rear shocks on a 5 ton

Vintage iron · Nov 27, 2011

I work at a trucking company and Civilian semi trucks use shocks in the rear. Even the old Macks have rear shocks. I am singling out my M813 so there will be plenty of room on the outside of the frame off 4 shocks. I think they will help with the ride when empty. I hit some big highway seams on RT. 84 in Scranton Pa. and the ass of my truck was bouncing off the ground.

two.fiveM35 · Nov 27, 2011

Is there enough movement in the rear when its unloaded to even allow the shocks to offer any benefit?

Vintage iron · Nov 27, 2011

One would think so, but my boss has a R-model make with 44 rears and the springs are bigger than a 5 ton. His truck is having issues with the ass end being bumpy. We first replaced the tires and then found out the rear shocks were cooked. If you still don't believe me look at the your front end travel. There are shocks on the front and the front has a load on it all the time.

I am more worried that I won't find shocks with enough travel. I still want to go off road and full axle travel.

Hammer · Nov 27, 2011

The rear axles have a LOT of up/down travel.
I would look at shocks made for trucks with the big air bags that have a lot of drop when you dump the bags.
I KNOW they would help, especially with with a m818 running bob tail.

wreckerman893 · Nov 27, 2011

Since you are bobbing it why not go with air ride....you can prob find bags and shocks at a big truck salvage yard.

73m819 · Nov 27, 2011

wreckerman893 said:
Since you are bobbing it why not go with air ride....you can prob find bags and shocks at a big truck salvage yard.

WM, he said he is SINGLING, NOT bobbing

also most road 3 axle trucks have very little articulation, a military 3 axle has tremendous articulation

Hammer · Nov 27, 2011

73m819 said:
also most road 3 axle trucks have very little articulation, a military 3 axle has tremendous articulation

This is true, but they also drop the air bags for hooking/unhooking trailers. This seems like there might be 'some' out there that have decent travel shocks.

But, to be honest, you would probably end up putting the shocks on the inside (towards the pivot point) and tilt them inward as well.

Vintage iron · Nov 27, 2011

Yes, I am singling out my tires, not bobbing the truck! I will probable use stock upper front shock mounts and fabricate lower mounts. I need to see how it lays out.

I was looking at shocks today. King shocks and Road King shocks look the best. They are make shocks for heavy trucks like ours that go off-road like the Dakar Rally and the King of the Hammers, but they are pricey! Monroe makes a 70 series Heavy Duty shock that comes in a wide variety of lengths. I just need to measure my rear axle travel.

cranetruck · Nov 28, 2011

The '69 xm757 came with front and rear shocks from factory. I'll see about a part number...

Edit: Military part number only, 11601499 made by MAECO (Monroe?)

Vintage iron · Nov 28, 2011

Nice pictures Cranetruck! I would not have thought of mounting the shocks that way, but it makes sense. That is the direction that the axle pivots. You would need to leave room so the shock doesn't bind against other parts while giving proper dampening.

Vintage iron · Nov 28, 2011

I measured my rear suspension it is 4 1/2" - 5" inches to the bumper stops. So that gives me about 10" of travel. I will order shocks that have 12" to give room for droop when one axle is hanging. If you are worried about over extension you can put on limiting straps, that is what most off-roads do. You don't need to worry about bump stops, they are already there.

5ton beachbuggy · Nov 28, 2011

Look for some rears from 1990 s macks [44000 lbs] that have bolt on shock mounts on the axles that look like they would bolt right on 5 ton axles. Mike

Hammer · Nov 29, 2011

You need more then 12" of travel.
Your measurement only accounts for normal up down movement, but doesn't allow for side to side articulation. So if you go over a big bump that is a lot higher on one side, the opposite side will droop further. I measured close to 14" of travel.
Also, you can REALLY smash/flatten those bump stops with enough pressure. Trust me on that one...

Csm Davis · Dec 17, 2011

The air ride m931a2 that I have pictures of have shocks on the rear mounted on top of the axel tilted to the rear and mounted to the outside of the frame.

Floridianson · Dec 17, 2011

You can try shocks but my .02 it won't help with the big truck rear hop blues.
Weight on your donkey and or lower tire pressure.

Vintage iron · Dec 17, 2011

You would be surprised how much shocks help. If you don't think so take off your front shocks. Your front end is under a load all the time! Thanks for the suspension travel lengths. I was planning on putting on shocks with 12 of travel anyways.

I would like to see pictures some of these existing shock locations that some of you have listed. Who has pictures!

quickfarms · Dec 17, 2011

I have thought about adding rear shocks

Stalwart · Dec 17, 2011

I have shocks mounted on all the HEMTT axles. With so much unsprung weight, 600 lb wheel and tire and HUGE axles, it is a lot for a shock to keep under control. Mine are positioned much like Bjorn's but at a smaller angle, 10 degrees off vertical. I made measurements for Leonard Jones for his Baby HEMTT project. Thanks to 3dAngus, we have enough shocks to allow Leonard and I to have a spare set once we wear ours out.

Vintage iron · Dec 17, 2011

Stalwart do you have any pictures of what you are talking about? What were the shocks that you used? Do you have a part number?

Stalwart · Dec 17, 2011

You may have misunderstood me, I didn't "add" them they come standard on the truck. NSN 2510011324983 and a tag on them says PN 1313230. Let me apologize in advance for the pictures, it is VERY dark under the truck in the garage and I used my phone.

rear shocks on a 5 ton

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