Strip Down & Service of Miyota 8215 Automatic Watch Movement - Part1

[Odyseus 1]

Miyota 8215 Automatic Watch Movement Service – Part1

 

Part 1 Disassembly of the watch & movement.

 

This is very common 21j (21,600 bpm) automatic movement found in many genuine watches and although cheap to replace can still benefit from a service.

 

This watch movement is also a direct replacement for the popular Chinese movement DG2813.

 

The top side of the movement is shown in Figure 1, showing the date wheel, top balance wheel jewel and hour hand pinion.

 

Figure 1 - Top view of movement.

 

Figure 2 - Bottom view of movement.

 

Figure 3 Close up of balance wheel jewel.

 

Step 1 – Remove the rotor retaining screw (Part# 925-590) and rotor (Part# 119-246) as shown in Figure 4.

 

Figure 4 - Rotor removed.

 

Step 2 Remove the date dial guard retaining screws (Part# 923-630) and date dial guard (Part# 176-150) as shown in Figure 5.

 

Figure 5 - Movement fitted onto movement holder.

 

Step 3 – Remove the Dial washer (Part# 078-140) and Hour wheel (Part# 075-124) as shown in Figure 6.

 

Figure 6 - Date dial guard removed.

 

Step 4 – Remove the date wheel (Part# 105-950).

 

Figure 7 shows a close up of the canon pinion (Part# 014-108), date dial driving wheel (Part# 103-650) and date corrector spring (Part# 903-710).

 

Figure 7 - Hour wheel & dial washer removed.

 

Step 5 – Remove the date jumper (Part# 109-350), date corrector (Part# 116-300), date corrector spring (Part# 903-710) and intermediate date wheel (Part# 100-170).

 

Figure 8 - Date wheel removed.

 

Step 6 – Remove the date dial driving wheel retaining screw (Part# 923-600) & date dial driving wheel (Part# 103-650), screws for minute wheel guard (Part# 923-630) and minute wheel guard (Part# 079-600).

 

Figure 9 - Date corrector spring, date jumper & date corrector removed.

 

Step 7 – remove the Yoke retaining screw (Part# 923-640), Yoke (Part# 071-510) and setting wheel (Part# 076-430).

 

Figure 10 - Date dial driving wheel & minute wheel guard removed.

 

Figure 11 - Setting wheel removed & close up of cannon pinion.

 

Step 8 referring to Figure 12, remove the setting lever retaining screw (Part# 923-640) and the setting lever spring (Part# 077-680).

 

Figure 12 - Yoke removed.

 

Step 9 – lift up the setting lever (shown in Figure 13) and remove the stem (Part# 065-212) and the clutch wheel (Part# 064-450).

 

Figure 13 - Setting lever spring removed.

 

I found that the setting lever couldn’t be removed from the watch housing, however, it could be lifted up enough to allow removal of the stem (& hence the clutch wheel).

 

Figure 14 - Stem & Clutch wheel removed.

 

Step 10 – Remove the Canon pinion (Part# 014-108).

 

I did this by pulling off with tweezers (It did come off quite easily!) but it’s probably safer using some Presto watch hand pullers!

 

Figure 15 - Canon driver removed.

 

NB Be careful not to break off the second hand pinion, which you can see is very fine and fragile!

 

Turn over the movement as shown in Figure 16.

 

Step 11 – On this movement, there is one large bridge, secured by three screws (circled in red).

 

Remove the three bridge retaining screws (Part# 924-460).

 

Figure 16 - Movement turned over.

 

Step 12 – Remove the bridge (Part# 701-263) to reveal the drive train, barrel assembly and winding gears.

 

The various parts are listed in Figure 17.

 

Figure 17 - Barrel & train wheel bridge removed.

 

Step 13 – Remove the Reduction wheel & pinion (Part# 088-120.

 

Figure 18 - Remove the Pawl winding wheel & pinion.

 

Step 14 – Remove the 3rd & 4th wheels (Part# 017-760 & Part# 023-940) and remove the Ratchet wheel (Part# 059-560).

 

Step 15 – remove the barrel (Part# 001-870).

 

Figure 19 - Remove the Barrel & centre bridge retaining screws.

 

Step 16 – Remove the sweep second pinion (Part# 025-670).

 

Figure 20 - Remove the sweep second pinion.

 

Step17 – Remove Click retaining screw (Part# 924-460), Click (Part# 060-390), click spring retaining screw (Part# 923-600) and click spring (Part# 903-700).

 

Figure 21 - Remove Click & Click spring.

 

Step 18 – Remove the centre wheel bridge retaining screws (Part# 923-600) and then lift off the centre wheel bridge (Part#711-074).

 

Figure 22 - Remove the centre wheel bridge retaining screws.

 

Step 19 – Remove the escape wheel (Part# 032-106).

 

Figure 23 - Remove the escape wheel.

 

Step 20 – Remove the balance spring retaining screw (Part# 924-460) (circled in Figure 24) and then remove the balance spring (Part# 710-159).

 

Figure 24 - Centre wheel bridge removed.

 

Ensure that the balance spring is safely stored to avoid damage to the spring – see Figure 25.

 

Figure 25 - Balance wheel safely stored.

 

Step 20 – remove the centre wheel (Part# 012-116).

 

NB If it won’t come out, then you have probably left the cannon drive pinion still attached!

