"Rescued" M816 Wrecker

[Csm Davis]

opcorn: caught up with a trucker buddy of mine the other day and looked over his inventory of dead Freightliners, We came to the conclusion that once the snow breaks I can go shopping for air brake parts,--- pedal, vavles and switches, an air seat or two and some 24.5 steel wheels.....
Looking to install the trailer dash valve at least for now so I can not rely solely on the Mico for small things as opening a gate. Really nice to pop the red button and have the trailer park, while opening a gate or dropping the trailer.... kinda tired of a dust bath every time I disconnect the lines on the trailer.
I am currently eyeballing the drum parking brake on the 816s T case pondering how to put a small air can-like our #9 clutch cans to use as a momentary parking brake on the T case.... being that is that lately Ive been spending a lot of time under there staring at the golden driveshaft's former location....

Okay guys y'all do know that the 939 series uses a mechanical and air brake emergency brake handle? Or you can just leave the original mechanical brake and add the air buttons like a standard big rig.

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[red]

Okay guys y'all do know that the 939 series uses a mechanical and air brake emergency brake handle? Or you can just leave the original mechanical brake and add the air buttons like a standard big rig.

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Yes I'm going with a standard commercial PP8 valve for the parking brakes on the rear axles. Valving on my airbrake setup will be standard commercial parts.

Weather permitting on monday the drivers side front axle will be put back together and maybe the front passenger as well. Then it's break out the torch and finish cutting all those rivets off the rear axles.

 

[wcuhillbilly]

Okay guys y'all do know that the 939 series uses a mechanical and air brake emergency brake handle? Or you can just leave the original mechanical brake and add the air buttons like a standard big rig.

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Yes,,,, I was referring to dumping trailer air on my air braked 12 ton tag trailer so as to not have to take a dust bath when the glad hand is un hooked at the rear of the wrecker. I was also referring to the ease of being able to dump the trailer air and use that ( with common sense applied) as a momentary parking brake in order to open a gate or such, instead of having to trip the MICO. being that I don't fully trust my juice brakes. Bled them multiple times and I still have hard good pedal and brakes one minute, and nothing the next. no leaks,
Ultimately an S cam system is what Im after.
Secondly, in the interim I was considering retrofitting a small air can onto the T case in the 816 in order to use air for the activation of the drum parking brake, as of right now, if the drump brake is adjusted up to the point of actually working, it will smoke and rub going down the road..... an air can will provide enough travel to solve the rub in motion while allowing a moderate amount of hold while stopped...

 

[Csm Davis]

Yes,,,, I was referring to dumping trailer air on my air braked 12 ton tag trailer so as to not have to take a dust bath when the glad hand is un hooked at the rear of the wrecker. I was also referring to the ease of being able to dump the trailer air and use that ( with common sense applied) as a momentary parking brake in order to open a gate or such, instead of having to trip the MICO. being that I don't fully trust my juice brakes. Bled them multiple times and I still have hard good pedal and brakes one minute, and nothing the next. no leaks,
Ultimately an S cam system is what Im after.
Secondly, in the interim I was considering retrofitting a small air can onto the 1138 T case in the 816 in order to use air for the activation of the drum parking brake, as of right now, if the drump brake is adjusted up to the point of actually working, it will smoke and rub going down the road..... an air can will provide enough travel to solve the rub in motion while allowing a moderate amount of hold while stopped...

Okay first please don't trust the micro line brake without the hand brake, I have seen many leak down or just not work.
Your hand brake is a great brake but may be missing a spring or worn to the point of needing to be rebuilt, I would start by loosening the handle completely then check the shoes and springs to make sure the shoes are being pulled away from the drum and then adjust the nut on the cable, it should correct your problems or point you at the bad points.

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[wcuhillbilly]

Okay first please don't trust the micro line brake without the hand brake, I have seen many leak down or just not work.
Your hand brake is a great brake but may be missing a spring or worn to the point of needing to be rebuilt, I would start by loosening the handle completely then check the shoes and springs to make sure the shoes are being pulled away from the drum and then adjust the nut on the cable, it should correct your problems or point you at the bad points.

