# Arm retraction issue

**URL:** <https://forum.hello-robot.com/t/arm-retraction-issue/1393>\
**Category:** Ask\
**Created:** [September 3, 2025, 6:40am UTC](https://forum.hello-robot.com/t/arm-retraction-issue/1393 "2025-09-03T06:40:15Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![seongwoncho](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.hello-robot.com/seongwoncho/32/937_2.png) [@seongwoncho](https://forum.hello-robot.com/u/seongwoncho)\
**Post date:** [September 3, 2025, 6:40am UTC](https://forum.hello-robot.com/t/arm-retraction-issue/1393/1 "2025-09-03T06:40:15Z")

</div>

Sometimes, after running robot code, the arm does not retract completely — it stops about 3–4 cm short of fully stowing. Even after running `stretch_robot_home`, the arm does not always go all the way in. This causes timeouts in my scripts.

**When I try manually pushing the arm in, it moves smoothly at first but becomes noticeably stiff in the last few centimeters, requiring extra force.** This makes me think the issue may be mechanical rather than software.

- Has anyone experienced this kind of partial retraction?

- Is there a recommended procedure to check or service the arm mechanism (e.g., cleaning, lubrication, partial disassembly)?

Thanks in advance for any advice.

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<div class="post-metadata">

**Author:** ![bshah](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.hello-robot.com/bshah/32/55_2.png) [@bshah](https://forum.hello-robot.com/u/bshah)\
**Post date:** [September 6, 2025, 5:01am UTC](https://forum.hello-robot.com/t/arm-retraction-issue/1393/2 "2025-09-06T05:01:12Z")

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Hey @seongwoncho, I’d recommend using the `REx_calibrate_guarded_contact.py` CLI described in [Practical guide to guarded contacts](https://forum.hello-robot.com/t/practical-guide-to-guarded-contacts/654)

While it is possible to service the arm, it is easier to ensure the calibration for the arm motor is up to date.

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<div class="post-metadata">

**Author:** ![seongwoncho](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.hello-robot.com/seongwoncho/32/937_2.png) [@seongwoncho](https://forum.hello-robot.com/u/seongwoncho)\
**Post date:** [September 7, 2025, 7:03am UTC](https://forum.hello-robot.com/t/arm-retraction-issue/1393/3 "2025-09-07T07:03:48Z")

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Hi again and thanks for the quick reply earlier!

I ran the `REx_calibrate_guarded_contact.py` CLI as suggested (screenshots attached). The calibration completed but printed warnings that the contact thresholds are pegged at the limits:

```bash
Warning: Contact threshold of -90.000000 near minimum of -90.000000.
There may be a mechanical issue with the joint. Contact Hello Robot support.

Warning: Contact threshold of 90.000000 near maximum of 90.000000.
There may be a mechanical issue with the joint. Contact Hello Robot support.

```

```bash
Prior contact defaults were:
  Positive direction: 47.663993 (Effort)
  Negative direction: -42.573275 (Effort)

New contact defaults are:
  Positive direction: 90.000000 (Effort)
  Negative direction: -90.000000 (Effort)

```

It’s still usable, so before considering shipping the robot, is there any simple inspection/maintenance I can do myself?

(Screenshots + logs attached)

 ![calibrate_guarded_contact_arm_neg_effort_pct_20250906235352](https://canada1.discourse-cdn.com/flex030/uploads/hello_robot2/original/2X/2/2fe218417990dcceb29487bab4800df2ebab01de.png)

 ![calibrate_guarded_contact_arm_pos_effort_pct_20250906235352](https://canada1.discourse-cdn.com/flex030/uploads/hello_robot2/original/2X/2/2d58d2dcda014213cd381da19ced459caa05bd1f.png)

[calibrate\_guarded\_contact\_arm\_results\_20250906235352.log](https://forum.hello-robot.com/uploads/short-url/3C5bXMfAtdJJKY66i5kEx4TcA2L.log) (34.2 KB)

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<div class="post-metadata">

**Author:** ![bshah](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.hello-robot.com/bshah/32/55_2.png) [@bshah](https://forum.hello-robot.com/u/bshah)\
**Post date:** [September 9, 2025, 8:40pm UTC](https://forum.hello-robot.com/t/arm-retraction-issue/1393/4 "2025-09-09T20:40:16Z")

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Thanks @seongwoncho, you’re right, the arm mechanism is at the upper limit of what the arm motor can safely handle. Would you reach out to [support@hello-robot.com](mailto:support@hello-robot.com) so we can coordinate the repair?