Customer reviews from LEGO
LEGO - Technic Liebherr R 9800 Excavator 42100
Average customer rating
4.6 out of 5
4.6
(28 Reviews)
Open Ratings Snapshot
Rating breakdown 28 reviews
5 Stars
21
4 Stars
4
3 Stars
1
2 Stars
2
1 Star
0
93%of customers recommend this product. 
(
26 out of 28
)
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Customer Reviews for LEGO - Technic Liebherr R 9800 Excavator 42100
Customer Rating
5 out of 5
5
Father - Son building time
on August 6, 2020
Posted by: LondonMama
My husband got this for him to build with our two sons, however our oldest son (12) did most of the work lol
It took roughly 3 days to complete as they only worked on it for 2 to 4 hours a day but enjoyed every min of it. They were a little disappointed when they completed it so I may need to get them a bigger, more challenging set in the future :
;-)
I would recommend this to a friend!
Written by a customer while visiting LEGO
Customer Rating
5 out of 5
5
What a monster!
on August 2, 2020
Posted by: RVick
Not only is the build fun, but the play factor is just as fun with all of the motors and functions of the final product. The hubs connect well, and have only had minors issues with the tracks slipping while driving on carpet
I would recommend this to a friend!
Written by a customer while visiting LEGO
Customer Rating
4 out of 5
4
Missing pieces
on July 18, 2020
Posted by: cgfox1995
A number of times, i found the needed pieces in the next numbered bag (misplaced) and I'm also missing all 3 of piece #6257336, which is vital for tread function. Not sure how that happened, especially with the hefty price tag.
I would recommend this to a friend!
Response from LEGOBy EmilyCustomer ServiceAugust 3, 2020
Thanks for your review. You shouldn't find the pieces you need for one bag in another. If it ever seems that way, it's a good idea to go back and double-check your build. There may be some similar parts that were accidentally swapped. Or the parts you need could be hiding in the corners of a bag or dropped on the floor.

If you’ve checked all over and the parts haven't appeared, don’t worry! It’s super easy to request replacements. Just go to LEGO.build/BricksPieces-BV to get started.
Written by a customer while visiting LEGO
Customer Rating
5 out of 5
5
Everything You Want From a LEGO Build
on March 25, 2020
Posted by: QuitWhiningStuR
What an incredibly fun, challenging build this was!
Directions were extremely clear - at no point did I feel I was flying blind. When things didn't work or fit, it was inevitably my mistake. Figuring out those mistakes was part of the fun.
Mid-build Bluetooth motor testing went perfectly. I had a couple of issues with a previously-connected power pack having problems reconnecting, but that was because I exited, but did not terminate, the Connect Plus app. It was easily fixed by taking out a battery and, essentially, rebooting the pack.
When all was done, the last test - the moving of the scoop front to back - failed. I heard the ending purring perfectly, but the gears and scoop did not move. I figured out that I didn't put one key dowel into the red motor input (I accidentally put it in a hole just to the side), and with very little deconstruction got it in the right spot.
That didn't end the problems - the hinges that connect the front scoop panel to the motor/gears were connected wrongly. After about an hour of trial and error, I finally got everything in the right spot, successfully calibrated the unit, and I was off to the races.
I hope this doesn't sound like a criticism of the set - as I said, every error was my own fault, and it was a sick kind of fun figuring out every which way I went wrong. When the unit finally worked perfectly, it was incredibly gratifying.
I will say the Bag # 5 set of parts (the last stage of construction) was a little tedious - lots of ladders, lights, trim, but I do have to say the once it was done (after about 90 minutes of work), all these little bits added up to a better-looking, more realistic excavator.
I haven't played much with the set other than to test out what it can do, but that will come, now that I finally worked out the bugs.
Bottom line: I absolutely LOVED this build. It required a level of focus and attention to detail that I found very, very rewarding.
This takes the place of the Roller Coaster (10261) as my favorite build. I can't recommend this any higher!
I would recommend this to a friend!
Written by a customer while visiting LEGO
Customer Rating
2 out of 5
2
Excitement quickly turns to disappointment.
on March 25, 2020
Posted by: Grandpop
Excitement quickly turns to disappointment. When I first saw this set, I was very excited to build and share this experience with my young grandson. My grandson loves “diggers” as he calls them and was very excited to help grandpop build this set. Although, too young to build this set himself, I built the set completely, then removed a few pieces so we can complete the set together.
The positives with this set are few compared to the negatives in my opinion. The set is large, well designed and interesting to build. The control app works well when used with a tablet. I made sure all motors were connected to the Bluetooth controller before testing which worked well.
On the minus side is the set was missing parts to complete the build. The parts missing were cosmetic and did not affect the function of the build. Lego, please don’t tell me “Usually they're found stuck in the packaging or hiding on the floor!”. I can assure you they were not included in the set. Stickers on a high-end set like this; really? What good is a set like this if you cannot play with it? The drive system is significantly underpowered. The loose-fitting tracks only add to the issue, jamming frequently. The model is easily impeded by short pile carpeting as the drive motors strain in agony. In my “play” case a couple of corks stopped it cold when I was trying to pick them up in the bucket. The boom, dipper arm and pitman arm work well, however, the bucket closure drive train over travels and the application is unable to calibrate for the situation.
My wife watched as we played, then asked the cost of the kit. I answered her question, she paused and said, next time, just put the money into his 529 plan, and she walked away. A smart woman she is.
No, I would not recommend this to a friend.
Response from LEGOBy EmilyCustomer ServiceMarch 26, 2020
We're sorry to hear this. If you’ve checked all over and the parts haven't appeared, don’t worry! It’s super easy to request replacements. Just go to LEGO.build/BricksPieces-BV to get started.
Written by a customer while visiting LEGO
Customer Rating
5 out of 5
5
Best build so far.
on February 18, 2020
Posted by: Skyd1ve
The LIEBHERR is a challenging and fun build. I enjoy watching the pieces develop into parts and the parts developing into the build.
I really liked being able to verify your gearing is correct and working before moving on to next section.
This was a fun project and can't wait for next large TECHNIC release.
I would recommend this to a friend!
Written by a customer while visiting LEGO
Customer Rating
5 out of 5
5
Awesome Set
on February 6, 2020
Posted by: AMSGuru
Highly rewarding build. I took my time and had a lot of fun putting this set together. The bucket open and close function could be better and I wish the app would allow for some manual tweaking of the calibrations and speed reactions. Otherwise great. Looking forward to more great Technic sets this year!!
I would recommend this to a friend!
Response from LEGOBy SamuelLEGO Customer ServiceFebruary 7, 2020
Thank you for your review. It's great to hear you had a lot of fun putting it together!