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Thanks Jeff,
But I know where my weak link is,,,,, it just needs re-engineered. Did the shoes immediately after I got it, and put all new springs on at the same time. couple miles down the road I could smell it, adjusted, and adjusted and came to the conclusion that if its adjusted up to where it needs to be to work,,, then it will rub and start smoking the shoes. Had to pay $150 to get the rascals re-lined when I put them on. I like the hand brake, and have experimented while driving by twisting the adjustment on the handle, and I can get it close to not smoking, but try and park with it and it is just not cutting the mustard.
I hate the MICO,, had it seize on me with a ranchers rescue hanging on the rear. jerked enough trying to free the breaks that the chain broke and the recovery haul went back down the canyon..... Likely is not that the drum is warped or needs replaced. I would love to have a 1138 air shift in there, and get rid of the Sprague too, but that will have to come with the 10 spd as the front axle over/underdrive will be an issue then.

 

[Csm Davis]

Thanks Jeff,
But I know where my weak link is,,,,, it just needs re-engineered. Did the shoes immediately after I got it, and put all new springs on at the same time. couple miles down the road I could smell it, adjusted, and adjusted and came to the conclusion that if its adjusted up to where it needs to be to work,,, then it will rub and start smoking the shoes. Had to pay $150 to get the rascals re-lined when I put them on. I like the hand brake, and have experimented while driving by twisting the adjustment on the handle, and I can get it close to not smoking, but try and park with it and it is just not cutting the mustard.
I hate the MICO,, had it seize on me with a ranchers rescue hanging on the rear. jerked enough trying to free the breaks that the chain broke and the recovery haul went back down the canyon..... Likely is not that the drum is warped or needs replaced. I would love to have a 1138 air shift in there, and get rid of the Sprague too, but that will have to come with the 10 spd as the front axle over/underdrive will be an issue then.

Might try replacing the cable it could be the problem also. When useful it is a good system.
The micro line lock can be re worked with new parts.

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[Csm Davis]

Yes I'm going with a standard commercial PP8 valve for the parking brakes on the rear axles. Valving on my airbrake setup will be standard commercial parts.

Weather permitting on monday the drivers side front axle will be put back together and maybe the front passenger as well. Then it's break out the torch and finish cutting all those rivets off the rear axles.

Are you going to keep the manual hand brake?

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[red]

Are you going to keep the manual hand brake?

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No. My stock parking brake has proven to be too unreliable. With an 1/8 of a turn on the lever in the cab it goes from zero clamping ability to requiring a 18" cheater pipe to get the lever to move all the way up, which flexes the floor of the cab from pulling so hard. Can't tighten the cable on the tcase anymore because it's all the way at the end of the threads. Setting up spring cans on both rear axles is a massive upgrade over the stock m809 series parking brake so I won't even bother with the stock setup anymore.

For reference originally I was not planning to go with air brakes on my m816. Debated it for awhile. The stock hydraulic brakes have worked great for me, lock up all 6 of the 395's and throw you through the windshield. Was planning to install pinion brakes on the rear axles to serve as true emergency brakes/good parking brake but the trade for m939 airbrake parts popped up and I went for it.

wcuhillbilly keep an eye out for the tcase pto with the t1138. Unless your going to convert both the crane and rear winch to hydraulic run off the transmission PTO.

 

[wcuhillbilly]

wcuhillbilly keep an eye out for the tcase pto with the t1138. Unless your going to convert both the crane and rear winch to hydraulic run off the transmission PTO.

planning on using the wet kit on the trans,,,, by having to move the T case back, it will put it into a crossmember, and thus I don't really want to rodeo shafts again. the 138 is live feeding our pwr dividers all the time, and that would put a lot of stress on a hydro unit unless a shift mechanism was put inline.... biggest thing for me is the moving the t case back and trying to fit 10lbs of crap in a 2lbs sack.... I live for the day I can drop the pwer divider and the associated linkages, rods, and such.

 

[Csm Davis]

No. My stock parking brake has proven to be too unreliable. With an 1/8 of a turn on the lever in the cab it goes from zero clamping ability to requiring a 18" cheater pipe to get the lever to move all the way up, which flexes the floor of the cab from pulling so hard. Can't tighten the cable on the tcase anymore because it's all the way at the end of the threads. Setting up spring cans on both rear axles is a massive upgrade over the stock m809 series parking brake so I won't even bother with the stock setup anymore.

