42131 - CAT D11 Bulldozer

[anyUser]

21 minutes ago, howitzer said:

Now I'm similarly curious about this bulldozer too,

My guess on a potential issue:
Start of gearbox assembly is around step 70 (book 1). The other 'end' gets fixed -completely- in step 127 (also book 1). Until then, the rather long axles could be considered as hanging free/ sticking out. This could lead to disorder of the function selector. It may be possible to accidentally loose a gear.

There is a row of red 16tooth gear transferring rotation between left and right side where you should pay attention to minimise the friction.

[Rusty43]

Hello

Can anyone advise me as to how long it takes to configure a lego 42131 Cat D it seems to go on forever 

Thank you in anticipation for your cooperation

 

[doug72]

On 1/22/2022 at 12:01 PM, anyUser said:

My guess on a potential issue:
Start of gearbox assembly is around step 70 (book 1). The other 'end' gets fixed -completely- in step 127 (also book 1). Until then, the rather long axles could be considered as hanging free/ sticking out. This could lead to disorder of the function selector. It may be possible to accidentally loose a gear.

There is a row of red 16tooth gear transferring rotation between left and right side where you should pay attention to minimise the friction.

Agree.

After for the 2nd time building this as per Lego Instructions, thought I had succeeded.

Control+ connected and followed on screen tests etc.

On running the rebuild all functions except one worked as intended. 
But The blade lift failed to work but gear noises heard.

Check the universal couplings on the drive to blade lift were OK and that the black 20T DB Gear was in place.

Conclude that change over in the main gear box for blade raise was out of sync.

Now stripped the 2nd build down and now starting to rebuild using the PF Conversion instructions.

So far:- built the drive unit for track sprockets and the 4 PF motor module which tested and found much easier operation use PF controllers than C+.

Edited January 27, 2022 by Doug72

[Ngoc Nguyen]

37 minutes ago, Doug72 said:

found much easier operation use PF controllers than C+

[Milan]

On 1/25/2022 at 5:09 PM, Rusty43 said:

Hello

Can anyone advise me as to how long it takes to configure a lego 42131 Cat D it seems to go on forever 

Thank you in anticipation for your cooperation

 

Merged with the proper topic.

[Ngoc Nguyen]

The other day I noticed that the model sags heavily in the middle and thus bends the four 5x7 LBG frames in the bottom down inside. It looks kinda like this.

 

 

Since the model I have is the PF mod, I'm not sure if my mod causes extra weight or the stock model is already like that. Can anyone with the model take a look and confirm this?

[doug72]

@Ngoc Nguyen

Now up to step 887 using Lego instructions.

Re PF Conversion Sagging,

I have checked my build so far with both battery boxes in place and see no sign of sagging.

Still to add the track units and blade With actuators.

One problem I had was that he motor leads for Red & Yellow appeared to be too short.

Found they were routed the wrong way around a beam, had to remove some beams to re-route the cables and both now connected to the PF Rx. Tested and OK.

Edited February 4, 2022 by Doug72

[doug72]

Cat D11 finally finished for the PF Version by Ngoc Nguyn

This was my third attempt at building the cat D11 Dozer !

1st build - unable to get motor test done on step 198 to work.

2nd Build completed and calibrated with Control +.

All worked except for one for the ladder.

3rd attempt successful using Ngoc Nguyn excellent instructions and the Lego instructions where indicated.

All functions are working and it is very easy to control using a group of four PF Controllers.

IMG_8532

Only one item not working as the dummy engine does not rotating.

I may have missed a step somewhere but as motor cannot be viewed unless engine casing doors are open I will leave it as is.

Some problems:
Found it difficult to change the batteries in box under the dummy engine block.

A total of 12 cables need to be routed very carefully to avoid gears, beams  etc.

I made a 1L gap at bottom of each of the larger engine access door son each side for the two forward PF Receivers which were positioned 3L higher as cables were snagging on the tracks.

Overall impression:-

A very challenging complex and at times frustrating build, requiring close checking each step was correct.

Only one thing the driver was late getting in the cab !!

IMG_8536

IMG_8531

 

 

 

IMG_8533

 

IMG_8534

 

IMG_8535

Edited February 5, 2022 by Doug72

[Ngoc Nguyen]

40 minutes ago, Doug72 said:

Only one item not working as the dummy engine does not rotating.

It is supposed to work though. The drive train from the sprockets to the engine looks like this.

 

 

There are 3 16z gears to the left and 3 to the right. I think you might have missed one of the three to the right. Based on that assumption, for the upper two on the right side you can easily remove the rear battery box and insert them from behind. For the bottom one on the left side you can insert from beneath the model.

 

 

If you miss a gear on the right then you need to remove the cabin module, and that should be enough.

 

40 minutes ago, Doug72 said:

Found it difficult to change the batteries in box under the dummy engine block.

That battery box is held in place by these three axles, all of which can be pulled out from the outside. When you remove them all, the battery box will fall down.

