Clutch master/slave cylinder issues (solved)

Rig

Veteran Member
Joined
Apr 14, 2010
Location
New Mexico
TDI
1998 Jetta TDI, 210k miles
Currently I cannot shift gears on my manual mk3. Clutch pedal falls all the way to the floor without resistance and won't return. Clutch will not disengage so I can't switch gears unless the engine is off.

This now the third time I've been in this scenario with this car in the last 5 years. What do you think might be causing the failure? I usually notice the clutch not fully returning a few days prior to it completely failing, which it did again this time.

Previously the issue was fixed by replacing the clutch master and slave cylinders. It's a decent amount of work though, and I don't like throwing money at parts, not to mention the inconvenience of not being able to shift beyond 1st gear without turning the engine off.
 

Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
Firstly - any leaks? Is there sufficient fluid in the reservoir?

If no/yes to the above, then the master has failed. If there are leaks or the fluid is low - find and fix the leak (slave most common).
 

JETaah

Vendor , w/Business number
Joined
Jan 18, 2001
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mi 48836
TDI
96 B4V, 1999.5 jettaIV,2005 BEW Beetle
What level is the brake fluid in the reservoir?
 

Rig

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Apr 14, 2010
Location
New Mexico
TDI
1998 Jetta TDI, 210k miles
reservoir is completely full. It's actually past the max line and appears to be leaking fluid everywhere...
 

Rig

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Apr 14, 2010
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New Mexico
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1998 Jetta TDI, 210k miles
I should mention it's probably been over 5 years since I've changed brake fluid >.>
 

Rig

Veteran Member
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New Mexico
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1998 Jetta TDI, 210k miles
Well I did a search and found this old thread. https://forums.tdiclub.com/index.php?threads/hydraulic-clutch-problem.523243/#post-5746435

Most likely I have bad brake fluid after so many years of not flushing it. @Mongler98 says to change it every year!

Guessing I will have to replace the master again. Some say it can be rebuilt but not sure if that's worth my time.

Wondering if I should take it to a mechanic for a flush or buy the tools to do it myself... seems like a hassle and likely the mechanic could do it more thoroughly.
 

Abacus

That helpful B4 guy
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Nov 10, 2007
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Relocated from Maine to Dewey, AZ
TDI
Only the B4V left
Yeah, forget the flushing every year thing, especially here in the dry desert. That’s just not needed at all.

It’s either the master or the slave, as before. I’ve had poor luck with non-OEM parts, or at least non-premium parts, which is why I recommend ID Parts or Cascade.

A Motive Power Bleeder for these cars is (was) around $50 and money very well spent. It attaches to the reservoir and pressurizes the system, making bleeding effortless.
 

burpod

teh stallionz!!1
Joined
Nov 27, 2004
Location
cape cod, ma
TDI
82 rabbit vnt ahu, 98 jetta vnt ahu, 05 parts car, 88 scirocco.. :/
yeah, 3yrs schedule for bleeding is almost certainly fine for where you are. even here, i don't always even do it 2yrs on the dot, have probably gone 3, and have never had any brake or clutch master cylinder problems. only brake problems i've really had are the common rear caliper sticky parking brake....
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
I let mine go when I had other projects on the table, ruined the brake master but the clutch master / slave managed to survive.

I would pull the clutch master apart first and see what condition the bore is in before calling it dead. Same thing on the slave except that those are pretty cheap to replace.

Speaking of which It's time to flush fluid again on the Jetta and wagon.

Steve
 
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ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
My power bleeder is a spare reservoir cap with a quick release air nipple… total cost about $2. Been using it for decades. Regulate pressure to 10-15 psi and watch the reservoir level. You can flush the entire system with under a pint of fluid and around 15 minutes of your time.

-Todd
 

Rig

Veteran Member
Joined
Apr 14, 2010
Location
New Mexico
TDI
1998 Jetta TDI, 210k miles
It’s either the master or the slave, as before. I’ve had poor luck with non-OEM parts, or at least non-premium parts, which is why I recommend ID Parts or Cascade.
As a rule I usually buy the most expensive parts I can find. If there is an upgrade I buy that. These cylinders were OEM and purchased from ID parts.

So I wonder what else could be going on here causing the cylinder to fail so frequently?