For reference originally I was not planning to go with air brakes on my m816. Debated it for awhile. The stock hydraulic brakes have worked great for me, lock up all 6 of the 395's and throw you through the windshield. Was planning to install pinion brakes on the rear axles to serve as true emergency brakes/good parking brake but the trade for m939 airbrake parts popped up and I went for it.

wcuhillbilly keep an eye out for the tcase pto with the t1138. Unless your going to convert both the crane and rear winch to hydraulic run off the transmission PTO.

Red try backing off the nut on the cable, it sounds like it is to tight. It needs enough slack to not catch until the handle is near the breakover point, I am not trying to talk down just give a little help.

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[red]

Red try backing off the nut on the cable, it sounds like it is to tight. It needs enough slack to not catch until the handle is near the breakover point, I am not trying to talk down just give a little help.

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Tried messing with it a few times. When loosened off at the tcase then it doesn't catch at all. Plenty of material on the shoes and the mechanism appears to be moving correctly.

Kind of a moot concern on this particular wrecker though since it's sitting like this and will remain immobile until the air brake conversion is complete.




Eventually the stock tcase parking brake will be completely removed from the truck. Won't be necessary for use, adds extra weight to the drivetrain, and takes up space.

 

[red]

planning on using the wet kit on the trans,,,, by having to move the T case back, it will put it into a crossmember, and thus I don't really want to rodeo shafts again. the 138 is live feeding our pwr dividers all the time, and that would put a lot of stress on a hydro unit unless a shift mechanism was put inline.... biggest thing for me is the moving the t case back and trying to fit 10lbs of crap in a 2lbs sack.... I live for the day I can drop the pwer divider and the associated linkages, rods, and such.

Yea theres a bunch of PTO shafts/linkages on the m816 wreckers. Really funny part is I'm going to add 1 more on mine haha. Got my hands on the subframe/components from another m51a2 dump truck and going to remove the pump/valve from the subframe and relocate it to the m816, powered from the rear output on the transmission PTO. Use some of those hydraulic quick disconnect couplings so it can power whatever lower flow/volume hydraulic systems needed/wanted.

 

[wcuhillbilly]

going to remove the pump/valve from the subframe and relocate it to the m816, powered from the rear output on the transmission PTO. Use some of those hydraulic quick disconnect couplings so it can power whatever lower flow/volume hydraulic systems needed/wanted.

Do I see, hydraulic outriggers, ground spades in your future.......?????

 

[red]

Do I see, hydraulic outriggers, ground spades in your future.......?????

possibility as time goes on. The initial idea with the on board hydraulics is to power a trailer. Going to take whats left of the m51a2 I parted out and turn it into a trailer with multiple platforms, similar to Soni's FEMMT build. Dump bed, water hauler, whatever is needed. If I start making some money with the wrecker and have to use the outriggers or ground spades often then it will absolutely get those hydraulic upgrades.

 

[Csm Davis]

One of you guy's ask for a picture of the rear winch drive on a 936.

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[red]

Last time I was in Arizona I took a look at the rear winch setup on a m936. Same exact winch as the m816 but one big difference. on the m936 the gears on both the hydraulic motor and the winch are the same size, kind of small. On the m816 the PTO drive gear is small like the m936 but the gear on the winch is much larger, nearly twice the diameter. That loss of leverage would explain at least part of why the winch on the m936 is so much weaker, it lost that gearing advantage.

M816

 

[wcuhillbilly]

One of you guy's ask for a picture of the rear winch drive on a 936.

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Think Red was looking for the winch related stuff, I was curious about the Crane pump config due to mine dumping the CVs

 

[Csm Davis]

Think Red was looking for the winch related stuff, I was curious about the Crane pump config due to mine dumping the CVs

Thought you were wanting to see the rear winch hydraulic motor setup?

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[wcuhillbilly]

Thought you were wanting to see the hydraulic rear motor setup.

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That would be correct, the pump motor that powers the crane drive. particularly the pass through from chassis side to crane turret. are you still parting out that 936 that we talked about over the Phone some months back?

 

[Csm Davis]

That would be correct, the pump motor that powers the crane drive. particularly the pass through from chassis side to crane turret. are you still parting out that 936 that we talked about over the Phone some months back?

Okay yeah still have 2 that's coming apart and if red doesn't mind I will post some more pictures here or we can put them on the golden shaft thread.

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