clutch problems

[wackos00]

Hello All,
Ok so I have finally got round to doing some work on the van (rather I have found the time and money!). I have aproblem with my clutch. To be honest I have done almost nothing mechanical to the van since April. Basicaly I cannot depress the clutch pedle it is locked in the fully up possition. The clutch slave cylinder is fully extended, and the leaver on the bell is fully down, if I put it in gear, drive is still engaged. It is as if there is no return pressure on the leaver, as if the thrust bearing is not pushing against the spring fingers of the preasure plate. I don't really want to take the engine back out so was wondering if there is anything that you think I might have missed or what the solution could be. Ive a 1992 EJ22 fitted to a 1982 Air Cooled T25 with all the RJES bells and whistles.
Cheers,
Jack

[rjes]

Copy of the e-mail sent to wackos00 about this problem and how to resolve it:

Hello Jack,
Was you bus originally a diesel, or more specifically, is the clutch arm which the pushrod from the slave cylinder pushes against from a diesel? I have recently discovered two things about the clutch release mechanism which I didn’t previously know when a friend converted his diesel van, and have not yet written a web page about them. This text will become the basis of the web page, as it’s the first time I’ve had to write this info down:

1. The clutch arm is subtly different on diesels. The splines are in a different position in the hole, which rotates the arm on the clutch shaft slightly. This was originally to suit the different slave cylinder bracket used on diesels. See the attached photo petrol_vs_diesel_arm.jpg. The upper arm (shiny) is a petrol shaft, and the lower one (slightly rusty) is a, diesel. They are both fitted to the splines on the same shaft. You can see the difference the spline alignment makes. Using a diesel arm with an RJES bell housing effectively makes the pushrod 20mm too short.

2. There are two lengths of slave cylinder pushrod out there (to confuse things further). Why this is is a complete mystery as the VW ETKA and ETOS parts catalogue CD’s show one part number for the entire slave cylinder assembly (which includes the pushrod – it was not available separately) suiting all years and all engine types. I suspect there were maybe two suppliers, with a different pushrod length each. See attached photo short_vs_long_pushrod.jpg . From end to end the short pushrod is 90mm, and the long one is 100mm.
For info, new slave cylinders from Topran (whoever they are – they don’t seem to be online) come with the short pushrod.

These explain why one customer mentioned he had to lengthen his pushrod. I couldn’t understand why at the time, but he didn’t provide me with any more info. I have since found a second person with the same thing, although he sorted it out when he installed his conversion (a couple of years ago), and never mentioned it at the time. You are the third.

The bell housing was designed around parts from a 1991 model petrol Syncro, including an OEM slave cylinder made by FAG, which proved to have the longer pushrod. My friends conversion had a petrol clutch arm fitted (I supplied it), but turned out to have the short pushrod. It took us a day to finds that this was the cause of the problem. His clutch pedal moved all the way to about 40mm from the floor before the slave cylinder ran out of travel and hit the circlip at the bottom of the cylinder (the cause of the pedal stopping dead). This prevented the clutch from fully disengaging (clutch drag), making it difficult to get gears. The solution in his case was to fit a longer pushrod.

As you describe your pedal as being locked up at the top of it’s travel (ie very much higher up than we saw in my friend’s conversion), I suspect that you must have the worst possible combination of parts – a short pushrod and a diesel clutch arm?

To solve this you have a number of options, assuming that you do have the above combination of parts:

a) Swap the arm for a petrol one and the short pushrod for a long one. Note that getting the clutch arm back on may turn in to an engine out job if it was a tight fit on to the arm – see the note below for how to avoid.

b) Fit just a longer pushrod or a petrol clutch arm. This may make enough difference, but I doubt it in your case.

c) In theory, you can make a petrol clutch arm out of a diesel one by filing away the spline inside the arm away which is furthest away from the ball joint. This will allow the arm to turn to the same position as a petrol one, but will leave you with only three splines engaged instead of 4, and will require some extremely careful filing. Done carefully, it would probably not cause any problems, especially wi the more lightly sprung nat asp clutches. I'll let someone else find out though....

d) Lengthen your pushrod. To determine how much longer it needs to be, you need to know whether you do have both the short pushrod and diesel clutch arm. If you just had a short pushrod, lengthen if by 15mm. If you had just a diesel clutch arm, lengthen it by 20mm. If you had both, lengthen it by 35mm. If it’s both, make it 30mm. The neatest way to do this would be as follows (lathe and welder required):
* Find some steel tube with the same OD as the pushrod.
* Cut the pushrod in half.
* Turn a shoulder on the end of each half to suit the wall thickness of your tube, with a chamfer as a weld prep where the tube will butt up against.
* Cut the tube to the required length, and turn a chamfer on each end as a weld prep.
* Weld each half of the pushrod to the tube around the two V shaped weld preps. You will need to be carefull at the ball joint end not to burn the plastic. One tack at a time, allowing the rod to completely cool ought to be OK.
With a lengthened pushrod you will need to check that the ball joint between the two does not run out of travel as the slave cylinder moves.

e) Moving the slave cylinder down some how is an option in theory, but far more complex than any of the above.

Note about swapping the clutch arm in situ:
Be careful if you do this in situ, as any force when removing the arm will be reacted by pushing the delicate nylon bush, and any force when refitting will be reacted by pushing the release bearing sideways. The arm should not need much force if it fits correctly. If yours is tight you can always carefully file or sand the damage or corrosion which makes it tight away if necessary. It should not be a loose fit, but also should not need more than a very very light tap onto the arm. Putting Copaslip between the two will help should you ever need to remove the arm in future.

I hope this helps
_________________
Regards,

Richard,

R J Engineered Solutions
Quality Subaru Powered VW Components
www.rjes.com

[wackos00]

Hi Richard,

Got your email thanks. The van was a 2l air cooled petrol, with the 4 speed box.

I'll have a look at it tomorrow and get back.

Jack

[rjes]

That ought to rule out a diesel clutch arm then, unless it's got swapped at some point for the wrong type. Very strange. The difference between the petrol and diesel arms is very subtle. Let me know if you want me to try to take a better photo of the two. Hopefully you'll be able to see the difference and work out what type you have. It'll be difficult in situ though. The mystery continues!

Just a thought - Are you certain that the pedal is locked because the slave cylinder piston has hit the circlip in the bottom end of the cylinder, not for some other reason? If not you can easily see it if you take the rubber boot off.
_________________
Regards,

Richard,

R J Engineered Solutions
Quality Subaru Powered VW Components
www.rjes.com

[wackos00]

Hi Richard,
I just sent you an email with a photo of my push rod, its about 103MM long total.
Cheers,
Jack

[rjes]

I got your mail, thanks, and have just replied with some more suggestions which ought to point us towards what is going on here.
_________________
Regards,

Richard,

R J Engineered Solutions
Quality Subaru Powered VW Components
www.rjes.com