brackets etc. I just hate blocks. They always look like an after thought to me. No biggie, just thinking out loud here.
Old thread, I know, but cool thread. What about 53-56 Ford F100 front springs? They look like they would work just as nicely in a 40 Ford...
Yes, I bought a complete 54 Ford F100 front suspension, just for the brakes. Then I noticed how similiar the front springs were to the AD truck springs.
Or if you want to go lower without the need for blocks, you could fab your own mounts and mount the rears thru the frame and the fronts inboard like Posies does.
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