Honda CBF 125. Rear drum break

Majeeko · L Plate Warrior Joined: 20 Jun 2015 Karma :

Hi all, i'm a relatively new biker, done about 1700 miles on my CBF 125, just commuting to work and back. its second hand and a 2010 model. Yesterday i noticed rear break didn't feel right, when i pressed the pedal it didn't spring back like it use to, i have had a look and all the linkage seems fine it appears to be the workings inside the drum break

https://youtu.be/1tjmBwIWxQI

I've attached a short video for clarification. ideally id like to do the repair myself to save a few quid but i'm nervous about taking the wheel off and getting it back safe enough to ride.

there is also a squeaking sound when i first use the rear breaks, it stops after a few minutes.

i'm guessing that some of the internals have seized or i need new break pads or shoes but i would like a more expert opinion please.

Many thanks in advance

Luke

spottedtango · Trackday Trickster Joined: 04 Dec 2015 Karma :

Brake drums usually have 2 main springs inside them.

-A main return spring within the drum to pull the shoes back from the drum once the you've applied the brakes.

-A smaller retaining spring usually connecting the two brake shoes at the bottom holding them in.

Id inspect inside the brake drum to see if these springs have snapped as they tend to rust up. I think in your case the return spring inside the drum has corroded and snapped causing your brake pedal to not return.

Its not too difficult a job, theres plenty of youtube vids and how tos on the web. Id do some research

MCN · Super Spammer Joined: 22 Jul 2015 Karma :

Is you're break broaken?

The mechanism is relatively simple.
Check that all the pivots are free to move.
Check that the brake linings are not worn down to the quick.

After the checks you need to adjust the linkage as per the O.E.M. instructions.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

Hi Luke.

Assuming that you've lubed the actuator arm and it's not helped then you are going to have to start stripping and cleaning. Could be a snapped spring, could just be gummed up with crud like the rear on my GPz305 when I got it. You're not going to know until you get in there.

It's not complicated and this video covers it.
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Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

From how far wound in the adjuster nut appears to be on your video (pretty much fully compressing the control rod spring). I'd surmise your brake shoes are very nearly worn out causing the cam to start going over-centre.

There may be some corrosion around the cam pivot area too.

I'd suggest you blow £13.50 on a set of brake shoes in preparation for stripping and cleaning your rear brake drum.

You may find this helpful.

Don't do nothing because the next step may be the brake locking on and staying there. Not much fun if you're moving at the time.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

Majeeko · L Plate Warrior Joined: 20 Jun 2015 Karma :

Thanks everyone. The break still works although not very well. it looks like i will be spending one Sunday stripping and cleaning.

The video and guides are really helpful.

Luckily i've found a mobile bike mechanic near me so if all goes tits up ill ask him to come round and help me put it back together.

Very Happy

MCN · Super Spammer Joined: 22 Jul 2015 Karma :

Majeeko · L Plate Warrior Joined: 20 Jun 2015 Karma :

Majeeko · L Plate Warrior Joined: 20 Jun 2015 Karma :

Rogerborg · nimbA Joined: 26 Oct 2010 Karma :

I wouldn't wait for a Sunday, because as stinkwheel says, there's some risk of it locking up. Really, it's as simple as it looks. There are no surprises lurking in there, and for once, reassembly really is is the opposite of disassembly, as the Haynes Book of Lies is fond of claiming.

Just take care to get the spacers on the correct side and the right way round (slide them onto the axle as soon as its out so that they don't go astray or get mixed up), go over it twice to be sure that you've done everything up, and get the wheel alignment and tension right, and you're done.
____________________
Biking is 1/20th as dangerous as horse riding.
GONE: HN125-8, LF-250B, GPz 305, GPZ 500S, Burgman 400 // RIDING: F650GS (800 twin), Royal Enfield Bullet Electra 500 AVL, Ninja 250R because racebike

mauzo · Nova Slayer Joined: 30 Jun 2015 Karma :

Also, if you're cleaning and greasing: DO NOT get any grease on the friction surfaces or the drums they press against. Also don't breathe the black dust inside the brake drum, it'll give you cancer.
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'04 CG125, '07 CBF500