90 CLUTCH(ing at straws).. Problem.

Hi, any ideas on this problem with a 90 Tdi clutch?

I replaced the leaking clutch master cylinder two weeks ago with a new
girling one from Craddocks. All reassembled, bled and working fine by end
of play that day. Has worked fine since then, until this morning...

Got in the L/R first thing and the clutch went straight to the floor, no
resistance at all... No pool of brake fluid on the floor, no visible leaks
from the system. Taking the lid off the reservoir showed no fluid but
filling up and bleeding again did not cure the problem, although there are
no air bubbles coming out in the fluid from the nipple now. Clutch goes to
the floor and will not return.

Completely puzzled. What can have failed between reversing into the drive
last night and this morning? I'm going to take the lid off the pedal box
and see if that reveals anything but if it doesn't where do I go from there?
If the slave cylinder was leaking where would that go - into the bell
housing??

Any suggestions / help much appreciated!

Thanks,

M

"McBad" <[email protected]> wrote in message
news:[email protected]...
> Hi, any ideas on this problem with a 90 Tdi clutch?
>
> I replaced the leaking clutch master cylinder two weeks ago with a new
> girling one from Craddocks.

Removing the lid of the cylinder box shows no problems with the new master
cylinder. Will try removing and replacing the slave cylinder and if that
doesn't work I expect I'm into mega-£ and taking out the engine or the
gearbox? (

>>Hi, any ideas on this problem with a 90 Tdi clutch?
>>
>>I replaced the leaking clutch master cylinder two weeks ago with a new
>>girling one from Craddocks.
>
> Removing the lid of the cylinder box shows no problems with the new master
> cylinder. Will try removing and replacing the slave cylinder and if that
> doesn't work I expect I'm into mega-£ and taking out the engine or the
> gearbox?

If you are losing fluid do not worry about removing engine or gearbox.

Whatever your fluid loss problems, pedal should always return - pedal
return spring missing? If the spring was missing when you bled the
system it is probable that it was never properly bled.

"Mr.Nice." <[email protected]> wrote in message
news:[email protected]...
> Twas Sat, 16 Oct 2004 12:55:04 +0100 when "McBad"
> <[email protected]> put finger to keyboard producing:
>
>>
>>"McBad" <[email protected]> wrote in message
>>news:[email protected]...
>>> Hi, any ideas on this problem with a 90 Tdi clutch?
>>>
>>> I replaced the leaking clutch master cylinder two weeks ago with a new
>>> girling one from Craddocks.
>>
>>Removing the lid of the cylinder box shows no problems with the new master
>>cylinder. Will try removing and replacing the slave cylinder and if that
>>doesn't work I expect I'm into mega-£ and taking out the engine or the
>>gearbox? (
>>
>
>
> I once had the rod thingy that conects between the slave and the
> clutch thing break away from the thingy, the symptom was the clutch
> pedal locked hard in the up position so a mechanical failure beyond
> the slave seems to be ruled out in your case.
>
> will the pedal still move up and down?
> if so then try the bleed nipple on the slave, if nothing there
> disconnect the pipe on the master and see if it pumps fluid from
> there.
>
> if the pedal is doing something else then disconnect the pipe from the
> master and see if the pedal will pump up and down, this will point you
> towards the slave as the problem (a doddle to replace, be sure the
> exhaust is cool though). if the pedal isn't playing with the pipe off
> the master then I suspect the master has failed.
>
> I've heard alot of tales of sudden failures of replacement masters,
> mine (replaced a month or 2 ago is fine) most people talk of metal
> swarf within the master shredding the seals.
>
> I hope this all helps a little.
>
>
> Regards.
> Mark.(AKA, Mr.Nice.)

There should be a quite strong return spring in the clutch master cylinder,
strong enough to return the clutch pedal anyway, I'de check there first.

Peter.

