300tdi soft clutch - update

Set off to town this morning and the clutch pedal went to the floor when I
changed gear at a T junction. I pulled the pedal up again with my toe and
it worked fine for a few more gear changes, then down to the floor again.
Stamping made no difference but lifting with the toe did and I was able to
change gears again.

No clutch fluid leaking out, inside or outside the vehicle, that I can see.
Clutch pedal return spring is fine.

Spoke to a few local gurus and the consensus seems to be clutch cylinders
but no decision as to which one, so I have ordered both on a sale or return
basis on the assumption that if one has gone the other will be sure to
follow.

At least it didn't happen at Dromochter!<g>

Derry

> Set off to town this morning and the clutch pedal went to the floor when I
> changed gear at a T junction. I pulled the pedal up again with my toe and
> it worked fine for a few more gear changes, then down to the floor again.
> Stamping made no difference but lifting with the toe did and I was able to
> change gears again.
>
> No clutch fluid leaking out, inside or outside the vehicle, that I can
> see.
> Clutch pedal return spring is fine.
>
> Spoke to a few local gurus and the consensus seems to be clutch cylinders
> but no decision as to which one,
>
Its the master cylinder.
If fluid leaks past the seals in the master, it goes back into the
reservoir.
If fluid leaks past the seals in the slave, it leaks out.
as you have no visible leak, it must be the master that has failed.

Having said that, it is wise to change both, as they have both done exactly
the same amount of work, and if one has failed, the other wont be far behind
it.

"SimonJ" <[email protected]> wrote in
news:[email protected]:

>> Set off to town this morning and the clutch pedal went to the floor
>> when I changed gear at a T junction. I pulled the pedal up again with
>> my toe and it worked fine for a few more gear changes, then down to
>> the floor again. Stamping made no difference but lifting with the toe
>> did and I was able to change gears again.
>>
>> No clutch fluid leaking out, inside or outside the vehicle, that I
>> can see.
>> Clutch pedal return spring is fine.
>>
>> Spoke to a few local gurus and the consensus seems to be clutch
>> cylinders but no decision as to which one,
>>
> Its the master cylinder.
> If fluid leaks past the seals in the master, it goes back into the
> reservoir.
> If fluid leaks past the seals in the slave, it leaks out.
> as you have no visible leak, it must be the master that has failed.
>
> Having said that, it is wise to change both, as they have both done
> exactly the same amount of work, and if one has failed, the other wont
> be far behind it.
>
>
>

I was underneath today and there is weeping from the drain plug hole in the
bell housing. Not much but enough.

Thanks everyone. I removed the master cylinder today and the new parts
(both cylinders) arrive tomorrow.

Derry

Derry Argue wrote:
> Set off to town this morning and the clutch pedal went to the floor
> when I changed gear at a T junction. I pulled the pedal up again with
> my toe and it worked fine for a few more gear changes, then down to
> the floor again. Stamping made no difference but lifting with the toe
> did and I was able to change gears again.
>
> No clutch fluid leaking out, inside or outside the vehicle, that I
> can see. Clutch pedal return spring is fine.
>
> Spoke to a few local gurus and the consensus seems to be clutch
> cylinders but no decision as to which one, so I have ordered both on
> a sale or return basis on the assumption that if one has gone the
> other will be sure to follow.
>
> At least it didn't happen at Dromochter!<g>
>
> Derry

You need to stamp the damned thing while it works! The sudden and higher
than usual pressure expands the seals just enough extra to 'repair' it for a
fair period extra. Had this tip from a local engineer who said it worked
nine times out of ten when I actually went in to change cylinders. I am a
good customer so he had no illusion of lost profit ;-)
Worked for me and gave another two years of hard use before seals actually
started to leak externally.