 

Figure 26 - Remove the centre wheel.

 

Step 21 – remove the pallet bridge retaining screw, circled in red in Figure 27 (Part# 923-600).

 

Now the pallet bridge can be lifted away.

 

Figure 27 - Remove the pallet bridge retaining screw.

 

Step 22 – Remove the pallet fork (Part# 035-560).

 

Figure 28 remove the pallet fork remaining.

 

Figure 29 - All components removed from the barrel side.

 

Figure 30 - All components removed from the dial sider.

 

This concludes the disassembly of the Miyota 8215 automatic watch movement!

 

Part 2 will describe the oiling and reassembling of the movement.

 

Thank you for watching !! :)

[Mechwarrior 2]

Great info!!!!!

[agntkerr 0]

Amazing.

[simey83 1,978]

WOW!

[JSJ 0]

Wow! You are a star mate! Thank you!

 

Now I'm really keen to read part 2!

[frapzzor 2]

Great tutorial, love these things, and you make it seem easy enough for anyone to be able to do this!

[cnwh 0]

Bookmarked! This is going to be a damn great tutorial!

[Odyseus 1]

Cheers Guys ! - hopefully I'll have time to do part 2 soon enough - the watch movement is still in bits ready to be re-assembled :)

 

BTW I got my movement from

 

http://www.ebay.co.u...=item3ce3cd319b which is cheaper than Cousins (UK) !!

[onelund 0]

impressive, ty for the details

[SSTEEL 0]

Great job John, really helpful mate

[JSJ 0]

Cheers Guys ! - hopefully I'll have time to do part 2 soon enough - the watch movement is still in bits ready to be re-assembled :)

 

BTW I got my movement from

 

http://www.ebay.co.u...=item3ce3cd319b which is cheaper than Cousins (UK) !!

Thanks mate. I think I've heard of him before but never found him (why is ebay so hard to search???). The 8215 is so much better than most of the 2813s we see and at that price it's a killer.

[kkz88 0]

Great info

I m sure that you took a lot of time to make this threads.

;-)

Edited July 6, 2014 by kkz88

[gran 198]

Great stuff!!!

 

Direct swap is good news! DG2813 has hack function I guess while the The Miyota 8215 is a non-hacking one (guess no-hack is better or more reliable?)

[Kcore 0]

Thank you, thank you, thank you!!!

 

I'm pretty sure all the adjectives have already been said but in this case, worth repeating - fantastic, WOW, amazing, great, impressive, great.

[10:10 Watch Repair 1]

The 8215 is so much better than most of the 2813s we see.

Which tells you just how bad the Chinese movements are.

[jingo.smile 0]

Thank you, thank you, thank you!!!

 

I'm pretty sure all the adjectives have already been said but in this case, worth repeating - fantastic, WOW, amazing, great, impressive, great.

 

I'll just second that!

[fast960 0]

Great Post but where's the assembly Part 2 ? We need!! TY

[dremelts 0]

Odyseus, I just became a member of this board so that I could thank you for this great tutorial!

 

I have an Invicta 8926 with the Miyota 8215 movement and after about 12 years it quit running and has been setting unused for about a year. I considered just replacing the movement but came across this tutorial and figured I had nothing to lose (well, except for a bunch of small pieces and parts), so figured I give it a try. While I do have a basic understanding of mechanical watches I freely confess to a lack of skill.

 

So, I was quite concerned about the six-pivot main bridge but it wasn't as difficult as I thought it would be. In fact I put it back together three times! The first time I reassembled it I had one of the screws on the dial side in the wrong location. The screw was too long and it jammed against the barrel and so I was getting no power to the train. Of course, I did not discover that until I had taken it apart again. The second time I reassembled it I somehow managed to get the leaf spring on the underside of the bridge bent out of shape so it must have been jamming one of the train gears.

 

The third time was the charm. After getting the bridge on I was getting good locking and impulse on the escape wheel with only about a single turn on the main spring.

 

I too wish we had Part 2 but I pretty much just put it back together in the reverse order of your tutorial.

 

Thanks again!

[krag90 0]

Sick mate! Keep it up! Love this kind of posts. How does your camera rig look like/ what you got camera wise?

[Sommelier 0]

On 03/04/2016 at 19:26, dremelts said:

I too wish we had Part 2 but I pretty much just put it back together in the reverse order of your tutorial.

Well, you need to oil some stuff, take care of some other stuff. It would be a must to get part 2!

[hanski 40]

After spending a healthy couple hours rebuilding two of these movements of learned a couple things: 

First, if you rearrange the letters and numbers in A2813 it spells “Satan’s illegitimate demon spawn”. 

Second, after struggling through aligning the six pivots over and over - I finally realized the dang click is constantly in the way. I ended up using a very small piece of rodico to hold it open while I set the bridge. Voila! I set it first shot after that. With the click not pushing on the  paw winding wheel it stood straight and made life easier. Just be careful not to place the rodico in a way that get it pinched and gummed in there once assembled  

 

[brang1 3,988]

Have not seen this thread before, unbelievable work, i got a headache just looking at the work involved

[Earloflondon 8]

What an incredible effort to make a tutorial like this. Congrats

Sent from my Lenovo K53a48 using Tapatalk

[GenTLe 1,490]

Another trick is just to turn it 180° and put it back after the plate has been mounted. It works perfectly