Wrong part in 8421 technic mobile crane??

[5150 Lego]

I'mnearinng the end of building the crane arm,andi'm atthe part i need to intallthe rope's with the eyelets on. Problem is, that one is considerably shorter than the other. Is this right? Are they supposed to be differnt lenths? Or do i have the wrong part? Sorry for al lthe questions about this set recently. Just its fustrating when you've spent this long building a set to find out you have wrong parts at the end.

[keetongu]

Can you give a picture?

[Lost Viking]

  5150 Lego said:

I'm nearing the end of building the crane arm, and I

[gylman]

Hi, I've built this one and its sitting in front of me. I am not sure what the problem is from your description. A camera, or at least a page reference from the instruction manual may help.

Gyl

[5150 Lego]

  gylman said:

Hi, I've built this one and its sitting in front of me. I am not sure what the problem is from your description.  A camera, or at least a page reference from the instruction manual may help.

Gyl

Second booklet, page 67. After building the rest of the crane,i found out that i do in fact have the wrong lenth rope. Both are suposed to be the same lenth.

Luckily, me being the spiffy lego builder i am, i was able to make the longer size work, intill lego sends me the proper size, along with my new decal sheet (i seem to have misplaced mine).

[gylman]

Oh my. Definitely. Those are definitely supposed to be same length.

Now that you are done, or nearly so.... what did you think?

I found it a good model, but it seemed to me that for so much money, so many pieces, it shuld have done more. The pneumatic part is almost an afterhtought - if you release the lever the whole boom comes crashing down. It should be some sort of smooth coast. Of course that's fixable, but why would they release the model that way? They would have been better off with a gear for elevating the boom.

I can think of 5 technic models that have way less parts, cost less, and are way cooler (855 and 8460, both cranes; 8858 Airtech Claw, the best bar none, 8094 universal and 8455 or 8862 (backhoes)

Anyway. Here's hoping 2006 will bring something new. At least Lego seems to have revived the line, there was some talk in 2003 of the "end of technic" after a number of weak years.

[5150 Lego]

Finshed the set last night, and over all i really like this set.

main points that i like....

- i really like the out rigger design. They come out far, and do a good job of stabalizing the crane during lifting(a problem i had in 8460,it kept tipping over).

-Love the 8 large wheels, and 6 wheel steering. This crane probbly has the best turing radius out of all my sets.

-I like the 3 boom lenths . Nice change from the conventional single extention.

-The motor to extend the hook, and boom are a nice touch.

-Anything that uses a piston engine has my approval.

What i don't like.....

I agree with you on the bad points of this set.

-The pnuematic cylinders use nearly all there power to just lift up the arm itsself. You can forget lifting anything with cylinders with half air.

- that brings up when you lower the boom. Like you said gylman, it just crashes down. I'm guessing that conecting the remaining air chamers, to the valve (this is the first time i've ever seen it where lego didn't hook up those lines) would help make the boom come down a bit slower What do you think gylman?

Also, i felt it should have been big enough to acomadate a technic figure. You can get onein the passenger seat no problem, but you have to remove the steering wheel, for him to fit in the drivers seat. And forget about the operators cabin. (but i am working on making that bigger, as well as moddifing the cab to better suite the driver)

- Then there's price. I did feel that $150 was a bit high, but when youfactor in that youre getting pneumatic cylinders, and a motor,and battery box, its not bad concidering the peices. I can defenatly see this being a very sought after set after it gets discontinued.

I do believe that there are better sets for the money, (8460, crane, and though i don't have it yet 8455 back hoeand yes, i do feel that the air tech claw rig was the best valve for the dollar), but if i asked if i would pay $150 for this set again, i would say yes.

Over all i really like this crane. I'm going to add 2 more cylinders to give it more lifting power, enlarge the operaters cabin to acomodate a techinc figure, and add a hitch so i can tow one of my trailers.

[chewie]

  5150 Lego said:

I agree with you on the bad points of this set.

- that brings up when you lower the boom. Like you said gylman, it just crashes down. I'm guessing that conecting the remaining air chamers, to the valve (this is the first time i've ever seen it where lego didn't hook up those lines) would help make the boom come down a bit slower What do you think gylman?

well, I'm not Gylman, however, I do have this set and I like it a lot, I also did find the boom crashing down quite annoying, so, with some extra pneumatic hosing, I connected the two open ends of the pistions to the switch, so now when I release it, it does not come crashing down, try it out for your self, it works fairly decent.

[5150 Lego]

  chewie said:

  5150 Lego said:

I agree with you on the bad points of this set.

- that brings up when you lower the boom. Like you said gylman, it just crashes down. I'm guessing that conecting the remaining air chamers, to the valve (this is the first time i've ever seen it where lego didn't hook up those lines) would help make the boom come down a bit slower What do you think gylman?

well, I'm not Gylman, however, I do have this set and I like it a lot, I also did find the boom crashing down quite annoying, so, with some extra pneumatic hosing, I connected the two open ends of the pistions to the switch, so now when I release it, it does not come crashing down, try it out for your self, it works fairly decent.

Hey, thanks for the tip chewie! That was in fact what i was talking about doing the same thing. Its good to know that it will work. I'm going to hook them up right now!

