Really need some help guys...M101A2 Lunette ring height

[MarkM]

Hi Guys,

I just picked up a really nice M101A2 but ran into a problem. The Lunette ring height works fine for my pickup but really got the trailer to pull behind a Pinzgauer 712M. The problem is with the stock lunette ring height and the surge brakes the rear door on the Pins can not be opened as there is only 5" of clearance from the center of the pintle hitch to the bottom edge of the rear door. I need to raise the lunette height like 6" from stock and this happens to be right where the Pinz pintle is. Below is two pics I found online showing an adjustable lunette ring riser and I need to know if it will fit my M101A2 and where I can find one. Really appreciate some help.

Thanks,

Mark

 

[gimpyrobb]

It should fit fine, you'll probably need to drill some holes though. The tape shows relative measurements, pull your surge brake assembly off and check.

How is that going to help your problem? You gonna angle the nose way down? I think thats a bad idea.

 

[MarkM]

Thanks for the reply. I want to raise the lunette ring up to the top of the riser. This will put the trailer very close to level the the Pinzgauer and with the Lunette ring at the top of the surge unit the door of the Pinz will now clear the surge system. The pintle hitch center of the pinz is like 27" off the ground.

 

[gimpyrobb]

If there is a welding shop near you, I bet they could modify your lunette to match the one you have pics of. Cut off the ring and weld one the adjustable riser. Probably save you over $100.

 

[juanprado]

The part you need 16105 is direct from balcrank who makes the toledo surge assembly.

Check out the attached manual as I believe it is what you are searching for.

lunette ring for channel :
http://www.etrailer.com/Trailer-Coupler/Bulldog/BD1291010383.html

 

[MarkM]

Yep that's the part I need thank you. I have emailed the company about it. Does anyone here on the site have one for sale?

Thanks,

Mark

 

[juanprado]

never seen any of the m101 with it. The m105a3 has something similar as it has surge brakes but I am not sure if that is the same one? Never looked at one in person.

Not many m105a3 around as the other models like the m101 or m105a2.

I would thing you have to go to balcrank or a supplier. I bought my parts to rebuild a m101a2 at croft trailer. Try them also?

 

[gimpyrobb]

Yep that's the part I need thank you. I have emailed the company about it. Does anyone here on the site have one for sale?

Thanks,

Mark

Never even seen one stock on a military trailer, I doubt you will find anyone here with one. PM me if you decide to sell the lunette you take off, I'd be interested in it.

 

[juanprado]

found a good picture of the m105a3 and it does not look like the same attachment is used on this surge unit as the m101a2/3

 

[MarkM]

Yeah you are right as it is a different setup. The pic I put up shows the riser unit and it sure seems to be the same surge system I have on my m101A2. I removed my lunnette today and it was a PITA with the shock bolt and the master cylinder bolt. I guess they want you to take off the whole surge system to more easily get at these bolts. I have one outher trick up my sleeve. I have a 2.5" lunette tow bar and may heat it up and bend it to 45 degrees. Then weld the bottom of the shank of the bar to the topside rear of the standard lunette. I will end up with tow lunettes one 5.5" above the other and will not effect either truck. It will look a little strange but more than strong enough. Also included a pic of the Pinz to show the pintle setup and how high it is and how close above (5") the door is.

 

[tbone1004]

would you consider losing the surge brakes and going to one of the old style lunettes? would bolt right in and you wouldn't have the big honking box on the front. Can't imagine with the 6x6 you'd really need the surge brakes anyway. Gets you the much smaller front end and you can spin the ring up and down to match the height of the hitch

 

[MarkM]

No I really can't. The reg truck I have is a Mazda B2200 pickup and the brakes are stock and not the best when pulling a trailer. The truck does have a chevy 350 stuffed into it so power is not a problem.

 

[tbone1004]

could switch to electric brakes with an axle swap, those are fairly cheap since you have standard wheels on there. I'd be really concerned with moving the ring up because it would have a negative effect on the surge by putting a moment on the piston. The only way the surge would work properly is with the ring inline with the piston arm. Once it gets above it, unless you engineer it very well which a standard height adjustable hitch won't give you, you can actually be putting the surge force on the piston when you start pulling it. This is worst case scenario, but it is very possible.

Other option could be extending the arm of the lunette to give you more clearance. I'd go with the axle swap personally since it gives you better braking off the bat as well as fixing your problem with the Pinzgauer. Not the cheapest option at $350 ish for a 5000lb axle with electric brakes plus the controller, but certainly gives you safer brakes for the Mazda and the height option with the MV. Would also remove some serious tongue weight from the surge system as well as the unsprung weight.

 

[SteveKuhn]

If you look closely at the 5 position part in the PDF above, it looks like it is designed to push straight back on the piston regardless of the lunette position. If I was gonna do something like this and didn't want to change brakes and axle, it looks like a very good choice. If I could do the bending and welding of the 2 lunettes, I'd still forego it and buy the part.

And the civvy truck can be fitted with a riser that keeps it level because you have adjustment on the trailer and riser. I like it.

Steve

 

[tbone1004]

didn't see the PDF although that does look like it would work well if he can get the clearance that way

 

[MarkM]

Thanks for all the great suggestions guys I really appreciate it. I just ordered the riser in the pic below. So what I am going to do is cut the lunette ring off to give me a flat large surface area block to weld the new channel riser in. then I will just use the ring units listed below and I should be good to go. I will put up some pics of the progress.

Mark

 

[tbone1004]

double check the welds, not sure if the lunette is cast or not and weld appropriately. I fairly certain my old one on my M116 is cast, but it involves some interesting welding techniques to safely weld cast iron. Good luck!

 

[gimpyrobb]

Cast steel, not iron.

 

[tbone1004]

sorry, cast steel. Even with the cast steel, for something like the main connection point for a trailer I'd preheat and slow cool it. I don't know what the alloy is on there, but if it is a high carbon content then it has to be preheated.

 

[gimpyrobb]

Yup, preheat and use something with high nickle content(rode or wire). Then a slow cool down.