MB U1300L a good base to build on?

[boroburner]

what would be the hard parts to source? I guess the driveshaft legnth would be different due to the longer wheelbase? (again, i know very little about "mechanicals"... so far).

I have to say CTIS is appealing indeed. Does anyone know the cost to add it aftermarket?

 

[Jolly Roger]

what would be the hard parts to source? I guess the driveshaft legnth would be different due to the longer wheelbase? (again, i know very little about "mechanicals"... so far).

I have to say CTIS is appealing indeed. Does anyone know the cost to add it aftermarket?

The 1550 I recently purchased does not have CTIS on it. I inquired what the cost would be to install a system and was quoted two different options:

2,400 Euro
Four boxes with spiral hoses and quick couplers to the tire valves and one pressure regulation box.

12,000 Euro
Install of full system - would require new axles.

Although it would be a nice option to have, the additional cost didn't fit within my budget. So, if you can get one already installed, I think that would be a nice bonus.

In terms of the 2150, I was quoted a price of 3,500 Euro for a technical inspection, service and oil change. This included the removal of all wheels, checking of brakes, replacing of callipers if needed, etc. This cost would include the replacement of any non-functioning or warn parts affecting the technical function of the vehicle. Once the technical inspection was done, the company would be prepared to offer me a 3-month guarantee on the drive-train (engine, transmission, axles, etc.). If anything went wrong, replacement parts would be shipped to the destination of my choice, free of charge.

I believe the 35,000 Euro asking price is the same whether or not you take the box on the back or not. Additional details I received on this vehicle are as follows:

A30 Central tyre inflation system (CTIS)
B42 Dual line trailer brakes
B68 Trailer brake connections front
C26 Stabilizer, front axle
C29 Stabilizer, rear axle
C67 Fuel tank, 230Ltr.
F60 Hydr. tilting device for cabin
J32 Tachometer
L20 Reversing light
L25 Rear fog light
L30 Headlight protection
Performance 214 HP
P99 Cargo bed, LxB 4.500 x 2.400mm
Box body, de-mountable, LxBxH 4.800 x 2.400 x 1.600/2.000 mm rear doors and door rhs
Werner Front recovery winch
Aufbau / Implements
L41 Additional blinkers
L47 Front driving lights
M65 Vertical air intake
N16 Hi-speed PTO drive
P99 Cargo bed
Q** NATO-type trailer coupling
S12 Twin passenger seat
S21 Safety belts
S82 Wide angle mirror
S83 Ramp mirror
X19 GVW 14.000 Kg

Aside from the stated concerns regarding the extended lenght, it seems to be quite a good match for what you are looking for.

 

[Iain_U1250]

I know of a guy who sells a CTIS system retrofit for a lot less than $12K - it requires a bit of machining of the portals, but it all seems doable. I was thinking of fitting one to my truck, but I'm developing my own quick connect system which should be a lot cheaper and simpler.

It's still in the development stage, but I've got most of the concept worked out. It is digitally controlled through commercially available instruments - just set the pressure on the control for front or rear axle, open up the valves for inflation or deflation, connect the hoses to the tyres and the solenoids do the rest. It should cost less than $1000 all up and runs off the on board air system. On my truck I'll have two compressors capable of putting out around 15cfm in total and 50lt of 8 Bar air in the air tanks, so inflation should be quick enough.

I'll post up the details once I have it all working.

 

[LukeH]

what would be the hard parts to source? I guess the driveshaft legnth would be different due to the longer wheelbase? (again, i know very little about "mechanicals"... so far).

I have to say CTIS is appealing indeed. Does anyone know the cost to add it aftermarket?

It seems that the TC has been moved back, so the rear prop shaft is probably standard.
The only things that wil have changed is the link from engine to TC, and the front prop shaft. All the UJs, bushes and pivots will be off the shelf parts as usual.

Has anybody EVER needed to replace a front prop shaft on this (or any other for that matter) model of Mog?

