No clutch pressure..Sometimes?

General discussion forum about the 240sx, and a great place to introduce yourself to the board!
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Khost26
Posts: 121
Joined: Sat Nov 21, 2009 2:09 pm
Car: 1990 s13 blacktop sr20det

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So i did search. But my problems have a way of being unique. I was driving about 20 miles away from my house and its raining. I turned onto a street and all of a sudden my clutch didn't come all the way back out but about halfway down. I still had pressure and enough to get into second. I pulled over and checked if i had fluid. I did, i checked for any leaks in my lines that i would be able to see easily and nothing. The clutch regained pressure after i pulled it back out by hand. And i got enough out of it to back out of my parking space. Then i tried to get it into first and it wouldn't go in, like the clutch wasn't in. But it was still idling in reverse when i had the clutch in. Well i got it going in first and just shifted without the clutch the rest of the way home. As i got home i looked at everything really quick and the only thing i can think of is the cmc because it was dirty with what looked like break fluid and there was a lot of residue in the seam between the firewall and strut tower. But its raining out and everything is wet so i have to wait for it to dry out to check more.
Also i recently put in a new clutch with 86% more clamp load. I'm thinking that the extra pressure was to much for a 20 year old cmc? Any ideas would be awesome. Its my only car haha i need to fix it.
oh and its a s13 backtop sr. And it was a 5 speed swap. Shouldnt matter tho... right?


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S13_RB25
Posts: 556
Joined: Thu Jan 14, 2010 5:20 am
Car: A 240 but no RB yet!
Location: Burlington, NJ

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Well one thing is with aftermarket clutches is the damper box doesn't help at all, So get under the car and remove the damper box and bleed the clutch again. Its like this:
1) You'll see the hard line come in from the MC into the damper box and then out to the rubber wire that connects to the SC.
2) Unscrew the hard line from where it goes into the damper box.
3) Slowly bend towards the rubber line that runs into the SC.
4) And screw it in.
5) Bleed the clutch and your done.

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Khost26
Posts: 121
Joined: Sat Nov 21, 2009 2:09 pm
Car: 1990 s13 blacktop sr20det

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Is that my problem? Or is that just something i should do?

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adrianfromthecastle
Posts: 18849
Joined: Wed Jun 29, 2005 5:36 am
Car: 1992 Nissan 240sx
Location: California

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I'm kinda adding to what S13_RB25's is saying... get rid of that damper box thingy right next to the slave cylinder. Careful when you bend the hardline, you DONt want to pinch it. FRsport sells a stainless steel clutch line that kinda deletes the damper thingy and directly connects the hardline to the slave. I think I paid like $25 or something... its a great product, highly recommended.

and since you put in a new clutch, you might as well swap out the MC and slave while you were at it. It shouldnt cost that much... I think an OEM slave was like $30ish and OEM MC was like $40-50... you can even go like $20 cheaper with the factory replacement ones too. they work just as good imho (for stock clutches at least)

but about your whole problem about your clutch not engaging sounds like you have air in your system. Bleeding your system should fix it, but since you said the fluid was dirty, I'd highly recommend flushing it completely out and tossing in fresh new fluid. Bleed it more than once... you can never be too sure, lol. Use Dot 3 brake fluid.

good luck. I had this problem last week, I ended up replacing my old a** MC and tossing in new fluid, and my clutch pedal feels great now.

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Khost26
Posts: 121
Joined: Sat Nov 21, 2009 2:09 pm
Car: 1990 s13 blacktop sr20det

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Well so far ive bleed it twice through and no luck. Put brand new fluid in and bleed it again and still nothing. It feels stiff going down then wont come all the way back up. If i pump it though it will keep coming back up. As soon as i hold it down though it loses the spring.

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mattblancarte
Posts: 1978
Joined: Sat Jun 21, 2008 4:14 pm
Car: 2005 BMW M3 Comp. Coupe

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Good call, Adrian. My first impression was that it is either the slave cylinder, or the master cylinder. Could be both, though. Start with replacing the slave, then replace the master cylinder if need be. :)

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Khost26
Posts: 121
Joined: Sat Nov 21, 2009 2:09 pm
Car: 1990 s13 blacktop sr20det

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Turned out to be the mc. It was only 20 and it feels alot better. Thank you everyone that helped.


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