Clutch - Master or Slave cylinder?

[ymz]

(2003 Jetta) - Stuck in construction traffic, inching along, and... the clutch "catch" point is getting lower and lower... Eventually we get to actually driving with the clutch pedal up (had to push it up!!!!), and after that - normal city traffic, red lights, etc. everything's fine... (I know that cars don't usually fix themselves...)



Should I be thinking the Master cylinder's getting old, or could it be the slave?


Y.

 

[oilhammer]

If the slave fails, it will leak (on that car into the bellhousing). If a master fails, it can either leak inside the car OR leak "internally" and just be bypassing the seals.

I rarely ever see clutch hydraulics fail on the 02J cars. But look around for any leaks. If you do not find any I would suspect the master. You may try a thorough flush of the system with fresh fluid (this often gets neglected, even when the brake system doesn't), and see if some dark nasty gritty fluid comes out. You may have just gotten something wedged in the master's seals and it pushed its way out. You said it was working fine later on.

 

[Mongler98]

Bleed the fluid.
If it's not fixing it, rebuild slave, it's just a few o'rings
Chances are it's just bad fluid.
Sounds like it

 

[eddieleephd]

Bleed the fluid.
If it's not fixing it, rebuild slave, it's just a few o'rings
Chances are it's just bad fluid.
Sounds like it

This is the start, of course after you ensure there's nothing dripping from the bottom of the transmission that's coming from within, and there's fluid in the brake reservoir.

Air and bad fluid have many effects.

Sent from my moto g(7) power using Tapatalk

 

[Mongler98]

What's probably actually happening is that its boiling
The engine bay is hot. Fluid that has just 5% moisture is literally half the boiling point. I had the exact same issue with my brakes and clutch when I got my mk3.
The fact that it gets better when cooled down, yes, flush the entire system including the brakes! It's all one system.

 

[ymz]

Thanks... I'll try later this week...


(edit) this is our "extra" car... I hadn't changed the brake fluid since we got it... any hints as to how to prevent the bleeder valves on the calipers from breaking off? (I had to resort to using a long "monkey" wrench when I changed the tie rod end - not so much for the tie rod end, but for the jam nut...


Y.

 

[ymz]

Just got to look at the car... fluid leak at the junction where the hose goes into the fitting that clips into the slave cylinder... Someone else posted the attached photo that has the same leak... If I were to replace the line, how does one access the other end of the hose? From the quick look I took, it appears that I may have to remove the ABS pump... that can't be correct...

[/FONT]

 

[Mongler98]

Remove line
Clean up both sides
Replace orings
Install
Unless the like is actually broken, it should be fine.

 

[ymz]

Unless the like is actually broken, it should be fine.

You think it's just leaking from the "O" ring? (I doubt the local dealer keeps them in stock...) It seems to he leaking from where the steel (?) hose goes into fitting that contains the "O" ring... I'll have a closer look, but other people have had it leak there...

Y

 

[Mongler98]

Ebay or amazon
Box of assorted sizes of orings for 10 bucks

 

[ymz]

Follow-up - the leak was not from the "O" ring... it was from the actual hose assembly - where the hard line enters the "plug" that actually fits inside the slave cylinder. That's now fixed (with J.B.Weld) and there are no more leaks.



However: after bleeding it the first time, the following morning had the clutch unable to be released, so I bled it again... this time, the "catch" point was nice and high... the following morning, it was closer to the floor, so... I bled it again... now it _seems_ to be OK - although there's a sneaky feeling that it's a tiny bit lower first thing in the morning, and after pumping it once or twice, it's back to the mid-higher "normal" setting...



Is this "feeling" just in my mind or could it be something in either the slave or master? I realize that it will probably clarify after a few days or weeks of driving...


Y.

 

[Nuje]

Contrary to one of the posts above, out of the five 02Js I've done transmission work on, I've had the clutch master cylinder go bad on two of them. Both times, there was no sign of leakage, but rather, the master wouldn't draw in new fluid and therefore couldn't be bled.

As for ymz's situation, keep in mind what kind of psi a typical hydraulic system is pushing around; JBWeld might be good enough to limp you home, but I certainly wouldn't trust it to hold long-term.

Removing the clutch line at the firewall is something of an adventure: getting to the retaining spring clip...OMG - what a PITA; you pretty much have to work blind and by feel in an area where you can just barely reach with screwdriver because of all the other things in the way.
Also, I wouldn't trust an o-ring that "looks about right" - as crazy as the price is from dealer, I'd get the OEM replacement; this is one of the last things you want to have to do a second time.

 

[Mongler98]

You know there is this thing called a caliper, it measures things like orings. You can make them yourself as well.