Hey all,

I am looking to revise the suspension of my Mog and had a question about coilovers vs air shocks. I have a 404.0 which uses 404 suspension and runing gear. Vehicle weight is 6700 lbs and it has a 416 doka cab on it. I am looking for some more travel and the ability to play with spring rate.

Here is one thing I am thinking of; http://f-o-a.com/shop/index.php?main_page=product_info&products_id=12

These are low cost coilovers. I am thinking of placing these in the rear. (They won't fit in the front) I plan to add some decent shocks up front, and have already placed rear springs in the front. (It added about 3 inches of height to the front!)

In going over my options, a friend brought up the idea of air shocks... Which I honestly don't know much about. From what my buddy said - they seem to be a shock that you can add/remove air to get spring function??? Is this right? Would this make it offroad air ride??

I figure someone on this forum will have some answers... Also, if anyone has a Mog with coilovers, I would like to see some pics or hear about your conversion.

Thanks!
-Kyle

with a 4x4 of that weight your better going coilovers rather than air shocks because these have a wieght limit the newer fox air shock might have better loading cappabilitys im doing an air shock conversion on the rear of my mog 411 but im planing on getting the weight as low as posible also as a downer on the airshocks if you blow the seals thats it no suspension at all but with coilovers the coils still suport the weight but would loose the damping in the shock but at least you could limp home

Good point... I am getting comfortable with the specs of the coilovers too. Not too hard to figure out.

Thanks for the input!

I know your pretty set on air shocks or coilovers, I have been in your shoes already and I really like my set up, it was a cheap and very effective way of setting up the suspension.
I went with 3/4 Ton aerostar rear coil springs in the rear of my 404 and 6" TJ rear coils in the front of my 404. I put 12" Fox Shocks on all 4 corners.

I think you will be amazed! If you drive it on the road a lot maybe try rear Ford expedition springs in the rear and your 404 rear springs in the front, that will still give you amazing flex and stabilty on the road.

My 404 is not safe to drive above 40mgh on the road, not that it can go much faster but I think you know what I mean. I have the expedition springs in the rear of my 416 and there were unnoticeable changes for on the road performance, yet it has great flex offroad and still can handle a load.

I hope i didn't make the decision more difficult.
http://i51.photobucket.com/albums/f354/Folsomlakebowl/SD532350.jpg
http://i51.photobucket.com/albums/f354/Folsomlakebowl/SD532351.jpg

I'm sitting in this boat right now as well. Are all aerostar vans 3/4 ton? If not how can you tell the difference. If I left the front 404 springs and changed the rear with either the aerostar or expedition, will the ride height match (front and rear)? Sweet MOG also!

I have a bit more weight on my rig than a regular 404. Plus, I really like the idea of dialing in the spring rate & ride height for my taste.

Goodtimes - Do you see the 12" shocks limiting downward travel at all up front??

Mjjeeps, thanks it was a lot of time and effort but it has came out just the way I wanted it to. Not all Aerostar springs are 3/4 ton, I believe it was available but only a small percentage of the aerostar vans out there had that upgrade. You can tell a pretty big difference in the thickness of the coils and they are progressive, so they go from thick to thin. I believe the aerostars that are regular are not progressive. They definitely are thinner in spring diameter. I attached a photo for you to check out. With the 6" TJ rear springs in the front & the aerostars in the rear it sits level. It did give it a 1-2" overall lift, but it is very stable and in my opinion the best possible setup offroad. If you are going to drive it on the road you could do one of two things. One you could put a quick disconnect sway bar system with this same spring setup, or secondly you could go with the rear 404 springs in the front and maybe the stock aerostar springs in the rear. I personally would go with the first option if you drive a lot on the road.

Bigmelon, all I can say is that I've been where you are and I thought for example that hydro steer was a better way to go than 406 or 416 power steering and I was wrong. So take it for what it's worth, that spring combo I was telling you about well blow your mind off road.

Have you weighed your mog or are you guessing on weight. I brought mine to the weight station and the total weight was 5400 lbs and mine is a Doka. I also have Over 120' of DOM Roll cage tubing that weighs a lot. I don't know how much you will have to pay for those coil overs but between the junk yard & the internet you can get all 4 corners of springs for under $200 if you shop around, and if you don't like it you can sell the rear springs for $100 and get your coilovers. Just trying to help, keep us posted on what you do!

