XM816 Wrecker - Only Took Ten Years

[Flyboy207]

Well, after watching GovPlanet and having an email alert set for about ten years, I finally got a wrecker.
I bought it last week, went down a few hours south to take a look at it yesterday, and it got delivered today.



It's an XM816 which was owned by a movie rental company, fortunately for me it seems they kept up on maintenance since it runs, drives, and stops (better than I expected!)



I'm excited to work on it, I've got a few things I'd like to do on it (including painting the top to match). Note the tire marks on the road, does the front axle auto-engage in reverse? I heard an air switch under the shifter I think.



As of right now, I only have one major issue that needs immediate attention, as seen here... The crane winch drum is... well... it's full of bees. Any suggestions?

Thanks all!

 

[Mullaney]

Well, after watching GovPlanet and having an email alert set for about ten years, I finally got a wrecker.
I bought it last week, went down a few hours south to take a look at it yesterday, and it got delivered today.

View attachment 942657

It's an XM816 which was owned by a movie rental company, fortunately for me it seems they kept up on maintenance since it runs, drives, and stops (better than I expected!)

View attachment 942658

I'm excited to work on it, I've got a few things I'd like to do on it (including painting the top to match). Note the tire marks on the road, does the front axle auto-engage in reverse? I heard an air switch under the shifter I think.

View attachment 942659

As of right now, I only have one major issue that needs immediate attention, as seen here... The crane winch drum is... well... it's full of bees. Any suggestions?

Thanks all!

.
Wow! Seems like "you done good" .

I looked for bees on the crane winch. I didn't see anything? If they are hornets or wasps, I would give them "the business" with a can of WD40 or similar. If they happen to be honeybees, try calling the local agricultural extension to save them. Relocate them and you could end up with honey for your pancakes!!

YES. Be careful on the road when you drive in reverse. There is a sprag that engages and backing up will crack your transfer case. There is a way to bypass that air engaged sprag...

Congratulations!

Be sure to download the TM's for your truck in the 5-Ton section.

 

[Flyboy207]

.
Wow! Seems like "you done good" .

I looked for bees on the crane winch. I didn't see anything? If they are hornets or wasps, I would give them "the business" with a can of WD40 or similar. If they happen to be honeybees, try calling the local agricultural extension to save them. Relocate them and you could end up with honey for your pancakes!!

YES. Be careful on the road when you drive in reverse. There is a sprag that engages and backing up will crack your transfer case. There is a way to bypass that air engaged sprag...

Congratulations!

Be sure to download the TM's for your truck in the 5-Ton section.

I'll have to check out the TM's regarding that transfer case sprag, I'm sure a T-case isn't cheap.

The bees are in the little hole at the bottom of the winch drum in the picture. They are honeybees, but the local colony collection folks said the only way to get them out and save the colony is to take the drum off and cut it open to remove the honeycomb and queen. So, I might just have to put a plate over it of some kind, because not even the bee folks cared enough to sacrifice the drum for the bees.

 

[biscuitwhistler37]

Take em some water for a peace offering, it'll probably be denied but you can't say you didn't try

Looks way better in these pics, congrats!

 

[Flyboy207]

Take em some water for a peace offering, it'll probably be denied but you can't say you didn't try

Looks way better in these pics, congrats!

Thank you!

 

[NDT]

I had bees in the bellhousing of a WWII TD-18 bulldozer. I too didn't want to kill them. What caused them to pack up and leave was me setting up a water spray on the opening to the colony, which was an inspection cover on the bellhousing. I had to leave it spraying for days.
Very nice wrecker BTW.

 

[Superthermal]

Transfer Box & Air Shift x Sprag Operation

Hi, I'm Daniel, I live in Brazil. This is my first post on this forum. I bought a truck manufactured here in Brazil by Terex, here its rating is 5 ton. I bought it without the drive shaft and without the front wheel drive mechanism. I'm doing a lot of research here on the forum to understand...

www.steelsoldiers.com

This is a good read for Sprag operation.

If you have any questions shoot me a note.
Just follow this two rule law:
NEVER allow the rig to roll backwards when in a forward gear. EVEN IF THE CLUTCH IS PRESSED IN.
Never allow the rig to roll forwards when in a reverse gear. EVEN IF THE CLUTCH IS PRESSED IN.
Done.

