Clutch Issue 1.4tdi 75 unusual

Ami

A2OC Donor
This morning at 7 o'clock on the way to work, I suddenly found my clutch pedal flat on the floor, as I was already in fifth gear, decided to carry on & hope for the best, when I got to the T junction where I have to turn right, I was fearing the worth, as I came to a halt, I put my foot under the clutch pedal & lifted it up & said god help me, to my amazment the pedal came up & stayed up & remained normal for the rest of the journey.

The question is what caused it & when is it gone happen again, or actually God rescued me on the busy A24 turning ( in which case Thank God ).:)
Thanks guys,
Ami
 

depronman

A2OC Donor
Unless you are buying a genuine part From Audi I would forget about buying new as most of the aftermarket ones are total crap
I’m 99% sure that I have a very good condition second hand vag one that I would part with for £15 plus delivery
Pm me if interested


Cheers. Paul


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carlston

Active Member
It looks like the OEM part number for the RHD or LHD clutch master cylinder is 8Z1721388A. It appears to be the same OEM part number whatever the engine version. The clutch slave cylinder for example, does appear to vary depending on engine version.

RHD Clutch Master Cylinder

LHD Clutch Master Cylinder

There is a new genuine Audi one on ebay for about £60, and a new Sachs one on ebay for about £40. There are also a couple of secondhand ones on ebay for about £20. Search for them using that OEM part number.

The clutch master cylinder appears to be made of plastic, which may explain why it hasn't lasted as long as the car.
 
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Ami

A2OC Donor
Unless you are buying a genuine part From Audi I would forget about buying new as most of the aftermarket ones are total crap
I’m 99% sure that I have a very good condition second hand vag one that I would part with for £15 plus delivery
Pm me if interested


Cheers. Paul


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Thanks Paul for your kind offer:
Let me find out exactly what it is & get back to you.
Thanks again
Ami
 

Vic

Member
Try to bleed the clutch. It is easy DIY job with no tools (only 11mm wrench and one more person to push the pedal) and can fix the problem but it is unclear for how long.

20210209_104312.jpg
 
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Ami

A2OC Donor
Thanks Vic very much, appreciate your help, I will try this on Saturday & see if I need to change the master cylinder or not. :)
The Picture is perfect
.:)
Thanks again,
Ami
 

Pinkythelabrat

A2OC Donor
I had this happen to me and it was that my floor mat had slipped up against the pedal and this rubber friction had pinned it in place as was stopping it coming back up.

I’ve also had it happen with an accelerator in a different car.

Not sure what I’m doing wrong but could be worth a check if your mat is loose.


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Ami

A2OC Donor
I did check, very strange, my pedal was loose, like nothing holding it & when pushed it with my left foot, it recovered:rolleyes:
I will try bleeding it on Saturday as per Vic picture.
Thank you guys for all the efforts.
Ami
 

Howey

Member
FTE manufacture a large majority of clutch hydraulic parts, no need to go to dealer but buy the best availible from euros ect
 
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depronman

A2OC Donor
What you will find is the slave cylinder is worn, it’s an abs plastic part with a metal piston sliding in the abs lubricated by the break fluid
As the clutch is depressed the cylinder is pushed partly out of the abs housing but is now pushing the clutch plate open this places in turn a side load on the piston. When you release the peddle the side load is enough to jam the piston in the housing due to the housing being worn. If you then apply pressure to the clutch peddle it tries to open the clutch a little further and as you release the peddle (likely quite sharply) the piston does not have time to jam in the housing and therefore retracts in to the housing properly
At this point you are left scratching your head as to why it happened
It may not do it again for a day or a week or a month but it will eventually do it
As the wear increases on the housing there is more opportunity for the piston to jam and the occurrence of it sticking down increases
Once the skin of the abs is worn away the wear rate rapidly increases so it will need fixing
Luckily it’s only the pipe and two bolts to change it and it’s easy to get at being on the top of the gearbox

Cheers. Paul


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Howey

Member
£35.44 for a Valeo unit from carparts4less.co.uk
(some times part numbers have to be found on euros site and then manually searched for on cp4l)
 
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Ami

A2OC Donor
What you will find is the slave cylinder is worn, it’s an abs plastic part with a metal piston sliding in the abs lubricated by the break fluid
As the clutch is depressed the cylinder is pushed partly out of the abs housing but is now pushing the clutch plate open this places in turn a side load on the piston. When you release the peddle the side load is enough to jam the piston in the housing due to the housing being worn. If you then apply pressure to the clutch peddle it tries to open the clutch a little further and as you release the peddle (likely quite sharply) the piston does not have time to jam in the housing and therefore retracts in to the housing properly
At this point you are left scratching your head as to why it happened
It may not do it again for a day or a week or a month but it will eventually do it
As the wear increases on the housing there is more opportunity for the piston to jam and the occurrence of it sticking down increases
Once the skin of the abs is worn away the wear rate rapidly increases so it will need fixing
Luckily it’s only the pipe and two bolts to change it and it’s easy to get at being on the top of the gearbox

Cheers. Paul


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Great description of the issue Paul.
The picture above posted by Vic, for bleeding, is that the master cylinder or slave cylinder.
From what you said, best to replace the slave cylinder first, bleed the system & if the problem comes back, then replace the master cylinder
which you have kindly offered to sell in your earlier tread.
Thank you & everyone for your advice.
Regards,
Ami
 
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