"Mr.Nice." <[email protected]> wrote in message
news:[email protected]...
> Twas Sat, 16 Oct 2004 14:35:20 +0100 when "Peter Seddon"
> <[email protected]> put finger to keyboard producing:
>
>>
>>"Mr.Nice." <[email protected]> wrote in message
>>news:[email protected]...
>>> Twas Sat, 16 Oct 2004 12:55:04 +0100 when "McBad"
>>> <[email protected]> put finger to keyboard producing:
>>>
>>>>
>>>>"McBad" <[email protected]> wrote in message
>>>>news:[email protected]...
>>>>> Hi, any ideas on this problem with a 90 Tdi clutch?
>>>>>
>>>>> I replaced the leaking clutch master cylinder two weeks ago with a new
>>>>> girling one from Craddocks.
>>>>
>>>>Removing the lid of the cylinder box shows no problems with the new
>>>>master
>>>>cylinder. Will try removing and replacing the slave cylinder and if
>>>>that
>>>>doesn't work I expect I'm into mega-£ and taking out the engine or the
>>>>gearbox? (
>>>>
>>>
>>>
>>> I once had the rod thingy that conects between the slave and the
>>> clutch thing break away from the thingy, the symptom was the clutch
>>> pedal locked hard in the up position so a mechanical failure beyond
>>> the slave seems to be ruled out in your case.
>>>
>>> will the pedal still move up and down?
>>> if so then try the bleed nipple on the slave, if nothing there
>>> disconnect the pipe on the master and see if it pumps fluid from
>>> there.
>>>
>>> if the pedal is doing something else then disconnect the pipe from the
>>> master and see if the pedal will pump up and down, this will point you
>>> towards the slave as the problem (a doddle to replace, be sure the
>>> exhaust is cool though). if the pedal isn't playing with the pipe off
>>> the master then I suspect the master has failed.
>>>
>>> I've heard alot of tales of sudden failures of replacement masters,
>>> mine (replaced a month or 2 ago is fine) most people talk of metal
>>> swarf within the master shredding the seals.
>>>
>>> I hope this all helps a little.
>>>
>>>
>>> Regards.
>>> Mark.(AKA, Mr.Nice.)
>>
>>There should be a quite strong return spring in the clutch master
>>cylinder,
>>strong enough to return the clutch pedal anyway, I'de check there first.
>>
>>Peter.
>>
>
> that is a damn good point there.
>
>
> Regards.
> Mark.(AKA, Mr.Nice.)
> --

Just had another look at the manual for a disco and it shows a return spring
on the pedal as well so there should be no reason why the pedal will n ot
return. Uless the master cylinder is also goosed.

Peter.

On or around Sat, 16 Oct 2004 15:22:10 +0100, "Peter Seddon"
<[email protected]> enlightened us thusly:

