Reading Janacek's post about the poor front brake on his bike reminded me that there is a mod to improve the 7" front brake fitted to the older machines but I can't find any details about this anywhere. Does anyone on here know what the mod is?
The simplest mod would be to change it to an 8" Single-sided brake, as I did on my Star Twin, and it's a great improvement.
That said, the 7" brake on my ZB32 works far better than the original ST one ever did. New softer linings from Villiers Services and some laborious fettling worked wonders.
Having swapped out a 7" front brake on a 55 B31 for an 8" off an A10 its a huge improvement and a very simple mod. No parts need to be altered, the A10 brake stay and wheel spindle fit straight on and the fork lug does not clash.
The key to the 8" is that its a cast drum not a pressed one so its much more rigid and runs truer. Over time the 7" can get warped by the spoke tension.
I wasted a lot of time on the 7" getting the drum machined and shoes etc but the 8" was so much better straight away.
Quote from: V500 on 17 May, 2026, 12:10 The simplest mod would be to change it to an 8" Single-sided brake, as I did on my Star Twin, and it's a great improvement.
That said, the 7" brake on my ZB32 works far better than the original ST one ever did. New softer linings from Villiers Services and some laborious fettling worked wonders.
I agree and having had past experince with the 8" brake I know that they are far better. However, my bike is 1948 and I would prefer to keep the original appearance as far as posible and to complicate matters it has a 21" front wheel. Changing to an 8" hub would require rebuilding the wheels with suitable length spokes. I'll be happy just to get a little improvement with the existing brake. I have made sure the shoes are centred but have no idea what linings are fitted, they came with the bike.
Then the "best" solution is to get the wheel spokes tensions right then send the wheel and brake to a specialist to have the drum skimmed and the brake shoes turned to fit with a modern high friction lining. The problems is the diameter as you want to find someone who can munt the whole wheel. A lot of places will do the hub/drum but that means rebuilding the wheel with the risk of distorting the drum.
The common fix if its an offroad bike is to have two front wheels, the standard one and one with a modern Jap alloy brake, this will get you a nice light 6" or 7" hub/brake that works well and these are often 21" as they come off trail bikes. I was looking at brakes a the Talmag as I have a 350 Matchless set up as a trail bike, about 50% of the pre-65 bikes had small Japanese/Spanish/Italian front hub / brake units on 21" rims
I have had similar experiences with front brakes, 7"-> 8"-> and ultimately the Pearson version of Dow in A65 wide finned drum. Light years better.
However I too have a '57 competition as a trail bike with newly made 21" rimmed front 7".
I did the 'lapping' with self adhesive abrasive on the shoes and then in the drum, centred and arm adjusted correctly with decent cable. Better but still a 'slower downer' vs a 'stopper'.
I am currently modding a plate to TLS as per an article from A7/A10 forum. This requires an extra cam and cam spindle tube and splitting both fulcrums and adding them to one side of each cam. Still requires a new stay and good cable. I've lots on so slow process as I've pinched the diamond shaped plate support and spindle the off a scrap plate. It is an experiment and of course the pressed up plate and drum are limiting factors. I'll try to find the link to the article.
That sounds like a good mod Neil. I'd certainly be interested in the article if you can find it. It shouldn't be too difficult to find a use 7" brake to experiment with.
I feel that my current brake is probably as good as expected in it's current form, like your's it's a slow downer" rather than a Stopper". I like that analogy.
Here is a link:
https://www.a7a10.net/forum/index.php?topic=7691.0
You may have to join the forum to see pics etc
I am using straight levers (although I have a set of cranked Triumph ones)
I've not decided whether to locate the backplate with boss or flat stay yet, to get cable run and cam angles at optimum positions.
Thanks Neil. I can see all the pictures without joining the forum and will cut and paste all the pictures and relevant text into a document of my own for reference. I'll now start looking for a used 7" brake to work on.
There are other ways to do something similar:
Get two brake plates and cut them in half then weld the two halves with the bosses in to make a single TLS plate.
Get two hubs and saw then in half and join in the middle to make a double sided brake. This has the benefit of giving a lot more heat dissipation area and is used for racing.
Adapt a new Royal Enfield 7" TLS brake plate, they are only about £60 new with shoes and levers (from India).
Quote from: limeyrob on 21 May, 2026, 10:33 Adapt a new Royal Enfield 7" TLS brake plate, they are only about £60 new with shoes and levers (from India).
At that price it could be worth a go.
The quality of those is abysmal.
