I'm looking to drop the rear of my '40 in as traditional a way possible. What would have been correct in the 1950's? I have a reverse eye spring on it but it's still way too high to match up with the drop axle and reverse eye spring I have on the front. Should I flatten the cross-member or swap it out for another one? I've looked and looked and can't find anything but talk about Chassis Engineering parallel leaf setups etc. (not interested in this route btw) I think I need another 4" of drop to get it looking right. Thanks for any help!
On the rear of your '40, take the top 2 leaves & put them back on the bottom of the spring pack, that will gain some drop. They are needed to maintain the thickness of the pack so the clamps will clamp. If the car doesn't bottom out, remove the next 2 leaves & put them under the bench.
Don't know how thick your spring pack is in the rear but removing a few springs in the pack will do the job,,you will need to make some spacers to replace the thickness of the springs removed. HRP
People used long shackles as a lowering means all the time back in the day. It was generally considered Mickey Mouse as it induced side sway, but people did it anyway. I was surprised in a conversation with Roy Brizio to hear him say that he used them too, and that it worked satisfactorily as long as a panhard rod was used to inhibit sway.
In my day,we just put longer shackles on it..I used 6" shackles on the rear of my 39 Deluxe cpe...truthfully we should have also used an anti sway bar with that long of shackles. you might still be able to purchase long shackles from Night Prowler..
No long shackles, please. Have the spring rearched to your desired height by a qualified spring shop. Another option is a Posie Spring per your spec's. I have done both with good results.
Truthfully, if you're already down ~1.5" with the reversed eyes, you're not going to find another 4" with any sanitary method. I went through this on my '36, and with serious lowering with the transverse spring, the ride was just intolerable. Even if you get the drop you want, constant bottoming on the frame will make you nuts.
Tony's comment above brings up a very important point which is often overlooked in discussions of customs from the past: most of 'em were junk on the bottomside. I still remember being given a ride by the older brother of a friend in his severely lowered mild custom '50 Chevy coupe. It sure sat great, low with a slight forward rake, and looked like a million bucks with shiny paint, whitewalls, red rims and Fiesta 'caps. But on the road it was a nightmare, bottoming on every dip and bump with a teeth-jarring crash of metal on metal. He'd removed the rubber snubbers to get what little suspension travel it still had. This was very, very common - even on the high end customs of the day as we are just now discovering as so many of the well-known old customs are being discovered and restored. Some of the cars we knew and loved in the pages of the "little books" were engineering and workmanship disasters beneath the lead and multiple coats of hand-rubbed lacquer. Oh, well, so much for the misconceptions of youth.
Thanks a bunch for all the input guys. I think I'll modify the crossmember in the interest of making a mechanically sound car whether it would be correct for the time or not. I think I'll end up with a cosmetically better solution with proper spring travel. Again, thanks for taking the time to help.
Are you sure you have the correct 1940 Ford rear spring in your car? They came in varying leaf counts. It seems that it would be a lot easier to modify the spring rather than the cross member. If you can, post a photo of the way your car sits now. The 40 below has the stock rear spring and shackles. Front has 5:60x15 tires with a 4 in. dropped axle. Rear has 7:60x15 tires with stock rear end and spring. Check with Posie's for a spring that will work for you.
I think your crossmember decision is a good one. You may want to consider C'ing the frame rails at the same time so that the axle has somewhere to go in its lowered position.
Just out of curiosity how low are you wanting it to be? Can you post a pic of it now with a measurement at the rear fender lip and how low you would like the fender lip to be (at the centerline of the axle) I think mine is at 26 1-2" with L78 tires
A big car like a '40 should have at least 4 inches of travel between axle and frame. You'll probably need to C the frame as the others have suggested. Or just leave it and the axle will pound a C shape into the frame rail (or vice versa).
jewlini, Please post photos of your car, including a side view. The 1938-41 Ford Chassis parts book shows that 1940 Ford rear springs were made with 8,9,10,11,12 and 14 leaf springs. Just curious - what is your rear spring leaf count? Is your car body assembled and on the frame or or you working with just the frame with the body off?
My first 40 sedan had long shackles and it was absolutely scary when I drove the curvy country side around this area. HRP
On the shackle issue...you want the shackles to be close to 45 degrees for stability. As they approach vertical you get sway, with the car effectively slung like a hammock. This condition was a problem sometimes on unaltered cars because of beat up springs sagging and so lengthening distance between the eyes and allowing stock shackles to go vertical in response... Speed catalogs of the day as noted above sold long shackles, quick and easy lowering with sway included. They also sold a cure...there were simple aftermarket sway/panhard bars that were easy to install because they bolted to the center spring bars at one end and a bolt-on arrangement out at wheel. Longer is better, of course, so if building go with a full width sway bar as on rear of a '42-8. The panhard route works, '48 Fords have vertical shackles and no sway problems. I think the design idea and the problem addressed by the bar was that the spring became JUST a spring, as on a coil spring car, and ALL suspension geometry was handled by the torque tube and the sway bar, whereas on pre-42 cars sway was addressed by transferring the force to spring via slanted shackles. Remember that sway here is sway, dammit, sideways motion parallel to ground, NOT roll as in the comic book mags that call an anti-roll bar a sway bar!
It's sitting on a 2.5" lower posie's spring through speedway and things aren't adding up. The highest point of the rear wheel opening is at 31" which seems to be higher than stock from pictures. I'm going to do some more homework on my "lower" spring. On the bench it is a couple inches lower than the original but it's also 2" wider which obviously reduces the needed stretch so it isn't de-arching as much as the stock would when hooked to the shackles.
I made longer shackles and still using the stock pan bar. You may have to heat and bend the pan bar, depending on how low you will go Posted using the Full Custom H.A.M.B. App!
There were a lot of ways or are a lot of ways to drop the rear. In the '50s and even into the '60s longer shackles were popular as was de-arching the springs, or removing leaves. I don't know how your '40 sits but if it is '50s you are after her is a perfect example of a '50s '40 Ford just as it set the day that I was born.
I think I'd be sending that spring back and get one directly from Posie. I don't think that spring is what they are telling you it is. Call Posies directly and see what they say. I bet that's not the right spring .
Agreed, that description sounds WRONG. And of course with substantially longer spring, you will need a panhard sway bar whether car is lower or not...shackles will be vertical.
Why not flatten the rear crossmember, Kevan Sledge does that to all of his 39-40 Mercs and it looks great? Posted using the Full Custom H.A.M.B. App!
Two tried and true, traditional methods are to reverse the spring eyes on the main spring, (you have to grind the spring next to it back a little on each end to keep it from binding) and the second is to de-arch the main spring to make it flatter. And, trust me, the latter works really well. Once, I had Hollywood Spring and Axle reverse the eyes and flatten out my main spring, and it ended up being too much, and the '37 Coupe I had, sat down in the back it looked like, even with big tires on it. I was thinking about this today. I had to get another rear spring and start over. And, a word of wisdom, make sure you have some method of allowing the spring to stay under compression when you take the tie bolt out, that will allow you to slowly release it. Otherwise, it's like 52 Card PickUp with pieces of steel raining down.
I just read this whole thread and got to my post and it sounds like I was sleeping in class. Nonetheless, the above is true and sounds like where you are, now. Keep in mind if the spring is wider, we both know that can't make it lower because the extra length adds height. Longer shackles on the other hand allow the body to move down, as per reversing the spring eyes. As others have suggested, raising the cross member is physically the only alternative left.
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