>
>"Mr.Nice." <[email protected]> wrote in message
>news:[email protected]...
>> Twas Sat, 16 Oct 2004 14:35:20 +0100 when "Peter Seddon"
>> <[email protected]> put finger to keyboard producing:
>>
>>>
>>>"Mr.Nice." <[email protected]> wrote in message
>>>news:[email protected]...
>>>> Twas Sat, 16 Oct 2004 12:55:04 +0100 when "McBad"
>>>> <[email protected]> put finger to keyboard producing:
>>>>
>>>>>
>>>>>"McBad" <[email protected]> wrote in message
>>>>>news:[email protected]...
>>>>>> Hi, any ideas on this problem with a 90 Tdi clutch?
>>>>>>
>>>>>> I replaced the leaking clutch master cylinder two weeks ago with a new
>>>>>> girling one from Craddocks.
>>>>>
>>>>>Removing the lid of the cylinder box shows no problems with the new
>>>>>master
>>>>>cylinder. Will try removing and replacing the slave cylinder and if
>>>>>that
>>>>>doesn't work I expect I'm into mega-£ and taking out the engine or the
>>>>>gearbox? (
>>>>>
>>>>
>>>>
>>>> I once had the rod thingy that conects between the slave and the
>>>> clutch thing break away from the thingy, the symptom was the clutch
>>>> pedal locked hard in the up position so a mechanical failure beyond
>>>> the slave seems to be ruled out in your case.
>>>>
>>>> will the pedal still move up and down?
>>>> if so then try the bleed nipple on the slave, if nothing there
>>>> disconnect the pipe on the master and see if it pumps fluid from
>>>> there.
>>>>
>>>> if the pedal is doing something else then disconnect the pipe from the
>>>> master and see if the pedal will pump up and down, this will point you
>>>> towards the slave as the problem (a doddle to replace, be sure the
>>>> exhaust is cool though). if the pedal isn't playing with the pipe off
>>>> the master then I suspect the master has failed.
>>>>
>>>> I've heard alot of tales of sudden failures of replacement masters,
>>>> mine (replaced a month or 2 ago is fine) most people talk of metal
>>>> swarf within the master shredding the seals.
>>>>
>>>> I hope this all helps a little.
>>>>
>>>>
>>>> Regards.
>>>> Mark.(AKA, Mr.Nice.)
>>>
>>>There should be a quite strong return spring in the clutch master
>>>cylinder,
>>>strong enough to return the clutch pedal anyway, I'de check there first.
>>>
>>>Peter.
>>>
>>
>> that is a damn good point there.
>>
>>
>> Regards.
>> Mark.(AKA, Mr.Nice.)
>> --
>
>Just had another look at the manual for a disco and it shows a return spring
>on the pedal as well so there should be no reason why the pedal will n ot
>return. Uless the master cylinder is also goosed.
>
>Peter.
>

If the pedal doesn't return fully and thus the master cylinder doesn't
return fully home, it'll not let more fluid in from the reservoir, either -
it only does that bit at the very end of the travel at the "top" end. This
can also occur if you adjust the pushrod too tight.

On or around Sat, 16 Oct 2004 19:22:12 +0100, Mr.Nice.
<[email protected]> enlightened us thusly:

>Twas Sat, 16 Oct 2004 15:49:38 +0100 when Austin Shackles
><[email protected]> put finger to keyboard producing:
>

>>If the pedal doesn't return fully and thus the master cylinder doesn't
>>return fully home, it'll not let more fluid in from the reservoir, either -
>>it only does that bit at the very end of the travel at the "top" end. This
>>can also occur if you adjust the pushrod too tight.
>>
>
>out of interest, what happens if the pushrod is adjusted too loose?
>

not enough movement in the pedal. The pushrod, as I expect you know, or
maybe not, it not positively attached to the piston, it just literally
pushes it. it's held in a trunnion in the top end of the pedal by 2 nuts.
If too tight (i.e. pushrod effectively too long) then the pedal comes up
against a stop somewhere and maintains pressure on the piston, keeping it
from returning fully out. if the rod is too short, then the pedal will be
lower in the car and you may not have enough travel properly to operate the
clutch before it hits the floor. Also your clutch bite point will be lower.

Thank you to everyone who has replied. I'm going out to have another look
at it now - didn't do anything further yesterday as I couldn't get a spare
slave in the afternoon.

I'll start with the spring which is on the pedal somewhere; it's a sort of
rat-trap type spring around the pedal rather than a long spring between the
pedal and one of the six pedal box mounting bolts. Can't really see what
this spring does; doesn't the pressure from the clutch itself return via the
slave and hydraulic fluid to push the pedal back up? At the moment the
pedal seems to be stable in either the bottom position (ie it will sit on
the floor) or it can be lifted by hand and it will stay stable in the up
position, it just won't return on it's on and there is no resistance under
your foot when you press down. However, the spring has worked successfully
for two weeks and even if it had broken why am I not feeling any resistance
from the clutch via pedal when I put my foot on it?

I'm pretty confident that the pedal and the push rod are properly adjusted
as to 114mm from the floor in the up position and 1.5mm of play in the push
rod. As the pedal is lifted with the cap off the fluid reservoir you can
see a 'flicker' in the brake fluid level as the pedal reaches the top of its
travel, suggesting the fluid is available to the system from the reservoir.

