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KW & Holmes 750 with a question.

Orcas Tow

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Recently a friend retired his tow company his father started in 1962, I bought his 1981 Kenworth W900A, 350 Cummins/1962 Holmes 750 with a 30k Zacklift. I am getting to know her, never using a mechanical wrecker before there is a learning curve I understand. I have been over all the moving parts, inspecting, greasing, flushing fluids, adjusting PTO chain, replacing boom cables, etc. She's a good old girl that will serve me well on my small island. 
I am wondering if someone familiar with the split booms can enlighten me on if you can perform a hard side pull directly off the boom with them pinned together, say a heavy truck in the ditch on a narrow road, can I use one line directly off the boom on a hard side pull & the other down to a snatchblock off the tailboard D ring then to the casualty for a low pull. Will the center pin connecting the booms handle a hard side pull? Thanks.

builder 2 tubered.gif said:
I usually run a block off the d ring to help relieve stress from side load on the booms. You can also unlace the cable from the boom and pull directly from the mast, depending on the angle the side leg could be used. I have 2 A models that we run and I love them.
Orcas Tow tubegreen.gif said:
Thanks for the reply. So a hard (45 degree) side pull is not recommended then? Im thinking simplicity, the boom sheaves are 12' in the air, any words of wisdom about pulling the wire rope out of the sheave without manually lowering the booms or is lowering the only option? I do understand the physics of pulling directly from the mast but pulling the rope from the sheaves at 12' to achieve a mast pull seems sketchy for my health:).
builder 2 tubered.gif said:
You should be able to do a hard 45 degree pull from the boom, I just run a second line through a block or dead end the cable at the d ring to reduce side load on the booms/latch. As far as raising/ lowering the booms. That's the down side of non hydraulics. They will make you work.

