Review: 8258 Crane Truck

[starstreak]

I have now got all the stickers on the Truck and out of all the names to choose from I chose Peter after my Dad.

That works.

[Zerobricks]

Today i built it, and its a good set. The one thing bothering me, it broke my 12 tooth gear! I had to replace it and make sure erything turns as easy as possible. I took a video of my build:

It looks very nice, but lacks in functionality for me. Good for parts though!

[JunkstyleGio]

I guess i had the same problem.

Check my brickshelf!

Solving a problem!

And don't forget to ask the Lego Customer service for a new part!

Explain the problem in full. They will replace the part for free.

Good luck!

Edited September 5, 2009 by JunkstyleGio

[Milan]

Today i built it, and its a good set. The one thing bothering me, it broke my 12 tooth gear! I had to replace it and make sure erything turns as easy as possible. I took a video of my build:

It looks very nice, but lacks in functionality for me. Good for parts though!

I am glad you finally got it!

Good video.

[JunkstyleGio]

Had this week quite an intensive contact with LEGO considering various problems with the 8258. (The breaking of the 12t bevelgear in particular)

I made a document (inEnglish and Dutch) in which i explained the problems and added my solution. The were very pleased indeed!

I will be discussed by the North American AND European Product experts in their meeting with the designers in Denmark next month.

Let's see what will happen!

Edited September 15, 2009 by JunkstyleGio

[TechnicJuan]

I still don't understand why your 12t gear kept breaking. I have that same set and never had a problem. I also don't understand your solution to the problem by adding the Bushings to the axle. Is there something else that you modified also?

Could the gear not handle the torque from the Motor?

[Blakbird]

Had this week quite an intensive contact with LEGO considering various problems with the 8258. (The breaking of the 12t bevelgear in particular)

I made a document (inEnglish and Dutch) in which i explained the problems and added my solution. The were very pleased indeed!

I will be discussed by the North American AND European Product experts in their meeting with the designers in Denmark next month.

I'm interested in this problem because mine has been assembled and used for weeks and I've had no issues whatsoever. It appears that you are referring to the use of the linear actuator bracket as a gearbox housing. In this arrangement, a 12 tooth double bevel gear mates with a perpendicular 12 tooth bevel gear. Presumably you are experiencing some problem due to the fact that the bevel gear is free to float on the axle and could theoretically jam. You seem to have added some spacers to prevent axial motion of this gear. What I wonder is, why do some have problems and some do not? Perhaps it is related to how tightly the gear fits on the axle and therefore how likely it is to migrate.

Maybe you already said these same things in your document, but I can't read Dutch!

Original:

JunkstyleGio fix:

With this gearbox arrangement, if you were to put the yellow bevel gear on the wrong side, it would make the gray axle rotate backwards. This would result in jamming of the mechanism and possible destruction of the gear. I don't know if this is what actually happened in the cases posted here, but if so the fix had nothing to do with the addition of the bushings and was merely related to installing the gear in the right direction when it was put back together.

Edited September 15, 2009 by Blakbird

[TechnicJuan]

Is it breaking when you are trying to lift something with the crane?

[Front]

Could it be that the geartrain results in axial forces on the 12 tooth bevel gear ? And that those forces push it against the double gear if the friction on the cross axle isn't sufficient ?

[Anio]

On my 8258, the axle used to slide down.

To fix the problem, I add the same parts.

[JunkstyleGio]

Eric is totally right. And with the gears in the correct position and the bushels added, both problems are corrected!

Maybe there is a qualityproblem in the axles and gears? (That is thickness and diferent kind of plastics-quality...?)

Lets just see what TLC will answer after their meeting......

Anyway Eric: You probalbly can't read dutch (which i thought you might with your Dutch family name) but you made the right assumptions!

[Blakbird]

Anyway Eric: You probalbly can't read dutch (which i thought you might with your Dutch family name) but you made the right assumptions

My family name is actually German, but mein Deutsch ist nicht so gut. My Dutch is even worse.

I am interested to hear what comes of your solution and the TLG meeting though. How did you go about getting in touch with them?

[JunkstyleGio]

@ Blakbird:

Die Deutsche sprache ist nicht so schwer...... And Dutch even more. (Being Dutch German is almost like a second language for me....)

But back to your question.

After my complaint of having those broken gears i got an email adres to sent the results of my replaced parts testing.

And then it kind of went it's own way. Me being very persistent and so on.

We still have to wait and see what kind of result comes from all of this.

[vauxfan2k]

Hi guys

I just built the alternative model with my second set of this 8258,

The duty wrecker itself isnt too bad, a bit basic and looks rather bland without stickers tho.

The cherry picker trailer is pretty hefty, loads of parts poured into it, but again lacking lifting strength and for some reason the crane frame flops back and forth, I thought this was a mistake but I checked and rechecked the instructions.

disapointed in the alternatice model, so taking it apart to build a second crane truck, hopefully modifying the crane to be stronger and a tad faster.

cheers

Ste

[vauxfan2k]

Hi Guys

Ok Ive stripped the pickup and trailer, takes a good while!