 

[KN6KXR]

I have a 1972 M817 dump I use a bit here and there. It has a sprag for the front axle. The air shift you hear in and out of reverse is the unit locking out the sprag when you go into reverse. Aforementioned issue with cracking t-cases in reverse was an issue.

It works pretty well. My only gripe with it is that downhill in anything loose the front axle will disengage. This can be a bit hairy on downhill dirt corners with a dump full of stuff. You have to be careful and be ready for the front to suddenly start drifting out. Uphill it's great!

At some point I'd like to go with the modern air engagement scheme (like I have on my M35A2). I understand there was a retrofit kit at some point and all the vehicles got them. Mine must have left the service before they were fully deployed. I keep my eyes peeled for one of the kits they sent out but I think they are pretty few and far between now. Probably going to have to kit one myself....

 

[KN6KXR]

Nice 816 BTW. I have a 936 it's the same crane. Some stuff that might be handy:
-Those hydraulic lines on the crane look weathered it's common on old units to get a 100 gallon oil bath if left to themselves. Until renewal inspect them frequently.
-The swing gear case is a weak point. Drain the oil see how much water you get. Mine was left to itself and accumulated water which rusted the spiral hardened steel worm gear. This pitted gear then destroyed the brass drive gear it meshes with which in turn cracked the double ball bearing cases.... It was not a cheap or easy fix. BTW the brass gear is listed as a different part but it's the same as the M35 PTO winch brass drive gear. Much less expensive and readily available.
-Lube the heck out of the slew bearing (rotator bearing). It helps to have one person slowly turn the crane while another operates the grease gun.
-Pull out and slush all the lines. I spool them out then wind them in and as I wrap use a chip brush and some synthetic wire rope lube. Slather it down until it drips, make another wrap, etc....
-It's fairly normal for the hoist drive to weep and leak. The drum end seals are just felt. Keep it topped up. If it tends to spew while hoisting you may have a later model drive motor that needs (but was never fitted with) a inter seal bleed off (the port was capped). If this happens it's easy to run a line back to the tank. I used 1/4" copper hard tube with a grease gun hose at the pivot. It still leaks but it doesn't spew out.
-The hydraulic valve block has a port you can install a gauge on. After tuning the relief pressure I have a gauge on there with a quick disconnect so I can observe the working pressure during hoisting. Tells me when I'm at or near my limit of the machine. Besides the obvious stuff like the tires coming off the ground.
-The drag winch rollers and level wind assembly seems some sort of moisture magnet. I hit it with a grease gun at least a couple times a year and every time some water smooshes out. Same but not as bad on the front winch.
-Glad hand adapter with shutoff to an air hose adapter, plus air hose and some air tools are your friend. I've needed them to get a jumped cable free at the end of the crane and some other stuff. Get a air powered grease gun or your going to wish you had the forearms of Popeye.

All I can think of at the moment. My only regret about owning a wrecker is not buying one sooner than I did.

 

[Flyboy207]

Transfer Box & Air Shift x Sprag Operation

Hi, I'm Daniel, I live in Brazil. This is my first post on this forum. I bought a truck manufactured here in Brazil by Terex, here its rating is 5 ton. I bought it without the drive shaft and without the front wheel drive mechanism. I'm doing a lot of research here on the forum to understand...

www.steelsoldiers.com

This is a good read for Sprag operation.

If you have any questions shoot me a note.
Just follow this two rule law:
NEVER allow the rig to roll backwards when in a forward gear. EVEN IF THE CLUTCH IS PRESSED IN.
Never allow the rig to roll forwards when in a reverse gear. EVEN IF THE CLUTCH IS PRESSED IN.
Done.

Copy that, thanks! Seems pretty straightforward.

