[OS]

While lending the car over the weekend, a clutch problem evolved, If waiting
with the clutch depressed, at for instance a traffic light, the clutch will engage after a short while, with a resulting engine halt.

I guess the pressure is leaking slowly so the slave engages, although the pedal is down.

From previous posts, I recon the trouble shooting is sort of tricky, and that people tend
to have to replace booth master and slave and bleed before sorting out the problem.

Any suggestion on how to troubleshoot? Is it any point in trying a bleed before replacing? Also is the recondition kits for the master/slave worth it? Here in sweden a new master is about EUR 100, and the recondition kit is EUR 9!

 

[cdaly]

Are you losing fluid?
If so, is there any leaking out of the clutch housing (there's a small drain hole near the bottom, hard to see)? If so, it's the slave cylinder.

If not, it's the master cylinder. There still could be fluid leaking out at the clutch pedal with a failed master or it could be leaking past the internal seal in which case you'll get no fluid loss.

I'ts worth trying a rebuild kit for the master 'cos you can almost do it in the car but the slave requires the clutch out and so it depends on how valuable your time is. If you do a slave rebuild and it fails, you've wasted all the hours doing the job...

I've successfully rebuilt both master and slave and a brake master in the past. The brake master wasn't perfect and may require replacing in the future. Make sure everything is clean, clean, clean...

 

[Alex]

To check at which end the problem lies, press the clutch and then clamp the flexible pipe which connects to the slave piston. If the clutch stays out the problem is with the master if the clutch returns then its the slave.

 

[OS]

Thanks, that is excelent advice guys!

If I get you right, if the slave fails, it always leaks some, so no sign of leakage there would rule it out, right?

 

[Alex]

Generally if things aren't leaking it is a sign that the master is on its way out. Unfortunately once the master is fixed this can then cause the slave to fail due to the extra loads placed on it (as happened on my T16).

 

[OS]

I did this job on the weekend, and must say it went well. A master rebuild fixed the problem. Some comments though:

* The booring an teedious job is to remove the panels and get them back

* If the master is clogged, there is no use renovating the cylinder in place.
I had to bang the cylinder very hard to get the innards out. It only took me 4 extra minutes to remove it the cylinder from the car.
* If you don't have cleaning spirits; Hot water and detergent will do the trick,
with a final rinse of Absolut Vodka (with lime) .

* A home made bleeder with a bicycle valve in the cap works fine. It is very usefullt to have a second person to just watch the level though.

* With an ordinary LPT with ABS, there is plenty of space to remove the master, bleed and check the clutch operation without removing anything in the engine space. (regardles what Haynes says).

Can you preassure bleed the brakes too?

 

[cdaly]

Can you preassure bleed the brakes too?

Yes you can. In fact it's recommended. If you have ABS, you use the ABS pump to bleed the rear brakes and an ordinary pressure bleeder for the front.

For the rear brakes with ABS:

1. switch on ignition and wait for ABS light to go out and pump to stop (very quiet buzz)
2. Attach a bleed tube to the rear caliper bleed nipple and open the nipple
3. press the brake pedal and watch fluid exit
4. Tighten nipple
5. Repeat for other side

NOTE! Do not allow the ABS pump to run for more than 1 or 2 minutes at a time. Allow to rest for 10 minutes between runs to allow it to cool.

 

[Matthew]

The booring an teedious job is to remove the panels and get them back...It only took me 4 extra minutes to remove it the cylinder from the car.

The master cylinder can be removed without also removing any of those panels!

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[Alex]

The method in the Haynes manual is the official and correct one. The method used by dealerships (which doesn't involve removing the under dash panels) isn't shown in the Haynes.