Builds MM40-The Adventure Continues

Joined
Apr 2, 2008
Messages
8,875
Location
Victoria, BC
Where I've read of the most problems is when users take their one ton, add 5000 lb bags, and then feel they can now carry three tons without doing anything to the frame to carry the extra weight. They are then surprised when their frame complains that they carried 2 yards of sand.
 

65swb45

Elder Statesman
Supporting Vendor
 
 
Joined
Apr 14, 2004
Messages
25,207
Location
818-953-9230
Well, I called and left a message for @SLOCRUISER to take a look at the pic and advise.

With the airbags in place I was able to move forward on the aux tank install. Put the tank into place with a floor jack so I could measure where to add rear mounting tabs to the angle iron I used to replace the missing rear crossmember of the frame. :rolleyes:

Mounting a filler neck is going to be its own special challenge.
 
Joined
Aug 25, 2005
Messages
93
Location
Cambria, California
Hi Mark,

I see in your picture of the inflated airbags. Normal installation of the brackets is more like 12 o'clock to 6 o'clock. I just wonder how things were modified on the 40 to fit the motorhome because I don't recall the upper bumpstop being in that location. Ask Dave up in Atascadero if he has any history of the modifications.

The airbags should still work as installed as they are stout.

John

HJ47 LA09 MOUNTED.jpg
 

65swb45

Elder Statesman
Supporting Vendor
 
 
Joined
Apr 14, 2004
Messages
25,207
Location
818-953-9230
Hi Mark,

I see in your picture of the inflated airbags. Normal installation of the brackets is more like 12 o'clock to 6 o'clock. I just wonder how things were modified on the 40 to fit the motorhome because I don't recall the upper bumpstop being in that location. Ask Dave up in Atascadero if he has any history of the modifications.

The airbags should still work as installed as they are stout.

John

View attachment 1847076
John

The airbags are just barely installed; it will be several months until they are plumbed. I decided to leave the truck on jack stands while I am doing the tank install; that is why they look inflated.

I am virtually certain that the upper mounts are in the stock location. The suspension was basically stock when Sam bought the truck from Dave. And if you look at the lower plate you can tell it is flat. IOW, the upper mount is virtually directly above the lower. Its just that that’s where the arch in the frame is. (12o’clock-6 o’clo I)

So if the brackets were made with a Cruiser in mind, and there was a concern regarding having the plates more parallel, they would have had to build some angularity into the mounts in addition to the creative use of side-to-side offsets they already have.
 
Last edited:

Downey

 
Joined
Jun 5, 2007
Messages
4,300
Location
Brea, Calif.
I have to agree with the parallel mounting for two reasons: (1) I'm afraid you'd wear a hole in the top bag were it has 10%-20% contact with the bag directly below it, instead of 100% (360 degree contact would be ideal), and (2) I'm afraid you'd be trying to snap the top mounting bolts since the upper mount would always be trying to shear off the bolts on an angle ???
 

65swb45

Elder Statesman
Supporting Vendor
 
 
Joined
Apr 14, 2004
Messages
25,207
Location
818-953-9230
I have to agree with the parallel mounting for two reasons: (1) I'm afraid you'd wear a hole in the top bag were it has 10%-20% contact with the bag directly below it, instead of 100% (360 degree contact would be ideal), and (2) I'm afraid you'd be trying to snap the top mounting bolts since the upper mount would always be trying to shear off the bolts on an angle ???
These are good points Jim. Hoping John has some more input. I would say however that what we are looking at is probably the worst case scenario, as the rig is at full droop right now. The axle will undoubtedly rotate some once I get it off the stands.

The plan was to mock the tank in yesterday, start marking for the filler neck, and drop the truck from the stands. Unfortunately, because the bed of the motorhome does not have the one inch ‘step’ that the 40 does, the mounting hardware was not long enough. I bought some longer hardware on the way home, but now it is raining.
 
Last edited:
Joined
Aug 25, 2005
Messages
93
Location
Cambria, California
Hi Mark,

How about fabricate a wedge to create more of 12 o'clock position or flat surface for the upper bracket to sit.

BOSS designed the LA09 brackets to fit the leaf spring Land Cruisers. It appears from the photo you posted, the axle maybe a little forward of the original stock location. Maybe to accommodate the motorhome body, the axle was moved forward. The BOSS upper bracket should be attached at the highest point of the arc in the frame bend and not forward of the highest point.

John
 

65swb45

Elder Statesman
Supporting Vendor
 
 
Joined
Apr 14, 2004
Messages
25,207
Location
818-953-9230
I am not going to belabor the point. The apex of the frame is 5.5” behind the center of the axle, as it is on both my ‘68 and ‘69FJ40s. There is nothing anomalous about this frame or these leaf springs.

I agree with everyone that the top and bottom plates should be as close to parallel as possible, regardless of the company’s instructions calling for reusing the factory bumpstop holes.

In a perfect world, I would probably move the upper bag mount to the apex anyways, where I would still have to build a wedge to align it with the bottom plate that would now be angled back. I cannot do this on this Cruiser without having to make new brake lines and further modify the junction, as the tight fit of the passenger side bottom plate is already within 1/8” of the brake line junction. A factory junction and breather combo wouldn’t have made it past square one.

I am going to make wedges.
 

rkymtnflyfisher

I’m going fishing
SILVER Star
Joined
Aug 29, 2011
Messages
4,618
Location
Montana
Where I've read of the most problems is when users take their one ton, add 5000 lb bags, and then feel they can now carry three tons without doing anything to the frame to carry the extra weight. They are then surprised when their frame complains that they carried 2 yards of sand.


What do you mean I can't carry an extra 2 tons of material in the bed!

Now what am I going to do? Buy a 5500?
 

65swb45

Elder Statesman
Supporting Vendor
 
 
Joined
Apr 14, 2004
Messages
25,207
Location
818-953-9230
What do you mean I can't carry an extra 2 tons of material in the bed!

Now what am I going to do? Buy a 5500?
You can subsidize the 5500 by offering services to the local road maintenance service. Those D70 pumpkins are so big, and the duallies can’t ever seem to not to go over the center divider.

So you might as well hang a paint bucket from the diff and offer to paint the center stripe as you go! :p
 
Joined
Apr 2, 2008
Messages
8,875
Location
Victoria, BC
5500... my other rig was based off an E350 cutaway. I believe it's frame is the same as an E450. With 4K packs on each side, in nicely carries the 6k+ that the rear weighs empty. It's a tad beefier than a 40 series. It's good to know the place for each vehicle and use it for what it's designed for.
 

65swb45

Elder Statesman
Supporting Vendor
 
 
Joined
Apr 14, 2004
Messages
25,207
Location
818-953-9230
The taper went from the thickness of the .18 wall tubing to 2.375 near the apex of the frame.
 
Top Bottom