Anyone know about hub brakes?

[swee'pea99]

My daughter's pub bike has started emitting plaintive mewing squeaks from the front wheel hub, and turning the bike upside down and revolving the wheel has narrowed it down (I think) to the hub brake, which seems to be binding slightly (you can feel the friction). I know absolutely nothing about hub brakes, and don't really want to start taking things to bits blind...I envisage little springs sproinging themselves out onto the lawn. Am I worrying unduly? Should I just have a bit of a dismantle? Or is there anything I might try lubricating first? (There's a hole right at the top in the pic, which looks like it could be for lube - but if it isn't, I could end up putting oil on the working pads/parts, which I can't help feeling would be A Very Bad Idea.)

It looks like this, in case it helps, and is a Panasonic, apparently:

Any hints & tips much appreciated.

 

[weareHKR]

Well, I'm definitely no expert on these but it could be either a drum brake or a band brake...
if I'm correct then I don't think there's anything in there that will pop out like a jack-in-a-box never to be seen again...
If it's binding slightly it may just need a clean & a drop of lubrication on the pivot points &/or a new brake band!
Give it a bit longer & there may be some guys on here who have previous experience ...

 

[battered]

It's going to be like a hub/drum brake on a motorcycle or a car. When you operate them you have 2 C shaped shoes being pushed apart in a drum. Springs keep them together when they are not being applied. They won't explode if you simply take the drum off to have a look.

 

[swee'pea99]

It's going to be like a hub/drum brake on a motorcycle or a car. When you operate them you have 2 C shaped shoes being pushed apart in a drum. Springs keep them together when they are not being applied. They won't explode if you simply take the drum off to have a look.

Thanks. Sounds like a poke about is in order...

 

[battered]

I suspect that your hole is just to let water out in set weather. As you say, keep the lubricant out of there unless you know where it's going.

 

[swee'pea99]

Well that was interesting! I got as far as disconnecting everything to enable me to remove the wheel, only to find that the wheel's secured by the only nuts I've ever seen that don't have parallel faces, so can't be shifted with a regular spanner. Thiefproofing. Presumably there's a special spanner. Anyway, removing the wheel is not going to be possible. Which prevents me actually getting to the innards of the (not a hub brake after all but a) drum brake. I can't help feeling there should be soe kind of facility built into such a mech to allow the application of a little light oil every now & then, but I can't see any promising looking holes.

One thing...

Anyone know what that bottom screw adjusts? The one wrapped in a spring that engages with the white disc ...'thing'.

Or how to lubricate a drum brake.

Ta.

 

[battered]

1. Do NOT attempt to lubricate this. Drum brakes need no lubrication beyond a very light smear of brake grease or coppergrease on the non friction parts when they go in for service.
2. You can undo the 5 sided nut with water pump pliers. I know, this is not a purists' solution but needs must.
3. The bottom screw will adjust to compensate for wear, I imagine. (edit - yes it does, I looked at some pics)
4. A drum brake is, in this case at least, a hub brake, because it's a drum mounted to the hub. I have seen drum brakes attached to driveshafts (Land Rover, Citroen 2CV, Alfasud, Jaguar XJ6) but they aren't bicycles.
5. Having brutalised the 5 point nut with water pump pliers you can replace it with a conventional nut of that size. Or you can buy the security socket so that you can lose it and the next time you need it you won't have it then either.

 

[battered]

Oh, and my guess is that after about 1 Brazilian years' service the brake friction material has worn off and you have metal against metal, hence the hideous noises. God knows where you get spares for these. Drum brakes normally last well, 50,000 miles on small cars wasn't unheard of back in the day. They were usually done for by hydraulic leaks. On things like light motorbikes where they were cable operated and there was no oil or hydraulic fluid to leak onto them they lasted basically for ever.

 

[palinurus]

I find the pivots can get sticky from time to time which can lead to binding (I find this manifests itself first where there is a bit of binding after applying the brake and then it eases off as the shoes finally retract- the release is a bit retarded by the dry pivot)

It's pretty easy to access the pads (if you have normal wheelnuts 😅)

A little drop of oil carefully placed on the pivot between the shoes is OK- wipe off any excess. If it's sticky pivots that will often fix it.

While you are in there have a look at the pads themselves of course. Usually a bit of binding isn't that noisy so might be more serious.

 

[swee'pea99]

Or you can buy the security socket so that you can lose it and the next time you need it you won't have it then either.

"I know I put it somewhere sensible..."


I did try to shift the nuts using locked-on mole grips, but they are on really tight. I'm minded to leave 'em be for now, since every attempt ends up rounding off the nuts just a bit more, and I'd like to preserve enough flat so I at least retain the option to get the wheel off at some point in the future if I really need to. (I'd just have to access the proper spanner, perhaps at the LBS.) For the moment I think I'll tell dear daughter the slight chaffing/squeaking (because it really isn't that bad) isn't important and can safely be ignored. I'm pretty sure the pads aren't actually too worn, and there's no metal on metal action. It's just a cheap Chinese bike that's a bit ropey...but it'll still get her/friends from A to B, safely if not necessarily silently.

Thanks all.

 

[battered]

If ignoring it is no longer an option, you could try filing flats on the nut. It looks accessible. If not then you can get universal sockets with springloaded pins that claim to unscrew rounded nuts.

 

[tyred]

As mentioned, it will be a really simple drum brake. The lever thing the cable attaches to will have a cam on the other side to spread the brake shoes apart. It's probably just sticking.

I have worked on Sachs bicycle drum brakes from the 1980s and Elswick-Hopper ones from the 1940s and they hold no great surprise or complications and I expect this will be similar if not indentical.

In theory the return spring (s) may have broken or become detached but it's pretty unlikely.

I did once encounter a random and unlikely cause of rubbing sounds from the drum brakes on my 1960s Ford tractor when the brake liner had cracked and split between the rivets and part of the loose brake liner was rubbing on the drum but I expect yours are new enough to be bonded on so that shouldn't happen to it.

A small Stilton type wrench if you have one should unscrew the nuts. Otherwise pop into a friendly garage as they really ought to have something to grip it and it's a two minute job. Then replace with hexagonal nuts.

 

[battered]

Bonded brake parts can fall apart too. Some 5 years ago or so I had a Mondeo that was fine going forwards but in reverse the front brake would give a clunk and start grating. When I took it apart the friction material fell off one pad. Going forwards the disc kept it in place, in reverse it was dropping out of the carrier and jamming. New pads fixed it.

 

[Poacher]

A small Stilton type wrench if you have one should unscrew the nuts. Otherwise pop into a friendly garage as they really ought to have something to grip it and it's a two minute job. Then replace with hexagonal nuts.

Wouldn't use a Stilton - they're made of cheese!

Stilson, maybe.

 

[tyred]

Wouldn't use a Stilton - they're made of cheese!

Stilson, maybe.

Stillson indeed. You have to love autocorrect