 

40 minutes ago, Doug72 said:

I made a 1L gap at bottom of each of the larger engine access door son each side for the two forward PF Receivers which were positioned 3L higher as cables were snagging on the tracks.

The cables for the Receivers on each side are supposed to pass through the gap in the 5x11 frames and under the tapered 5x11 panel. There's no need to change the doors.

 

 

 

Edited February 5, 2022 by Ngoc Nguyen

[doug72]

@Ngoc Nguyen

I have now checked the drive train to the dummy engine and lifted the cabin off to get a better view.

Checked as per your image and found that the RED 16T gear between the two Grey 16T gears is missing. For now I will keep it as is.

New Problem:-

When driving forward both tracks move smoothly but when driving in reverse the tracks make a cracking sound and drive is jerky, tried altering track tension but without result.

Removed the 15 beam for with the red ball joints at each end between between bottom of the blade and chassis with slight improvement.

Does anyone else have this problem ?

When Cabin lifted clear discovered the the  2 X 5  angle beams were distorted on one side, something is out of alignment.

Then found I had an extra link in each track 59 instead if 58 - excess link removed from both sides.

Tested but still smooth running forward & jerky in reverse.

I fear I will have to rebuild for the 4th time !!!!!

see photos.

IMG_8539

 

IMG_8540 

Edited February 8, 2022 by Doug72

[Ngoc Nguyen]

28 minutes ago, Doug72 said:

When driving forward both tracks move smoothly but when driving in reverse the tracks make a cracking sound and drive is jerky,

I got this problem too and I don't know why.

[Zerobricks]

Since you are talking about issues with a modification of the set, I would suggest opening a different topic for that, not to confuse people?

[doug72]

@Zerobricks 

The track sub assemblies are identical for both Lego & PF versions.

Finally found the problem causing the jerky drive when running in reverse.

[Andman]

2 hours ago, Doug72 said:

Finally found the problem causing the jerky drive when running in reverse.

I love these kind of responses. Would you mind to tell what it was? It might be helpful for others, too! ;-)

[doug72]

On 2/11/2022 at 12:53 PM, Andman said:

I love these kind of responses. Would you mind to tell what it was? It might be helpful for others, too! ;-)

At step 624 Book 1.
I found the top yellow 7L beam was missing  along with two 3L blue pins & two 2L black pins. which clamps the idler sprocket to the 5 X7 frame.
Hence top idler sprocket was able to flex as direction of rotation changed.

Edited February 12, 2022 by Doug72

[Richombx]

Wow the d11 looks awful with all that unnecessary PF gear hanging out, the remote setup also looks pretty non user friendly so someone has solved a problem that didn’t need solving.

[doug72]

1 hour ago, Richombx said:

Wow the d11 looks awful with all that unnecessary PF gear hanging out, the remote setup also looks pretty non user friendly so someone has solved a problem that didn’t need solving.

The remote controls are very simple & easy to use &set up and are tactile, unlike Control +

agree cables need tidying up a bit.

[Pybricks]

Following up on @AVCampos' nice example for the set, we've made one as well. Thanks to @Jim for letting us borrow his set for this (and thanks for the tea!).

You can find the code here.

We only calibrate the function selector at the start. Since it's so easy to control the functions, it really doesn't seem worth calibrating the end points for the function motor. But let us know if you want to see a more detailed code example of how calibration can be done!
 

 

[BrickWild]

Started building mine but I have a question;
The motors make a humming noise and there's a slight pause during the testing phase of each part of my Caterpillar D11 - Is this normal or is there something locking up?

I'm in doubt...

 

[Gimmick]

I think he high pitch sound comes from the calibration process, when the motor runs into the stopper. After that it selects the correct gear.

But I'm not sure about the step @ 0:27 it's a bit dark and the cable onn the top left seems to move, maybe check that section again, so nothing gets stuck.

You can compair the movements of all outputs and the gear position with this (timecode):

 

[allanp]

I don't have the set but I think @Gimmick is correct. The noise only comes when the motor that switches the functions is calibrating correct? 

[J159753]

I was thinking of cobbling together parts for this set and building an approximation of it. To use the Control+ app must I have the PU large angular motors, or can I substitute the SPIKE prime large angular motors? Thanks!

[Gimmick]

@J159753 I don't know, but you can test it by connecting all motors to the hub and start the C+ app. If it does not work, you can still use the PU app.

[Polarlicht]

On 2/28/2022 at 3:53 PM, Pybricks said:

Following up on @AVCampos' nice example for the set, we've made one as well. Thanks to @Jim for letting us borrow his set for this (and thanks for the tea!).

You can find the code here.

We only calibrate the function selector at the start. Since it's so easy to control the functions, it really doesn't seem worth calibrating the end points for the function motor. But let us know if you want to see a more detailed code example of how calibration can be done!
 

 

I might try this one day

Edited June 12, 2022 by Polarlicht

[Polarlicht]

@PybricksI don't have bluetooth on my pc, so i tried it with my phone. But the it doesn't wanna paste the copied code into the cody thingy.

Edited June 12, 2022 by Polarlicht