Air Brake Conversion....M818..?

[M920]

Has anybody done this, or does anybody know what's involved, to convert a 818 to straight Air Brakes, like used on the 900 series 5 ton's?
I know how to plumb it all, so I'm just interested in the mechanical part of the conversion. (parts needed at the wheels) Any input would very much appreciated....

Thanks Soni

 

[98hd]

I think you could just use all of the parts from the backing plate out from the 939 series trucks. Problem is crossing the parts to Civvy numbers. I had talked to Dave P once about it and he thought a civvy equivalent wouldn't be too hard to find, of course he had some 939 axles to take parts off of.

I'd love to convert mine, although after redoing the brake system I can lock up all 6 tires on gravel, w/ 16x20's.

One negative I can think of, is that the military eventually put ABS on teh 939 series trucks because of loss of control when the air brakes locked up (too much braking force when unloaded). Would probably get the same on these trucks, although one could plumb in a valve that increased braking force to the rear tires when loaded. Kind of like the 94-02 dodge trucks had, only for air.

 

[Alredneck]

Memphis Equipment offers a kit to convert over to full air on the 800 series trucks. Im sure its real exspensive, but from talking to one of the guys involved with the project, they out sourced some of the parts from readily available sources. To bad he wouldnt give up the information on how to do it.

 

[NDT]

Memphis at $6760 on the web site, rears only, S-cam. The 900s are wedge.

 

[jwaller]

it's cheaper, safer and better to buy a 900. or a road tractor and paint it green.


BTW if you want a 900A2 tractor, I've got one I need to sell.

 

[Alredneck]

Right now im just researching stuff, I was wanting to have better brakes for my M814 for when it tows my big trailer. ( Adding a M818 5th wheel n ramps ) I was trying to figure out how to get full air but lately been thinking of the possiblity of air discs. Only thing about disc would be being able to keep using a 20in rim. Bendix makes a air disc setup up but requires bigger than 22.5s. As im broke right now all I can do is read n drool. Hopefully things will turn around this new year and be able to actually start building something. ( I have the M814, S250, 5th wheel, 40k drag winch, and 14.00 XLs w/ Hemmt wheels, also a 20k winch for the front ) The S250 im turning into a sleeper so it would be more comfortable than even the Naty. Will post pics but other things are more important right now. Lots of lil parts lying around that may go on it as well.

 

[M1075]

I have the M814, S250, 5th wheel, 40k drag winch, and 14.00 XLs w/ Hemmt wheels, also a 20k winch for the front )

Sounds interesting. If you plan on pulling a big trailer, you might also want to look at the NTC-400 and Allison tranny I have listed in the classifieds!

 

[Alredneck]

I been reading about adding a turbo to the 250 as well,, I have thought about swapping to a different motor the 400 would be a good replacement. Thanks for the heads up! I might be sending you another order for some more wheels after the begining of the year, will be in touch.

 

[73m819]

somebody on SS took the backing plates, ect for the rears from a old brockway, along with the valves, and used 900 fronts for full air on his 819. the rears are timken (rockwells)double reduction, old cranes, gradalls,mixers, ect. used these axles, if you can find a doner, get the power divider, or the LOCKING INTER-AXLE DIFF.. will not have both together. both can be used on our axles

 

[M920]

Thank you all for the heads up on this and the leads.

I will let you know what I end up doing.....

Thanks Soni

 

[rmgill]

S-cams would be FAR better than wedges.

 

[73m819]

you can find both types of air brakes on doners, yes wedge will hang up if maintance is lacking

 

[DaveP]

This set up was under a grade all type machine on top load 44,000 rockwells.

I would rather use the wedge type myself.

I dont mind the small amount of maint when you get better braking and

increased ground clearance.

maybe the s cam would be better for the trucks that stay on the road most of

the time.

 

[73m819]

those pics show a low mounted S-cam, thay are also top mounted, your pot does not hang below the axle

 

[Army Ed]

This is only my personal opinion but i like the M818 brake setup as far as maintenance,options and just in case of a air problem u still have hydro brakes.At least over seas we loved havin them.

 

[DaveP]

I ran accross several conversion set ups done by memphis and they all had the cans hanging very low.

thats not a problem if the unit does mostly hard surface driving.

 

[Oasis-3]

Air brakes for a 20" 10 lug wheel should not be hard to come by. I know as a car hauler we can buy new trailers with air brakes on 19.5" standered 10 lug wheels.
Any big truck shop should be able to get you the parts you need.
Good Luck
edit: and they have the cans on top of the axles

 

[73m819]

This is only my personal opinion but i like the M818 brake setup as far as maintenance,options and just in case of a air problem u still have hydro brakes.At least over seas we loved havin them.

if you loose air, the MAXIS set, you dont go ANYWAY unless you back off the brakes or cage them

if i had the money (ha,ha) i would air the 819, there is something about going down the road in a #36000 truck at 60 mprh with a SINGLE circut HYD. brake system that just bothers me just a little bit (ok i lied ,bothers me a LOT)

 

[Army Ed]

thats what im sayin,while we were rolling we didnt have time to go cage brakes,so we were set...it wasnt the best way to roll but it worked..lol

 

[No.2Diesel]

Hi,

Thanks for your interest M920. I appreciate all the work done to the M920. It really looks sharp and makes people think its an M1070 HET.

On to the brake issue:

Thank you 73M819, my brother and I are the ones that did the air brake conversion. We were going to use those rockwell Brockway rear brake parts but didn't want to mix and match s and wedge since it was difficult finding a civvy app. that has a rockwell front drive axle. Its much easier to source 939 series mil. parts.

Here is the associated thread with all the pictures etc. http://www.steelsoldiers.com/5-ton-up/18915-m819-receives-ntc400.html It explains all the gory details.

The thread and project has been in hibernation for about a year now due to my brother's lack of work from the current economy. The good news is that he has a nice new permanent job/career in a similar line of work so major work will resume. We are still excited about the end product and have not lost any faith. I think you'll like it when its finished.

We learned a few things along the way:

-Its much cheaper to hunt and peck for a carcass, or individual parts than it is to buy an entire kit from the major surplus dealers but obviously it takes time and some roadtrips.

- You can't buy Mil. part no. brake parts from even the best brake parts or truck parts stores, we've tried. When a mil. part no. comes up on the computer the guy says "we don't have access to that." Your limited to the several Mil. surplus sources which is actually alot.

- Wedge brakes will always have better performance numbers than S-cams thats why they were chosen for Mil. apps. The only reason for the addition of ABS was a response to all the in-experienced operators as well as the reckless ones causing rollovers fatalities. It doesn't take a genius to figure out what happens when the brakes are slammed when the truck is empty and the roads are slick. This will happen in any type of truck with any type of brake system.

- Wedge brakes when modified (adding a grease zerk) will never freeze and don't have any more maintenance issues than S-cams.

- As is stated in the attached thread, 900 series brake parts will bolt on to the axle housing from the backing plates-out.

-939 series "cans" are mounted in the "3" and "9" o'clock position on the backing plate so they are no lower than the axle housing. They protrude parallel to the axle housing.

I hope this and the attached thread helps. I apologize for the lack of posts in it, life gets in the way. It really is one of the best things you can do to your 5ton. You'll also be using a much wider brake shoe.

It boggles the mind why in WWII all tactical trucks from the 4ton Diamond-T 969 and up had full air brakes then right after the war they went to the extremely silly air/hyd. system.

Now get out there and start converting!