MMI, some bad, some good

[tc4332]

Scott, Thanks mate, I'll pull the screen cover first when I start. I am waiting for the gears to arrive but don't know what they are. Hoping they are brass/ phosphor bronze. Bronze would be best 'cos they hold the lubrication better.

Mike, Understand where you are coming from suggesting using one plastic gear but I would think that is a weak point and would entail doing the whole strip down again in the future. I'm afraid this old lady will have to give us a lot of years service. As far as I am aware this is the first time these gears have failed on her (I have loads of paper on her) so at 12 years old they have done well. Shame that yours seem noisy, not heard that before, did you lube them?

[mcs]

Originally Posted by tc4332

Mike, Understand where you are coming from suggesting using one plastic gear but I would think that is a weak point and would entail doing the whole strip down again in the future. I'm afraid this old lady will have to give us a lot of years service. As far as I am aware this is the first time these gears have failed on her (I have loads of paper on her) so at 12 years old they have done well. Shame that yours seem noisy, not heard that before, did you lube them?

Yeah I coated the gears in silicone grease. I suspect that the noise is why they were plastic from factory. The metal gear for the lid and the metal gear on metal for the screen drive make noise since its metal on metal. It isn't a bad noise, it's just a bit uncouth for me. The gear that commonly fails is the screen drive gear as it is small. The largest plastic gear that is attached to the motor (I think from memory) I left plastic on a mate's car and the noise of the mechanism working is quiet.

I replaced all my gears in one go with the brass ones. I am considering changing the bigger motor drive gear back to plastic. It generally isn't the one that breaks so should be fine.

Mike

[Takemetothepub]

Just replaced mine with the brass ones, including the motor drive gear and is silent.

My only tip would be as already said, protect the air vents when pulling up the little tabs so you don't scratch anything.

Also, make sure you have a size T9 torx bit as it a bloody awkward size most kits don't have.

[tc4332]

Mmmm! T9, I'll have a look in my boxes. Knowing my luck I'll have a 8.5 and a 9.23 but no 9
The gear kit came on Wednesday and I'm planning on doing it Saturday, only one job in and hopefully nothing else will appear.
Watching the video it looks like there are four gears!! My kit only has three.
It looks like the video guy reused the big gear.
I have tried offering the two smaller gears upto each other and they are a bit too tight. Looks like I'll have to trim the shaft slightly for it to fit into the other one.
Or am I, as usual over engineering?

[Takemetothepub]

They are tight, but with a little bit of GO IN YOU BUGGER! And a little tap they fit But don't try and fit them together until you have the plastic bit that goes between them!!!!

Yup re-use the bigger gear. Just follow the vid and you'll be fine.

[tc4332]

Did it.
It works quietly.
SWMBO is a happy bunny.

BUT, again mine is different.
Once indoors, unit on the table and I found a piece of string fitted to it. Nobody has mentioned this so I have taken two photos.

First photo is a side view showing where one end of the string is fastened.

Second photo shows the "hook" on the motor that the other end of the string is hooked to. I have written hooked because it is obviously designed to come off the motor whilst the other end is permanently attached.

Now, conundrum, what is it for, why has nobody else spoken about it.
My supposition, and I am open to other explanations from the more knowledgeable folk on the forum, is that it is to hold the screen mounting frame in the "open" position whilst working on the unit. Well it did that perfectly for me. The loop that was on the motor was the exact length needed to do that job.

I have also realised why the video emphasises having the vents open whilst pulling them out of the dash. It is because the centre vents have two flaps that are closed/opened by an arm inside the dash. If the vents are not open when the vents are pulled out there is a chance you could break the mechanism. Likewise when pushing the vents back into the dash. Note that these flaps are connected on the vent body by a plastic link which was missing on one of mine. Then another magic moment, the other link was an exact double of a piece of plastic that I found soon after buying the car. Nobody on the forum could explain what it was but being a bit of a hoarder I put the said plastic thingy safe. This morning I went to the safe place and there it was. Tried it and now my vents open/close correctly. Note that this only applies to the inboard vents, the outer ones are purely mechanical.
It took a long time. I started at 06:00 and finished at 12:30. OK I stopped for breakfast when management came to see what I was up to. She had heared me drive the bus in but finally realised I had not returned to bed. (I might have slipped up there, but then again the 8 is rather important). I did have another 5 or twenty breaks for cuppas and tv watching and chats with passing neighbours.
Now she needs a bloodie good wash and brush up, the 8 is a bit dirty as well.

[Takemetothepub]

Ah mine had the string, was racking my brain trying to remember what it was that wasn't mentioned when I opened mine up. That's what it was.

Glad you got it sorted OK, did you use all the brass fittings or leave the motor one plastic?

[chewy]

My mmi screen is currently stuck half way, it started grinding a while back and was able to help it up prior to it being stuck.

I've sourced the brass parts and found a video showing how to remove trims to get mmi unit out.

The video on this thread can not be viewed and showing as private. Does it show how to change the gears? Anyone able to share the video if it does? Will i be able to remove the screen out with it being stuck in the half position?

Thanks in advance.

[steamship]

One video on removing the screen: https://www.youtube.com/watch?v=GWohs_QvEII

One video on changing the gears: https://www.youtube.com/watch?v=_0vHyFQ0CCY

and also a step by step guide with photos: https://www.audiworld.com/forums/a8-...tions-2849359/

[chewy]

Thank you so much steamship! I'll give it a go in a few weeks and let you know how I get on.