Patracy's "SEMTT"

[patracy]

Work has been busy, but tonight I got parts! The shocks and battery equalizer came in. I also got my emblem stencils. Guess I'll be wrenching soon!

 

[patracy]

I got the air shocks mounted today. I pumped them up to 120psi. It didn't lift the front end any (well the bumper moved about 1/8" upwards from the stick I laid on it). But I'm guessing this will at least change the spring rate and help cushion downtravel. It might also gain a little more height when it's not pointing nose down and moves around a little. The shocks can handle 200psi. I might crank up the compressor and bump it to 150psi. But I want to leave some room for error since I'm using them in a fashion they weren't really designed for LOL. I mounted the filling port on the drives side fender. I also picked up a circuit breaker for the 12v lead from the battery box to the cab. I think there's enough room in the box for the equalizer. I plan on getting that wired up tomorrow. I also bought a hood latch pin kit (think hot rodders). I'm going to drill out them and mock up the mounting, then tear them down and paint them flat black. I've got a few other trim parts taken care of as well. But it's looking like rain for the next couple of days. So I'll just work on it as I can.

 

[marchplumber]

You're gettin there! Great project! Remember, they always said in military, "Attention to detail!" Seems like you got that down already!

God bless,
Tony

 

[Hainebd]

Last time I saw you you where working on the knuckle boom. Instead of more pressure how about two air shocks or even cylinders. Cylinders with duel air circuitry and cushions both ends would work. You need to get her/him done so we can see it work.

 

[patracy]

Last time I saw you you where working on the knuckle boom. Instead of more pressure how about two air shocks or even cylinders. Cylinders with duel air circuitry and cushions both ends would work. You need to get her/him done so we can see it work.

Problem is real estate really. I'm going to give these shocks a go at first, if they don't work, I'll take a look at adjustable coilovers. I was really just looking at this to have some "adjustablity" to the ride.

 

[patracy]

And as an update, I've got the batteries removed and the equalizer mounted in the box. I needed to crimp some cables for it, but realized that the crimpers were in the cab of the truck still taped up. So I went ahead and installed the stencils and sprayed them. Turned out great I think. Tomorrow I plan on getting the wiring of the equalizer and 12V lead ran to the cab. Also going to finish up on some trim parts and install the hood latches. Also gotta install the headlamps again. (Still looking for some LEDs!)

 

[quickfarms]

What is the diameter if the air shocks?

How much do you want to raise the front end?

On trucks it is/was very common to use spacer blocks on the front axle to level out the ride height before air ride.

 

[patracy]

What is the diameter if the air shocks?

How much do you want to raise the front end?

On trucks it is/was very common to use spacer blocks on the front axle to level out the ride height before air ride.

I honestly didn't measure them, but I'm guesing about 4" in diameter across.

Not really worried about height. Just wanted something to help "dial it in" if needed.

I'm not keen on blocks up front. Kinda risky in my mind. But perhaps a flat 1" plate large enough to have holes drilled in and the U bolts passed through would be an option.

 

[quickfarms]

Based on the 4" diameter and 120 psi the air shocks have a capacity of about 1,500 lbs each if they are vertical, if they are not vertical the capacity is reduced by the angle. This is considerably lower than your front axle weight. You would have to weigh you'd truck to see what the front axle weight is. For a class 8 truck the max front axle weight is 12,000 lbs of the capacity of the tires, which ever is less.

The shocks on a truck are only there to dampen the suspension.

Air shocks and of coil overs could cause you undue scrutiny if the truck is inspected or a DOT inspector happens to see the truck. Worst case scenario would be an accident and the subsequent investigation.

You should do this correctly. Due to safety issues the front suspension on a truck is not adjustable. If the front suspension is sagging you gave probably overloaded the springs. This can have some very bad consequences with the drive line geometry.

You need to get the frame so the geometry is the same as the stock truck. This can be accomplished by rearching the springs, adding blocks or converting to full air ride.

The blocks on the front axle if a class 8 truck are actually short very thick leafs added to the spring pack.

 

[patracy]

I can easily remove and reinstall the stock shocks. Again, I'm not looking really to increase ride height. Just something to help with the ride that's easily adjustable. These shocks are not holding the weight of the vehicle. Just assisting.

