Dt466 1995 f350

cquestad said:
I wasn't guessing when I said that...take it for what its worth.
Click to expand...

To the OP...this guy has ran pretty hard on some large tires of the years I remember being on the forums...I'd guess he's broken some suspension parts in his day.


Just FYI...

Looking at the length of that suspension mount, and the amount of torque that could be applied through it, I'd brace it as well. Much easier to do it now, rather than trying to rebuild it after it rips it off.

Chris
 
Constructive criticism is good. You are right, it does look like leverage would have it way. As I said, more supports were already in the plans. I wanted to point out that those brackets are a lot more stout than they might appear in a picture.
While talking suspension, do you guys think there is enough force on a track bar to shear a .75" gr8 bolt? I plan to replace the ball joint Ford used, with a bushing and a heim joint pinned with a .75" bolt. Probably something very similar on the frame side, as I don't have much room for brackets hanging between the frame and axle.


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No, .75" bolt on the track bar is cool...my old Thuren bar bolted in like that, as did the steering knuckles. Shear strength of a 3/4" bolt is something like 40K lbs if memory serves correctly.


1/4" plate boxed like that is tough, but a gusset behind it would make a heck of a difference in strength, even if you just cut an angle of 1/4" plate and welded it behind it going up to the frame.

Chris
 
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Finally sitting on it own suspension up front. Shocks, steering linkage, and sway bar, then the front end is done.


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They make 6, 9, 12 and some 15 inch travel ones if you have the time to search the thousands of part numbers...I have been eyeing a 12 for the rear of a tow rig. I like the way they look in real life!
 
If they ride too firm...use a blow off reservoir for each bag....and a ball valve to act as adjustable dampener. Message me if you ever need ideas.
 
I'm using 4 independent mechanical leveling valves, so it should add just enough pressure to maintain ride height. I think pretty similar to what you were describing.
My question is when it comes to off road, are the outside springs going to try to flip the truck in an off camber situation? I don't do any hard off roading, but I do see some washouts, ditches, mud, and things like that. I was thinking maybe a shut off valve between the spring and leveling valve turned off before leaving pavement might help?


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That's not what I am talking about at all. Lets say you have a load...1000 lbs on the bag (for easy math) . The cross sectional area of that bag is approx 30sqin...so it would take 33.3psi to ride at set ride height....lets say 4.5 inches....middle of travel.

So...in order to cycle 3 inches up on a bump...the pressure would increase to 100psi (volume decreased by a third...so pressure spikes by 3 times in a closed system) 100 psi on a 30sqin bag means a 3000 lb force (or spring rate).

Example two with a 1/2 cft (864 cin) reservoir...still takes 33.3psi at 4.5 inch ride height. Cycle the bag 3 inches up...volume changes the same in the bag...but the reservoir doesn't...bag goes from 135 to 45cin...but bag plus reservoir goes from 999 to 909cin. So less than 1/10 decrease in volume means less than 1/10 increase in pressure...or force...1100 lbs (perceived spring rate). I am not saying you want a reservoir that BIG...but you need one if you want any movement of the axle while driving.
 
Using a ball valve between the reservoir and bag will allow different settings to increase or decrease the speed that the reservoir dampens the bump load.
 
One per bag...between bag and leveling valve. Use as big of airline between reservoir and bag as possible. Even if you had a 1/8 cubic foot...like 6 inch pipe...8 inches long...two weld pipe caps it would help tremendously. The line from the leveling valve to the reservoir can be 1/4 or 3/8 and long...but the line from the reservoir to the bag needs to be 1/2 or bigger and short as possible. The ball valve can go right on the reservoir between the it and the bag. I always pictured mounting them just outboard of the frame immediate being the front fender wells...and right in front of the rear fender wells. A guy could easily reach the ball valve and and adjust it almost closed for heavy towing...or wide open for offroading.
 
Cool thanks! I appreciate the help.
I was planning a reservoir for each spring...but in my head, I had them on the wrong side of the leveling valve.
Do you think the leveling valves are going to cause me problems in off road situations? For some reason I'm having a hard time imagining how it will work anywhere but flat ground.


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Interesting discussion here. My 72 has large bags in the back and when you hit a large bump you can feel the rear jump up. I had plans to add a sway bar to help provide some resistance. I figured it was acting just like a bob tailed tractor. This damper is probably a better solution though. I'm envisioning something like a reservoir for a nitrogen filled shock? Is that what yours looked like when you were done with them cquestad?
 
DieselWrencher said:
Interesting discussion here. My 72 has large bags in the back and when you hit a large bump you can feel the rear jump up. I had plans to add a sway bar to help provide some resistance. I figured it was acting just like a bob tailed tractor. This damper is probably a better solution though. I'm envisioning something like a reservoir for a nitrogen filled shock? Is that what yours looked like when you were done with them cquestad?
Click to expand...

Yes, just a small air tank to make the volume of the bag seem bigger, so that the change in pressure isn't as large.

Makes a big difference in most applications.
Chris
 
Yes! Sway bar will only hurt you...not help. The largest res that is still practical gives you the most flexibility to go from "soft" to "stiff" ride characteristics. Air bags DO NOT have linear spring rate...the ramp up crazy fast...especially when the bag is small.
 
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