BRESSER Messier EXOS 2/EQ-5 GoTo - Worm gear problem?

[SydLappen]

Hi!

I have bought a second-hand mount and I'm trying to make it work OK (found problems as soon as I tried photography). As it's the first time I deal with this type of mechanics (has mainly been in cars and boats before 😝) I am bit lost...
The worm gears, when I turn the cog wheel on the right, it does not turn effortlessly and smoothly (I imagined it would) but with a bit of resistance and with some "choppiness"? A bit like turning a ratchet wheel, it's a bit hard to describe... 😬

Is it normal or do I need to change the ball bearings?

All advise is welcome

Thanks!

Magnus

PS. Then I need to adjust the gears, but that's next step  

 

[Cosmic Geoff]

There will be some resistance to turning the gear.  The gap between the worm and wormwheel should be adjusted to minimise backlash without making it too tight, lest the worm rotation bind.

There is no way the bearings will have worn enough to need replacing.   The plain bearings in my old car engine lasted for billions of revolutions.

[Peter Drew]

Probably not worn but there might be some sort of inclusion into one of the bearings to cause the roughness, these mounts have a history of bits of swarf etc in the system.     🙂

[SydLappen]

It's true that wear is not so likely, they are not sitting in an engine after all. My thought was more some sort of damage, since there is a slow sort of vibration when I turn the cog wheel.

I suppose it's not very expensive to change them? Just to be on the safe side... 

[bosun21]

3 hours ago, SydLappen said:

It's true that wear is not so likely, they are not sitting in an engine after all. My thought was more some sort of damage, since there is a slow sort of vibration when I turn the cog wheel.

I suppose it's not very expensive to change them? Just to be on the safe side... 

More likely to be the worm gear meshed too tight.

[Rusted]

Does the roughness occur in the absence of the wormwheel? Let's assume you are talking only about the worm in its housing. [As pictured.]

Ease off the end pressure adjustment [if any] on the worm bearings until you obtain shake-free smoothness of turning.

"Cogging" is extremely commonplace where ball bearings are overtightened. Typical of an overtightened bottom bracket bearing on a bicycle or headset. [Forks] Though much less common after journal bearings took the place of loose balls in cups.

I am concerned about the broken casting just above the worm in your picture. Is there any debris in the worm grease? 

[SydLappen]

12 hours ago, Rusted said:

Does the roughness occur in the absence of the wormwheel? Let's assume you are talking only about the worm in its housing. [As pictured.]

Ease off the end pressure adjustment [if any] on the worm bearings until you obtain shake-free smoothness of turning.

"Cogging" is extremely commonplace where ball bearings are overtightened. Typical of an overtightened bottom bracket bearing on a bicycle or headset. [Forks] Though much less common after journal bearings took the place of loose balls in cups.

I am concerned about the broken casting just above the worm in your picture. Is there any debris in the worm grease? 

Thank you for the explenationsons!
I'll try that.

About the casing, I checked after you mentioned it, it's OK. There was just string of dirt.

Thanks!