I unfortunately didn't have the forethought to take a before pic of the leaf springs to bump stop height, but luckily I recalled a recent thread where someone painted their drums. From that I've figured out I've lost about 3/4 to 1" of ride height from the gap. Still well within the range of use. The front driveshaft runs off a pillow block before going into the pinion shaft. The difference there is negligible. This is also a bit exaggerated at the moment due to it being parked on a slight hill nose facing downhill. Still a little concerned, I went over to my wrecker (M543A2) and measured it. Low and behold, they're identical at the moment in gaps between the springs to the bumpstops. Granted it's not a apples to apples comparison. But the basic suspension shares the same exact design. (But with the wrecker having a front winch loading the nose down)

It's of my opinion that the springs aren't overloaded given the two examples I've compared. But I will be weighing it by axle and calculating the CG when all is done. I also did eyeball the front perches. How they clamp on, I could build an insert that would be held captive by the perch. But that's only if need be.

 

[73m819]

If anything is nose heavy it is the m819 and it uses the same 5t front springs as the rest of the 5ts, I believe that you are going to have a rough rid because of the fulcrum effect of the cab being in front of the wheels, any bump will be magnified by this so any dampening will help.

 

[patracy]

If anything is nose heavy it is the m819 and it uses the same 5t front springs as the rest of the 5ts, I believe that you are going to have a rough rid because of the fulcrum effect of the cab being in front of the wheels, any bump will be magnified by this so any dampening will help.

That's honestly what I'm after, just a increase in compressive dampening.

 

[quickfarms]

If you are not using the air shocks to raise the truck and only using them to dampen the suspension I would consider leaving them in there and and set it up so you adjust the pressure from the cab. They might work but it might be a fail.

For 1" I would not hesitate on blocks, they would be spacers.

 

[patracy]

If you are not using the air shocks to raise the truck and only using them to dampen the suspension I would consider leaving them in there and and set it up so you adjust the pressure from the cab. They might work but it might be a fail.

For 1" I would not hesitate on blocks, they would be spacers.

It's honestly just a $100 experiment. I haven't even driven it around other than in the yard. I've just heard so many stories about HEMTTs being a rough ride, it's just something I wanted to test out. If it proves adjustable/meaningful.

I've never had a problem with blocks in pickup trucks. Heck my CUCV has them in the rear, 5" tall ones at that. But the rear axles are just following the front's lead. Under braking conditions they're actually loosing weight on them. But in the front, I just know it's a huge no-no on leaf sprung trucks to use them there. That's where my concern comes from about the front end I guess. I do realize that they do use "block" under larger trucks though.

 

[patracy]

Well, today was spent more on the road than wrenching. But I have the battery equalizer wired up. I've also reused the breaker block that the MK48 came with for a section of always powered terminals and switched terminals via some of the 24v relays I have. I still am waiting on one more fuel solenoid. But I'll go ahead and wire up the fuel gauge selector and relay. Going to use a 12v relay for this one as the switch will trigger 12v to the relay and flip the fuel level signal. The fuel solenoids I have are 12v, so it will also power those. I've got a stereo laying around here. I just need to find an enclosure to mount it in. I'm going to have to shop for some speakers as well. I'll also pick up some cig lighter ports. I've got a smaller inverter that I'll install in the cab as well for 120v.

 

[patracy]

Got a little wiring done, waiting on more parts...

Installed a cd player, wired out to the speakers (waiting on them), installed a usb/cig plug for the driver, dual cig plug for the passenger, installed a 400/800watt inverter for laptops. I think I'm going to run a power lead up to the roof for a cb or ham radio. As well as another lead for a rear view camera.

 

[swiss]

What about the hot tub, you could put it on top of the engine cover and heat via a heat exchanger to the cooling system!

 

[patracy]

Maybe I'll do that in the M750!

 

[tobyS]

Which Behr color paint did you use? Is it FS 34094 (green 383) or is that olive drab, FS 34088?

I remember having car(s) with air shocks. They got harder in ride as you increased the pressure...less dampening. Seams like 4 regular (truck) shocks would be about right, since you are cantilevered out front of the axle. Did you remove bags. What size were they?

 

[patracy]

383.

There's no room for four shocks. The truck never has had air bags, again, no room. That's why I looked at these air shocks.