 

[Flyboy207]

Nice 816 BTW. I have a 936 it's the same crane. Some stuff that might be handy:
-Those hydraulic lines on the crane look weathered it's common on old units to get a 100 gallon oil bath if left to themselves. Until renewal inspect them frequently.
-The swing gear case is a weak point. Drain the oil see how much water you get. Mine was left to itself and accumulated water which rusted the spiral hardened steel worm gear. This pitted gear then destroyed the brass drive gear it meshes with which in turn cracked the double ball bearing cases.... It was not a cheap or easy fix. BTW the brass gear is listed as a different part but it's the same as the M35 PTO winch brass drive gear. Much less expensive and readily available.
-Lube the heck out of the slew bearing (rotator bearing). It helps to have one person slowly turn the crane while another operates the grease gun.
-Pull out and slush all the lines. I spool them out then wind them in and as I wrap use a chip brush and some synthetic wire rope lube. Slather it down until it drips, make another wrap, etc....
-It's fairly normal for the hoist drive to weep and leak. The drum end seals are just felt. Keep it topped up. If it tends to spew while hoisting you may have a later model drive motor that needs (but was never fitted with) a inter seal bleed off (the port was capped). If this happens it's easy to run a line back to the tank. I used 1/4" copper hard tube with a grease gun hose at the pivot. It still leaks but it doesn't spew out.
-The hydraulic valve block has a port you can install a gauge on. After tuning the relief pressure I have a gauge on there with a quick disconnect so I can observe the working pressure during hoisting. Tells me when I'm at or near my limit of the machine. Besides the obvious stuff like the tires coming off the ground.
-The drag winch rollers and level wind assembly seems some sort of moisture magnet. I hit it with a grease gun at least a couple times a year and every time some water smooshes out. Same but not as bad on the front winch.
-Glad hand adapter with shutoff to an air hose adapter, plus air hose and some air tools are your friend. I've needed them to get a jumped cable free at the end of the crane and some other stuff. Get a air powered grease gun or your going to wish you had the forearms of Popeye.

All I can think of at the moment. My only regret about owning a wrecker is not buying one sooner than I did.

Thanks for the tips! I had a sprag transfer case in my deuce and I wanted to switch it to air, hopefully that retrofit is available for the 5 tons.

As far as all the lubrication and wrecker hydraulic hoses, I’ll get a better idea of what shape it’s all in after I can get the bees contained or gone. Do you know what size that little hole is in the side of the crane cable drum, and why it’s there?

I’ll check the oil level in the hoist drive and probably put that pressure gauge in as well. It’s probably going to be used mostly in dry areas including the desert, reading the TM’s last night mentioned not to lube the cables in dusty areas? I know that’s to avoid attracting abrasive junk into the cable, but it seems like they’ll just rot out if left with no corrosion protection.

 

[US6x4]

From all I've read on here over the years, the cracking t-case in reverse is an issue with the T-1138 in the 939 5-tons and not with the T-138 in the 809 5-tons. This is because the 10:1 reduction of the reverse gear in the Allison automatic created too much torque for the T-1138.

 

[Superthermal]

Thanks for the tips! I had a sprag transfer case in my deuce and I wanted to switch it to air, hopefully that retrofit is available for the 5 tons.

As far as all the lubrication and wrecker hydraulic hoses, I’ll get a better idea of what shape it’s all in after I can get the bees contained or gone. Do you know what size that little hole is in the side of the crane cable drum, and why it’s there?

I’ll check the oil level in the hoist drive and probably put that pressure gauge in as well. It’s probably going to be used mostly in dry areas including the desert, reading the TM’s last night mentioned not to lube the cables in dusty areas? I know that’s to avoid attracting abrasive junk into the cable, but it seems like they’ll just rot out if left with no corrosion protection.

@Flyboy207
I bought the "M35 kit" for my rig from @fuzzytoaster here in SS. This kit does not "fix" the sprag issues necessarily, it works as following:

When the"Kit" is installed it allows you to cut supply air to the Sprag switching valve on the transmission and importantly, release/exhausts the downstream air in the sprag switching valve, and additionally down stream of that, the air pressing the sprag air piston on the transfer case itself. What this in turn does now that there is no air pressure in any of those lines/valves, The sprag fork which has two springs, one on each side of the forward/reverse fork will now sit evenly between forward and reverse position, which will not allow either the front or rear sprag to engage. This effectively makes the front axle disengaged even if the rear wheels slip. Now the front driveshaft is still going to get spinning and all that weight in gears is still going to pull down MPG unless you take and additionally find some front hub axle shaft caps and have the teeth milled out of them so the tire can turn without tuning the shafts.
Here is a diagram of the springs and "shuttle assembly" that shifts forward and back with air pressure. The two springs#4 here keep it centered with no air pressure.

