Broken Lego 1/4 Circle Gear racks.

[doug72]

Recently I have been dismantling some older GBC Train modules that used these gear racks.

Dispite carefully  disconnecting them, many of the yellow ones were found to have split 0r cracked end connections.

Tried gluing the crack ends without success. Black gear racks don’t seem to have this problem.

Possibly yellow ones are made from a different material.

Has anyone found a use for the broken ones ?

[Zerobricks]

15 minutes ago, doug72 said:

Recently I have been dismantling some older GBC Train modules that used these gear racks.

Dispite carefully  disconnecting them, many of the yellow ones were found to have split 0r cracked end connections.

Tried gluing the crack ends without success. Black gear racks don’t seem to have this problem.

Possibly yellow ones are made from a different material.

Has anyone found a use for the broken ones ?

Yes, I broke a couple of yellow ones too. Black are fine.

[TechnicRCRacer]

Can anyone confirm they are made of ABS? If so, you can use solvent-based glue to chemically weld then together.

[astyanax]

A bunch of my yellow ones cracked, even with light/careful use.

[weavil]

4 hours ago, TechnicRCRacer said:

Can anyone confirm they are made of ABS? If so, you can use solvent-based glue to chemically weld then together.

They should be ABS, but the colored pellets may cause them to become weaker.

[Zerobricks]

31 minutes ago, weavil said:

They should be ABS, but the colored pellets may cause them to become weaker.

I think there was somewhere a topic of how different colors seem to have different mechanical properties. It would make sense, I had more yellow perpendicular connectors broken than black for example.

[astyanax]

15 minutes ago, Zerobricks said:

different colors seem to have different mechanical properties

In my experience LBG seems weakest -- connectors with axle hole like are cracking over time even without use, just lying in their little drawers. (And no direct sunlight, ever.) Much fewer issues with black and red, for example.

I barely own any yellow though, so lacking experience there.

[2GodBDGlory]

46 minutes ago, Zerobricks said:

I think there was somewhere a topic of how different colors seem to have different mechanical properties. It would make sense, I had more yellow perpendicular connectors broken than black for example.

I believe The Unofficial Lego Technic Builder's Guide suggested that red was the weakest color, while yellow was the strongest. Most of the evidence for these different things is probably fairly anecdotal, though!

[howitzer]

The colour is one obvious variable of course, affecting strength of parts, but that's not the only thing there is: Some people seem to have a lot of problems with cracking parts which have the bushing-type axle connection. On the other hand I have never had any issues, and I have significant amount of those bushings and related parts from five decades in perfectly usable condition. Somewhere there was speculation about the reason, and one idea why this might happen is that there are different factories providing parts to different areas of the world, and those have somehow different conditions, producing parts which look identical but have somewhat varying quality.

[Nazgarot]

I have lots of gray frames that have cracked or become brittle. I have no problems with black ones. Might actually be that the black plastic somehow is more resistant to aging/UV/mechanical stress...

_ED_

[1963maniac]

I'd have Lego replace them with black ones. I have had many cracked LBG bushes over the years. I suppose TLG may have made a bad batch.

[dr_spock]

9 hours ago, TechnicRCRacer said:

Can anyone confirm they are made of ABS? If so, you can use solvent-based glue to chemically weld then together.

Plain acetone seem to weld LEGO pieces together pretty good.

[TechnicRCRacer]

I don’t think anyone can say what color is strongest and what color is weakest — it seems many batches are using plastic from a different supplier. I got a UV flashlight recently and I notice some same color parts fluoresce while others don’t, even if they were made in the same year. Yellow is one of these colors. This also works well to differentiate the yellow engine piston parts and mismatching red connectors. I will check the yellow gear rack with the light.

[astyanax]

I've observed cracking in all bushing-type axle connectors, except this one:

From the touch of it, it seems to be made from a softer plastic, and I don't really like the look of it (lack of shine), but it does seem way more durable...

[langko]

Personally the only parts I've ever had crack are  and the older type of  before it got reinforced. Colour hasn't really seemed to matter.

[astyanax]

Mileage varies, it seems. For me the worst 'crackers' by far are .

Perhaps local climate and differences in temperature and humidity play a role as well? Here the official classification is "humid subtropical". In summer my man-cave gets really hot for a prolonged period, whereas in winter humidity is very low.

[damian_kane_iv]

I've had quite a few light blue grey pieces from around 2014 onwards crack after sitting around in storage for a few years. Breaks are also over-represented around axle connection points. 

Interestingly I also had a blue liftarm chip and break on another model after a few years (in the dark as well)

[Johnny1360]

There is a thread somewhere, I can't seem to find it now, I thought it was in general discussion, anyway it goes quite in-depth to how different colors are susceptible to breakage and why, reddish brown seems to be the worst offender.

[weavil]

I found this from an old post:

And this one too:

 

[dr_spock]

On 1/28/2023 at 12:34 PM, Johnny1360 said:

There is a thread somewhere, I can't seem to find it now, I thought it was in general discussion, anyway it goes quite in-depth to how different colors are susceptible to breakage and why, reddish brown seems to be the worst offender.

Could be.  I have more reddish brown break than any other color.