Looking at the photo of the brake plate, the smaller top lever arm seems to be set at an anusual angle. It could be that you only have one shoe actually acting when the handlebar lever is operated.

I would suggest you start with a total reset of all the moving parts. Check the inside of the brake plate. Make sure that when the cable is pulled both the inside cams begin to lift their respective shoes at the same time.

Setting these TLS brakes can be a bit fiddly especially if one shoe has worn more than the other.

I note that a similar posting about damp TLS was made last year. Check out

Twin leading shoe braking issue

using the Search Site above.

The 2LS brake when set up correctly is very powerful.

You can reset the tie-bar adjustment easily enough or better still remove the wheel and clean the internals and lubricate the cams....then do the final adjustment.

I would recommend cleaning and lubing first so here is how to do it.

1) remove the cable and then the wheel and remove the brake plate.

2) with a bucket of very hot soapy water (Fairly Liquid) brush out the dust from the drum and clean out the dust from the brake plate and shoes.

3) After a quick wipe, the parts will be dry due to the heat of the water and you can remove the tie plate and remove the shoes by levering off the springs.

4) once again clean up the brake shoes and brake plate which is now more exposed...and dry again.

5) remove the cams and clean thoroughly in paraffin and old grease from the pivots and cams.

6) the cams will be likely to be scored so carefully file and polish these with wet and dry to get them really polished and smooth...this is essential....Likewise smooth off the steel pressure plates on the ends of the shoes...make sure they are dead smooth with NO ridges at all.

7) grease carefully any parts that bear on any other metal parts....Eg cam spindles...cam faces.... shoe pivot holes.

8) refit shoes springs and retainer plates....(might have to lock the bolt heads by turning over the plate edges?)

NOW the 2LS adjustment:

1) refit wheel and brake cable and re-tighten spindle and nut.

2) Slacken Tie-bar locking nut and turn tie bar so the upper brake arm moves up and away from pressurising its brake shoe.

3) Pull the brake lever hard on and tape it or strap it in that position (or get help).

4) Turn the tie bar in the opposite direction to move the top lever downwards until you feel the tie bar tightening up as it pulls on the lever to exert pressure on its shoe to make firm drum contact....Continue to turn the tie bar just a touch more to make sure all play is fully taken up and tighten the Tie-bar lock nut firmly.

6) lubricate the front brake cable (can be done at any stage but essential)

7) Readjust main adjuster for correct bar lever position....job done.

NOTE: The brake is now set up correctly but full power will be achieved over the course of the next few journeys and applications. You should then have a brake that can lock the front wheel with normal hand pressure ....whole job about 1 hour so don't dismiss the effort it WILL be worth it.

Les

PS: SUPERB LOOKING machine by the way....congrats.

PPS....Any drum brake that gets water into it will have reduced power especially the more leading shoes that the brake has as most of the power is exerted by the self servo action of the shoes being pulled onto the drum surface. This is why heavy lorries have trailing shoes only which rely on shear brute force of compressed air to apply the pressure so consequently water and heat fade are minimised and performance levels remain unchanged.

Just remember if the shoes are old then the dust will contain asbestos, so until the hot soapy water works and the dust is in the bucket with the water then wear a mask.

I think Phil is right, the top cam lever probably needs turning over to get it's axis more of less parallel to the bottom one when the shoes are in contact with the drum. Fairy liquid (and most detergents) is high in salt content so rinse well. Lubricating the cable is important and the cable with the stop light switch incorporated is poor, allowing water to flush out any lube. My Commando 2LS brake had no bracing plate and I don't think it would have made too much difference.

What do you experts have to say about brake cleaner instead of soap water?

In the absence of any experts, soapy water is best for removing dust. Brake cleaner is good for shifting oil or grease.

Its a good idea to centralise the brake before tightening the axle nut . In hubs from Bracebridge st you find small drainage holes at the back of the steel drum lining ,these block with lining dust, When I rebuilt my wheels I drilled 2 more . Always leave the bike with the steering to the side to allow the rain to run off the brake and not into it. SLS brakes are prone to leading shoe wear ,Although it sounds counterproductive I have found swapping the shoes over to put the thickest shoe into the leading position works out best . You may have to file a chamfer on the leading lining if it grabs.

With the Norton 2LS âcentralisationâ of the brake is not possible as the spindle hole in the plate is the same size as the spindle and will not allow sideways movement of the plate to occur UNLESS one enlarges the spindle hole but this is not necessary or recommended as the two shoes will self compensate automatically.

If any one shoe wears slightly more than the other one, the other thicker shoe will automatically wear down to match the thinner one until perfect simultaneous contact occurs. This self compensating wearing action occurs every time the brakes are applied so perfect synchronous contact is maintained. Obviously it is best to get the two shoes operating together to start with by manual adjustment to avoid a very long settling in period but once set they should track accurately for the rest of the lives.

