Page 1 of 2

Weird brake behaviour since brakes have been bought up.

Posted: Sat Jan 12, 2013 6:02 pm
by Matt
Since Rackers bought up the topic of his brakes it's got me thinking about something I have experienced recently, I thought I'll put it out there and see what you think guys. Basically it happened on the rear drum of my Bullet last year and it happend a few days ago on my Montesa. What it is, all of a sudden It felt like there was instant "wear" on the brake causing it to be a whole inch out in adjustment!? I had to move the brake arm back round a few splines to get it back to 90degrees and pulling the brake on again... Nothing appeared to have slipped and no damage. When it happend on the Bullet last year I thought I was just going mad but it happend to me again the other day like I say. Re-adjusted and everything works again 100% any thoughts or am I going mad?

Weird brake behaviour since brakes have been bought up.

Posted: Sat Jan 12, 2013 6:13 pm
by grunda 12
hi matt it sounds to me like brake rod streatch a very strange happening either that or the pixies in you garage are unadjusting your brakes overnight just a thought atb paul.

Weird brake behaviour since brakes have been bought up.

Posted: Sat Jan 12, 2013 6:17 pm
by Matt
Yeah, it feels exactly like I would imagine if the rod were to stretch but that's not the case obviously. The other day with the Montesa it happened whilst I was ridding. Last year with the Bullet it was an overnight occurrence.

Weird brake behaviour since brakes have been bought up.

Posted: Sat Jan 12, 2013 6:23 pm
by Gwilly
Hi matt, seeing as how your using the bikes on rough terrain, is it possible you clipped the brake arm or pedal on a rock which made either one jump a few splines.

You sure there not worn or stripped?? gwilly.

Weird brake behaviour since brakes have been bought up.

Posted: Sat Jan 12, 2013 6:38 pm
by Gwilly
Stupid probably but did the chain become slack as well... could the wheel move forward a touch?? not tight enough... Nah crazy thought. stick with the pixies theory.. hide your spanners at night.

Weird brake behaviour since brakes have been bought up.

Posted: Sat Jan 12, 2013 7:44 pm
by Matt
Good points. The wheel moving forward is the best possibility I think, but with the snail cams it's unlikely. I will check wheel alignment tomorrow... Could be on to something. As for bending, damaging/ breaking that's not happened. Last year it was on my 500 Bullet which is my road bike and treated with dignity (haha.) On my Montesa the brake arm and rod are above the bottom of the rear spring arm, very much out of harms way (the rod on the Montesa is actually a car clutch cable with a soldered nipple.) It's been on there years and didn't show any signs of stretching.

Weird brake behaviour since brakes have been bought up.

Posted: Sat Jan 12, 2013 9:08 pm
by Craig
Un Scientific But, My 350 happens to act the same * I Put it Down To The Brake shoe's sticking Part O Or Off",..Strip & Grease the rear Brake & New Springs??..But its Winter Again so I Will Put Up With it?.....
"Thought For Today: I have Changed My brake shoes some six times..But Replaced the shoe Springs? Never"..Perhaps that's the Fault.......Lastly I Can Roll My 350 std forward with One finger..Back wards though the Brakes Bind???..."Ride & Enjoy"...Cheers all CRAIG

Weird brake behaviour since brakes have been bought up.

Posted: Sat Jan 12, 2013 11:16 pm
by Riggers
This is a bit of armchair thinking and I'm not sure if it's physically possible but here goes... Could it be that you've applied the brake so hard that the activating cam inside the drum has turned full circle? Just a thought??? Cheers. Tony.

Weird brake behaviour since brakes have been bought up.

Posted: Sat Jan 12, 2013 11:21 pm
by Riggers
Thinking about it I don't mean full circle, but rather far enough for the cam to have turned beyond its flat - if you get my drift.

Weird brake behaviour since brakes have been bought up.

Posted: Sun Jan 13, 2013 9:28 am
by Gwilly
In this cold wet weather armchair thinking is productive planning...Thats what i tell herself.

Hi Riggers. for the cam to turn 180 degrees and leave the arm still pointing downwards still attached to the brake rod would entail completely stripping the splines i think..

Is it possible for a brake shoe to crack near the cam actuator?

Is the shoe cast alloy or cast iron?? Haven't got any to look at as i cleared the workshop. gwilly