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Technical 40-41 FORD PICKUP PARALLEL LEAFS

Discussion in 'The Hokey Ass Message Board' started by Bandit Billy, Nov 19, 2025 at 4:08 PM.

  1. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 15,875

    Bandit Billy
    ALLIANCE MEMBER

    Welcome cl***, todays is regarding the installation of parallel leaf springs on 40-41 Ford PUs. I will begin with an apology to everyone that has asked me whose products I used and to anyone that may have actually taken my advice (which my wife says is a fool's errand, whatever the hell that means).

    I have a 90 page (really?) build thread on my wife's 41 PU on here located here Technical - Yeah, Its got a Hemi/41 shop truck | The H.A.M.B. The truck turned out to be a very nice show winner and I have managed to put a whopping 550 miles on it thus far. However, there has been an ongoing concern regarding the rear end height of the truck. I have built many vehicles and know to expect springs to settle but I have never encountered an issue like this.

    This old picture shows the empty frame, no gas in the plastic tank and the leafs basically flat, slight arch. These are CE RS-3540 springs. You will note that they were installed in the frame, rather than under it, as I am not a fan of lowering blocks.
    upload_2025-11-19_12-57-35.png
    This is a picture of the truck with the bed, cab and fenders on, note the white wall on the rear 720's. I like it when the space at 9:00, 12:00 and 3:00 (it doesn't matter about daylight savings time which is stupid in my opinion) are all the same.
    upload_2025-11-19_13-3-2.png
    This is the truck nearing completion on its 5-year build. Again, paying attention to the ride height.
    upload_2025-11-19_13-4-17.png
    Just the way I like it.
    This is the truck today in my garage today.
    upload_2025-11-19_13-7-1.png
    My lift is tied up with my daughters truck and it is tough to crawl under there so I made my daughter do it. This is a view from the front of the rear tire looking back toward the rear.
    upload_2025-11-19_13-8-50.png
    As you can see, the only thing holding up the truck is the rubber snubber. For all of you that do not install snubbers over your axle, you can go now. Those remaining will note the reverse arch (actually more of a wobble) in my spring. Both sides are identical ride height BTW. You are looking at the e-brake cable p***ing the camera phone and the sway bar which I mounted over the axle.

    I called Ch***is Engineering this morning to find out of anyone else has ever complained about this issue and the answer was quite affirmative. A routine call in fact. The springs, as I was told, settle into a reverse arch position on the RS3540. He said the fix is to have him send me RS4148 springs that are 2" higher arch. I thought that would be quite nice of them to stand behind their product, of course at this point in the conversation I needed to pay him $649.00 for the springs plus shipping, handling, taxes and so forth.

    Just FYI, Summit Racing has them for $575 and free shipping.

    Next call was to a company that I actually trust and would have used but these pieces came with the project, Posies. I explained my situation, and he chuckled as he has just hung up with someone with the exact issue and that they get his call several times a week. They should have an auto answerer that says "if you are calling because you purchased Ch***is Engineering Springs please press 5", it would save time. He went on to explain that these RS3540 springs are Dodge D-100 springs that they repurposed. When I asked if Posie's makes a replacement he said no but they have actually considered it from the number of calls they receive like mine. He about choked on their $649 "fix" as their entire rear parallel leaf kit is only a fraction more than that and installs in the frame (like mine) not under it.

    The CE spring is 48" eye to eye, 2.5" across, .750" eyelets on either end. I was hoping Posie's made a super slide to fit but no such luck. Now I am between the horns of a dilemma as they say, and one of those horns is piercing my wallet.

    The truck is not drivable. Portland/Vancouver no longer has a spring shop with an oven to arch and retemper springs. It wasn't more than 15 years ago I had one of the Bandit cars over there having the ride height adjusted by re-arching the leafs, apparently that is no longer an option.

    I have shackles that are 4.25" eye to eye, the originals appear to be 2". According to Posies tech, I will get half of that in height, so 1.25" plus he said the longer the shackles, the more upright they have to be because the spring is only 48" long so I might gain another .250" possibly. That is not enough travel for a truck with an empty bed and a half tank of gas. And that ***umes the leafs are done sagging. If I remove the bump stops (not possible without it being raised) I fear the springs will sag further, if so, the shackles are going to do little to nothing. I already own them so I might as well give them a whirl once my lift is free.

    The other options are to buy the RS4148 form Summit, They are advertised as being 3-4" drop. But the tech at CE said they have 2" more arch than the RS3540 I have now. Maybe these and the longer shackles?
    upload_2025-11-19_13-55-9.png
    Or I tear my truck apart and start over on the rear spring mounts.

