This thread is meant to be an informative article rather than a place to complain. I would like to keep track of new developments here and would appreciate any updates on these or other issues you may have discovered. I'm interested in widespread problems here that are noted by multiple people, not the one-off glitches that occasionally happen.
Color and opacity inconsistency
White (late 2006-present)
Red (before 1988, late 2006-present)
Orange (late 2006-present)
Blue (before 1986)
Light bluish gray (2007-present)
Dark bluish gray (2008-present)
Dark red (2005-present)
Dark blue (2007-present)
Green (late 2009-present)
Reddish brown (late 2009-present)
There is a range of consistency problems present in a variety of colors. The typical issue is that many bricks in these colors look faded and partly translucent. The Lego logos on the studs are not as clearly defined as they should be and the studs cast noticeably dimmer shadows on the brick plastic. This applies to a wide variety of pieces in those colors. An example of this can be seen here, although the appearance of the bricks varies with ambient light and is hard to capture in a photo.
These issues go back a long way but became much more prominent at the end of 2006, when TLG switched from pre-colored to clear ABS pellets. At Brickfair 2008, a TLG engineer (Bjarke Schonwandt) confirmed that the first four colors are not meeting the company's quality standards, but claimed that yellow has been fixed in manufacturing and that the others should be also fixed by the next year. However, there continue to be reports of bad yellow pieces in recent 2009 and 2010 releases, even on new types of pieces that didn't exist in 2008. On the other hand, there are indications that white has been fixed in manufacturing.
Yellow seems to have been affected before the other colors, going by some sets I have. Red and blue also had the same issues in the past, during the 1980s. The grays were not among the colors mentioned by TLG, but although I have not seen problems with them myself, there have been a number of recent reports about them on EB. Green has not had problems during the last few years like the other colors, but some of the 2010 sets are exhibiting obvious flaws with it, and the same applies to reddish brown.
These color problems may vary with the theme as well as the location where the set is produced and/or sold, although I have not seen any correlation yet.
Untextured slopes (late 2006-early 2009)
All Lego slopes except for the cheese ones have traditionally had a rough, textured surface, but we saw a transition to slopes with smooth surfaces a few years ago. TLG has said that this change was unintentional and they reverted to textured slopes in manufacturing last year. They are still running through their stock of old smooth slopes, so we are currently seeing a mix of textured and untextured slopes in sets. Less common slopes like 2x4 or 2x8 are the ones most likely to be smooth.
Dull edged plates (2007-early 2009)
Some plates have blunt, rounded edges at the corners instead of sharp and well defined ones. This is mainly an issue with 2x6 and 2x8 plates, which can look bad if several of them are adjacent to each other in a model. I believe this has been fixed in production now, but there are still sets being sold with the old plates.
Weak brick clasping power (2005-2008)
There have been many changes to the gripping strength of Lego pieces over the years. Late 1980s bricks typically have a very strong grip, too strong for most purposes, but TLG steadily cut back on the grip over the next several years until a good compromise between strength and playability was achieved. It remained that way from 1995 until 2005 or 2006, when the clasping power was substantially weakened further. It is not clear whether this is actually a quality glitch or an intentional change, but the resulting pieces are considered too weak by many people and lead to flimsy models. However, there are reports that this issue has improved lately and the bricks in recent sets are staying together more firmly, although not at the 1990s level.
In my experience, the weakest pieces usually suffer from some other flaw as well, either a color problem or the blunt edges issue described above. Plates and tiles are affected by this more than bricks, and lighter colors tend to be weaker than darker ones. Large plates and wedge plates in any color seem to have an especially weak grip on the bottom.
Brittle and peeling stickers (1994-2005)
Some stickers will peel off by themselves over time, and if you try to push them back on, they will crack and break up into many pieces. This only concerns stickers printed on white paper (as opposed to clear, transparent paper), and only ink in certain colors. White, blue and red components of stickers are sensitive to it, while yellow and black components are immune. This effect is caused by UV exposure, but the stickers are much more sensitive to it than bricks and can go bad quickly even in a dimmed room. Taping over such stickers seems to be the only way to keep them intact.
I first saw this in 1994 Technic sets and last saw it in 2003 World City police sets, although it probably continued for a while longer. This was fixed by TLG at some point, since more recent stickers I applied in early 2008 don't appear to have any problem.
Oily tires (1997-present)
In 1997, TLG changed the material used on small tires to a sticky, gummy substance. The tires were usually packed with other pieces in the same bags and left a visible splotchy residue on the bricks. This substance does not come off under running water but can be removed with a soft cloth and alcohol, or by just rubbing your hands on the bricks vigorously. The tires harden over time and lose the stickiness if left on display for a few years. Last year, TLG switched to a rubber-like material that doesn't run off on other pieces. At this point, this problem seems to be specific to some locations only. The sets I purchased in the US after mid 2008 have all contained the new tires, but people in some other countries are still getting the oily tires in recent sets.
Crumpled instructions and sticker sheets (2000-present)
This has been an issue with large sets ever since TLG removed the plastic trays from big boxes in 2000. The instructions and stickers are no longer held in place by the trays and float freely inside the boxes, so they tend to get crushed between the parts bags and crumpled up. An obvious way to fix this is to put the instructions in their own shrinkwrapped packaging, which TLG finally started doing with some of the largest sets in 2011.
