Firstly I would say that new shoes will take a while to bed in so that their profile becomes a better match with your drum profile. Today's non-asbestos linings seem to be harder and less effective than the original material. (Soft(er) linings are available from companies such as Saftek).
Second, maybe your adjuster is nearly at its full extent due to you having a wrong cable....? i.e. too short an outer or too long an inner? Perhaps the cable is for a h/bar lever with an adjuster at the lever end and your lever doesn't have an adjuster....?
I guess the L/W brake is near enough the same as for my H/W. If so there's a brief compilation below of posts which I put on the Forum back in 2009 which may give you some food for thought, clues, or may even help., Even if the L/W isn't exactly the same the principles are generic to most if not all single leading shoe assemblies.
The whole original thread and various comments and Q&A's can be found here:
http://www.jampot.com/forum/viewtopic.p ... mprovement
Anyway here are my thoughts from 2009.....
Whilst I had the wheel out to do some serviceing I took the opportunity to photo the mod which I made 6 months ago to the front brake lining on my '54 G3LS.
Two pics:
1. Showing which is the Leading and which is the Trailing shoe. Arrows indicate direction of wheel rotation. Leading edge of leading shoe ('L') is adjacent to cam.:
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2. Chalked area of lining removed:
100_1399 (640x480).jpg
When you have the brake shoes assembly out of the wheel chalk an arrow on each brake shoe in the direction of wheel rotation. Be careful when marking the arrows as you'll be looking at the brake assembly 'back to front' i.e as a mirror image of when it's installed.
The arrow pointing away from the brake cam/expander is on the leading shoe and the arrow pointing towards the cam is on the trailing shoe.
The leading edge of the leading shoe is at the cam end of that shoe. The trailing edge of the the trailing shoe is also at the cam end, but of the trailing shoe.
Because the fixed brake shoe pivot doesn't move when the brake is operated the cam ends of the shoes touch the drum first.
If the trailing edge of the trailing shoe touches before the leading edge of the leading shoe (keep up at the back) you lose the 'servo' effect of the drum 'dragging' the leading edge of the leading shoe outwards towards the drum.
If you can follow all this rambling (!) you can visualise that the trailing edge of the trailing shoe is being 'pushed' inwards away from the drum when the brake is applied.
Furthermore, you also want as much area (length) as possible of both linings to contact the drum. Once one shoe (either shoe) has contacted the drum the cam will not turn any more therefore you want to ensure that it is the leading shoe which makes contact first.
To give an extreme example you could remove either shoe completely, refit the assembly, and the brake would still work, after a fashion. (Although it would not be possible to fit the pull-off springs).
This diatribe is only relevant to single leading shoe assemblies of course as a twin leading shoe (TLS) brake has two operating cams (one at each end of the shoes) and no fixed pivot, so both shoes are leading shoes.........
O.K, you can go now.
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I put the shoe in a vice, hacksawed through the 7/8" width of the lining then used a chisel to carefully 'lever' or slice off the lining material (starting from the cut and going towards the end of the linings as you don't want to risk disturbing the lining that's to remain).
I would imagine that removing just say half the thickness would be o.k. - enough to keep it clear of the drum.
Only tried it bonded linings though.
Later:
It's worth repeating that centralising the shoes on the fixed pivot and on the brake backplate after refitting the assembly to the wheel is essential, as is having the arm to inner cable angle close to 90 deg
at the point when the shoes contact the drum.
Handlebar lever should have 7/8" distance between lever pivot bolt and cable nipple; many pattern levers are 1" which means that they will require a significant amount more effort at the lever (than a 7/8" one) to obtain the same force at the shoes.
I also fitted a heavier duty cable as I found that the existing pattern cable had a flimsy outer (the 'conduit') which squashed/compressed when braking giving a very spongy feel to the lever.
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I had been researching both the theory and bar room waffle (which is the leading or trailing shoe?.. so forth) behind this mod for some time. However, ignoring the long-winded science/physics involved I can only say that my practical experience is that it's worth doing: Better initial 'bite' without grabbing, more powerful retardation with less strength needed in the hand and fingers thus reducing fatigue/cramp on long hilly rides.
It goes without saying that the brake needs to be correctly set up as well - i.e. the lower brake actuating lever should be at the most advantageous angle (i.e. 90 deg) to the cable
at the point when the shoes contact the drum, fixed pivot loosened then tightened after reassembling brake into drum and with the brake applied, shoes/backplate centralised (i.e. brake applied) before tightening the backplate locknut, and the cable run without sharp bends etc. etc. The centre of the lever nipple to pivot bolt distance should be 7/8" and no greater.