Triumph Rat Motorcycle Forums banner
1 - 11 of 11 Posts

· Registered
Joined
·
65 Posts
Discussion Starter · #1 ·
Doing some winter work on my '70 T100R and took upon the task of replacing the front TLS brake shoes. Got them installed but am concerned about their stopability. Currently they are not providing the stop action that the old ones did. I really don't want to risk 2000 miles of break-in time with a dicey setup. Does anyone have some secret procedures to obtain good TLS stopping power from the get-go? Thanks.
 

· Premium Member
Joined
·
261 Posts
From my notes, would this work?

1 Slack off the brake cable at the handlebars to remove all tension on the linkage
2 Remove the locking pin connecting the two cam levers together
3 Apply both cam levers stiffly
4 Adjust the link rod length until the loose end just fits into the other cam lever
5 Re-insert the locking pin and tighten the locking nuts on the lever
6 Make an adjustment at the hand lever for a slight slack in the cable
7 When adjustment is complete, rotate the wheel rapidly in its normal direction
8 With the wheel spinning rapidly, apply the brake hard to stop the wheel abruptly

Last two steps to center shoes before tightening everything up. Some say to tap the brake plate gently with plastic mallet to do the same.
 

· Registered
Joined
·
3,654 Posts
Hi Gutz,
There used to be a thing called brake arcing, where the brake shoes were machined to match the diameter of the brake drum. This has all but disappeared along with the special machines that ground the brake shoes to the correct radius.
That was for people who had the money to take thier brakes to the specialists, the poor kids used the ‘street’ method.
It might just work for your T100.

From the DIY store get some 60/80 grit sandpaper with sticky backing, the type designed to stick directly to orbial sanders, or, at a push some ordinary sandpaper and some double sided tape.

Set up the brake as described by Hermit, take the wheel off the bike but the brake cable still connected.
Slacken the adjuster at the handlebar and remove the brakeplate from the drum.

Cut the sandpaper into small strips the width of the brake shoe and about 1” long -
Clean the drum and stick the sandpaper around the drum on the braking surface.
With a felt tip pen (magic marker) draw a line along the length of the brake shoe.
Fit the backplate and shoes, and the wheel spindle.
Very gently apply the brake while turning the backplate backwards and forwards.
Check the shoes often, when the line disappears you are done.
Remove the sandpaper and clean the drum.
It is quick, takes about 5 minutes so check progress often.

Your bed in distance should now be about 20 miles, not 2000.

Oh, and wear a mask, there is no asbestos anymore, but the dust still could be quite nasty.

Regards
Peg.

P.S. You will need to set up the brake again using Hermits method afterwards.
 

· Registered
Joined
·
4,108 Posts
I always tapped the backing plate with a rubber, or plastic mallet while adjusting each shoe, until they were fully engaged. Now, some say this step isn't needed, and they may be right, but I also would apply the brake after it was adjusted, loosen and then re-tighten the backing plate center nut to centralize the plate/brake shoe assembly; a few more taps during this part was also in my regime. As I said, many don't think this step is necessary, and they very well may be right...…..it's just the way I chose to do it.
Hope this helps: Jim
 

· Super Moderator
Joined
·
11,711 Posts
Hi,

secret procedures
Note the information posted by Bruce isn't a "secret", it's in the Triumph workshop manual - http://classicbike.biz/Triumph/Repair/350-500/63-74-350-500cc-Repair.pdf if you don't have it - Section FF5.

Less well-known (because it doesn't appear to be in every manual) is the procedure Triumph called "burnishing" - essentially bedding-in the curve of new braking material to closely-match the curve of the drum by rubbing off the 'high spots' in the material. The procedure itself simply involves making a number of hard stops from higher and higher speeds - iirc, ten from 30 mph, ten from 50 mph and ten from 70 mph?

However, with the generally-poorer quality of modern new parts, and especially if you aren't noticing the improved braking towards the end of the first stage, it's likely worth taking the brake apart after the first ten hard stops and checking how much of the braking material is actually contacting the drum. If it still doesn't look like a lot, you might want to speed-up the bedding-in process with the "arcing" detailed by "Peg".

Hth.

Regards,
 

· Registered
Joined
·
28 Posts
Follow the factory adjustment to the letter! If the cams are not equal the brakes can be WAY to touchy. My Commando TLS could lock in humid/wet weather (not fun) until I synced it properly. It's actually a really effective brake when adjusted properly and now never locks up.
 

· Premium Member
Joined
·
683 Posts
Hi,


Note the information posted by Bruce isn't a "secret", it's in the Triumph workshop manual - http://classicbike.biz/Triumph/Repair/350-500/63-74-350-500cc-Repair.pdf if you don't have it - Section FF5.

Less well-known (because it doesn't appear to be in every manual) is the procedure Triumph called "burnishing" - essentially bedding-in the curve of new braking material to closely-match the curve of the drum by rubbing off the 'high spots' in the material. The procedure itself simply involves making a number of hard stops from higher and higher speeds - iirc, ten from 30 mph, ten from 50 mph and ten from 70 mph?

