front fork losing air in the cold

[Alvin Liau]

Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when the weather's warmer.
However, when it gets below freezing, the air seems to be leaking fast. For example, I'd pump it up
to about 150psi, and about 5 minutes down the trail, most of the air will be out. When I screw the
pump back on, the gauge will show about 40psi.

I'm going to dig into it this week, but before I do that, any clues on what I should keep my eyes
peeled for?

Thanks. alvin

 

[Huw Pritchard]

On Tue, 21 Jan 2003 12:12:27 +0000, Alvin Liau did issue forth:

> Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when the weather's warmer.
> However, when it gets below freezing, the air seems to be leaking fast. For example, I'd pump it
> up to about 150psi, and about 5 minutes down the trail, most of the air will be out. When I screw
> the pump back on, the gauge will show about 40psi.
>
> I'm going to dig into it this week, but before I do that, any clues on what I should keep my eyes
> peeled for?

My guess would be seals. If you've got a fork of that sort of age that's been used heavily then
stuff is going to wear. Clean the fork down externally, take it apart, see what sort of state the
seals are in and replace them if necessary.

--
Huw Pritchard | Replace bounce with huw | to reply by mail | www.secretworldgovernment.org

 

[Kinkycowboy]

On Tue, 21 Jan 2003 12:12:27 -0500, "Alvin Liau" <[email protected]> wrote:

>Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when the weather's warmer.
>However, when it gets below freezing, the air seems to be leaking fast. For example, I'd pump it up
>to about 150psi, and about 5 minutes down the trail, most of the air will be out. When I screw the
>pump back on, the gauge will show about 40psi.
>
>I'm going to dig into it this week, but before I do that, any clues on what I should keep my eyes
>peeled for?
>
>Thanks. alvin
>
Same problem caused the Shuttle Challenger crash; rubber seals losing their flexibility at sub zero
temperatures. Replacing the seals might help if they're already old and worn, as new ones will have
less work to do to close the gaps.

Kinky Cowboy

*Your milage may vary Batteries not included May contain traces of nuts.

 

[Alvin Liau]

"Alvin Liau" <[email protected]> wrote in message news:[email protected]...
> Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when
the
> weather's warmer. However, when it gets below freezing, the air seems to
be
> leaking fast. For example, I'd pump it up to about 150psi, and about 5 minutes down the trail,
> most of the air will be out. When I screw the
pump
> back on, the gauge will show about 40psi.
>
> I'm going to dig into it this week, but before I do that, any clues on
what
> I should keep my eyes peeled for?
>
> Thanks. alvin
>
>

Just to close the loop in case anyone does a search in the future, we took a quick look at the fork,
and couldn't find anything wrong. Replaced the screw-cap-assembly (where you pump the air in) with
one from another fork, and still leaking.

Since it was 11F that night and the garage wasn't much warmer, we punted and took it to the LBS. The
mechanic took the fork apart, cleaned it, put it back together, and voila, no more leak. Good deal!

Cheers, Alvin Liau

 

[Tj Poseno]

"Alvin Liau" <[email protected]> wrote in message
news:<[email protected]>...
> Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when the weather's warmer.
> However, when it gets below freezing, the air seems to be leaking fast. For example, I'd pump it
> up to about 150psi, and about 5 minutes down the trail, most of the air will be out. When I screw
> the pump back on, the gauge will show about 40psi.
>
> I'm going to dig into it this week, but before I do that, any clues on what I should keep my eyes
> peeled for?
>
> Thanks. alvin

My guess is that the metal is expanding in the cold and the gaskets arent sealing right when it gets
that cold and the air is leaking.

 

[Spot T. Rex]

Metal Contracts in the cold and expands with heat.

"Alvin Liau" <[email protected]> wrote in message news:[email protected]...
> "Alvin Liau" <[email protected]> wrote in message
> news:[email protected]...
> > Hi! I have a 2001 Manitou Mars that's acting up. It performs fine when
> the
> > weather's warmer. However, when it gets below freezing, the air seems
to
> be
> > leaking fast. For example, I'd pump it up to about 150psi, and about 5 minutes down the trail,
> > most of the air will be out. When I screw the
> pump
> > back on, the gauge will show about 40psi.
> >
> > I'm going to dig into it this week, but before I do that, any clues on
> what
> > I should keep my eyes peeled for?
> >
> > Thanks. alvin
> >
> >
>
> Just to close the loop in case anyone does a search in the future, we took
a
> quick look at the fork, and couldn't find anything wrong. Replaced the screw-cap-assembly (where
> you pump the air in) with one from another
fork,
> and still leaking.
>
> Since it was 11F that night and the garage wasn't much warmer, we punted
and
> took it to the LBS. The mechanic took the fork apart, cleaned it, put it back together, and voila,
> no more leak. Good deal!
>
> Cheers, Alvin Liau

 

[Matt O'Toole]

"TJ Poseno" <[email protected]> wrote in message
news:[email protected]...

> "Alvin Liau" <[email protected]> wrote in message
news:<[email protected]>...

> > Hi! I have a 2001 Manitou Mars that's acting up. It
performs fine when the
> > weather's warmer. However, when it gets below freezing,
the air seems to be
> > leaking fast. For example, I'd pump it up to about
150psi, and about 5
> > minutes down the trail, most of the air will be out.
When I screw the pump
> > back on, the gauge will show about 40psi.
> >
> > I'm going to dig into it this week, but before I do
that, any clues on what
> > I should keep my eyes peeled for?

> My guess is that the metal is expanding in the cold and
the gaskets
> arent sealing right when it gets that cold and the air is
leaking.

All the materials contract in the cold, including the gaskets. The gaskets also harden, which may
affect their sealing too.

Matt O.

 

[Spider]

"Matt O'Toole" <[email protected]> wrote in message
news:<[email protected]>...
> "TJ Poseno" <[email protected]> wrote in message
> news:[email protected]...
>
> > "Alvin Liau" <[email protected]> wrote in message
> news:<[email protected]>...
>
> > > Hi! I have a 2001 Manitou Mars that's acting up. It
> performs fine when the
> > > weather's warmer. However, when it gets below freezing,
> the air seems to be
> > > leaking fast. For example, I'd pump it up to about
> 150psi, and about 5
> > > minutes down the trail, most of the air will be out.
> When I screw the pump
> > > back on, the gauge will show about 40psi.
> > >
> > > I'm going to dig into it this week, but before I do
> that, any clues on what
> > > I should keep my eyes peeled for?
>
> > My guess is that the metal is expanding in the cold and
> the gaskets
> > arent sealing right when it gets that cold and the air is
> leaking.
>
> All the materials contract in the cold, including the gaskets. The gaskets also harden, which may
> affect their sealing too.
>
> Matt O.

Not so for natural rubber. It's an odd material.

Spider