Huw

Derry Argue wrote:
> "SimonJ" <[email protected]> wrote in
> news:[email protected]:
>
>>> Set off to town this morning and the clutch pedal went to the floor
>>> when I changed gear at a T junction. I pulled the pedal up again
>>> with my toe and it worked fine for a few more gear changes, then
>>> down to the floor again. Stamping made no difference but lifting
>>> with the toe did and I was able to change gears again.
>>>
>>> No clutch fluid leaking out, inside or outside the vehicle, that I
>>> can see.
>>> Clutch pedal return spring is fine.
>>>
>>> Spoke to a few local gurus and the consensus seems to be clutch
>>> cylinders but no decision as to which one,
>>>
>> Its the master cylinder.
>> If fluid leaks past the seals in the master, it goes back into the
>> reservoir.
>> If fluid leaks past the seals in the slave, it leaks out.
>> as you have no visible leak, it must be the master that has failed.
>>
>> Having said that, it is wise to change both, as they have both done
>> exactly the same amount of work, and if one has failed, the other
>> wont be far behind it.
>>
>>
>>
>
> I was underneath today and there is weeping from the drain plug hole
> in the bell housing. Not much but enough.
>
> Thanks everyone. I removed the master cylinder today and the new parts
> (both cylinders) arrive tomorrow.
>
> Derry

Was it weeping brake fluid? In which case you are right to change the
cylinder but I can't see why you would change both. You Scottish farmers
must be made of money LOL

Huw

On or around 16 Jan 2006 21:38:55 GMT, Derry Argue <[email protected]>
enlightened us thusly:

>> Its the master cylinder.
>> If fluid leaks past the seals in the master, it goes back into the
>> reservoir.
>> If fluid leaks past the seals in the slave, it leaks out.
>> as you have no visible leak, it must be the master that has failed.

Also, you have classic master cylinder not-returning symptoms - lifting the
clutch pedal with yer toe helps it return. If the master cylinder doesn't
return "home" it never gets any more fluid from the reservoir. The master
cylinder return is by means of a spring inside it, so anything interfering
with the movement of the piston stops it.
>
>I was underneath today and there is weeping from the drain plug hole in the
>bell housing. Not much but enough.
>
>Thanks everyone. I removed the master cylinder today and the new parts
>(both cylinders) arrive tomorrow.

when you refit the master, make sure the pushrod is adjusted right. You
need small amount of play such that when the pedal is fully up (it should
have springs inside the cab lifting it) there's no pressure on the MC
pushrod. This ensures the cylinder piston gets all the way back to the home
position.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"There are three sorts of people in the world - those who can count,
and those who can't" (Anon)

Austin Shackles <[email protected]> wrote in
news:[email protected]:

> when you refit the master, make sure the pushrod is adjusted right.
> You need small amount of play such that when the pedal is fully up (it
> should have springs inside the cab lifting it) there's no pressure on
> the MC pushrod. This ensures the cylinder piston gets all the way
> back to the home position.

Been there, done that! Had that problem years ago with a Renault 5 van. Set
off from 40 miles north of Inverness for sheep sales on Anglesey, North
Wales. The clutch stopped working at Inverness. I was not amused,
especially as the job had been done by a local garage to make sure it was
"done properly" and I had to hire a car to get me down there in time for
the sale next day. In all adjustments, I now always measure what has been
taken out and make sure the replacement corresponds.

I've done a Google and see that bleeding the system from the bottom is
recommended as it was for my old 504's. The trick of using a pipe from a
brake bleed nipple is pure genius but as I am single handed I'll probably
go with the oil can method through the slave cylinder.

I think the logic about replacing both cylinders is that (a) the seals in
both cylinders are the same age so presumably in a similar state of
decrepidation, and (b) the fragments of rubber etc from the worst cylinder
will hasten deterioration in the second.

From posts here, it does seem that both cylinders are either out or on the
way anyhow. (Non-return of clutch pedal = master cylinder failure, weeping
from drain plug = slave cylinder failure). There is logic in my madness
<vbg> but thanks for the warnings.

Derry

How's the replacing going Derry?

Regards

William MacLeod

"[email protected]" <[email protected]> wrote in
news:[email protected]:

> How's the replacing going Derry?
>
> Regards
>
> William MacLeod
>
>

Finito!

Seems OK. The test will be my regular trip to Bridge of Allan in a day or
two - 380 miles!

Thanks for all your help.

Derry

Derry Argue wrote:

> Finito!

Excellent. I can stop looking for green 90s with failed clutches at
the side of the road ;-)

Regards

William MacLeod

"[email protected]" <[email protected]> wrote in
news:[email protected]:

> Derry Argue wrote:
>
>> Finito!
>
> Excellent. I can stop looking for green 90s with failed clutches at
> the side of the road ;-)
>

Just be careful you don't run down the poor old bald fat bloke in the
middle of the road trying to flag you down! Everything is working fine at
the moment and that is always a bad sign...

Derry