Made in USA leaf springs

[jd1923]

13 hours ago, 2008RN said:

I decided to use Dexter wet bolts instead of the Alcans .  After I did that I was able to get grease in all wet bots. A couple I had to still jack up the trailer to remove some weight to get the 2 wet bolts to take grease, I am OK with that.  The ez-flex moves freely now.

We were asked in another thread or maybe pages back on this one, "What would we do differently?" (re Alcan)

My answer is what Bob ended up doing. Instead of buying new EZ Flex separately I would have bought the full installation set including the Dexter shackles and wet bolts, and purchase only  leaf springs and U-bolts from Alcan.

15 hours ago, DanielBoondock said:

Step down bolts (why why why size your nut under your bolt?

(Bob answered this in another way.) The 1/2" nut on the 9/16" bolt creates the shoulder. Bob mentioned 40 ft-lbs that held and allowed for greasing. The 40 ft-lbs is torqued against the shoulder, creating a standard spacing for the leaf springs. There is no real force on the 1/2" nuts, they just hold the spacing constant.

Oh yes the, 1/4" steel plate hangers on the frame do get pulled in, actually bend some from the torque of the 9/16" bolt. Try 80 ft-lbs on these bolts without the leaf installed between and you will clearly see them bend (but not a good idea to try).

The shoulder bolts are the better design and perhaps after another 20K miles on the Oliver, I may purchase a new set. For now, instead of 80 ft-lbs on the end bolts, I went with 64. And instead of 65 on the inner wet bolts on the EZ Flex, I went with 52 ft-lbs. If you divide my numbers by Alcan's, you'll see I'm torquing to 80% of the Alcan recommendation (NOT the U-bolts, keep them at 90). I found the EZ Flex will still appear to hang when lifted but will not when weight loaded.

Watch each axle both sides going slowly over some speed bumps in you neighborhood. If all is good, you should see the tires travel smoothly up and down. When I grease there's always one bolt on each side that must be loosened to accept grease, just one bolt but not all. Perhaps my 80% take is helping.

I am reporting what I have done on our Oliver based on my feelings. Proceed with caution, make your own decisions in doing your work. I am NOT making recommendations for anybody else. With this warning, I accept no legal liabilities.

I also use the stabilizer jacks to lift our hull. The manufacturer OTT does not recommend this practice.

[ScubaRx]

9 hours ago, DanielBoondock said:

I get that, but any way you cut it it’s mechanically weaker and can’t take as much torque. The only advantage I can see is easier installation which may well be the reason. 

I've always hated the step down wet bolts. After installing a couple of dozen sets of springs using these, I will attest that easier installation is NOT the reason. They are a PIA to get that second shoulder to slip into the far side of the hangers. @Boudicca908 is delivering a complete set of new Alcan hardware to me at the Rally. Anyone who wants to see how this is done is welcome to come and watch (or help) as I plan to install them during the Rally.

[DanielBoondock]

19 hours ago, jd1923 said:

(Bob answered this in another way.) The 1/2" nut on the 9/16" bolt creates the shoulder.

The shoulder I was talking about was on the inner side, between the spring and hanger, caused by the inner bronze bearing.

Anyhow I checked with Gemini which is pretty good for these kinds of things since it primarily trolls the internet

Quote

 

Dexter steps down the threaded end of their 9/16" wet bolts to 7/16" to create a positive mechanical shoulder stop that prevents the shackle links from being over-torqued and binding the leaf spring. [1, 2, 3]

Mechanics of the Stepped Wet Bolt

Trailer suspension joints operate differently than standard rigid automotive joints. The bolts do not clamp down hard on the moving parts; instead, they must hold the outer shackle straps rigid while allowing the inner bronze or nylon bushing to rotate freely. [1, 2, 3]

The 9/16" Bearing Shoulder: The thick unthreaded portion of the bolt provides a strong, wide journal surface that matches the inner diameter of the suspension bushing. This thickness handles the heavy up-and-down shear loads of the trailer bouncing on the road. [1, 2]

The 7/16" Stepped-Down Thread: By shrinking the threaded tip down to a smaller diameter, Dexter creates a physical "step" or shoulder stop. When you tighten the flanged lock nut, the shackle link hits this solid shoulder. [1, 2, 3]

Preventing Suspension Bind: If the bolt had a full 9/16" thread all the way across, tightening the nut too much would pull the shackle plates inward and crush them against the sides of the leaf spring eye. This step-down design ensures the outer links lock firmly against the fat shoulder, leaving just enough clearance for the spring to articulate smoothly without locking up

 

I think we may be onto something - this feels correct and may have already been discussed (apologies if it has). So Dexter is trying to prevent over torquing and binding. Alcan solves it by being a stickler for torque and Nylock. I’ll take Alcan and argue with Dexters approach. Stepping down doesn’t prevent anything, a monkey can still over torque and bind it up. Can’t prevent installation error with that one IMO.