The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Lucas, Ignition, Charging, Electrical => Topic started by: Chillipepper on 01.03. 2015 12:16

Title: AAR unit removal
Post by: Chillipepper on 01.03. 2015 12:16
Hi All
I have recently purchased a 1952 Plunger A10 and I am in the process of a full strip down as the bike has been sat for over 30 years - anywho, I have followed the manuals advice of undoing the nut that holds the AAR unit expecting it to release the unit but to no avail - any ideas on how to get it off ??

Thanks

Chillipepper
Title: Re: AAR unit removal
Post by: WozzA on 01.03. 2015 13:16
Keep screwing..   *eek*  the bolt acts as a puller, as you unscrew it you'll feel resistance...
keep screwing & it will pull free from the maggy  *smile*
Title: Re: AAR unit removal
Post by: Chillipepper on 01.03. 2015 20:16
Hi WozzA
Yeah been un screwing for 5 mins an still fails to release - was thinkin bout undoin maggi an using a wooden drift on maggie in the hope it will budge the aar unit but hopin for some better advice as using force is never a good thing !!!
Title: Re: AAR unit removal
Post by: metalflake11 on 02.03. 2015 03:53
Mine doesn't come off by just unscrewing the nut either. A little tap with a small hammer on one of the flats has always done the job though.
Title: Re: AAR unit removal
Post by: duTch on 02.03. 2015 08:51

Quote
Yeah been un screwing for 5 mins an still fails to release - w...
...= don't come easy/no fun....aaahh- before I cause trouble, try metalflakes idea..maybe the threads have jumped ship- screw it back in and start again and maybe pull the nut out as you go, it may have a bit of flaccidity from its hibernation...

 
Title: Re: AAR unit removal
Post by: fido on 02.03. 2015 08:53
If I recall correctly there is a slotted washer which can fall out, making the puller part inoperative.
Title: Re: AAR unit removal
Post by: beezermacc on 02.03. 2015 08:56
This is quite a common problem. Fortunately, the taper is quite steep so not a lot of force is required to separate the AR from the mag. If you been unscrewing and the internal mechanism hasn't released I would recommend the following..... Screw the nut back in, but not very tight, just finger tight should be OK. Drill and tap the centre of the nut to take a 5/16 bolt or 7mm, unscrew the nut until it is loose again then run a 5/16 or 7mm bolt into the threads you've cut, Hold the ATD nut firm and square and tighten the 5/16 or 7mm bolt which should put pressure on the armature shaft and extract the ATD.
Title: Re: AAR unit removal
Post by: beezermacc on 02.03. 2015 09:13
If I recall correctly there is a slotted washer which can fall out, making the puller part inoperative.
The washers don't have any effect. The extraction is achieved by the internal left hand thread riding over itself as the nut undoes on the armature shaft. That's also the reason why the left hand threads are always bu88ered and the nut won't come out of the ATD. One of Joe Lucas' s poorer designs..... of which there were many!
Title: Re: AAR unit removal
Post by: Chillipepper on 02.03. 2015 17:46
Thanks for the advice all, mag now off via this method - unsrewed nut until completely loose, supported mag body with small wooden wedge (to keep body level) then a couple of hits wit hammer on wooden drift on body of mag an away the aar came 👍👍👍👍