98 Jetta TDI clutch slave/master cylinder / shifting problems

Hi guys. I've searched to no avail. The clutch is not disengaging. Sounded to me like the slave cylinder wasn't holding its pressure so I ordered a new one, installed, and bled it. No change.

You have to "bump" the accelerator to spin the syncrhos up to shift it, because the clutch isn't disengaing all the way. Its hard to shift period. Any other options other than replacing the clutch at this point that might be the culprit? I know nothing about how these clutches work in these cars at all.(The hydraulic part)

It was working fine and then all of the sudden this just happened. It hasn't been progressive, which leads me to believe something else may be at fault. Perhaps adjustment or something? But I have no idea if it has an adjustment or how to get to it / where it is etc. Any help is greatly appreciated.

re : clutch won't disengage :

You didn't mention how many miles are on the current clutch, but
given the year of the car perhaps the clutch has a lot of miles on
it, and some clutch parts have fatigued and failed.

I think it's possible ( likely ! ) that some sort of debris is preventing the
clutch friction disc from having little or no pressure on the
flywheel face when the clutch pedal is depressed fully.

It's known that the coil springs incorporated in the clutch friction
disc can break, and when the springs break sometimes pieces
of the spring become lodged in the clutch and cause the clutch to
fail to release fully. It only takes a small amount of drag to make
it impossible to shift into first gear from neutral with the car at
a standstill. Once the car is moving, shifting may be possible but
careful timing might be required to avoid grinding gears.

Here's something you can try, and it may not help but I've seen
it work before. NOTE : this is NOT a long-term solution, but it might
buy you some time until you can replace the clutch.

First, buy at least two cans of Brakleen or equivalent spray-can
brake cleaner. If possible, plan to have a person available to
help you during the steps below.

1) set the parking brake in your car.

1) a) remove the rubber "timing hole" plug ( found on the transmission bell
housing near the clutch slave cylinder ).

2) start the engine and let it idle.

3) attach the small spray tube to the spray nozzle of the brake cleaner
and carefully insert the spray tube into the timing hole which was
exposed when you removed the timing cover. NOTE : make sure the
spray tube is FIRMLY attached to the spray nozzle. You do not want the
spray tube to fall into the hole.

3) a) Spray lots of brake cleaner into the timing hole, with the engine
running ( the idea is to hose down the clutch and flywheel with brake cleaner ) and if you have a helper, get him/her to repeatedly press the
clutch pedal in while you spray the brake cleaner.
NOTE : AT NO TIME SHOULD YOU INSERT ANY PARTS OF YOUR HAND
OR ANY TOOL INTO THE TIMING HOLE. Ok, this *should* be obvious,
but serious injury is possible so a warning was in order.
The idea is to loosen the crud which might be holding the broken
pieces of friction plate or its spring in place, such that the pieces of
spring will be ejected and the clutch will then release.

It's likely a puddle of brake cleaner mixed with "crud" will appear under the car where the engine and transmission mate, so you might want to put
something ( towels, newspaper ) under that area to catch the spill.

Again, remember that you probably need a new clutch, and this is not going to change that, but it might buy you some time.

DMF coming unglued?

White Crow said:

DMF coming unglued?

Click to expand...

Not likely. '98 and earlier is a simgle mass flywheel.

My vote would be to replace the clutch master cylinder. If that doesn't work, then replace the clutch assy.

Tony

Cool. We're going for master cylinder. It seems as if the clutch works fine then gets spongy the more you use it. We have replaced the slave cylinder already.

We have ordered a master cylinder for the clutch and it will be her Wednesday. We'll install then, hopefully this fixes the problem. Its acting like the pressure is bleeding off when you use it more and more, so I'm leaning towards master cylinder as well. If not, we'll go for clutch.

Post back and let us know how it goes.

Tony

re : replacing the clutch master cylinder

cr9c1 said:

Cool. We're going for master cylinder. It seems as if the clutch works fine then gets spongy the more you use it. We have replaced the slave cylinder already.

Click to expand...

If possible, use a pressure-bleeding apparatus to bleed the clutch
hydraulic system. A pressure-bleeder tends to give significantly better results, with respect to removing all the air bubbles from the system.

Also, removing the driver's seat makes the task of replacing the clutch
master cylinder a lot easier. It takes maybe two minutes to remove the
seat but it opens up some room so you can lie down where the seat used to be and deal with the R&R of the clutch master cylinder. It's usually quicker to go ahead and remove the seat rather than suffer with the contortions required with the seat in place.

And please do let us know how it goes.

If it's the clutch master, wouldn't the pedal push to the floor and stay there until you pull it back up? That's what would happen with my B4 when my clutch master was failing. Still much easier to replace the master before digging into the bell housing though. If the pedal just feels spongy, then you prob have air in it. Make sure that the brake reservior stays topped off during the clutch bleeding since the hose where the clutch draws hydraulic fluid from is higher in the reservior.

The throwout bearing might have failed. Enough spin of the flywheel side of the clutch is passing through the dragging bearing to spin the friction plate and input shafts to make shifting tough.

Mines doing the same thing.
Any results on the master helping.
I think my line is infiltrating air because it will work for a minute after bleeding then go back to not (dis)engaging the clutch.

Hey guys any luck?

djbobo said:

Mines doing the same thing.
Any results on the master helping.
I think my line is infiltrating air because it will work for a minute after bleeding then go back to not (dis)engaging the clutch.

Click to expand...

Master - if there are no visible leaks outside of the lines/fittings or slave cyl and it works after bleeding then stops working soon and has air in system again.. replace master cyl

1998 VW Jetta TDI

Hey guys i got a problem on mine, the clutch pedal tends to suck in all the way down when u barely tap it and it stays down, i have replaced the clutch master cylinder on the pedal, replaced the slave cylinder, and just yesterday replaced the mechanical side of the clutch, and still no luck, pedal is still down. Any help would be nice

Might have been easier to start a new thread of your own rather than tagging
on to one that's 2 years old. Just sayin.

What do you mean when you say you "replaced the mechanical side of the clutch"? New clutch?

borrado512 said:

Hey guys i got a problem on mine, the clutch pedal tends to suck in all the way down when u barely tap it and it stays down, i have replaced the clutch master cylinder on the pedal, replaced the slave cylinder, and just yesterday replaced the mechanical side of the clutch, and still no luck, pedal is still down. Any help would be nice

Click to expand...

Is the over center spring intact, just above the pedal?

Has the system been bled?

Yblocker said:

Might have been easier to start a new thread of your own rather than tagging on to one that's 2 years old. Just sayin.

Click to expand...

Agreed...you'll get more specific attention to your issue, as well as troubleshooting history specific to your issue.

Tony