1954 G80 Rear Brake Problem

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
mrpjhancock_LAPSED
Posts: 19
Joined: Thu Feb 08, 2018 10:27 am
Location: LEICESTERSHIRE UK

1954 G80 Rear Brake Problem

Post by mrpjhancock_LAPSED »

Hi. I have a problem with the rear brake on my 1954 G80. When I spin the wheel there is a scraping sound. I took the wheel off and inspected the brake. The problem is when the brake cam rotates it moves the brake shoes away from the back plate and after a couple of brake applications it touches the drum and that creates the noise. I have replaced the brake cam and it is a good fit in the hole through the back plate . . . . no excessive play. Has anyone come across this before ?
I have attached photos showing the brake assembly and before and after photos
You do not have the required permissions to view the files attached to this post.
Winkie
Posts: 111
Joined: Sat Nov 26, 2005 10:47 pm
Location: WEST MIDLANDS UK

Re: 1954 G80 Rear Brake Problem

Post by Winkie »

I had a similar problem with my front brake. It was caused by the pivot pin being loose, which allowed the shoes to move about.
Mick D
Posts: 2886
Joined: Mon Mar 24, 2014 5:44 pm
Location: Aberdeenshire

Re: 1954 G80 Rear Brake Problem

Post by Mick D »

Hi

Try fitting the retraction springs from the other side of the shoes.

Regards Mick
alanengineer
Member
Posts: 1175
Joined: Wed Oct 12, 2005 10:45 pm
Location: KENT UK

Re: 1954 G80 Rear Brake Problem

Post by alanengineer »

Try adjusting the brake plate a bit further away from the hub, probably only needs a turn
User avatar
ajscomboman
Member
Posts: 3963
Joined: Mon Jan 01, 1990 12:00 am
Location: HAMPSHIRE UK

Re: 1954 G80 Rear Brake Problem

Post by ajscomboman »

alanengineer wrote:Try adjusting the brake plate a bit further away from the hub, probably only needs a turn
It's a rear brake Alan, not adjustable like the front.
mrpjhancock_LAPSED
Posts: 19
Joined: Thu Feb 08, 2018 10:27 am
Location: LEICESTERSHIRE UK

Re: 1954 G80 Rear Brake Problem

Post by mrpjhancock_LAPSED »

Hi chaps . . . . just tried changing the springs to the top side and the pivot pin is solid . . . . . No difference :(
User avatar
Pharisee
Member
Posts: 1126
Joined: Tue Mar 15, 2016 8:51 pm
Location: Lincolnshire UK
Contact:

Re: 1954 G80 Rear Brake Problem

Post by Pharisee »

Are the thrust pads worn and driving the shoes up as the cam bears on them?
I'm from the Fens.... Gimme six.
alanengineer
Member
Posts: 1175
Joined: Wed Oct 12, 2005 10:45 pm
Location: KENT UK

Re: 1954 G80 Rear Brake Problem

Post by alanengineer »

I have just replaced some brake shoes and used new or remanufactured ones. They were painted gold also. I had to do some interesting filing to get them to fit. I wonder if that is your problem also. Not the same problem as mine, but quality control. Maybe, the shoes are too wide and just need a good file to fit.
Your photo shows the scraping on the shoes, how about a photo of what the shoes are scraping on.

Apart from putting new shoes and springs in, have you done anything else that might be relevant.
Maybe silly, and its your time, try putting the springs in the other way round.

AJScomboman, good point, forgot that bit!
mrpjhancock_LAPSED
Posts: 19
Joined: Thu Feb 08, 2018 10:27 am
Location: LEICESTERSHIRE UK

Re: 1954 G80 Rear Brake Problem

Post by mrpjhancock_LAPSED »

Iv tried the spring thing with no luck . . . . I was at the AMOC parts shop today and tried exchanging my brake shoes for some new ones. Unfortunately my shoes werent good enough to exchange. Apparently they need to be in perfect condition!
So Im stuck with the ones I have
I have attached a photo of the brake drum its self. looks like its the hardened pads that are coming into contact
You do not have the required permissions to view the files attached to this post.
alanengineer
Member
Posts: 1175
Joined: Wed Oct 12, 2005 10:45 pm
Location: KENT UK

Re: 1954 G80 Rear Brake Problem

Post by alanengineer »

Is that a new brake drum
Locked