However this is not the case for single leading shoe brakes that do not feature automatic compensation (I.e. they have a fixed cam spindle and shoe pivot positions) The imbalance is caused by the slower wearing (thicker) trailing shoe holding back the cam action so that the faster wearing (thinner) leading shoe is robbed of movement and thus pressure.

With this type of brake, having a larger size spindle hole will allow manual compensation (centralisation) by being able to shift the plate and allow simultaneous shoe contact. Unfortunately this will have to be done regularly at intervals to maintain the adjustment...

Unfortunately, over a longish period the difference in shoe thickness might exceed the brake plates enlarged spindle hole adjustment range so before this occurs the shoes can be swapped over (trailing to leading and visa versa) this will in practice allow further centralisation to be carried out for the remaining life of the shoes....

Les

The imbalance is caused by the slower wearing (thicker) trailing shoe holding back the cam action so that the faster wearing (thinner) leading shoe is robbed of movement and thus pressure.

Not always true, if you look at the cam it depends on the cam rotation, if the outer part of the cam lifts the trailing shoe first then this will direct more wear to the trailing shoe and balance the wear with the leading closer than if the outer part lifts the leading shoe. Downside of the more even wear is a less effective brake as the leading shoe is doing less work but most SLS brakes are set up this way. You can get a more effective brake by turning the brakeplate so the cable can pull the cam lever the opposite way and then the leading shoe will wear out quicker and when you need more shoes only one is really worn.

An even better solution is to keep the cam rotation for even wear but to flatten the base of the cup on the shoe end that runs on the pivot so they become floating ie move forwards and backwards, the leading shoe can do more work but the even wear is retained.

Hi John...The reason the leading shoe wears more quickly than the trailing shoe is to do with the self servo action the leading shoe is subject to. The natural action is to pull it much harder in an attempt to grab it onto the spinning drum surface thus increasing friction and wear rate. The opposite is true for the trailing shoe where the natural rotating action brushes away the shoe so less pressure is created on it. This can even be seen in SLS brakes which utilise hydraulic rams where both sides of it push in equal pressure against the shoes....the leading shoe ALWAYS wear more quickly round about a factor of 2 to 1..

As I explained some year back the Tracking of wear can be helped if the cam operates in a way that puts the inner part of the cam lobe to operate the leading shoe. This helps moves the faster wearing leading shoe a tiny fraction more compared to the trailing shoe..but this is not the real cause of the faster wear and please note the Norton brakes have it the wrong way round in any case....Please read my extensive write up: which you may have read before?:

http://www.nortonownersclub.org/noc-chat/technical2-heavy-twins-forum/347672034?b_start=0#236581524

Les

Here's a story about 2LS brakes. When I joined the RAF in 1974 there were a number of Malaysian students in training alongside us at St Athan. One of them told me that he replaced the springs between the front brake shoes with tell tale copper wire and never used the front brake. The idea being that any thief would apply the brake, the wire would part and lock the front wheel. Good in theory (apart from the total reliance on the rear brake) the problem being that the victim of this cunning ploy was his now badly scarred younger brother.

Surely: Norton brakes are applied by positive displacement (i.e. movement of the cam) rather than positive force (e.g. hydraulic brakes).

The rate of wear must be greater for greater pressure. Therefore the two shoes of an SLS brake mustwear at the same rateand thus provide the same effect because the leading shoe will wear back until this is true. - IF the forces are applied by cams - but as Les says it is not true for hydraulic brakes.

More complication is that the Norton TLS has a link rod between the cams rather than a cable pulling the cams together. The link rod allows both cam pivots to be the same radius from the axle so the cams act at the same radius because they turn in the same direction. BMW used the connecting cable with cams therefore turning the opposite ways. So to keep the cam action point radii as nearly the same as possible, the cam pivots are at different radii from the wheel spindle. I assume that means they compromise a bit as the shoes wear and the radii of the contact points on the shoes will slowly change with wear.

But why do Norton always have two independent pivots for the two brake shoes on SLS brakes? Cananyone explain?

For what it's worth - I set up my new shoes on the bench by adjusting the rod until both lift of the stops at the same instant. I never found it very easy to do it the 'proper way' by applying both levers and setting the rod to fit. At least I know they start in the middle (assuming it was accurately manufactured). And as others have said - always apply the front brake lever hard before tightening the wheel spindle nut. I won't adjust them again if I can avoid it before I need new shoes.

