front brake backing plate modification

Curious to see if anyone has tried the front brake backing plate mod suggested by Vintage Brake and Old Brits. It consists of boring the axle hole and installing a bushing to reduce the clearance between the axle and the backing plate. Was this worth the effort?
Also, is anyone familiar with using sticky back sandpaper in the hub to arc the linings? I was figuring about 180 grit.

sticking sand paper in the hub is not arcing the linings.

I reamed out the brake plate on my Atlas to give more play. There is a service note from Norton somewhere that gives the recommended tolerances. This allows the shoes to be centred in the drum before tightening the axle nut. The axle runs in the bearings, not the brake plate. I found this information on either this forum or Norton owners club. Atlas SLS is as good as the standard disc on my Commando.

Gilesy said:

I reamed out the brake plate on my Atlas to give more play. There is a service note from Norton somewhere that gives the recommended tolerances. This allows the shoes to be centred in the drum before tightening the axle nut. The axle runs in the bearings, not the brake plate. I found this information on either this forum or Norton owners club. Atlas SLS is as good as the standard disc on my Commando.

Click to expand...

That modification is in the pre-Commando twins workshop manual, but you shouldn't need the bigger hole in a twin leading shoe backplate.

Top of page 48:

http://classicbike.biz/Norton/Repair/1960s/NortonRepair1960-1968.pdf

Pretty sure DogT had something on here a few years back ‘bout the sandpaper trick , think he was pleased with results,it was a while ago
Craig

I can't find my old post. But yes, I did use sandpaper and tacky glue on the drum to sand down the shoes to fit the drums better. Need to take out the slipper plates with new shoes to get some clearance. I used 80 grit cut into strips wide enough to fit in the drum. Used the adjuster on the brake to keep tightening the brake as I lay on the ground and turned the wheel by hand. I went from about 20% contact to greater than 80% contact and the difference in braking was stunning to say the least. It didn't take long, as usual the setup and clean up took most of the time. It doesn't prevent fading and loosing brake power though. I thought that backing plate was way to expensive for what it was so I never got one. The other thing is to properly set up the lever system on the TLS so both shoes contact at the same time and also to tighten the axle with the brake applied.

As I said in my earlier post, it was like the difference between dragging your feet on the ground to stop (or planing 3 miles ahead and gearing down which I did a lot of in the 70's) and a real front brake. Who'd a thunk?

Make sure you chamfer the edges too when you're done or they'll grab.

I was not the first one to write this up that would be norbsa.

Here's norbsa's post but the old link doesn't work any more:

So time for fresh Ferodo shoes. These need to be turned but no need for a lathe or hundeds of dollars. This is what I did it works well. Clean the drum with sand paper on the inside with 60 grit this knocks down the glaze and prepares the surface for rubber cement. Cut some strips of 60 grit the width of the drum, you will need to paint up the back of the strips with rubber cement as well as the inside of the drum. The paper needs two coats, let it dry and line the inside of the drum no gaps with 60 grit. now assemble your new shoes on the backing plate just like you were going to run it this way. You will need to back off all your adjusters but go ahead and hook up the cable. Ok now for the helper bikes on the center stand and the stands on a piece of 2x wood helper is on the bike keeping the bike on the rear wheel and gently applying the front brake you are on your side on the ground turning the front tire buy hand when your helper tells you the handle has touched the handle bar it's time to pull it apart for a check. When you get 90% touching your done with the sanding. You now need to sand a half inch of taper on the leading side of each shoe don't skip this step or it won't quit stopping. Now after you have got this done and every thing is clean and relubed don't forget to put a little grease on the shoes were they contact the cams, It's time to adjust the two shoes. Again you need a helper to get this right. The first shoe is the one that the cable pulls directly on and the second shoe is the one that is pulled on by the adjustible rod. You need to start by backing off the second shoe so there is no contact when the brake is on. Now hold the brake on with your hand and have your helper slowly adjust the second shoe till you feel the lever move just a little in your hand. This is critical and may take a few trys to get right. Each time having your helper back off the adjuster just a little while you take rests from holding the brake on by hand. Make sure that it's as close as you can get it re adjust and tighten everything, time for a brake in also critical. This is first gear work take the bike up to shift point and use the brake easy at first than harder and harder each time till your skidding to a stop. You are heating the brake up to very hot on this first run. Now let it cool down all the way and re adjust everything. I took mine apart at this stage just to clean out the dust and recheck the lube and such. With all the cleaning and fussing plan on four hours work and an hour of cool off time than another hour of cleaning and readjustment. The only time this system shows it's weekness is when your riding with bikes that have two front disk brakes and they are using them hard in their riding style. My brake will lock the front wheel at anything shy of 65 MPH if I really grab a handfull. I have left out some details on grease types and tighting sequinces to keep this shorter but you get the idea. If you need more info PM me.norbsa

The description above makes it sound like more work than it is. It takes no time at all once you get setup, and the difference in braking can be huge.
Last time I did a brake job the oversize shoes I ordered didn't fit in the drum, so I mounted them on the backplate and turned them on a lathe.
If you are lucky you might have a buddy with an old school brake grinder.
In the bad old days bodgers would do the job with a file and chalk to reveal the contact area.
I would call any of these methods "arcing the lining".

Stephen Hill

Arcing explained:
(1) rebond the shoes with oversize linings (1/4")
(2) fit shoes to brake plate with lever,springs and adjuster rod adjusted
(3) fit 1mm shim under foot of both shoes (between shoe and camshaft)
(4) mount brake on mandrel or axle in lathe
(5) machine to exact drum diameter
(6) remove shims and dress up shoes , taper of end of linings.
Now when you apply brake in theory you will have 100% contact area

I will go ahead and give it a try. I thought #60 grit would be to aggressive.
I already have the stiffening plate, an improvement over the original set up. Its about $120 at OB
Is there a good tool for removing springs or just the screwdriver method?
Any advantage to reducing the clearance of the backing plate to the axle via a new bushing?

seattle##gs said:

I will go ahead and give it a try. I thought #60 grit would be to aggressive.
I already have the stiffening plate, an improvement over the original set up. Its about $120 at OB
Is there a good tool for removing springs or just the screwdriver method?
Any advantage to reducing the clearance of the backing plate to the axle via a new bushing?

Click to expand...

I use a screwdriver and needle nose pliers to urge the spring onto the brake shoe tab. Understand that this tab can be broken
off if not careful, rendering the brake shoe useless.

fit the springs to the shoes first. fit the shoes on to their pivot posts together, then spread the shoes to insert the camshafts.

Vice grips worked for me with the springs.

As Stephen said, the difference can be huge.