Here is the link to my build up: http://web.mac.com/dansflb/iWeb/DanDreher/Unimog%20Photos.html

Here is a closer look at the rear aerostar 3/4 ton springs
http://i51.photobucket.com/albums/f354/Folsomlakebowl/SD532342_2.jpg

I couldn't find a single pic of the unimog on flat ground, every pic was of a progressively larger rock. I took this snap shot of a video, sorry about the picture quality, but as you can see the ride height is pretty level.
http://i51.photobucket.com/albums/f354/Folsomlakebowl/Picture1-1.png

Different kind of Doka... I've run her over the scales. 6,700 lbs on the dot.

Wow, that's significant. I would go with the expedition springs in the rear. I have them on my 416 and I love them. They will lift the rear up a little, so maybe the answer will be to go with front 416 springs for the front of your mog. That combo works really well on my 416. I will go flex it out and take some pictures for you as soon as I get my locker lever fixed, which should hopefully be next week!

i am looking at a similar setup for my 421, its currently got xxxtra heavy duty snowplow springs on it and has about as little flexas you can get :(

i'm thinking of making up adapters and using landrover springs, HD range rover ones and long travel shocks

i am looking at a similar setup for my 421, its currently got xxxtra heavy duty snowplow springs on it and has about as little flexas you can get :(

i'm thinking of making up adapters and using landrover springs, HD range rover ones and long travel shocks

Keep in mind that the factory curb weight of a 421 is >6000 lbs...

Keep in mind that the factory curb weight of a 421 is >6000 lbs...

I hope to trim the weight down considerably, going to make up a cage to replace the cab and fit a rag top. the back tub will come off too.

http://i233.photobucket.com/albums/ee71/steveplowman/mog2.jpg

I hope to trim the weight down considerably, going to make up a cage to replace the cab and fit a rag top. the back tub will come off too.

Then, anything like a RR would probably be workable. Except, the 421 has a huge forward bias in weight compared to the Rover...

I'll have to get it to the weigh bridge and do some homework :laughing:

hi pal your having the same problem as me when i got mine 411 snow blower the bast way is to sorce some original standard springs like i did i ended up getting them straight from germany they were half the cost than in england i use andrae pistorus hes great and has second hand parts aswell but if your after a modifide spring i will let you know how mine goes on the long wheelbase its having airshocks at the rear but im trying grand cherokees on the front but this is only going to be used as a offroad play toy and is not going to be worked

just so happens, ive got asetof G Cherry springs sitting in my shed, came off my old WJ when I lifted it.

I'm probably going down the play route myself as most of my work needs on road ability and the 421 just aint suited to road work

It is a 416 doka 1975, it has the 12" racerunner air shocks and the aeroastar springs on the front,and 16" 2.5 bilstine coilovers on the rear. so far i like it but once and a while it binds up,but i have been told it is what that suspension setup does when it flexes that much.

more pic's.

hi whats the point in having both airshock and a coil on the front the idea of using a a airshock was to save weight of using a coil and a damper and making the rig lighter
why not just have the air shock charged correctly for the wieght of the mog and just use that you can alter the damping on the fox units aswell
of are you just using to ramp up the springrate at full compression

I am using the springs with the air shocks because the weight of the mog exceeds the weight rating of the air shock,plus if i get a air leak the springs get me home without bottoming out.

Shawnmog, cool Mog and your suspension set-up flexes great.

I really want to see more pics of that school bus hauler though. Any chance you could PM me pics of the inside/outside and some of the specs on it?

Thanks.

Hey ShawnMog when you say it binds up, can you explain more. Do you mean in the front or rear, the springs or the air shock? I switched the rear suspension to Ford Explorer coils and have been really happy with the rear flex but I haven't done anything to the front. Which brings me to my second question, do you like the offroad characteristics of your front suspension or would you do it differently? Lastly how is your setup on the road because that is a big factor for me, does it handle well or do you think it would need a swaybar to handle better?