Hi all,

John/David, I have to concur with Les regarding the servo effect of the brake shoe against rotation. On a SLS the leading shoe is dragged from the cam against its fulcrum end giving the servo action, whereas the trailing shoe is pushed back from it's fulcrum end against the cam. This means the brake will work equally well if the bike is going forwards or backwards, with the load alternating from one shoe to the other.With the 2LS both shoes willeach have a servo action when going forwards and is probably around 40% more effective than the SLS, EXCEPT when the bike goes backwards. If you have a 2LS brake or have a friend with one, stop the bike on a very steep hill facing upwards and see how difficult it is to hold on the slope with just the front brake.

Manx models used a single fulcrum pin from 1937 to 1953 on their SLS front brake which used magnesium alloy brake shoes which are forked together at the fulcrum end. The Manx 2LS brake was introduced for the 1954 season. I am not sure about the brakes used in the pre 1930 period, but they may have used a single pin fulcrum at some time.

Regards, Richard.

True , Richard. My TLS Dommie front brake is hopeless in reverse. But all I'm saying is that with SLS brakes (rear on one and both ends on the other) the shoes must wear evenly owing to the cam action. Therefore they must both apply the same braking force. It's interesting to read that lorry brakes use two trailing shoes but big force. The self servo is actually a problem as it is unpredictable. Hence disc brakes...

I use 3 bikes regularly all have SLS ,all three benefit hugely when I switch shoes round ,but all can have the front wheel sliding back on hills. Only one (the oldest at 80) does not have a problem with rolling back on hills ,can you guess why?.( I bet Gordon knows!)

Asbestos shoes?

Reply to David Cooper: Quote:

Surely: Norton brakes are applied by positive displacement (i.e. movement of the cam) rather than positive force (e.g. hydraulic brakes).

The rate of wear must be greater for greater pressure. Therefore the two shoes of an SLS brake mustwear at the same rate....etc.

Hi David, regarding SLS brakes, you would think that the shoes do move at the same rate but there are two reasons that they don't.

1)The operating cam has two lobes set across the face of the shoes pressure plates. Whatever way it turns the more outer end of the cam creates a bigger levering point from its shoes pivot point compared to the inner end of the cam which as the lever is acting nearer the pivot will move its shoe a greater distance (but also with the same reduction in force)

2) More importantly though is the fixed cam spindle position. The cam can only turn until the rotation is stopped by the shoe touching the drum. As the trailing shoe wear more slowly than its partner it will be thicker and stop the cam rotation BEFORE the faster wearing thinner leading shoe can really make strong contact....Ah, you may say the trailing shoe will therefore wear down, which of course it does, (you are in effect using the trailing shoe only at this point) but you then have a situation that the weaker trailing shoe is dictating when the leading shoe can get its good share of force, and as soon as it does, the leading shoe is again worn that much quicker and loses power again. The scenario I describe in practice does notdevelop in these discrete stages but is in a dynamic state (continuous) the overall effect is that the leading shoe is always receiving less force than it would if the cam pivot was allowed to float to accommodate the different wear rates and not be influenced by its partner.

The reason for two pivot positions must be a design idea to allow a better arc of swing for the shoes than would occur with a single central pivot position but this allows flexing which then needs cross bracing between the two pivots. I would imagine the better arc ensures a more even wear rate across the entire length of the shoe rather than have it concentrated at one end..

Another method where SLS shoes can be improved is to have the pivot positions floating but solidly linked where the force of the leading shoe is transmitted as movement at the pivot end to force the trailing shoe across and outwards to create a âquasiâ twin leading shoe arrangementâ?.this is probably not as effective as a genuine 2LS type....This design also creates automatic wear compensation which is useful too...(note they will still need adjustment to compensate for the OVERALL wear) ....The shoes are held in with pressure springs set halfway along the side of the shoes...often seen in car brake design....

Les

Previously David Cooper wrote:

Asbestos shoes?

Nope, Its down to having linked brakes, which means the back brake is doing the job (with the weight of the bike on that wheel) .With the normal old Brit bike the left foot is used to balance the bike leaving the right foot to engage gear and relying on the front brake alone to cope and the tyre to slide as the weight is not on it. Still have to do a fast shoe shuffle to pull away though ,even with a Rudge.

The exception is the sls Manx brakes, which have one pin to locate both brake shoes. One is plain, the other forked

Paul

Previously David Cooper wrote:

But why do Norton always have two independent pivots for the two brake shoes on SLS brakes? Cananyone explain?

Previously les_howard wrote:

The 2LS brake when set up correctly is very powerful.

Thank you for a very clear and comprehensive explanation, Les. I'll be sure to use this when I've got the bike back together. It may be my age or just that I'm used to modern machines now, but my 650SS 2LS is scarily ineffective!

Kevin