Rear brake stud part number

Information relating to the Matchless G12 or AJS Model 31 650cc twin
Andy G
Member
Posts: 358
Joined: Mon Jun 01, 2020 9:42 am
Location: Aberdeenshire UK

Rear brake stud part number

Post by Andy G »

I need to replace the stud that passes through the frame for the pivot mounting of the rear brake pedal.
It's approx 33 cms long, threaded at both ends.
Bike is '62 31CSR.

Am I correct with 025178?

Thanks
Bombling contentedly around rural Aberdeenshire
Mick D
Posts: 2886
Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Rear brake stud part number

Post by Mick D »

Hi

I think I'd plump for 022248 or 021715 - if I couldn't identify the correct one by length I'd check with Steve Surbey

Regards Mick
Andy G
Member
Posts: 358
Joined: Mon Jun 01, 2020 9:42 am
Location: Aberdeenshire UK

Re: Rear brake stud part number

Post by Andy G »

Hmm, not sure Mick. Both those parts seem very short (less than 11") compared to what I have (12"), which is only just long enough to pass through the frame and be bolted up..and I believe the stud isn't original as it shows signs of being home made or shortened.

Currently fitted stud is 12" by 7/16" and was assembled with a single aluminium spacer on the right side of the frame. I also found a matching spacer unused in the spares that came with the bike and I'm guessing this should be fitted on the left side to help the foot pedal clear the chain case?
That would make the overall length of the stud needed to be 13".
If there shouldn't be a spacer on left, then stud still needs to be 12". Thoughts appreciated!
Last edited by Andy G on Wed Apr 28, 2021 1:49 pm, edited 1 time in total.
Bombling contentedly around rural Aberdeenshire
Andy G
Member
Posts: 358
Joined: Mon Jun 01, 2020 9:42 am
Location: Aberdeenshire UK

Re: Rear brake stud part number

Post by Andy G »

brake stud.jpg
I'm not aquainted with Steve - is he on the spares team? Can't see his details in the mag
You do not have the required permissions to view the files attached to this post.
Bombling contentedly around rural Aberdeenshire
User avatar
Samuel
Member
Posts: 1067
Joined: Tue Sep 09, 2003 1:00 am
Location: Somerset UK

Re: Rear brake stud part number

Post by Samuel »

Steven Surbey of AMC Classic Spares - http://www.amcclassicspares.com/
Sam
Mick D
Posts: 2886
Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Rear brake stud part number

Post by Mick D »

Hi Andy

I don't own an AMC heavyweight twin so my advice may be off, but I don't see any spacers listed in the Parts Lists. I think I'd start by identifying whether the brake lever is correct as a spacer and longer stud may have been fitted in order to allow a non standard lever to clear the PCC.

Regards Mick
User avatar
dave16mct
Member
Posts: 3234
Joined: Mon Jan 01, 1990 12:00 am
Location: LANCASHIRE UK

Re: Rear brake stud part number

Post by dave16mct »

My stud is 11" long and there are no spacers.
Dave.
Andy G
Member
Posts: 358
Joined: Mon Jun 01, 2020 9:42 am
Location: Aberdeenshire UK

Re: Rear brake stud part number

Post by Andy G »

Samuel wrote: Wed Apr 28, 2021 3:36 pm Steven Surbey of AMC Classic Spares - http://www.amcclassicspares.com/
Thanks Sam, that's def a contact to keep handy!
Bombling contentedly around rural Aberdeenshire
Andy G
Member
Posts: 358
Joined: Mon Jun 01, 2020 9:42 am
Location: Aberdeenshire UK

Re: Rear brake stud part number

Post by Andy G »

Mick D wrote: Wed Apr 28, 2021 3:48 pm Hi Andy

a spacer and longer stud may have been fitted in order to allow a non standard lever to clear the PCC.

Regards Mick
Yesssssss, entirely possible - I was told the bike had been "retired" following a crash and there are several signs to back that up, including gouging to the PCC where a brake lever presumably carved its way.
However, without a spacer on that side, the lever operates and just about clears the PCC so I'll leave it for now.
I think the main reason for the "spacer" on the right side however may actually have been not so much a spacer as a sleeve - see the phot. I'm guessing that the correct stud is stepped on this side and a replacement wasn't. So the "spacer" is there to fit the recess in the frame, and for whatever reason was made long enough to then require a longer total stud length.

Or I may just have been reading too much Sherlock Holmes.

Anyone know if the stud should have a step on one end?
Brake stud spacer.jpg
And as the spacer/sleeve is exactly 1" long, when added to Dave's 11" for the correct part:
dave16mct wrote: Wed Apr 28, 2021 4:18 pm My stud is 11" long and there are no spacers.
Dave.
I am back to the 12" home-made stud that I have!

Thanks Chaps, I think I now understand enough to make this work.
You do not have the required permissions to view the files attached to this post.
Bombling contentedly around rural Aberdeenshire
Mick D
Posts: 2886
Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: Rear brake stud part number

Post by Mick D »

Hi Andy

I've just been out and measured my G15 - the stud is PN 022248 and is 11 1/16" long, it is not stepped as far as I can remember. I think you'll find that if you ditch the spacer this stud will fit.

Do a sanity check and measure the dimension between the outside faces of the rear loop bottom attachment - the pedal spindle sandwiches the tab washer which restrains the spring on the left hand end, the right hand side is secured with a plain washer and nut

The brake levers are made from cast steel and as such can be 'adjusted' cold to give a better fit.

Regards Mick
Locked