    I am at a loss at the moment and trying to regroup. It is winter and this is the time for such nonsense. I didn't think I would have to drop $575 and replace brand new springs at this point but here I am. To say the least I am disappointed in the CE product. I cannot fault their tech guy, and I am not the original purchaser of this product, I inherited it with the truck.

    I hope this does serve as fair warning to those using their products, do your homework. If you are installing parallel leafs in your Ford, call Posies's and save some money and aggravation. If you took my advice and bought the CE kit, sorry about that.

    If you have other ideas or suggestions (other than buy a horse), I am listening. And I will continue to post to this thread until I rectify the problem in case others run into the same snag. I guess lowering blocks are that silly of an idea after all. All I would have to do is cut them down to fix the height. No money out of pocket and problem solved.

    We recently discussed the hobby dying, machine shops closing, parts houses gone, paint shops doing only collision work and you can add no spring shops with a damn furnace. We used to make fun of 1-800 car builds, now that is becoming all the resources a home builder has available to them.
     
  2. Doublepumper
    Joined: Jun 26, 2016
    Posts: 1,806

    Doublepumper
    Member
    from WA-OR, USA

    I recently had Gitt's Spring in Auburn, Washington make a set of leaf springs and u-bolts for me. They told me they can re-arch, reverse eyes and make whatever.
    (253) 833-6806 1-800-228-2861
     
  3. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 15,875

    Bandit Billy
    ALLIANCE MEMBER

    That 2 hours and 25 minutes IF you miss traffic, easy 4 and half if you do :cool:. I can't drive at the moment, haven't been able to for a couple of months and it is getting old. Shipping 144 miles both directions would be at least $400, likely more. I used the UPS calculator at 80 pounds, $234 one way. Add the cost of re-arching and I will exceed the cost of summit's springs easy.

    I just called them, they do not reheat, big press to re-arch. He said no guarantee they would hold the arch and the fact that they fell so easily and quickly, he doubts they will take a 3" arch and hold it. 1 hour labor per spring.
     
  4. Tim
    Joined: Mar 2, 2001
    Posts: 20,162

    Tim
    Member
    from KCMO

    That’s frustrating man, I spent a couple days last year trying to find a spring shop within 3 hours away that still turns on their furnace and I found none.

    be curious to see how you solve this.

    be tempted if you have a press to take the springs apart and rearch them. Sorta like when you reverse a spring for a hot rod but not quite.


    Edit: just saw your reply we musta been typing at the same time
     
  5. Johnboy34
    Joined: Jul 12, 2011
    Posts: 1,658

    Johnboy34
    Member
    from Seattle,Wa

    I think new D100 springs are half that costs on rockauto.
     
  6. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 15,875

    Bandit Billy
    ALLIANCE MEMBER

    Trouble is I don't know how much arch they have and I can't find reliable specs. I looked at Eaton and they get $350 per side! And that is not shipped! They had a drop down box to request 1, 2, 3" lower or higher, price add was $150 for 3" drop. That's a grand!

    When I talked to the shop in Auburn and told him that CE told me that it is normal for a spring to reverse arch, he said he has been working in the industry for 20 years and never heard that one yet, more importantly has never seen it except for worn out, overloaded springs. He really questioned the quality of spring steel in those CE products.
     
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  7. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 15,875

    Bandit Billy
    ALLIANCE MEMBER

    Yeah, he said the furnace was just too expensive to run, too much energy.
     
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  8. Johnboy34
    Joined: Jul 12, 2011
    Posts: 1,658

    Johnboy34
    Member
    from Seattle,Wa

    I was thinking more in the line of the less expensive lighter weight stock springs to swap the mainleaf or add one of the center leafs. A few new center bolts & some time to mix and match to a desired ride height. Just thinking out loud here, good luck.


     
    Last edited: Nov 19, 2025 at 7:01 PM
  9. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 15,875

    Bandit Billy
    ALLIANCE MEMBER

    Along that line of thought, I just hung up with Darrel Schroeder over in Troutdale, OR. He built the frame under my roadster and is local guru in the hot rod world. He has had this issue and somewhere he has the specs for the spring and a guy that can make them (if he is still in business). He warned me not to try to re-arch these, he said they will not hold.

    Interesting factoid, he said he went through the whole spring building thing with Oregon Spring back in the day. He said the springs were made from regular mild steel and only hardened on the edges, just an inch or so. For this reason, you could still drill the centers. It also sounds like these may have never been treated at all, just pressed and shipped. It would explain the quick failure I have had and makes me fear the RS4148 that Summit is selling.

    I had considered a "helper" spring or 5th spring in the pack, what it would do to the ride quality and would it even help?
     
