Auto advance removal

[tonyairconchap]

Hi  all,  new to the forum   i need some advice please on my 1958 A10
After 20 years my magneto has given up so i need to remove it for repair. It has the auto advance retard setup.
I have removed the bolt which secures it to the pinion. I assume its fitted on a taper, but how do i remove it.
Do i need a bolt to screw into the hole, if so what size is the bolt and thread size?
How far do i need to screw the bolt in?  Do i tap it once its screwed in?

Any help would be greatfully received

Thanks
Tony

[muskrat]

G'day Tony,  .
Wow, you mean after 20 years this is the 1st removal of the aa unit  .
The pinion and aa unit are joined (as in riveted together). The nut in the center is a self extractor so once it is lose you keep winding and it is supposed to pop the unit off with the pinion.
Cheers

[chaterlea25]

Hi and welcome to the Forum Tony 

Have a read here

https://www.a7a10.net/forum/index.php?topic=11841.msg91082#msg91082


John

[tonyairconchap]

Thanks for the quick replies.

Yes 23 years at least since its been off,  think the warranty has run out now!

Muskrat, you say the centre nut is a self extractor,  what do you mean by loosening then continue to wind...all i end up with is the bolt in my hands...is that wrong?

John, am i right that i just undo the bolt a turn and give it a sharp tap to loosen from the taper.

Tony

[muskrat]

After you undo the three mag mounting nuts.
Cheers

[tonyairconchap]

Gents, i have tried loosening the 3 mag bolts and then tried to wind in the centre bolt, self winder? The only thing that happens is that i turn the aa unit. Nothing frees up. Am i right in thinking that the aa unit is on a taper?

Also tried what John suggested, giving it a good tap with a hammer after loosening the 3 securing bolts. Still no joy..

What am i doing wrong?

Any u tube videos on the removal of the aa?

Tony

[bsa-bill]

I'm not sure giving it a tap will have  the desired effect if the magneto is loose ( three nuts slackened), try tightening them up again, then unscrew the central nut, when it becomes tight again then give it a tap (small hammer please), to assist you could lever behind the gear with a thin flat bar as you do the tap (very positive tap)

[tonyairconchap]

Hi Bill,  thanks for the reply.
when i unscrew the centre nut all i am doing is unscrewing it off the armature shaft, it does not go tight as i unscrew it.
do i need an extractor tool to remove the auto advance unit?
tony

[Greybeard]

Hi Bill,  thanks for the reply.
when i unscrew the centre nut all i am doing is unscrewing it off the armature shaft, it does not go tight as i unscrew it.
do i need an extractor tool to remove the auto advance unit?
tony

I know this is a repeating query here. Have you tried searching the forum?

[tonyairconchap]

Hi Greybeard, yes , searched for hours over the last few nights, searched the net, all i can find  is that the centre bolt is a self extractor which muskrat suggested.  But tried that and still not doing as suggested.
so sorry if this subject may be repeated time and again, but i do research before asking.
Tony

[berger]

I am going to get a slap! your not at the points end are you, as dido said , its just a thought definatley going to get slapped ive just read the first post , oh well pub tmow

[Greybeard]

Priory Magnetos website may be useful for tips. I found this PDF to download and read: https://sites.google.com/site/priorymagnetos/tech-tips-1

Did you find this page? https://www.a7a10.net/forum/index.php?topic=9333.msg67521#msg67521

[tonyairconchap]

Hi all,  think i have found an issue with the centre bolt.
from what your saying is that as i loosen the bolt from the main shaft it should go tight again.  I think the thread further up the bolt shaft has failed, almost completly missing,  . Also what looks like a thread  in the auto advance is almost  gone.
so bugger, what do i do now?
tony

[Greybeard]

I'm glad to say I've not had this problem. I hope someone comes along with a definitive answer for you.

I'm wondering if a slide hammer could be screwed into the thread in the ATD and used to jolt the thing off the shaft

[berger]

undo mag nuts completely get someone to steady it, try and get some wooden wedges between auto unit and inner case, get hardwood dowel or very soft brass drift onto mag armature shaft and bash it,, no don't bash it play with it gently while muttering let go you bastard