The Marston Sunbeam Club & Register Forum

General Category => Technical Discussion Forum => Topic started by: jfrith on September 10, 2021, 07:33:04 AM

Title: 1931 M9 Front brake cable
Post by: jfrith on September 10, 2021, 07:33:04 AM
Hi
Front brake cable on my model 9 is a bodge job, wrong adjuster that fits in Webb forks and no yolk that fits onto brake plate lever, cable is just wrapped around a nut and bolt which passes through brake lever.
Does anyone have the dimensions of the inner and outer cable and where I can get correct yolk and adjuster? Also planning to fit inverted levers, Is this correct for the year 1931, also are they much of a job to fit?
Thanks John
Title: Re: 1931 M9 Front brake cable
Post by: klaudius on September 10, 2021, 08:54:57 AM
I have some difficulties with the language. Please forgive me. I'm still teaching, you mean the screw? Bj.31 still had fine threads. 32 already the coarser one.
Greetings Claudius
Title: Re: 1931 M9 Front brake cable
Post by: singleminded on September 10, 2021, 12:16:35 PM
Hi John.
Vic has or is getting the shackle for the brake lever made,check with him.
I guess the thread in the forks is 3/8"x 26 tpi cycle, the 1932 bikes are 3/8" BSF as already mentioned by Klaudius. You will need to identify correctly the thread for the adjuster.
To fit the inverted lever is not a problem, they fit into the end of the bar and once you are happy with the position you drill and tap to fit a grub screw to lock it in place.
There are some bikes where the handle bar is slit ans a small clamp is used to hold the inverted lever in place, mine still kept rotating though.
There can be a problem if you have the internal pull throttle with getting both cables to fit through the bars without them  binding each other up, I gave up and fitted an external straight pull twistgrip. If you are using a standard twist grip there is no problem and you can use a slightly heavier duty cable( which is preferable,,less sponginess).
The photos are not as sharp as I'd like but you should get the idea..I think that the shackles from Vic will include the shouldered bolt and cable fitting.
John
Title: Re: 1931 M9 Front brake cable
Post by: jfrith on September 10, 2021, 02:11:54 PM
Hi Klaudius / John
Thanks for the help!
I'll be ordering the yoke etc from Vic later and be looking for an adjuster, same thread as the rear. So not too bad
You wouldn't have a picture of your handle bars and where the cables run?
Thanks John
Title: Re: 1931 M9 Front brake cable
Post by: singleminded on September 10, 2021, 03:09:05 PM
The bars on my 9A are original Sunbeam clean bars,7/8" diameter.
Originally the throttle and brake cables both came out of the righthand hole, looking from sitting on the bike.
On my internal slide throttle the inner cable is pulled and the outer pushed to give a quicker/less travel operation.This didn't work with modern cables as the outers jammed against each other.I think the original cables were sized between a throttle cable and modern brake cable diameter.
I have not found any one producing these bars, but 1" bars to this shape can be got from the Scott spares scheme. not sure about 7/8" ones though.
I hope these pics help. I can Email full format pics if needed,they are too big for this site.
I forgot to say that the adjusters on my bike are 7/16" diameter which makes more sense.

John
Title: Re: 1931 M9 Front brake cable
Post by: jfrith on September 10, 2021, 03:26:16 PM
Photos are great thank you!
I had been sent the dimensions of the small covers that the fit on handlebars and the cables run through
Hopefully it will all be sorted out soon
Thanks for all your help!
John
Title: Re: 1931 M9 Front brake cable
Post by: klaudius on September 10, 2021, 06:06:05 PM
I also have an M9A 1932 with original trains from the factory. The whole thing is still like 1932. I would like to add that the small aluminum disc that is used for locking is missing in the photos shown. This ensures that nothing is misaligned. Foto M7A 1932 Claudius
Title: Re: 1931 M9 Front brake cable
Post by: Ken the Sec on September 15, 2021, 06:09:02 PM
Hello John
The lower area was not originally covered. At that time, however, many pushed a bit over it with a lot of play in order to have some corrosion protection. Think about the cable holder and the washer with notch. Both were made of aluminum.

Greetings from Germany
Claudius

(This came to me as admin - perhaps Claudius hit the wrong button and sent an email instead of posting his response.)
Title: Re: 1931 M9 Front brake cable
Post by: singleminded on September 15, 2021, 06:27:20 PM
I went with the outer cable below the adjuster as my original cable had it and the parts list for 1932 lists it. i feel it adds a bit of protection to the cable also.
Title: Re: 1931 M9 Front brake cable
Post by: klaudius on September 15, 2021, 07:15:43 PM
How new is this text?
I still have all the covers on my 9A 32 and the first ones. My team 7A 34 already had the lower hulls. Was that so? Apart from that, they make little sense at the bottom. As a result, they could have been removed over the course of the decade for this reason as well.
I partially had to repair my casings and marinated them in fussy Glicerin for weeks. The cables are new.
Greetings Claudius
who still doesn't write proper English ...