Yes, it looks too wide but its an ally plate and of course the shoes are ally so it may be a case of getting the saw out. I had a look at the photos on e-bay and I think its got potential. Perhaps you can get your hands on one and measure it? Just google "7" TLS brake" and plenty of the RE ones will come up.
Quote from: V500 on 21 May, 2026, 17:25 The quality of those is abysmal.
As least you won't feel guilty taking a saw to it.. :)
Quote from: Derek996 on 21 May, 2026, 09:56 Thanks Neil. I can see all the pictures without joining the forum and will cut and paste all the pictures and relevant text into a document of my own for reference. I'll now start looking for a used 7" brake to work on.
Suggest you crack on with it (based on my exerience this am) met two huge tractors in lane this am. Car in front slowed and stopped. I slowed and did not stop!!
Quote from: neil1964 on 24 Jun, 2026, 13:42 Quote from: Derek996 on 21 May, 2026, 09:56 Thanks Neil. I can see all the pictures without joining the forum and will cut and paste all the pictures and relevant text into a document of my own for reference. I'll now start looking for a used 7" brake to work on.
Suggest you crack on with it (based on my exerience this am) met two huge tractors in lane this am. Car in front slowed and stopped. I slowed and did not stop!!
I know the feeling. 3 or 4 years ago on a single track road I came round a corner with a high hedge on my side obscuring any view round the corner. One third the way round I met a huge 4x4 coming towards taking up the whole road. Luckily I was on my Ducati Supersport with ABS. I came to a halt with about 2 feet to spare and the back wheel in the air. If I'd been on the ZB32 I'd have been mince!
Yes I'll look into that brake improvement but it's not likely to happen until the winter. I'll just have to be extra careful in the meantime.
Quote from: Derek996 on 24 Jun, 2026, 16:39 Quote from: neil1964 on 24 Jun, 2026, 13:42 Quote from: Derek996 on 21 May, 2026, 09:56 Thanks Neil. I can see all the pictures without joining the forum and will cut and paste all the pictures and relevant text into a document of my own for reference. I'll now start looking for a used 7" brake to work on.
Suggest you crack on with it (based on my exerience this am) met two huge tractors in lane this am. Car in front slowed and stopped. I slowed and did not stop!!
I know the feeling. 3 or 4 years ago on a single track road I came round a corner with a high hedge on my side obscuring any view round the corner. One third the way round I met a huge 4x4 coming towards taking up the whole road. Luckily I was on my Ducati Supersport with ABS. I came to a halt with about 2 feet to spare and the back wheel in the air. If I'd been on the ZB32 I'd have been mince!
Yes I'll look into that brake improvement but it's not likely to happen until the winter. I'll just have to be extra careful in the meantime.
Yes, though I was too. I wonder if partly moving from one very similar bike (the ABSAF 600) with razor sharp brake to the scrambler with poor 7" I clearly was not being as careful as I should have.
New stanchions, wheel rim, mudguard and headlamp shell will be needed. Heaven knows how much the electric Beemer will cost - afraid that will be down to insurance.
the 7 "brake with the threaded fork is a good stopper. also used for the b40 /44. good quality linings needed.
the better b40 brake plate can be used on the earlier b31/ plunger if the bearing spacer behind the brake plate is swopped also. the later brake plate is stronger but the b40 wheel rim offset is different so no wheel swop.
another mod i use is building up the brake cam profile with arc weld so there is more early bite.
the brake squeels and snatches at first on a ride before bedding in nicely after the first corner.
surprising how good they can be with fettling . however glazing is your enemy.
Re gazing, yes its really important to use drum brakes as hard as you can from the off with new linings. I often hear of people "bending the shoes in gently" and know they will be doing a lot of filing to get back to the fresh material.
Quote from: EDDIE SIMPSON on 25 Jun, 2026, 20:47 the 7 "brake with the threaded fork is a good stopper. also used for the b40 /44. good quality linings needed.
the better b40 brake plate can be used on the earlier b31/ plunger if the bearing spacer behind the brake plate is swopped also. the later brake plate is stronger but the b40 wheel rim offset is different so no wheel swop.
another mod i use is building up the brake cam profile with arc weld so there is more early bite.
the brake squeels and snatches at first on a ride before bedding in nicely after the first corner.
surprising how good they can be with fettling . however glazing is your enemy.
The brake is arc'd both ways and I used genuine Ferodo linings (getting rare now). MOT tester said that they passed ok (I watched has he did the test as it was post restoration and I was worried that this was the weakest part of the machine. Important to note new cable and correct 90 actuator when fully applied etc. As I said a slower and not a stopper (at least on a healthy GS scrambler engine!)
