Anyone have a dump with a scissor hoist?

[K30_dump]

Hello all,

Now that the weather is finally warming up, I am continuing my K30 project with the hopes of driving her this year. Started with an '80 K30 dump, which had a very rough life (was used to plow, hauled WAY too much, etc). Scissor hoist appears to be around 10 ton capacity, judging by current models with matching specs (5" cylinder bore, approx. 20" stroke). Should work well .

Anyway, planning now to use an '84 K30 cab & chassis frame, so everything must be switched over and/or redesigned. The hoist was originally welded to a 1/2" plate that spanned the leaf spring crossmember. The rear hinge was welded to the truck frame as well. I have heard different things about not welding to these frames, being high strength steel. That aside, I'm considering moving the hoist forward on the frame (around 24" back from the cab crossmember). I am very anxious about moving anything though, as I'm afraid it may not line up correctly or work right. The way it was isn't ideal per most hoist installation notes, but I assume it worked fine that way. I think by moving it forward, it will not only increase the hoist's capacity, but will also place a lesser load on the front hanger area for the rear springs (frame is pitted and kinda thin in that area ).

So, anyone here have a dump with a scissor hoist? Maybe get some pics and/or measurements of things?

Thanks in advance,

Joe

[tucsonjwt]

I don't have a scissor hoist, just a Pierce Wrecker conversion hoist - good for 2 ton max. However, if you move the hoist forward it will lift less - but with a big hoist it won't matter since I don't think you should put a 5 ton payload on your chassis (don't know for sure, but my C20 payload is 1.5 ton max.) My 2 ton hoist had to be located forward of the normal location because the pump and motor had to be mounted transverse between the frame rails (since I have a dual tank where the motor and pump would normally mount.) This reduces my lifting capacity to 1 ton max.

[K30_dump]

Originally Posted by tucsonjwt

However, if you move the hoist forward it will lift less

Hello,

Thanks for the reply. I am under the impression that, the further forward the lifting point is, the greater the leverage and mechanical lifting advantage. Not only that, but Rugby states in their literature that moving the hoist forward will decrease dump angle, but increase capacity. Moving further back increases dump angle, but will decrease capacity.

In any case, as you said, I can probably stand to lose a little bit of capacity . With the spring packs I built for the truck (11 mains and 5 overloads), I imagine I'll probably be able to haul 3-4 ton. Even with the weight of bed that is only 5 ton total, and the hoist is roughly a 10 ton unit.

Would still like to see some more square body dumps. Anyone?

Thanks,

Joe

[GM72K10]

Hoist is all the way in the front, 3 stage, will lift almost anything. Pivot is welded to back of frame as it was on donor truck. Works great.

[K30_dump]

Gerry,

Thanks for the reply. That's an awesome truck .

I must rethink what I was planning in my first post. Thinking about it this morning (after 12 hour night shift ), I must've overlooked that the hoist hanging down will hit the spring crossmember if moved forward. Therefore, I'll likely just put it right over the spring crossmember as it was before. As said though, my frame has some thinner spots there (darn PA rust from the confined area of the crossmember and gussets). Think the hoist pushing down there will pose any issues? I really don't want to plate the frame, as a bolt-in will only invite rust. I dont want to weld one in because I want to avoid welding to the frame as much as possible. Its not like I plan to use this daily for a work truck. Simply a hauler for occasional dump runs and such around the house. Thoughts?

Thanks,

Joe
Posted via Mobile Device

[RuralRoute C-30]

Not sure if it'll do more than serve as merely another illustration of a scissors lift set-up, yet here are some pics taken just after I bought this C-30 dump truck just over a year ago. Previous owner sold the wrecker half and converted this to what it is with what I believe to have discovered is a Knapheide dump bed set-up.

Ignore the pipe,jack stands and other 'safety blocks' in the pics as I was installing new rear shocks and wanted to hedge my bets working around this "new dump bed" truck at the time. Preferred overkill to being killed on the safety aspect.

Besides, I tend not to trust that much steel over my head anytime let alone being a "new old" truck I had yet to get acquainted with!





So far it works for everything I've used it for and operated like it should with the heaviest loads being primarily hauling firewood. A large boulder and some dirt last summer were easy compared to the wood loads.


Good Luck,
Mark

[K30_dump]

Mark,

Very nice truck . Those pictures helped a lot actually, as the hoist is very similar to mine. I can see there that your hoist is closer to the cab (as I'd like mine to be). Would it be too much trouble to take a few measurements? Curious on cab-to-hoist (frame mount) distance, cylinder size, hoist pivot to front of bed...if its not too much trouble .

Does the hoist touch the leaf spring crossmember when lowered then?

Thanks a lot Mark, really helps

Joe
Posted via Mobile Device

[RuralRoute C-30]

Thanks, Joe,

Heading out to the day job but will work on some info after that.
Mark

[tucsonjwt]

Actually, I got it backwards. I meant to say that the load has to be toward the rear of the box to increase "dumpability", since my hoist is located farther to the rear. My hoist should be located farther toward the cab, but the pump and motor are in the way because I could not use the outside frame rail location due to dual tanks. My hoist is electric over hydraulic - just a baby dump. You probably have a pto hydraulic.

[RuralRoute C-30]

See if this helps., Joe:
"Cab-to-hoist (frame mount) distance": 12" (red line)



"Hoist pivot to front of bed":14" (red line)

Sits just on the cab side of that bed cross-support.

"Does the hoist touch the leaf spring crossmember when lowered then?"
Sits on this if that is what you're referring to.


Cylinder size is about the same, being what I measured roughly to be a 5" x 20".

Obviously this set-up was installed with the pivot arm welded to a bolted plate on each side. Like I mentioned, the closest I can find resembling this set-up is a factory Knapheide scissors lift. Just forgot the link where I found it.

I have noticed, unlike a single cylinder lift, it lifts the weight evenly with no potential "side to side sway" I've seen in some smaller single cylinder lifts. So it does appear stable in design.

Anyway, good luck. Hope this info helps and feel free to ask for more info if needed. I'm still learning too.

Mark

[K30_dump]

Originally Posted by tucsonjwt

My hoist is electric over hydraulic - just a baby dump. You probably have a pto hydraulic.

Hello again,

Thanks for the pics, really helps. My hoist was originally mounted roughly where your is (maybe a few inches forward, but still on that crossmember). Hate to risk moving it, but I would like it more toward the cab...

As for the pump, mine is indeed electric like yours. Don't sell your truck short just because it doesn't have a PTO. Nothing "baby" about electric pumps, I actually prefer them. Not only can you raise the bed with the engine off, but I'd have to have my transfer case in neutral to engage a PTO. Then I couldn't drive forward while dumping. Anyway, have always much preferred the electric pumps .

Thanks for the help,

Joe
Posted via Mobile Device

[K30_dump]

Mark,

That's exactly what I was looking for, thanks so much. Even took more pics, very nice .

I'd like to move my hoist to within 24" of the cab, and that also puts it where manufacturers are now installing new units. Just nervous about moving it . Mine uses a pipe through the main bed rails to secure it to the hoist. I'd have to patch the previous holes as well. Anyway, something to consider I guess.

Thanks for taking the time to get the measurements and pics. Helps a lot .

Joe
Posted via Mobile Device

[tucsonjwt]

Funny you mentioned that, because I have a granny 4 spd with a PTO cover on it. Glad I don't have to use it.

[donut]

Thanks for the pics guys! Making my bed dump again is on my to-do list. This thread is being bookmarked for future reference.