  10. Johnboy34
    Joined: Jul 12, 2011
    Posts: 1,658

    Johnboy34
    Member
    from Seattle,Wa

    If the 5th leaf you speak of is the thick bottom one, that is basically an overload. Riding on that would be a rough ride I suppose. Changing the main leaf or just trying a stock spring could be a good start. It sounds like whichever way you go will be a guess.
     
  11. 60 Special
    Joined: Sep 8, 2007
    Posts: 299

    60 Special
    ALLIANCE MEMBER
    from Omaha Ne.

    You might give a call to Weedetr Hot Rod Parts. He builds rear suspension kits for 35-40 Fords. He is a smart guy with years of experience, not just a parts seller, but a builder too. He was in California, but is now located in Tennessee. 60 Special
     
  12. okiedokie
    Joined: Jul 5, 2005
    Posts: 4,942

    okiedokie
    Member
    from Ok

    I agree with talking with Dale Caufield at Weedetr. I have used CE springs in four 40 builds without your complaint. I agree that they reverse bend but that has caused me no problems. 50,000 miles on the one in my avatar and still working fine.
     
  13. That brings into question ALL the springs they sell. I would start off fresh with new springs (not from them) and a lesson learned for all of us.

    I know it's far but there's a great spring shop down here, it might be worth talking to them at least. Get some springs made to your specs (to the existing brackets).

    https://deaverspring.com/

    For some reason if they won't ship I can pick them up if need be.
     
  14. Eh-Bone
    Joined: Sep 4, 2015
    Posts: 70

    Eh-Bone
    Member

    Hey Bandit,
    Because they are relaxed in the downward position and have a reversed eye.. could you take the spring pack apart, keep the springs on the side they are on currently and just physically flip them and put the pack back together? The reverse eye coupled with flipping the “sag” in the other direction may get you back 2.5”(just guessing) or so?
     
  15. Eh-Bone
    Joined: Sep 4, 2015
    Posts: 70

    Eh-Bone
    Member

    A friend has a set of Dodge springs on his 52 Merc p/u. I remember seeing those springs back when it was getting put together and they were damn near flat then and its hotta be 20+ years ago…I’ll have to look at his next time as soo how they look now out of curiosity.
     
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  16. hotrodA
    Joined: Sep 12, 2002
    Posts: 7,333

    hotrodA
    ALLIANCE MEMBER

    Ah, yes. The dreaded reverse arch.

    Having worked in a spring shop as part of the truck tire business, the furnace was only used to heat, form and temper raw spring steel to turn it into complete truck springs and replacement leafs.
    Re-arching was done on a special forming anvil and a big hammer (BFH). By hand.
    We later installed a special hydraulic forming press that took all the fun out of it. The time tested hammer method was thought to be better, as the sharp blow from the hammer striking the steel cold helped it giving it a “set”. But it took two men and time.

    The demise of working spring shops can be laid directly upon the availability of complete new ***emblies from foreign suppliers for less than the cost to re-build the old spring. But I digress.

    It may be tedious, but if you’ve re-arched front springs, you could do these with your press.
    After re-arching and getting the ride height you want, I would suggest adding a single leaf as the second leaf next to the main. Dead fit it with no gap in the arch next to its neighbors for strength. The added leaf could be from any donor of the same width and thickness, just cut to length.

    The downside may be a slightly stiffer ride, which your bride may find undesirable. Or not.
    The clips may need to be replaced with longer ones for the added thickness, or just heated and stretched to fit.

    The CE springs come with less arch than the stock Dodge stock spring. For the kool low ride.
    So instead of simply settling, they start to go to the reverse.
    You may be able to find that OE arch spec on line as there is a set of spec books listing every spring made going back to the 30’s.
    EDIT: I found (I think) that stock arch is 1-1/2”

    It may be worth a second inquiry of the shops. They DO NOT need a furnace to repair your springs. You pull them, drop them off with what you need for arch, and pick them up. They can advise on the addition of a leaf.

    Or just call Dale at Weedetr. 731-608-9010 , Henderson, TN. https://www.weedetrstreetrod.com
    Moved his whole shop and business from CA to TN! He’s been there, done that. Good guy.
    Maybe the spring he uses for his Weedetr kit will be a good replacement for yours, as it mounts the spring inboard also.
     
    Last edited: Nov 19, 2025 at 9:51 PM
  17. Taboo56Chevy
    Joined: May 21, 2018
    Posts: 2,016

    Taboo56Chevy
    Member

    There is a spring shop out in Sherwood area off HWY99, Oregon Auto Spring Services. Might try calling them and see what they can do. They made a pair of main rear leafs in a 33 pickup we flipped a couple years ago that had a old homemade dual leaf rear using first gen Bronco pieces. Think they take the specs you need and have a line to a shop that can make leafs.

