LCGB Forums

Ok this is a weird one.....

Back brake is adjusted so that even a light/ minuscule press of the foot pedal activates the pads.
Stationary, with the foot pedal depressed it's impossible to move the scoot, forward of backward- the brakes lock firm

But.....when traveling, even at low speeds the rear brake does not function, even when pressed very hard....


Any ideas chaps????

SIL 200 casing?

Have you checked the routing of the cable? Could it be that when you have weight on the scooter and the engine pivots upwards with suspension movement the cable adjustment alters in some way?
Paul

Hi guys

Yes SIL 200 casing...

Ref cable routing- routed in the normal way..as OP, works OK with rider weight when stationary

I think some of the later casings had the brake cam hole machined slightly out. Not sure how old your case is and if it may be affected by this.

With the SIL casings it's hit and miss as to whether the back brake works or not. The problem is caused by the brake shoe pivots being slightly mis-aligned. This can cause only part of the brake shoe to work and one brake shoe catching before the other.

There are 2 common solutions; use a Jockeyboxenstop (probably spelt wrong !!) rear brake kit which allows the brake shoes to be adjusted to suit......good luck setting them up !!

The second option is to get the existing brake shoes skimmed to suit. AF did this for my mate and they charged £20 including new brake shoes. He drove the scooter there and they did the job in less than half an hour. Top service and £20 well spent.

Thanks mick

Does anyone know where the brake skimming can be done in the Midlands??

Thanks all

Steve

You could try marker pen on the linings then fit hub and tighten up. Spin the wheel and push the brake arm on at the same time to rub the ink off. Very often only one shoe touches the hub usually the bottom one. If so, fit a thin plate under the cam plate on the top shoe and try again. I have an old hub with windows cut in to check with a feeler gauge.

Wack wrote:You could try marker pen on the linings then fit hub and tighten up. Spin the wheel and push the brake arm on at the same time to rub the ink off. Very often only one shoe touches the hub usually the bottom one. If so, fit a thin plate under the cam plate on the top shoe and try again. I have an old hub with windows cut in to check with a feeler gauge.

Ditto , done this on a few mates scooters , works a treat

Thanks All - will try this weekend (hopefully) and post result in this forum

I've cut an old Spanish hub to help me skimming the brake shoes,
I had checked it first,for being true round on the inside.
I'll weld in the near future an adapter to attach the blades.

I had an original skimming tool unfortunately it was broken but the "blades" were what looked like segments cut from a course metal file and were adjustable via screws. It will be interesting to see yours done.

It will be something like this

http://www.lambrettaclubusa.net/topic/1 ... mmer-tool/

got my brake shoe trimmer tool from scooter restorations complete with vega / starstream adaptor some years ago

Gransport fixed it for me
3 main problems contributing to the issue
Rear brake cable routed incorrectly (over carb manifold, outer not fitting properly )
Very hard Italian shoes. Softer compound shoes fitted
SIL casing pivots misaligned. Rewelded to provide correct pivot profile.

So I have a useable brake now.

How much did they charge for that service Covboy? If its down to the pivots being mis-alligned, I'd rather get the casings rewelded and made good so its not an issue every time brake shoes are replaced.

Cheers

I forgot to add pics,sorry,
at the end,I tapped 3 holes to secure the 'homemade' blade.
Different heights can be used for different applications,
sometimes new brake shoes are too fat to fit a hub,
sometimes new brake shoes need re-profile,
sometimes worn shoes just need re-profile,
sometimes ...