 

[Flyboy207]

@Flyboy207
I bought the "M35 kit" for my rig from @fuzzytoaster here in SS. This kit does not "fix" the sprag issues necessarily, it works as following:

When the"Kit" is installed it allows you to cut supply air to the Sprag switching valve on the transmission and importantly, release/exhausts the downstream air in the sprag switching valve, and additionally down stream of that, the air pressing the sprag air piston on the transfer case itself. What this in turn does now that there is no air pressure in any of those lines/valves, The sprag fork which has two springs, one on each side of the forward/reverse fork will now sit evenly between forward and reverse position, which will not allow either the front or rear sprag to engage. This effectively makes the front axle disengaged even if the rear wheels slip. Now the front driveshaft is still going to get spinning and all that weight in gears is still going to pull down MPG unless you take and additionally find some front hub axle shaft caps and have the teeth milled out of them so the tire can turn without tuning the shafts.
Here is a diagram of the springs and "shuttle assembly" that shifts forward and back with air pressure. The two springs#4 here keep it centered with no air pressure.View attachment 942809View attachment 942808

Thanks for the explanation! That sounds great, essentially adding a “neutral” that can reduce wear or potential damage, and you don’t have to change the transfer case like I was worried about. Pictures are great too!

 

[Flyboy207]

UPDATE:

The bee man with his nice suit has come and plugged the hole in the cable drum on the crane. There are holes in both sides, so the other is covered with duct tape until I can get another plug for it tomorrow. 1/2” electrical box plugs seem to fit perfectly, in case anyone wants to do this as a preventative measure.


Additonally, after bringing the truck into the yard, I decided to open the glove box… and found these! Two operators manuals, one from 1972 and one from 1985, a “Hand Reciept Manual”(?) dated 1979, a laminated lubrication order book, and an envelope containing multiple service records from toward the end of her career. Everything (including the bumperettes) indicate this truck was used most recently by the 126th Engineering Battalion from Moscow Idaho.

 

[US6x4]

That's awesome stuff to have!

 

[Flyboy207]

Quick question:

Can anyone tell me why the Mico brake lock is installed in these trucks when the handbrake is on the driveshaft? I had assumed (like a fire engine that I had) that the power divider required the handbrake drum/driveline to turn when powering the winches or crane. When I was underneath today, I saw that this isn’t the case.
They also say that you can’t drive the wheels while trying to recover with the front winch. Separate issue, similar reason?

Thanks.

 

[Mullaney]

Quick question:

Can anyone tell me why the Mico brake lock is installed in these trucks when the handbrake is on the driveshaft? I had assumed (like a fire engine that I had) that the power divider required the handbrake drum/driveline to turn when powering the winches or crane. When I was underneath today, I saw that this isn’t the case.
They also say that you can’t drive the wheels while trying to recover with the front winch. Separate issue, similar reason?

Thanks.

.
The Micro Brake Lock is to hold the truck still while you deploy the rear winch. Pump the brakes when you apply the lock and all it will do is slide the tires. Hopefully to keep the truck from moving... Unrelated to the handbrake...

 

[Flyboy207]

.
The Micro Brake Lock is to hold the truck still while you deploy the rear winch. Pump the brakes when you apply the lock and all it will do is slide the tires. Hopefully to keep the truck from moving... Unrelated to the handbrake...

It makes sense that locking all the wheels would have more holding power than that little drum. That said, I avoid using them on the other vehicles I’ve worked on because they have a tendency to cause leaks from the wheel cylinders. This is the main reason I want to convert to air brakes, so that I can have spring brakes in the rear.

 

[Mullaney]

It makes sense that locking all the wheels would have more holding power than that little drum. That said, I avoid using them on the other vehicles I’ve worked on because they have a tendency to cause leaks from the wheel cylinders. This is the main reason I want to convert to air brakes, so that I can have spring brakes in the rear.

.
Yessir, and once you convert to air brakes - the BrakeLoc goes away. They are really good pieces of hardware. They do require a set of cylinders that are in good condition. After a rebuild, they would last for about 5 years...