clutch slave cylinder

[lindbergh]

I was wondering if is a good idea and go ahead and replace the clutch slave when dropping the tranny? I'm thinking it may be easier to get to and better to preventively replace it.

[WelmoedJ]

If you're going to follow that road, do replace the clutch line too.
This way you just cut the old line and worry about the connection to the slave cylinder once the tranny is out of the car.

This is also the moment to judge the state of the clutch, plate and bearing (and the rear crank seal).
It would also be the time to look at the master clutch cylinder.

[dmc6960]

This way you just cut the old line and worry about the connection to the slave cylinder once the tranny is out of the car.


?!?

There is a small section of metal hard-line mounted to the transmission which directly attaches to the slave. Cutting an original plastic line would serve no advantage here. Also, there is no need to replace it if it already has been replaced. If nothing has ever been done, it would be advantageous to replace the master, slave and line. Its also certainly not impossible to replace the slave with everything in place. It can be done from above or below if you didn't want to spend the extra money right now.

[Mark D]

If your clutch slave is not currently leaking you may not necessarily have to replace it, but I'd definitely remove it and take it apart to inspect the condition of the cylinder walls. It's a million times easier to do it with the trans out of the car. Taking it apart is very easy and all you need to do is remove the outer boot that covers the piston. Once the boot is off the piston and spring will fall right out.

If you see any pitting or corrosion inside the cylinder the whole thing should be replaced, but if the walls are still completely smooth you may just want to get a rebuild kit that replaces the rubber boot and seals as a preventative measure.

If you decice not to touch it and leave everything as-is when you reinstall your trans and bleed the clutch with fresh fluid you will upset the 'delicate balance of crud' that is most likely preventing any current leaks.
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Oh and another thing to note. Be extremely careful with the hard line that attaches to the slave. When you go to loosen the fitting you'll need a 16mm wrench to hold the adapter fitting on the slave and a 13mm wrench to loosen the hard line end fitting. The hard line tends to get frozen to the end fitting and when you loosen it you'll twist the hard line off. It's a $60 part to replace, so be careful.

I opted to disconnect the hardline where it connects at the chassis bulkhead fitting rather than try to remove it at the slave cylinder connection. Then when I could get the slave on my bench top it was easier to get the hard line off without damaging it.

Once you get the hard line off you need to remove the adapter fitting also. Replacement slave cylinders do not come with this fitting. There is also a copper o-ring that seals the adapter fitting to the slave that you don't want to forget about either :-)

http://dmctalk.org/attachment.php?attachmentid=14504&d=1351980331

[lindbergh]

Thanks for the tips, I think I will replace since it is 31 years old. Will also replace the clutch, doesn't make sense to me to leave an old clutch when you are already there.

Another question, I am a little confused about the plastic line, you have a hard line coming off the slave (right?), where does the plastic line come into play?

[Mark D]

Normally there is a flexible line coming off of the clutch master that runs the length of the chassis to a bulkhead fitting just above the transmission shift linkage. From there the hard line runs up along the trans and connects to the slave cylinder.

The original flexible lines were a plastic material that would expand when warm and that would lead to only partial disengaging of the clutch. 99% of owners have now converted over to teflon flexible hose that is overbraided with a stainless cover to prevent the line from expanding.

Ref the parts diagram at the link below, Item 11 is the flexible hose, and Item 6 is the hard line you see in the photo I posted above.

http://store.delorean.com/c-384-4-4-1-clutch-hydraulics.aspx

What is the reason you are dropping the transmission anyway? As you mentioned already it would be a good idea to replace the clutch while you're in there. There is also a small roll pin inside the transmission that engages 2nd gear that tends to bend/shear off (due to the expanding clutch hose problem explained above). While you've got the trans pulled out it might be worth going in there to replace the pin and/or add a second pin inside to reinforce it.

[lindbergh]

Thanks for the clarification on the plastic line. I am dropping the tranny to fix 3rd gear rough shifting that occurs unless I nurse it in when upshifting and never downshift to 3rd. Just tired of playing with it. Thanks for mentioning the 2nd gear issue, I will replace that pin. Is there anything else that is a "known problem" that I should check? I do tend to tear it apart until I find what the issue is. Also, will DMC have all the parts I need to rebuild whatever I need to rebuild in the tranny? Getting parts is a little bit of a concern to me. Thanks again.

[stevedmc]

If I remember correctly, the clutch is supposed to be changed every 30k miles. I think this is complete nonsense but maybe it will make you feel better about changing it while you are in there.

I would definitely change it when pulling the transmission whether you need to or not, just for convenience. You can always keep the old one as a spare part. Then just drive on the new one till it quits working (way past the 30k rule).

[dmc6960]

If I remember correctly, the clutch is supposed to be changed every 30k miles. I think this is complete nonsense

On a strictly pure mileage standpoint this IS complete nonsense. (But I think I know where you heard it from). If your clutch legitimately wears out at 30k your doing it wrong. That said, there are many other factors that can prompt a good reason for *DeLorean* owners to change it out early. Noisy throwout bearings, premature failed pressure plates, things that fail when a car sits untouched for 30 years then is pressed back into service. Already having the engine and/or transmission removed for other work is a fairly compelling reason as well. Especially if your paying someone else labor on all that.

My D's first clutch was changed at at least 65k. I probably wouldn't have changed it this early but I had an opportunity I couldn't pass up (especially since I was not capable at that time to do it myself). This clutch now has lasted at least another 60k miles and I can probably get another 60k out of it. When I had my engine/transmission removed for the engine rebuild I did, that clutch would have had about 35k miles on it. Didn't even think for one second to replace it.

[DMCMW Dave]

On a strictly pure mileage standpoint this IS complete nonsense. (But I think I know where you heard it from). If your clutch legitimately wears out at 30k your doing it wrong. That said, there are many other factors that can prompt a good reason for *DeLorean* owners to change it out early. Noisy throwout bearings, premature failed pressure plates, things that fail when a car sits untouched for 30 years then is pressed back into service. Already having the engine and/or transmission removed for other work is a fairly compelling reason as well. Especially if your paying someone else labor on all that.
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I think Jim has this correct - 30K is way too low for a clutch but is pretty common on this car for a lot of other reasons:
--It's apart anyway and looks worn and/or rusty
--My suspicion is that for many owners (original and current) the DMC is their first manual transmission car, and they learned on it
--I've seen pressure plates and throwout bearings fail from storage conditions (rust) way before the disc
--The original plastic clutch line that tears up roll pins and sliding gears isn't doing the clutch disc any good either
--They tend get a lot of around town/traffic/parade miles. A car like Jims that runs a lot of highway miles puts very little "wear per mile" on a clutch.
I have replaced legitimately trashed clutches with less than 10K miles. Most likely due to #2.