[JINZONINGEN73]

  5150 Lego said:

  gylman said:

Hi, I've built this one and its sitting in front of me. I am not sure what the problem is from your description.

[gylman]

  5150 Lego said:

  chewie said:

  5150 Lego said:

-  I'm guessing that conecting the remaining air chamers, to the valve (this is the first time i've ever seen it where lego didn't hook up those lines) would help make the boom come down a bit slower What do you think gylman?

well, I'm not Gylman, however, I do have this set and I like it a lot, I also did find the boom crashing down quite annoying, so, with some extra pneumatic hosing, I connected the two open ends of the pistions to the switch, so now when I release it, it does not come crashing down, try it out for your self, it works fairly decent.

Hey, thanks for the tip chewie! That was in fact what i was talking about doing the same thing. Its good to know that it will work. I'm going to hook them up right now!

Yep, that's it. Bizzare that the instructions don'tsay to do that. It doesn't eliminate the problem, but certainly reduces it. Hech, there's extra hose,two open air ports..... what's the reason not to show the connection?

The set definitely has $150 worth of parts. It does not have $150 worth of fun. Still, I am glad that Lego is taking technic seriously and I am hopeful that something sexier will come along in the second half of 2006.

[Devious E Simian]

I was a bit confused by the set too. My dad had an old Technic crane set, and it was a beautiful, solid, elegant thing. My girlfriend got me the new Mobile Crane for Christmas, and while I greatly enjoyed the build, and it has some very interesting parts (8 identical wheels!) there do seem to be some odd things about the design. The turntable isn't "controlled" at all, the pneumatics, as has been mentioned, are a bit half-done (I'd expected air tanks, even a motorised compressor) and the motor really seems to struggle.

I have 6 fresh AAs of a passable quality but the boom takes literally (and I mean literally in the sense of "actually", not "not at all" as seems to be The Fashion) minutes to extend.

I'm wondering if I built it a bit wrong - I seem to have the choice of either making the string go in and out, or of having the string go in and out at the same time as the boom. Surely it should be one or the other, though the mechanism does what I'd expected.

The base is a rather nice design, but the crane itself leaves me a bit cold. I'm wondering about making a new crane jib based on a Mindstorms set with multiple high-torque motors.

[Devious E Simian]

  Lost Viking said:

Like other's have said, grammer is your friend...

I really hope those mistakes were intentional...

[5150 Lego]

  Devious E Simian said:

I was a bit confused by the set too. My dad had an old Technic crane set, and it was a beautiful, solid, elegant thing. My girlfriend got me the new Mobile Crane for Christmas, and while I greatly enjoyed the build, and it has some very interesting parts (8 identical wheels!) there do seem to be some odd things about the design. The turntable isn't "controlled" at all, the pneumatics, as has been mentioned, are a bit half-done (I'd expected air tanks, even a motorised compressor) and the motor really seems to struggle.

I have 6 fresh AAs of a passable quality but the boom takes literally (and I mean literally in the sense of "actually", not "not at all" as seems to be The Fashion) minutes to extend.

I'm wondering if I built it a bit wrong - I seem to have the choice of either making the string go in and out, or of having the string go in and out at the same time as the boom. Surely it should be one or the other, though the mechanism does what I'd expected.

The base is a rather nice design, but the crane itself leaves me a bit cold. I'm wondering about making a new crane jib based on a Mindstorms set with multiple high-torque motors.

Well,lets first talk about the turntable. I have crane 8431, whitch uses a crank in the back to turn the turntable. Though its a nice touch, if had any kind of load on the hook, the turntable wouldn't move with the crank. You would always have to use your hands. So this new simple design is welcomed.

As we all have mentioned before, the pneumatics are half done. I conected the open ends of the pistons to the switch like chewie sugjested, and it does help,but not a true fix.

I fell that there's just to much weight for 2 cylinders to handle. Espeacially when the boom is fully extended. I think adding 2 more cylinders will not onlysolve the problem,but also give the crane much more lifting power.

I myself haven't had any issues in termes of speed wise for extending the boom, or the string. But remeber that it does have very low gearing to make it less stress full on the motor. If its taking longer than you think it should, try checking all the gears, and related bushings. Make sure nothing binding up, or to tight. I probbly spent an extra 1/2 hour or so just making sure all the gears moved smoothly.

I glad you mentioned about the string moving with the boom extending. Mine does the same. I too thought i might have built that wrong, but if we both have that funtion, than i think we got it right. I for one like it that way anyways. It Keeps from having to constently switching over between the two.

Are you talking about andding a jib extention to the already exsisting boom,or just making a new boom design? Either way im sure we'd all like to see that when completed. I added a jib extention, second hook, and line to crane, and it came out preety good. Though i'm limited to what i can pick up with the jib extention on. With it on, its abolut 7, or 8 inches taller than 8421.

[Devious E Simian]

Aye - some good suggestions, thanks. :)

I'll try checking over all the axles to see if there's some friction somewhere - it really is very, very slow on mine. I was talking about building an entire new crane part to go onto the existing base - if I do come up with anything worthwhile I'll post pictures.

[5150 Lego]

No problem! ;) Hope it all works out. Good luck on your project!