If I recall, the last time I put new brake fluid in it was DOT4 racing grade fluid....
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
reservoir is completely full. It's actually past the max line and appears to be leaking fluid everywhere...
If it’s leaking everywhere, how can it be full?

I should mention it's probably been over 5 years since I've changed brake fluid >.>
I’d say you’re due for a flush.

If I recall, the last time I put new brake fluid in it was DOT4 racing grade fluid....
How long ago was this? If your components are rusty inside, every time you stroke the brakes or clutch, that’s like sandpaper on the seals.

As others have said, look for the leak(s), repair or replace faulty parts and do a full system flush. I’ve flushed fluid that looked like coffee, in the past.

-Todd
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
As a rule I usually buy the most expensive parts I can find. If there is an upgrade I buy that. These cylinders were OEM and purchased from ID parts.

So I wonder what else could be going on here causing the cylinder to fail so frequently?

If I recall, the last time I put new brake fluid in it was DOT4 racing grade fluid....
I'm notorious for buying what I feel is the best price / quality relationship...it might not be the super cheap but it's not the most expensive. I've found that more money does not equate to better quality.

You can use Bosch ESI6 brake fluid, it's better than 3, 4 or 5.1. I think it's even better than MB's DOT 4+.

Steve
 
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Rig

Veteran Member
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Apr 14, 2010
Location
New Mexico
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1998 Jetta TDI, 210k miles
If it’s leaking everywhere, how can it be full?
I assume it overflowed... i don't know. Mechanic could have "topped it off" past the max mark. I don't see any leaks coming from either cylinder or any of the lines.

Might just try replacing the supply line and see how dirty the fluid is.

Has anyone ever had issues with the line coming from the master to the slave?
 

Rig

Veteran Member
Joined
Apr 14, 2010
Location
New Mexico
TDI
1998 Jetta TDI, 210k miles
and this is the clutch master I've been purchasing (on 2nd one right now) So I will likely try a difference brand in case the part itself is defective


I've had success with parts place parts. but this one doesn't list a brand:



This one from FCPeuro also doesn't list a brand https://www.fcpeuro.com/products/vw-clutch-master-cylinder-jetta-golf-vag-1h1721401
 

Rig

Veteran Member
Joined
Apr 14, 2010
Location
New Mexico
TDI
1998 Jetta TDI, 210k miles
The brand is OE. VW dealer sourced.

-Todd
well it's also discontinued I just noticed. Maybe I can find one elsewhere. Definitely looks different than the one I have in right now.

What are thoughts on the ID parts one, Metalli brand?

I want to purchase an OEM reputable brand this time, because I really want this to be last time I replace the cylinder. Yes, I will do a thorough brake flush and use some good quality fluid.

So I drained some fluid from my reservoir and this is what it looks like. Pretty black. I assume the original color was yellow but may have been mixed with something else I have no idea.


 

Rig

Veteran Member
Joined
Apr 14, 2010
Location
New Mexico
TDI
1998 Jetta TDI, 210k miles
So for anyone else ever having the same issue...

I bought Pentosin DOT4 brake fluid at autozone. We bled the brake fluid the old school way of pumping the brakes. Took 3 people. One to fill the reservoir, one to pump the brakes, and the other to loosen and tighten the bleed valve while draining so no air got into the system.

I ordered a pressure bleeder so I can do this by myself next time. Should be much easier.

Brake fluid was BLACK. way overdue for a flush. I'll probably do it again in 6 months just to be sure I got all the black out.

Master cylinder was definitely the issue, when the piston was pushed in, air came out. Seal broken. Part was FTE and looked a bit cheaper than the SACHS part I replaced it with but can't be sure. Undoubtadly, the bad fluid was really to blame here.

Slave seems to be functioning fine so we left that alone, so I have a spare one just in case that does go out at some point.

To access and remove the master cyclinder I just took off one plastic boot covering the steering drive shaft. I used an extra long extension with a swivel head to remove both bolts. The white clip actually popped out and in fairly easily. Biggest pain was accessing the nut on the right hand side but it can be done with the right extension and with a swivel head.

Moral of the Story: Replace brake fluid every two years or as needed. Get a pressure bleeder to do it yourself. Buy quality german parts.
 
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