It strikes me as one of the best mods you could do to a Mog destined for overland/camper use. You've actually got a decent load bay length.
And it has CTIS (oh how I would like that) and all those other options - mmmm-
IF I were convinced that Mogs were a good camper base, that unit would tick all my boxes for the different compromises needed for an overland camper.
And that unit goes a long way to convincing me that a Mog could be a good camper base (length being an important criterion).

But then I'm a mechanical engineer and appreciate the engineering that's gone into a Mog, a novice mechanic could be a bit daunted by the complexity of it all.

 

[boroburner]

Wowezers!!!! 12K! Could buy another mog for that almost.

I carry a compressor in the back all the time in my FJ and its a pain in the a** to stop and change pressure with any kind of regularity. And thats with stock 32"s. If changing terrain a few times in a day i spend a great deal of time on the side of the road already. I would dread to fill the monsters that are on the average mog. Even with a huge tank/compressor, i can imagine it would take some time to fill, not to mention setup/cleanup? CTIS seems to be fairly common on alot of the european used models, if i do get a Mog i think i will lean toward looking for one with it already equipt.

Luke, your explanation was exactly what i was looking for. Thank you. I wouldnt even catagorize myself in the class of novice mechanic yet, i have never fixed so much as a lawn mower. I can change my own oil/flats and have swapped a fuel pump in a 82 tracker. This is my mechanical exp....
Limited i know. Ive never had anything else to fix?

 

[dan johnson]

Down side of the CTIS

I have had two mog with CTIS a U500 and a 1550 that I still own. When they work they are great but it adds another level of complexity to the system. The system on both mogs are divide between the front and rear. When you lower the rear tires you do both of them at the same time. The same with the front. On the U500 I did not drive it much in the winter and in the spring both rear tires were flat and off the beads. It takes a little while to jack up both tires and get out the air cannon to get them back on the beads. The other option is to take off the tires and haul them to a repair shop but at a couple of hundred lbs per tire the first way is easier. If you have a flat tire on one side the other side will also go flat. So now you have two flat tires. To stop the good tire from going flat you have to take off 3 lug nuts to disconnect the CTIS for that tire.

The 1550 has the same system as the U500 but does not have the computer to tell you the tires are low and it will blow them up if they are below the accepted level when you go over 40 mph. The one advantage of the 1550 is that you can disconnect the CTIS by only removing two 17mm bolts that hold the protection cover on. I kept a 17mm ratchet in the door pocket for those occasions.

One time while going across the Altar Desert in Mexico I was going down over a sand dune and got more sideways than I should have and both the downhill tires came off the beads. I was running between 10-12 psi in the tires. It is sort of a sinking feeling when you realize you have 3 tires to rebead and one to re-inflate. I was able to disconnect one of the uphill tires before it debeaded but not fast enough to do both. I was with a few other mogger and it only took about an hour or so to get going but we were all very experienced at doing this.

When I first got my 1550 I was told that the CTIS system had just been rebuilt. I replaced all the seals in the system since then once. I think that sand in the tires does not help the system much. I also do not think it is a good idea to use those beads they put in tires to help balance tires. At the present time the 1550 does not have the CTIS system hooked up. But I know when I want to use the mog that there is a good chance the tires will be up.

The system is nice when working but I would not pay any extra for it. It does not make the mog any more reliable.

Dan

 

[Iain_U1250]

Based on your experience I think that the standard CTIS system is a bit lacking in the engineering department. I would have thought that if you get a puncture, then the air system would try it's best to keep the keep that tyre up to pressure - and you would notice the overall system air pressure dropping (or at least one circuit) that would give you an indication that you were losing air. If all it does is to manually allow you to adjust the pressures, then it seems to me to be hardly worth the effort. The after market kit I was looking at would certainly be trying to continuously re-inflate the tyre with a puncture.

