Curing a sticky brake cable on a Brompton?



G

Glenn Ammons

Guest
I have a Brompton that I ride to work year-round; I'm in New York
state, so that involves rain and snow. Also, because the bike folds,
the front cable's route is peculiar: the cable leaves the brake lever,
drops below the caliper and then curves back up to the caliper's
housing stop. That is, the route resembles a capital J and the cable
attaches to the caliper from the bottom.

I've had the bike two years and, each year, the cable has started
sticking in the housing and I've had to replace both cable and
housing. This year, it got so bad that I couldn't even pull the cable
through the housing by hand. I'm not sure why it's sticking but I
suspect water damage.

I use plastic-lined housing and stainless cables. I don't oil the
cable. The cable at the caliper is covered by a rubber boot that came
with the bike.

What can I do to keep the cable running freely? I'm getting tired of
replacing the cable and housing every year.

Thanks.
--glenn
 
On Feb 27, 12:14 am, "Glenn Ammons" <[email protected]> wrote:
> I have a Brompton that I ride to work year-round; I'm in New York
> state, so that involves rain and snow. Also, because the bike folds,
> the front cable's route is peculiar: the cable leaves the brake lever,
> drops below the caliper and then curves back up to the caliper's
> housing stop. That is, the route resembles a capital J and the cable
> attaches to the caliper from the bottom.
>
> I've had the bike two years and, each year, the cable has started
> sticking in the housing and I've had to replace both cable and
> housing. This year, it got so bad that I couldn't even pull the cable
> through the housing by hand. I'm not sure why it's sticking but I
> suspect water damage.
>
> I use plastic-lined housing and stainless cables. I don't oil the
> cable. The cable at the caliper is covered by a rubber boot that came
> with the bike.
>
> What can I do to keep the cable running freely? I'm getting tired of
> replacing the cable and housing every year.
>
> Thanks.
> --glenn


It certainly sounds like it's filling with water and corroding, or
just filling with crud - stainless steel or no.

Once I had an ancient mountain bike whose front derailleur cable ran
through a few inches of "J" shaped housing near the bottom bracket.
It, too, eventually got sticky with crud.

I was able to greatly improve - but not completely cure- the problem
by putting a dab of "Silicone Seal" (room-temperature curing silicone
rubber caulk) on each end of the housing. I'm not sure, but I may
have greased the cable before applying, to prevent the caulk from
sticking to the cable. Don't operate the cable until the rubber is
hardened.

In your case, you've got a boot at the bottom end. The silicone
rubber would merely be a supplement there. But you may have an
exposed, unsealed opening at the brake lever end. Sealing that end
may help more.

It may be worth a try.

- Frank Krygowski
 
D

Donald Gillies

Guest
Its a good idea to grease the cables, even if using lined housing.
A good coat of grease goes a long way towards preventing water from
entering cables at the ends. The grease can at the very least keep
the braided cable from wicking up the water.

Also, have you considered maintaining your cable housings ?? Like,
every six months, disconnect the cables, take it out, wipe it down,
regrease & reinstall ?? That way your cable would probably not wear
out ... I used to do it in the 70's, my brakes worked a lot better
every time I did it ...

- Don Gillies
San Diego, CA
 
N

Nigel Cliffe

Guest
Glenn Ammons wrote:
> I have a Brompton that I ride to work year-round; I'm in New York
> state, so that involves rain and snow. Also, because the bike folds,
> the front cable's route is peculiar: the cable leaves the brake lever,
> drops below the caliper and then curves back up to the caliper's
> housing stop. That is, the route resembles a capital J and the cable
> attaches to the caliper from the bottom.



> What can I do to keep the cable running freely? I'm getting tired of
> replacing the cable and housing every year.


Suggest you try the Yahoo email group which deals with Bromptons. I'm
fairly sure that this problem would have been discussed.


regards,

- Nigel


--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
 
A

A Muzi

Guest
Glenn Ammons wrote:
> I have a Brompton that I ride to work year-round; I'm in New York
> state, so that involves rain and snow. Also, because the bike folds,
> the front cable's route is peculiar: the cable leaves the brake lever,
> drops below the caliper and then curves back up to the caliper's
> housing stop. That is, the route resembles a capital J and the cable
> attaches to the caliper from the bottom.
>
> I've had the bike two years and, each year, the cable has started
> sticking in the housing and I've had to replace both cable and
> housing. This year, it got so bad that I couldn't even pull the cable
> through the housing by hand. I'm not sure why it's sticking but I
> suspect water damage.
>
> I use plastic-lined housing and stainless cables. I don't oil the
> cable. The cable at the caliper is covered by a rubber boot that came
> with the bike.
>
> What can I do to keep the cable running freely? I'm getting tired of
> replacing the cable and housing every year.


Water may collect in your upturned loop.

If indeed it is rusted, be sure your new cable (about $4) includes
teflon lined casing. A $4 cable and a $50 Campagnolo cable set will
have no difference in this regard. Few casings are unlined now but they
are out there, avoid them.

We wipe wires with oil on installation. Other good mechanics do not and
report success. The casing may be your problem but oil won't hurt.

All that to one side, my intuition says you more likely have a
crimped/kinked casing somewhere. Like broken clavicles which always heal
lumpy, they do not survive a bash. The casing ends oval in cross section
where it was folded or caught. Replace any damaged casing so the wire
runs free and keep casing lengths ample for smooth graceful curves.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
L

Leo Lichtman

Guest
If you cleaned it every day, it would never stick. If you cleaned it every
week it would never stick. Or every month, probably. So, your task is to
figure out how long you can let it go and still not have it stick.
 
G

Glenn Ammons

Guest
Thanks everyone for the advice. I just took a closer look at the
housing and managed to extract the cable. The housing (which is
Teflon-lined) has no visible kinks but the cable is covered with crud.
At the bottom of the J, the cable is black (with corrosion, I suppose)
and frayed. I guess the fraying was what really jammed things up.

I'll try the silicone idea when I put in the new cable+housing but
still expect to be doing this job again next year. Also, I found some
modified Bromptons on the web that have V-brakes and straight cable
runs which, according to the folks on BromptonTalk, still fold.
However, there are no V-brake bosses on my bike so that's not an
option for me.

Thanks again.
--glenn
Albany, NY, USA