With the way i have mine set up i have a 1 1/4 swaybar, but it limits my flex in the rear so i need a smaller one,but the 1 1/4 one really helps on the street.
I think it is the back that is binding up,it seems like it stays leaning over after you come back to a flat surface until i take off the lockers,it also makes it to where if the rear is at max flex the front dosent flex enough. I have had people tell me it is the front being too soft,so if i could i would squeeze some coilovers in the front.other than that one binding problem(wich is not a problem if i take it slow) i love my setup.:D

SO.. If I was building an almost pure trailer queen404.1, what would be the best setup in your guys opinion. Little to no street time to speak of needed. So that means no sway bars. I obviously want flexy springs, but not overboard. For the guys that maybe have tried this, what about rear Aerostar springs on all four corners? Or Explorer or Expedition, or TJ? Any help will be appreicated so I don't need to try all these setups. :grinpimp:

The place to start with flat out custom spring selection is getting a good idea of the desired outcomes you want. Obviously in this case you want to build a slow and soft setup, relatively speaking.the best possible system the first time around you need to calculate what the minimum required spring rate, free length and compressed length need to be.

The primary function of the spring is to support the chassis under dynamic loading and likewise the function of the damper is to control the rate of dynamic loading of the chassis.

The key to building a high mobility chassis is providing enough support to the chassis for stability while not limiting articulation. Given the low speed nature of most off road driving, spring rates can be as low the physical minimum to support the chassis while conversely damping rates need to be raised to control flutter and bouncing. The key to roll control, defined as the chassis rotating lengthwise about a moment of inertia is an anti sway bar which uses the lever action of compression to limit body movement relative to suspension angle. A properly constructed anti-sway system should still allow complete articulation of the suspension.

Taking things a step further towards the concrete world of the unimog, since these are solid axle systems, the limiting issues are how much linear travel you want from the axle as a whole, what percentages you want for directional limits, IE X total travel with % y+ (up) and %y- (down) and total included degrees axle rotation. Your primary limiting factors are body & chassis interference and drive shaft joint restrictions. Once you know the static mechanical limits, only then can you start calculating your dynamics.

Springs define how much force is required to move the chassis/axle from a static position. They also define how and to what degree the chassis resists these movements. A spring with the minimum load rating to support the chassis will be easily compressed by minimum chassis movement and will remain compressed until that movement is released. By increasing the load rating you require ever greater amounts of force to achieve the same movement. Increasing or decreasing the free & compressed lengths also effects how the spring behaves. With more coils each coil is required to bear less of the load as well a move less with the converse remaining true for less coils. Interesting thing happen however at 100% compression, where each coil is in contact with the others, in this state the spring is a solid and will transfer 100% of the forces through it. This is when mounting failures occur as not only do you have 100% of the shock forces being transmitted but you also have 100% of the stored energy trying to release. It is best to design systems where the springs are never at either 100% compression or extension.

Your dampers, either fluid/gas systems or simple torsion systems define the rate of travel and do so independently of the force required to move the chassis. The damper is designed to restrain violent movements and apply controlled transitions, dampers are not design to support the chassis and should not be used as positive stops for chassis movement, things break that way. Likewise sway control bars are intended to control the movement of the chassis under limited articulation, specifically when the vehicle is making a turn and inertia is carrying it over. At low inertia travel this is not encountered and including a sway bar is a personal choice if the vehicle is street driven.

Rates of travel & breakaway forces are a function of the dead mass and selected distance of travel that you have defined factored against the live mass of the chassis actually moving. Properly approximating your rates of acceleration and deceleration as well as the forces will allow you to select a spring and damper combination that best meets your needs versus a make due selection.

If anyone is interested in the fine mechanics of this, let me know and I can break it down in a much more specific way.

Ok sooo, anyone want to add what works well for the rear on their 404. I allready switched the stock rear springs to the front. Work good enough. I should add, my 404's cab is stretched to a four seater and the original 10 foot bed, cut down t0 5'. The rear frame was shortened 18". Back to the question. So far I have tried the rear areostar springs. WAY too soft with and unstable with the half bed. Next I tried a pair of stock XJ front springs. Better but still not very good. I am running 14" Bilstein in the stock mounting. They bottom out way too much.

Can anyone else share what works well for them. I have yet to find the Expedition springs, still looking though.

I have the same setup and I like the 3/4 ton aerostar springs, I also use the expedition springs on my 416 and really enjoy them as well. I would recommend one of those two springs!