Brakes

[paulmbsa]

Time is coming for new Brakes now I have a number of Bikes with Most types of hubs, years ago they were all fitted with linings machined to suit, I must say the Brakes are all fantastic, However they are all asbestos and I am being told Asbestos free are not as good. Also when looking at shoes for sale including a set just relined that do not work anywhere as good as the worn ones taken out I have noticed that there is no difference in the shoes IE no Leading or trailing shoe.

 I have recently had two sets done, One a Aerial Hub type and to be Honest a Brick on a rope would work better the Specialist relined it three times trying different linings.
 The same People relined a rear Full width Hub Set of Shoes and again I am considering installing a Brick on a Rope. The People I used are well known specialist and seem keen to try and sort it but why they can not get it right first time is a Mystery

 Any advice would be appreciated

 Regards

Paul

[a10 gf]

Hello, maybe obvious and already checked, but is the fulcrum pin correctly adjusted? Any spongy (too weak) cables? Correct contact surface (diameter) shoe>drum ?

Apart from this, have personally experienced asbestos shoes gripping better than new hard materials.

& some reading > http://a7a10.net/forum/index.php/topic,5554.0.html

[paulmbsa]

Hi everything is set up correctly and centred, now I work on Wagons and trailers, we get trailers in with a huge wear lip in the drum, we reline and send them Back out no Problem (We run them for a few say 10 miles then Brake test and they Pass) so this tells me oversize is not just the answer, also why do these bed in so Quick yes they are air operated so more force is applied but the only difference is how they are applied the Basic workings are the same

[paulmbsa]

I have just checked over a set of new shoes, they are identical no way of telling which is leading and which is trailing, now I have chalked up the shoes and put back in and spun the wheel no Matter what I do the trailing shoe is making first contact I have looked at some old original shoes and they are clearly marked 1 & 2 the one being the leading and clearly different from the trailing
my understanding is if the trailing hits first the Brake will not work correctly
Any experts put there ???
Regards

Paul

[muskrat]

G'day Paul.
Here's a site worth reading http://www.engineeringinspiration.co.uk/drumbrakes.html#LEAD
If the drums are oversize the shoes MUST be skimmed to match.
Truck / bike brakes are not a good comparison re the different pressure applied as you say. The air is strong enough to bend a shoe to conform with the drum.
Cheers

[chaterlea25]

Hi Paul,
The fulcrum pin between the shoes is clamped in place  by a locking nut
The hole is larger than the pin, so it should be loosened, brake applied and retightened while the brake is applied
This centres the shoes in the drum

HTH
John

[Triton Thrasher]

my understanding is if the trailing hits first the Brake will not work correctly

That's right.

[paulmbsa]

Triton

If this is correct why is this happening and how do I put it right


Regards

[BSA_54A10]

pivot is not centered to the drum.
Brake cam is upside down
Shoes with contact plateContact plate missing from shoes had had them fited