240SX clutch

[DavidM]

Already replaced the master and slave cylinders, removed the clutch dampener, and replaced the stock rubber line with a braided one. When it sticks down it actually sticks disengaged. It doesn't happen all the time, but it was happening more frequently the last time I drove the car.

David

[CRallo]

PP. I found a mouse nest in one once... With 3 or 4 mice. Or what was left of them.

[erlrich]

David - it's just the PP that pushes the T/O bearing & fork back; if you've already replaced the master & slave cylinders, and the clutch line, then you probably need to look inside the bell housing. One other possibility, did you check the hard line that runs from the master to the flex line? It that got dinged at some point it may be causing the problem. Otherwise I would guess PP. What clutch do you have in there now?

[Matt93SE]

If the front cover of the trans that supports/slides the TO bearing is worn, it's possible that the TO bearing can get 'hung' on it and not release the clutch.

another issue- VERY unlikely on a stock-style setup- is that you're over-extending the clutch and actually turning the fingers on the pressure plate inside out. I doubt that's the case here though.
The fix for that is to add an adjustable pedal stop on the firewall. when I went to a Wilwood pedal assembly, I added one and just welded a small bracket with a nut to the floor, then use a bolt and locknut for the pedal stop.



Can you make this happen in the garage with the car up on jack stands? If so, then you can diagnose a bit further..

.... another brainstorm is the hydraulic fluid is dirty and chunks of crap are clogging at some restriction in the line. considering everything you've replaced, I bet that's not an issue.

[DavidM]

It's a stock PP and disc as far as I know. Bob said he just used stock and that's probably what I'll use as well. Only a couple hundred bucks from Courtesy. I'll get a new TO bearing as well. I can't recreate the issue in the garage so it's been a guessing game. If the spindle that the TO bearing slides on is damaged is that something that can be replaced? I have a spare transmission I could scavenge parts off of if necessary. I don't know the condition of the internals on the spare so I'm not sure I'd want to use the whole thing, but that would be an option.

Thanks.

Edit: Is this the part that would need to be replaced if the TO bearing spindle is worn?
http://www.courtesyparts.com/32110-c...4-p-69353.html
Looks like there's a sleeve that fits into the TO bearing that slides on the spindle from the front cover.
http://www.courtesyparts.com/240sx-p...1487_1501.html

Double edit: I'm just going to order everything from the PP/disc down through the front cover. If I'm going to replace one thing I might as well go ahead and replace it all.

David

[erlrich]

As I recall, didn't you tell me that this has only happened on track, at speed? The more I think about that, the more I think it's probably a PP issue. Is this the same one that was in there when you bought the car from Bob?

FWIW, my car had a stock type clutch when I started racing it, and it wasn't long before I started getting slippage about 15-20 mins into a race. While I know our cars don't make much more power than stock, we are still abusing them well beyond what the stock components were designed to handle. When I built the engine I replaced the clutch with an ACT heavy duty plate & 4-puck disc, and I've never had a bit of trouble since then - 5+ years and maybe 15-20 events later. YMMV

[chuck baader]

SPEC clutch stage 4 with aluminum PP option...3 puck ceramic solid hub. About the lightest thing you can get. Chuck

[Matt93SE]

It's a stock PP and disc as far as I know. Bob said he just used stock and that's probably what I'll use as well. Only a couple hundred bucks from Courtesy. I'll get a new TO bearing as well. I can't recreate the issue in the garage so it's been a guessing game. If the spindle that the TO bearing slides on is damaged is that something that can be replaced? I have a spare transmission I could scavenge parts off of if necessary. I don't know the condition of the internals on the spare so I'm not sure I'd want to use the whole thing, but that would be an option.

Thanks.

Edit: Is this the part that would need to be replaced if the TO bearing spindle is worn?
http://www.courtesyparts.com/32110-c...4-p-69353.html
Looks like there's a sleeve that fits into the TO bearing that slides on the spindle from the front cover.
http://www.courtesyparts.com/240sx-p...1487_1501.html

Double edit: I'm just going to order everything from the PP/disc down through the front cover. If I'm going to replace one thing I might as well go ahead and replace it all.

David

Yup, if you're going to replace the front cover, purchase 32110, 32113, and 32112. one each.
you'll know what kind of shape it's in as soon as you pull the tranny out of the car. They're not that expensive and they don't wear out often, but you never know. I've seen one or two wear out in probably 30 clutch jobs on various cars. both failures were on nissans with >150k miles.


I would not recommend an OEM pressure plate (or clutch disc) for a race car. they just don't hold up well enough in the long run. I've used ACT products for years and have been happy with them- pick any brand you choose, but do your tranny a favor and keep a sprung hub configuration. the solid hubs are lighter and rev a tiny bit quicker, but transfer much more shock load to the crank and to the tranny. this beats up on the baulk rings, which are a known weak link in the KA tranny.

(FYI, I've been through 2 trannies in the last 3 dbl nat'l weekends. eek!) one was just plain worn out, the other I missed 4th and tried to find 6th at 85mph. there went reverse!

[chuck baader]

David, see that you entered the ARRC...what did you do for the clutch? Chuck