On the plus side based on your experience and thinking outside the box you will make this truck sing. Looks like a zacklift, any spades?
Orcas Tow tubegreen.gif said:
I restrung the 200' pair of 5/8" wire ropes on the drums & also replaced the wire rope for the booms, all bigger & heavier than what Im used to. Its been fun, really respecting the old school operators, no excuses, no second chances, no OSHA approved equipment, pay attention/respect to what your doing or someones getting hurt.  Yes hydraulic spades & a Z-30 Zacklift, can't wait to really put her to the test, trying to educate myself to use the combo to its full potential.
builder 2 tubered.gif said:
A lot of the 750's were on a shorter wheelbase, which helps doing recovery work on back road and tight spaces. Nice looking truck. If it was close to me I would have bought it.
MACK6X6 said:
   If you are doing a heavy pull / recovery, I would get the truck "set" with the lines in the booms.  Then, if you want to pull off the mast you can take the lines out and simply swing the booms out of your way rather than lower them.  On ours, we installed a large D-ring in the center of the tailboard at the very top and will run the line from the mast through a block, then back to the casualty.  Of course, we don't have all the obstructions on our tailboard that you do but you get the picture.  You may be able to get one in there.  Also, the feet on the Zach stiff legs are small - you may want to cut them off & install something larger along with Trebron concrete spikes.  Excellent recovery unit - looks nice.  Steve.
Bob Graham said:
looks like it has homemade booms and support frame , booms are too long / high
Orcas Tow tubegreen.gif said:
Correct, the booms have been replaced. What was the length of the original 750 booms? I was told it was a 1962 bed which would have been web booms (?), the bed sits on top of a heavy full length 6x6 I beam, the mast is bolted & then welded with gussets to the I beam, then the I beam sits on top of the KW frame. It was all done in the 90's & there is not a paint crack around any welds or mounting bolts. 
santiam01 tubegold.gif said:
Usually, you will tip the tow truck over, or drag the nose of the truck in line with the pull, before you do any damage to a 750, on a side pull, straight off the end of the boom. Just make sure the controls are in good shape, not much worse then getting a mechanical unit stuck in gear......By the way, that's a good looking truck, & I know you will make it even better!
MACK6X6 said:
 There were 2 different lengths of square (usually extendable) booms (that I know of anyway), depending on whether or not it was mounted on a single axle or tandem axle truck - but I don't know the length.  And Santiam is very correct, if you are on a hard pull, just because you "let up" on the levers doesn't mean they will disengage - sometimes you have to "yank" them out of gear - makes ya' a little nervous.  LOL.  Good luck, Steve.
Orcas Tow tubegreen.gif said:
This has been converted to large air rams to engage & disengage winches, I will click a picture later of the rams. Hope this will address any sticking engaged on a hard pull but the PTO & clutch air in/out are close to the controls in a pickle.
Reds tubeyellow.gif said:
Snatch blocks are your best friends with one of these, we run a few yet.  In reference to the winches staying locked in I believe your thinking free spool...not the case here, although if you look how your winches free spool with the air rams your referring to you have 3 teeth that disengage for free wheel or engage/winching operations...that same set up on a gear reduction is what's inside that winch box to forward the rope or reverse the rope hence the dogging in or clash sound of the gears when you hit the levers for winching. If your on a hard pull you've got the winches pulling cable in things are creaking and groaning just because you let off those levers doesn't mean she stops those internal gears will bind sometimes to where you have to actually yank the lever pretty good to make it stop winching, you'll know when it happens just be ready cause as mentioned it'll pull it's self right over.  At that point it simply means you need another part to the line.  On hard pulls with these I just put 3 parts to the line and let it work seems the leverage is so much better, its slow going but it is what it is.  As the booms look about right it is said roughly 12 inches above the mast +- keeps a little down pressure on the ass for you.  When I run directly off the mast I'll loosen the rope to the point of no weight on it take the rope out of the boom heads then split the booms  holding on to them so the don't swing to far out of the way .there heavy and hard to get back together once 90 out and they will get there if your leaning one way seems one side always goes down first on a hard pull. On one truck we put tabs at the base of the boom with chains to hold them from swinging to far.  There fun simple units to run and use, rigging and action reaction is the key thinking one step ahead.  On a couple side notes the 750s can spool 250ft comfortably 5/8 rope.  You also made mention you replace the boom rope with new and bigger, be careful in doing so larger rope on the pulleys can result in 2 very negative reactions 1) the rope doesn't fit well so it smashes it down into the groove of the pulley possibly breaking some strands leading to future failure. 2) The rope does smash down into the groove possibly splitting the pulley apart resulting in failure those pulleys were cast and they do break I've broke the ones where the rope comes through the mast back to the boom heads 2 of them on my 600's I suggest you replace them ASAP just because.  Trebron does have replacements that we've used there steel with a bronze bushing I'm sure if you look you'd see rope lines in the current pulleys (there soft metal)  They will always break when you have 105 ft of rope out so as to ruin the whole line LOL. As far as a side pull you can pull any angle you want on that unit and your not going to hurt it or the boom pin the truck will walk itself and find the happy medium now your front end may be on a embankment when said and done and you can't move cause your stuck but they are pretty tough to destroy or hurt. But you must respect them and listen to them they will talk to you through the chassis, wrecker, winch levers, etc.  Good luck....FYI holmes has 2 boom sizes for the 750s X-7 is what there referred to hence extend 7 feet. MECHANICALLY The 750 single axle boom length is 135 1/2 inches retracted 219 1/2 extended these were also found on a lot of 600's also they put bushings where they pin on to make them fit...simple economical business sense smarts it interchanges seeing's how holmes only made couple different size bodies.  The 750 tandem body used a 166 1/2 retracted and 251 1/2 extended boom. Boom heads typically hang a bit over the tailboard as todays hydraulics do. 1 more note as your booms were replaced or reworked they don't have the loops towards the base like OEM (find some pictures of other trucks and study the booms at the base) These loops can be used for a couple different things like I hang my snatch blocks from them...On one truck we have a short chain to them so they don't swing around...or you can hook the cable hook to them hit the lever raise it up a bit unlatch the boom cog WITH OUT THE CRANK ON THE DRUM and lower it down 1 side at a time set it right on the bed and reverse to raise the boom (no or minimal cranking involved) Just a few tad bits on that learning curve.  Send me a cell number I'll snap a couple pictures and send them to you if you'd like.
OrcasTow tubegreen.gif said:
Here's the air rams for the winch in/out. I have not loaded the winches yet but will this weekend for some testing, better to find out in private than in public.

Wesley, I believe the boom rope was 5/8" from the factory, thats what I re installed, it fits the sheaves well. Your the 3rd person to advise not leaving the boom crank in place:) I did notice the loops on the booms are not there, might be a handy addition in the future.
Trex said:
I own 2 750s and they re beasts and if u run a 3 part line when you need it well thats a beast on steroid
Just curious whats your wheelbase? hope you make a lot of money.
Greets from Panama.
builder 2 tubered.gif said:
Have you had to use it yet? Let's see some action photos!
Orcas Tow tubegreen.gif said:
A few times so far, a Garbage truck tow, Propane tanker winch & propane truck tow, all pretty straight forward. Will get something fun to share soon. Its amazing this truck handles the same empty or loaded with 30k behind it:)

Hello from sunny (when its not raining) Orcas Island

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