Quote from: limeyrob on 26 Jun, 2026, 08:39 Re gazing, yes its really important to use drum brakes as hard as you can from the off with new linings. I often hear of people "bending the shoes in gently" and know they will be doing a lot of filing to get back to the fresh material.
Similar to pistons, then...
Quote from: Derek996 on 17 May, 2026, 11:01 Reading Janacek's post about the poor front brake on his bike reminded me that there is a mod to improve the 7" front brake fitted to the older machines but I can't find any details about this anywhere. Does anyone on here know what the mod is?
[/quote
Just had my brakes re-lined (7 inch Ariel type hubs) by Villiers Services.
The drill is to measure the ID of your brake drum,and the diameter of the brake shoes on the brake plate just the metal and not the linings,and Villiers will fit linings to suit.
I asked for softer road use linings and the brakes are now very good.
Quote from: Janacek on 27 Jun, 2026, 09:44 Just had my brakes re-lined (7 inch Ariel type hubs) by Villiers Services.
The drill is to measure the ID of your brake drum,and the diameter of the brake shoes on the brake plate just the metal and not the linings,and Villiers will fit linings to suit.
I asked for softer road use linings and the brakes are now very good.
Thanks for that tip. It will also have to wait until the winter as I'm using the bike just now and intend to until late autumn.
And only £25 including return postage.
Quote from: V500 on 27 Jun, 2026, 18:41 And only £25 including return postage.
Yes they did the shoes on my Dow TLS front brake. Very reasonable and very speedy. Would certainly recommend them for relining. I've got whatever Phil Pearson put in his TLS version of Dow front brake.
I've had good results with the genuine Ferodo shoes on rear brakes, but the front one, despite my best efforts, was found wanting (the engine in this bike is long rod clubman's spec so 90 mph is easy on the shortish gearing 18/43, 19/42. I'll put it back together now and prioritise the TLS mod for the 7".
Interesting about the Ferodo linings. I drive a 1970 Series Land Rover on drums and there's a lot of discussion on brake friction and linings. The original Ferodo come out very well, most every aftermarket are terrible (too hard) but the latest polymer linings are very good. I now have high friction linings and my 2 1/4 ton truck can lock its wheels. The problem with the Ferodo shoes is that they are almost impossible to get hold of.
From my experience a modern high friction lining will be around 2x better than "standard" hard linings and rather more than that on a TLS as the higher friction is multiplied by the self-servo effect of the TLS so the lever pull is reduced.
Quote from: limeyrob on 28 Jun, 2026, 17:07 Interesting about the Ferodo linings. I drive a 1970 Series Land Rover on drums and there's a lot of discussion on brake friction and linings. The original Ferodo come out very well, most every aftermarket are terrible (too hard) but the latest polymer linings are very good. I now have high friction linings and my 2 1/4 ton truck can lock its wheels. The problem with the Ferodo shoes is that they are almost impossible to get hold of.
From my experience a modern high friction lining will be around 2x better than "standard" hard linings and rather more than that on a TLS as the higher friction is multiplied by the self-servo effect of the TLS so the lever pull is reduced.
Interesting. I fitted the TI console front disc kits to my SWB S3 about 25 years ago. They use Merc van callipers and work very well (still do). I had to replace discs and used BMW 3 series discs with adapter plates as the originals got worn after 40k miles. Yep the Ferodo lined shoes are now getting thin on the ground.
This is how I improved mine
Quote from: ducati2242 on 29 Jun, 2026, 17:04 This is how I improved mine
Yep, I've got two like that both of the 8" single sided finned drum type. Excellent brake, the Pearson one fitted to the ABSAF 600 has HD stainless steel levers, rod and torque stay. I've put an original 60's Taylor-Dow one on the 500 Clubman. This has aluminium levers and rod and it has standard torque stay.
The scrambler is the 7" single sided type. This has 21" rim and dual purpose tyres. I'd like to keep that but with greater efficiency that TLS brings. Front end rebuild will start when new seal holders arrive.
A question / thought. This bike is for some off-road use? If so you don't want a brake that's too fierce which TLS can be. Could you get enough improvement with modern high friction linings and cutting back the lining on the trailing shoe? I don't know but it may be worth a try.
i have reversed the brake lever on a a10 full width hub with good results. cant work out how to post photos on this site but mr Pike of bsa race developments department photoed their racer with the setup that i copied.