However, with the generally-poorer quality of modern new parts, and especially if you aren't noticing the improved braking towards the end of the first stage, it's likely worth taking the brake apart after the first ten hard stops and checking how much of the braking material is actually contacting the drum. If it still doesn't look like a lot, you might want to speed-up the bedding-in process with the "arcing" detailed by "Peg".

Hth.

Regards,



Instead of the full-on arcing, a light hand sanding of the high spots is often all that's needed. When finished it's important to spin the installed wheel, apply and hold the brake as the axle is cinched up. This works on virtually all motorcycle drum brakes.
 

· Registered
Joined
·
6,238 Posts
Hi gutz, On the '69 Bonnie the front brake had great power, but pulsated. Drum was out of round or more correctly had high/low spots. These could be plainly seen during drum "turning", or in this case grinding.

Tensioned spokes & trued rim. Then had drum turned by a friend that has gap bed lathe. Used tool post grinder in carriage to turn drum.

Front shoes had some wear. Owner wanted asbestos free shoes, meaning modern shoes. Original NOS were available & I would have used those if up to me.

Anyway, got new asbestos free shoes Emgo. These had terrible friction & bike would not stop. Of course linkage was adjusted & backing plate centered & all that to no avail. Tried the sandpaper glued to drum. This sort of helped, but still not good enough.

Bedding in for many miles did not help much at all.

Finally the machinist friend built a backing plate for lathe & mounted shoes. Used tool post grinder to arc shoes.

Again repeated the bedding in process as described by Stuart. After several bedding attempts brakes finally settled down to acceptable & safe. I know some friction materials need to get hot to "condition" the friction material. Not meaning they need to warm up to get friction like racing brakes may need, but the heat somehow changes the friction coefficient.


Now brake has good safe stopping power, but not so strong as with the original shoes. I feel the modern asbestos free material last the same friction as the originals.


Took a fair amount of friction material off shoes to get proper arc. I feel this also increased power as it gives the cams a better mechanical advantage to press shoes out.


Rear brake became same problem after replacing shoes to modern. It did not pulsate but was bell mouthed by about .010". I don't have the experience to say if that's enough to matter or not on these bikes.


Again trued drum, arced shoes. Got Ferodo shoes which worked worse. Then Emgo shoes which worked less worse. NOS rear shoes could not be found at the time. Like the front brake still not like original, but at least can lock rear wheel at 65mph now.


I've seen similar experience with T140 rear shoes. NOS don't seem easy to get for these either. My original T140 type rear brake shoes have great power & modulation. The day they wear out I'm really worried about. Same with front brake pads.


Getting someone to turn drum and or arc shoes is almost impossible here. Turnaround time can be months. I hope there is someone in UK that can provide these services in a timely matter for you.

Please keep us updated on your progress.
Don
 

· Super Moderator
Joined
·
11,711 Posts
Hi,

'70 T100R
Certainly as standard, it's exactly the same brake as on my T150 (100 lbs.? heavier than your bike). My T150's front brake hasn't ever given me any cause for concern on the road (if it isn't quite as good as the twin discs on the T160's); the only times I've ever manged to get the drum to fade is on track days ... :whistle

Follow the factory adjustment to the letter
Uh-uh, don't ... the 500 manual has an error, that could be one of the reasons for some of the bizarre advice in this thread ...

. The aforementioned Section FF5 is correct up to the end of the first part of the last sentence, "Reconnect the brake cable ..."; however, do not "adjust as described in Section F5" - specifically in the 500 manual, "Section F5" is about adjusting the earlier SLS brake, which advises the brake is applied when the nut on the brake shoes fulcrum pin (i.e. not the brake plate securing nut) is tightened.

. The major difference is the SLS brake shoes fulcrum pin nut is still easily-accessible when the wheel is in the forks, the TLS brake plate nut is not - something all said bizarre advice so far has failed to explain ... The TLS brake plate securing nut's thin and buried in a counterbore in the brake plate; with the wheel in the forks, you can only get the ends of an open-ended wrench on two of the nut's flats at an angle - in years to come, posts in these forums will ask why Triumph produced so many misshapen nuts and/or gouged brake plates ... :rolleyes: Wheel out of the forks? In years to come, posts in these forums will ask how Triumph could match the patterns on one end of the axles to the pattern of so many different vise-grip jaws ... :rolleyes:

. The contemporary 650 and Trident workshop manuals (http://classicbike.biz/Triumph/Repair/1970s/70-Triumph-Repair-Manual-63-70.pdf and http://classicbike.biz/Triumph/Repair/Trident/69-73TridentRepair.pdf) are clearer:-

650 manual, Section F5
AFTER DU.66246
The front brake being of the two leading shoe variety ...
The shoes are however self centreing ...
Trident manual, Section F4
The front brake being of the two leading shoe variety ...
The shoes are however self centreing ...
Hth.

Regards,
 
1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top