Regarding your debeading problem - I have Staun beadlocks in my wheels - I have not used the Mog as yet, but I know experience with smaller tyres (33") I can drop the tyres down to to "0" PSI and they won't de-bead. The Staun guys assured me this would still be the case with the Mog tyres as I would have 50 psi or so holding the bead onto the rim even if the tyres themselves were completely deflated.

 

[LukeH]

Don't be too hard on them (the engineers)

It's quite clear that a rotating seal isn't going to be as airtight as a fixed tyre valve.
Somewhere down the line there's a transition from fixed supply pipe to rotating part to feed to the wheel, that's always going to be a compromise.
You could make the seal pressure higher to keep the air in better, but then you'd have friction, lubrication and wear issues at that point forcing higher maintenance.
CTIS is going to make you less hesitant to air down which is a good thing for getting past obstacles, until you break the beads (which isn't the CTIS's fault after all)

I've watched the Truck trial Tatras start their day with six completely flat tyres. They just fire up the engine and wait, eventually they're aired up and off they go.

So it appears that some form of beadlock is a good idea, in any case.
One could also install a stop valve on each wheel where the CTIS connects to the tyre valve, just to be sure there's air in the tyres the next morning.

Personally I'd use the CTIS for levelling the truck in the evening, although it might get a bit wobbly if you let it down too much...

 

[boroburner]

Would you say overall youve save time with the CTIS system? Given extra; maintenance, 2nd tire rebeading, etc. As apposed to havig to stop and manually air up/down?

I too find it suprising that there isn't a valve of some sort on the system to prevent both tyres from deflating, if there is a problem? Esp. on the new computer controlled models. Surely there must exist something(similar to a "bradly check valve" to prevent syphoning) that could counter this??

Could it be for safety that the system would be designed like this? Maybe having 2 tyres deflated/ing provides better control when carrying heavy loads at speed?

 

[charlieaarons]

In the U500 it does automatically inflate when
a given pressure/speed ratio is out of range, unless
the override switch is on. After 4.5 years I only leak
1%/day out of the front, no change since new.

Charlie

 

[boroburner]

does the U500 system isolate the tire, or do you stll have the issue of both sides deflating?

 

[dan johnson]

Would you say overall youve save time with the CTIS system? Given extra; maintenance, 2nd tire rebeading, etc. As apposed to havig to stop and manually air up/down?

It all depends what you are doing. If you are going from asphalt to soft terrain a number of times per day it could be very helpful. If you use your mog on a regular basis on and off road it can be very handy. I my case the mogs sit for a long time between use so they bleed down as time goes by.

The system is nice in that every time you get in the mog you know exactly what your tire pressure is. If it is not right you can adjust it as you are going down the road. That will probably make your tires last longer. It is also interesting to watch the tire pressure increase as the tire temperature goes up.

On the u500 if the tire pressure get below a specific psi when you are going over a certain speed a buzzer goes off. On the 1550 if you do not catch the pressure gauge going down both tires can go flat. On one occasion I noticed the pressure dropping so I switched on the inflate switch and we we able to get to the camp we were going to before we had to stop and fix the problem.

The 1550 has a high output water cooled air compressor the runs off a belt. The system maintains an 18 bar pressure (260 psi).

If you have CTIS use it but if you find a nice vehicle without it I would not pass it up. Most people do not have it and do fine.

Dan

 

[grizzlyj]

My split rims currently deflate too quickly from either leaky beads or valves (new valves are in the post)

So whenever we move it can take an hour of inflation using the little Merc inflation tube to get the two or three that need attention to running psi. Not a normal situation, but remounting them, or getting back to highway pressure takes ages with this hose set up.

Maybe CTIS is overkill, but the four spiral hoses from one control box seems a big improvement over what I have now if the air flows more freely.

IMHO a decent sized box on a 1300 filled with long term stuff will probably put your weight too high for the chassis. Aim for a moderate box, or a severely light build and you should be fine