    Yeah I miss having Lentz spring in Portland.
     
  18. dwollam
    Joined: Oct 22, 2012
    Posts: 2,782

    dwollam
    ALLIANCE MEMBER

    My Dad always said "Long leaves provide the lift, short leaves provide the stiff."

    Dave
     
  19. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 15,875

    Bandit Billy
    ALLIANCE MEMBER

    It would be interesting to know what they look like now

    I call him in the morning. There has to be someone that can build these for me so I don't have to buy CE products.

    I called Oregon Spring and they said the most I could possibly hope for is adding 1.75" and that was not guaranteed.

    I like that and very similar to what the tech said at Posies, they don't do 48" springs.
     
  20. lothiandon1940
    Joined: May 24, 2007
    Posts: 32,384

    lothiandon1940
    Member

    Interesting conundrum, eager to follow along. Good luck @Bandit Billy .
     
  21. dwollam
    Joined: Oct 22, 2012
    Posts: 2,782

    dwollam
    ALLIANCE MEMBER

    I did a set of used '67 Dodge 3/4 ton front springs for the rear of my Forty Tudor after buying a set of spring hangars for those springs. It set in the air like a stink bug! Goal was an open drive with a column shift but there seemed to be a lack of space in the X member and the stink bug look so I went back to stock closed driveline.

    The spring set got thinned down a few leaves with the slider plastic liners in between and are under my '25 Dodge Brothers fenderless hot rod with a 318 in it. Pretty stiff on both ends but sits right.

    Dave
     
  22. Taboo56Chevy
    Joined: May 21, 2018
    Posts: 2,016

    Taboo56Chevy
    Member

    Doing a little checking for OEM 48" leafs, only thing I find is first gen Ford Bronco but they are 2 1/4" wide and have the pin for the pad on the rear end centered and not offset. 50-54 Chevy p***enger cars are 49" long but 1 3/4" wide.
     
  23. Tim
    Joined: Mar 2, 2001
    Posts: 20,162

    Tim
    Member
    from KCMO

    @Weedburner 40 there ya go I just tagged him for you.

    I think I liked the idea of a known good stock main leaf and putting the rest of your existing pack into it but sounds like they aint doing anything anyways.

    If Dale can’t point you in the right direction good stock leaf packs would be a good start. Going off the time tested early ford spring dances start pulling leaves every other and try it out.
     
  24. dwollam
    Joined: Oct 22, 2012
    Posts: 2,782

    dwollam
    ALLIANCE MEMBER

    I bought the parallel '40 spring brackets thru Dale Greer (RIP) in Tri Cities WA. He told me the D100 Dodge springs were what was used and gave me the length of each leaf and how many and which ones to use. They are 48" springs. Since I parted out my '67 D250 camper special I used those springs, which are heavier than D100. I could of made them work by using less leaves but the driveshaft interference was the killer at that time. Now, I'm glad I went back to stock springs and axle etc.

    Dave
     
  25. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 15,875

    Bandit Billy
    ALLIANCE MEMBER

    I had considered a narrower spring, I could use .125" spacers on either side of the spring. The center pin being centered is a ***** but not a deal killer. But how tall are those springs going to hang that *** end?

    I am looking forward to his input. Both techs (posies and CE) indicated I am far from alone on this issue. HAMB magic time! We need to fix my wife's saggy ***!
     
  26. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 15,875

    Bandit Billy
    ALLIANCE MEMBER

    That totally checks out with the Posie's tech. Sorry for the stupid question but are we talking front or rear D-100 springs? Or are both 48" x 2.5"?
     
  27. dwollam
    Joined: Oct 22, 2012
    Posts: 2,782

    dwollam
    ALLIANCE MEMBER

    Front. '65-'71

    Hey, maybe replace a leaf or 2 from a D250?
     
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  28. RAYT
    Joined: Sep 5, 2012
    Posts: 6

    RAYT
    Member

    WEEDETR. Great guy and parts.
     
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  29. RAYT
    Joined: Sep 5, 2012
    Posts: 6

    RAYT
    Member

    In '72 I did my 40 pnl rear leaf springs pair. Made my mounts and I think I used 56 Ford PU springs. Still riding on them.
     
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  30. Tow Truck Tom
    Joined: Jul 3, 2018
    Posts: 3,418

    Tow Truck Tom
    ALLIANCE MEMBER
    from Clayton DE

    Thank You for the heads up.
    Will be needing to address the profile of my '57 Chevy.
    Will be careful now
    Hope You can get it right.
    And fer gosh sakes,, take a drive again soon ( been there,, grounded yeow
     
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