Built the second truck, this time without the stickers, and also trying the mods to the gearing anf the pins at the universal jonit at base of crane.

I used the half bush along with the full bush in all of the actuator mounting joints (all have the flimsy cogs)

The first test run after build was flawless, except for when the crane closes fully. There is still the teeth clenching crunching of the cog pictured in the mod images.

This has ruled out the mod as being worthwhile. there has been no significant advantage in having the bushes in the other mountings either.

the only clear solution is to have another clutch cog in somewhere to prevent this, being a different size to the cogs in use.

Leave it with me. :O)

Edited September 21, 2009 by vauxfan2k

[vauxfan2k]

Hi Starstreak,

Im afraid you do have too many pieces left over, After building 2 of these I was left with all the same parts from both trucks.

the 2 black axle joiners, a half bush, and all the grey full bushes were NOT left over from my sets.

Makes me wonder where you missed them from or if you got more spares than the rest of us?

Cheers

Steve

Extras

Here's whats left after I finished the build. I'm thinking maybe I have too much... Nah.

[Anio]

The extras are not exactly the same in all the boxes.

When I built my MF 10179, I had many extras :

Edited September 27, 2009 by Anio

[JunkstyleGio]

The first test run after build was flawless, except for when the crane closes fully. There is still the teeth clenching crunching of the cog pictured in the mod images.

This has ruled out the mod as being worthwhile. there has been no significant advantage in having the bushes in the other mountings either.

Very strange that the mod did not work on your models. I've been testing some more and there is aboslutely no noise, no teeth clenching crunching with my model.

With many of the people i talked to and who applied the mod it seemed to work quite nicely aswell....

But then again there are many ways in solving the problem.

How are you doing with yours?

Please do not hesitate to share it!

Edited September 26, 2009 by JunkstyleGio

[vauxfan2k]

Hi,

I stripped and rebuilt the crane mechanism, as I was still not happy with the overall strength of the outer arm, This time I used some ports from an old 1980's technic set, the bushes and rods were far stronger, the bushes gave a tighter grip. I noticed that the older ones are made of a harder plastic which is harder to bend by hand.

The crane operates smoothly and when retracting the only clicking that comes from it is within the actuator, My next step is to open the actuator and use some lithium grease to coat the gearing inside. this should make the actuator quieter and more forgiving when wound too tight in extended or retracted positions.

as for lifiting power, the only holdback now is the white clutches and the general flimsyness of the plastic beams. White clutches can be temporarily replaced by normal cogs but the risk of damage to other components increases if the motor is left running unsupervised.

Ill keep going and see what else can be improved.

cheers

Ste

[VBBN]

Holy crap, That alternate mode truck(not the trailer) looks stunning, I may have to get that...

Great review. ;]

[CP5670]

Hi,

I stripped and rebuilt the crane mechanism, as I was still not happy with the overall strength of the outer arm, This time I used some ports from an old 1980's technic set, the bushes and rods were far stronger, the bushes gave a tighter grip. I noticed that the older ones are made of a harder plastic which is harder to bend by hand.

Yes, the old bushes and especially the half bushes (up to 1993 or so) have a much stronger grip than modern ones. This can make them quite useful in some situations.

[merman]

The other day I took my 8258 apart and something struck me. One of the black axles going to the xl motor has light bley powder on it where it went through a light bley beam. Like it caused much friction. Strange thing is the beam itself did not look damaged. Could the xl motor be too powerful for this set? could a m motor work???

[JunkstyleGio]

Check this for some great modifications on the 8258 by Designer Han

"Klick"

or check out his site:

Desinger Han

Edited September 28, 2009 by JunkstyleGio

[CP5670]

The other day I took my 8258 apart and something struck me. One of the black axles going to the xl motor has light bley powder on it where it went through a light bley beam. Like it caused much friction. Strange thing is the beam itself did not look damaged. Could the xl motor be too powerful for this set? could a m motor work???

I've seen this many times before, and not just with the XL motor. It usually indicates that the axle is not spinning completely freely or that the rotation speed is simply too high. As you said, it's strange because the nearby beams/gears don't have any sign of damage even if you look closely.

[vauxfan2k]

Hi Guys

Followed the instructions for modifying the gears to incorporate the extra clutch, This mod would be alot easier if done during building, but my trucks were alreay assembled, so a bit of fiddling and stripping down and I managed to do the mods to my second truck, I had to borrow a white clutch cog from another of my built sets, and some of the other parts like the L shaped beams are not included in the original 8258 set, so you will need to source these also.

Results are to be expected, no more crunching of gears and crane movements dont need to be closely supervised anymore.

A success!

Lego should provide revised instructions for future sets, or even an update leaflet to be inserted into existing instruction books,

Cheers

Ste

EDIT:

Seems I was a little hasty is calling this series of mods a success, The lifting power of the crane arm (lifting an object by use of upper or lower arm) is greatly reduced, this is because the newly installed clutches slip instead of allowing the arms to raise the object, if you prefer to use the manual winch to achieve this tho that works as normal.

pros and cons for everything it seems.

Edited September 28, 2009 by vauxfan2k