I'll go and have a poke round now and report back, I'll be interested to see
if the fluid level in the reservoir has dropped over night... Really
annoying watching all the other land rovers passing the bottom of the street
on the way to the RTV I was meant to be at today!

Cheers,

M.

Reservoir fluid level had dropped about an inch over-night. Back of the
pedal was damp but can't tell if this is a leak or if I spilled some fluid
yesterday when I was filling the reservoir, angle of the bonnet makes it
very difficult to pour accurately.

The spring on the pedal only seems to come into play on the last third of
the movement on the up stroke; if you lift the pedal from the floor when you
get two thirds of the way up to normal height the spring takes over and
forces it the last third. I guess this is to ensure that the pedal comes up
far enough for the reservoir on the master cylinder to open to the master
cylinder piston bore.

I took the pipe to the slave off the master cylinder at the 13mm nut. As I
removed the pipe air bubbles appeared at the joint from the master cylinder
and the fluid level in the reservoir dropped. Depressing the clutch pedal
then shot a very healthy dose of brake fluid from the open joint, suggesting
the master cylinder is ok. But how is air getting into the master cylinder?
It was bled to death yesterday morning???

FIXED IT (but for how long?)

Bled the system again and eventually got a hard and fully returning pedal.
Certainly confirms that it is not the clutch release bearing, lever or
clutch return spring that is at fault. Still very puzzled as to how an air
lock got into the master cylinder overnight and will be keen to find out if
pressure is maintained until tomorrow morning. I wonder if there is a slow
air leak into the master cylinder past the piston...

Cheers,

M

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

> But how is air getting into the master cylinder?
> It was bled to death yesterday morning???
>
>

Suggest you check the joints and connections of the pipe.

I had an intermittent problem with one of my Peugeot 504's. It
was driving me nuts! The clutch would fail at the most
inconvenient time at a location miles from anywhere.

Turned out to be a connection. Sucking air. I fitted an "O" ring
inside the connector and the problem was solved. Then I sold the
truck (stupid me!) and it has run perfectly ever since!

Derry

i take it you lost the fluid out of the master cylinder ? , but it isnt
leaking out of any pipes and you dont see any damp patches anywhere .

if this is so then its the slave cylinder thats the problem and youll find that
the fluid has leaked out of the slave cyl into the bellhousing .

the slave cyl only has one piston ring in it and these do fail after a while.

it was more prevalent on older 90s which had the slave cylinder right next to
exhaust downpipe and would get fairly hot in summer .

youll notice that the r380 box doesnt have slave cyl close to exhaust pipe .

on every range rover classic and landy 90 i have had, the slave cylinder has
failed at least twice in a handfull of years .

its cheap to buy a slave cyl repair kit and fix youreself if you have garage
eqpt as below ..

to do it comprehensively you need 1" a "delapeena" flexhone to hone the bore
of the slave cyl , with an electric drill moving it in and out rapidly so as to
get 45degree" lapping marks ".
this is to "clean " the bore of slave cyl and not to make it any bigger .

if you cant hone it out then you can just fit a repair kit of seals if youre
on a tight budget , but for price of a new slave cyl most people would opt for
a complete slave cyl unit .

when the slave cyls go they tend to leak only a little bit over a period of
time and you dont notice it until all the fluid has gone from master cyl and
down the hyd line .

if you lost all fluid and cant get fluid to pump out of master cyl the easiest
way to bleed the clutch cyls is by back bleeding from the slave cyl upwards .

fill master cyl first with brake fluid .

leave tube nut slack on hyd pipe off the master cyl , use a new "oil can "
filled with brake fluid with rubber hose attatched to it and to bleed nipple
on slave cyl .
pump oil can and fill slave cyl/pipe until fluid comes out of pipe at
slackened fitting on master cylinder , then tighten nut .

you should now be able to pump the clutch pedal and bleed out half pint or so
of fluid and this should get rid of any air in system and job will be done .