You may want to check out the Powered Up app, it's ideal for some extra tweaking. :)
Written by a customer while visiting LEGO
Customer Rating
3 out of 5
3
Expected more from Lego
on December 30, 2019
Posted by: BrickWagon
I have always expected great things from Lego since their name is synonymous with quality. I have enjoyed designing and building MOCs for some 35+ years. I was overjoyed to get this 42100 model, but very disappointed about the new Control+ system. I have tried time and time again to get the Control+ app to work on different devices, but needless to say, it doesn't perform 100%. The connection & testing of the hubs with my phone didn't work at all to begin with. I had not yet built the model because I wanted to do a quick test to see how the hubs worked with the new motors, but it kept failing to connect. I gave up and started building the model. As I completed the base, I did as the instructions said and tried to connect the hub to my phone. For whatever the reason, it worked... for this part. I proceeded to build and got to the next part to test (as there are 4 testing parts). The second one worked. I finished the model and tried to test all functionality, but I am still unable to sync the 2nd hub so that all functions are able to be tested. The model looks great sitting there, but otherwise functionally unless. I read a few reviews on the app and it appears that others have had similar issues. I generally buy sets for their parts and to see how Lego engineers figure out complex problems, which I was able to do with this model, but the Control+ app so far has been a big disappointment and you can't use the motors without the hubs, so there's that money down the drain until they improve the coding & testing of the app. On the Control+ page of the Lego website, it states very few Android devices that it was test on, but I would assume since it was Android, it should just work anyways, so I am guessing it is a bug within the app itself as I tried it on 3 different Android devices. Overall, I am very surprised that this doesn't work, but being so new, bugs are expected, just not from Lego and especially at the price. I would only recommend paying this price for the amount of parts you get and not the new hubs & motors until they get these bugs fixed.
I would recommend this to a friend!
Response from LEGOBy EmilyCustomer ServiceJanuary 6, 2020
Thanks for your review. We're sorry to hear that you were disappointed in the Control+ experience.

Our developers are always working to test new devices. With so many manufacturers and different implementations for Android, that can take a lot of time! If your device meets the minimum requirements to run the app, it should work fine, though it's possible you might run into the odd bug here or there.

Based on your description of the problem, though, it sounds like you'll want to double-check your build. Because the set has a lot of complex features, it's essential to have all your motors connected into the correct ports. If a connection's out of place, the app won't allow you to connect the hub. A little rebuilding should do the trick.

If you need further help, you can always get in touch at LEGO.build/Service.
Written by a customer while visiting LEGO
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