Confusing colors in instructions (2002-present)
It is often hard to tell the difference between dark gray and black in modern instruction manuals. This started around 2002 when TLG changed the appearance of the instructions, apparently in order to better distinguish dark gray (a color that was rarely used until the late 90s) from light gray. To make matters worse, the colors are not always consistent and can even vary between different pages of the same instructions, although this aspect of it seems to have improved in the last few years. Some other colors like blue and dark blue have also been mentioned as having the same problems.
Large window molding marks (before 1985, 2007-2009)
This is not really a defect as such, but has been the subject of many complaints because the molding marks look like bullet holes. In recent times, this glass piece has had a large blob-like mark on it, while smaller windows have four, small dots in the middle and/or faint circular marks along the edges. As of summer 2009, the first window seems to have been fixed, although some currently sold sets still include the older windows.
Deformable minifig accessories (2009-present)
TLG has recently been using a soft plastic for several minifig accessories that is flexible and has a brittle, waxy feel to it. It has been used for walkie talkies for a long time, but many other pieces use it now too. Several recent pieces made of this material have a problem where the part that the minifig hands clip on to is slightly too thick. Putting it into a minifig hand requires much more force than usual and creates noticeable scratches in the piece, and it can even cause fragments of the plastic to peel off. I have seen this issue on the tooth and spike parts in 5982 and the metal detector in 5984, and others have brought up the Atlantis trident, Castle broom and Pirate swords as well.
Oxygen-sensitive white bricks (1989-1996)
These look identical to normal white bricks but discolor much faster, in any ambient light conditions. It has been suggested that they actually discolor faster in the dark, although I haven't seen evidence of this myself. The yellowing is uniformly spread over the whole piece and is due to oxygen exposure rather than UV. Only some white pieces from that time period are affected. I have several 1990s sets (8839, 8858, 8880, 8480, 6483, 5581) that contain a few or many such pieces, but have not seen this effect in anything more recent. Many other sets from that time period don't have this problem either, so it may have been theme or location specific.
This issue seems to be amplified if the bricks are exposed to smoky air, in which case a lot more white bricks are affected. It can even be present in MISB sets that were stored in such conditions, especially if the box looks grimy and discolored. This mainly affects 80s and 90s sets, when the part bags were all perforated and not airtight. It should be possible to reverse the discoloring by using H2O2 as described here, although I haven't tried it myself.
Flaky chrome pieces (1996-present)
The electroplating on chrome pieces tends to come off in fragments over time, revealing a trans-clear interior. This is especially common with thin parts like antennas, as seen on various Model Team sets, while normal bricks are less prone to it. Apart from the costs, this seems to be one reason why TLG has heavily cut back on chrome pieces in recent years.
Printing discrepancies (all years)
It is common for the prints on two identical printed pieces to have variations in their brightness and position. This was quite noticeable in the 80s, especially on printed computer slopes, but it improved a lot over the years. However, differences in print colors are recently coming up again, particularly in "special" sets with non-standard numbers which seem to be manufactured in different factories. See This thread for more information.
Tough pneumatic hoses (before 1992)
The pneumatic tubing used in various 80s Technic sets is harder than the modern kind and grips pneumatic nozzles very firmly. Over time, it will wear down the plastic on the nozzles, discoloring them and shrinking the opening in them. If left on a piston for many years, especially in a colder room, it can develop such a strong grip that it may actually tear off the nozzle if you try to remove it. In 1992, TLG switched to a glossier and more flexible tube material that doesn't have any of these problems and is still in use today.
A few specific types of pieces are susceptible to developing cracks or breaking up after some use:
1x1 headlight bricks: The cracks usually form down the middle of the lower lip in the front. Lighter colors like white or gray are more prone to it. A single crack will not make much difference to its gripping strength, but multiple cracks will weaken it.
1x1 transparent round plates : These often develop many small, vertical cracks after extended use, but it doesn't seem to affect their clasping power. This only applies to ones in transparent colors, which are made of PC instead of ABS.
1x1 cheese slopes: Many people have reported cracks forming down the middle of this piece, if left on a model over a period of time. Strangely, only some people are encountering this issue, but it's reasonably widespread.
Technic bushes and connectors (1978-1998): The older Technic bushes and various axle connectors like this and this can develop cracks when used a lot over time. TLG went through several revisions of these parts over the years before settling on the current designs, which seem to be stronger than the old ones.
Space robot arms (before 1991): The earlier versions of this piece were made of ABS and the clip could break very easily. In 1991, TLG started making them out of a softer material that was more durable, which is still in use today.
Old road signs (before 2000): It's common for the poles on these to bend or break after a lot of use. The newer signs made up of three different pieces are stronger.
Bionicle socket joints (2006-2008): The socket joints on various Bionicle pieces in the last two or three years are fragile and break off easily, much more so than older parts.
Broken functional pieces
Micromotor (1993-1997): This may lock up if not used for a while. I haven't found any way to fix the 3 (out of 9) broken ones I have, and they are expensive to replace.
Code Pilot (1997): A rare brick, but there are several Brickset reports of this breaking over time and not turning on. The problem on mine was simple to fix though.
Damped shock absorbers (1999): The initial batch of these often broke after some use, particularly those in 8448. TLG was offering free replacements back then. Newer ones have no problem.
Studless pneumatic pistons (2003): Some people have said that the top seals on the 8455 pistons have a relatively high failure rate. 8455 has been the only set brought up in this context.
Edited by CP5670, 20 May 2012 - 05:56 PM.