1977 Datsun 200SX Clutch Issue

[OmahaJames]

I recently bought this 200SX for cheap because the previous owner thought it needed a new clutch, but after buying it I found that the clutch works fine... for about 5 minutes, then it stops disengaging, even when the pedal is depressed. If the car sits for a little bit it goes back to working fine. I am not sure what would cause that, bad fluid, fluid leaking past the clutch cylinder piston? Any suggestions would be appreciated. Thanks.

 

[Lockleaf]

I feel like that condition has to be hydraulic, though exactly what part is a mystery. Fluid itself should not cause that type of variable condition, but a flush isn't hard or expensive, so why not try it.

[datsunaholic]

Heat can cause the master or slave to quit working (leaking around the piston), or cause a hose to bulge.  So I also think it's hydraulic.  But you can easily check that with 2 people.  Compare how the arm moves when it "works" and when it doesn't.  If the arm movement is the same, it could be a delaminating clutch disc.

[banzai510(hainz)]

ck the fluid level?

[scooter]

Probably needs to be bled. Enjoy!

[kelowg]

 enough pedal free play could? 

[LenRobertson]

I had a similar problem on my SX a few years ago. I got a kit and rebuilt the clutch slave cylinder and the problem was solved. You might get by for awhile by just bleeding the system but then you won't know when the worn cylinder may suck air in again. You can check RockAuto.com and see how dirt cheap a new slave cylinder is. I would just buy a cylinder and not mess with rebuilding your old one. Might be wise to get one of the more expensive ones Rock sells rather than the cheapest. Maybe someone has a recommendation on a good brand name.

 

Also look under your dash where the rod from the clutch master cylinder comes through the firewall. Peel back the rubber dust boot and look for fluid that has leaked past the piston seal. If there seems to be a lot of fluid, I'd replace the master cylinder too. I've never replaced the master on my 200SX but I had to replace both slave and master on my 510. And wasted a whole lot of time and fluid not replacing both at the same time. Master cylinders are cheap too and you will have the peace of mind from knowing those parts shouldn't give you trouble again.

 

Len

[datzenmike]

Len don't the S10s have a brake booster? If the master leaks it would be between the master and the booster don't you think?.

[LenRobertson]

Len don't the S10s have a brake booster? If the master leaks it would be between the master and the booster don't you think?.

It took me two trips out in the dark with a flashlight to figure this out. Yes, there is a booster on the brake master cylinder but none for the clutch master cylinder. The clutch master has just a single fluid chamber too which is probably why it isn't very expensive compared with the brake master.

 

I'd recommend buying a flare wrench for removing the lines from the clutch cylinders. The hex fittings on the lines are fairly soft and very likely to round off if you try to loosen with a regular open-end wrench. You may be able to break the fitting loose with a smallish vise grip and then use a regular wrench to unscrew it. Harbor Freight has cheap flare wrench sets although I don't know about the quality. Probably good enough for occasional use.

 

I'll also give my standard advice of going to eBay and buying a 200SX Factory Shop Manual (not Owners Manual). You can probably find one for under $20 maybe including postage. They are a wealth of information especially for electrical and wiring info.

 

Len

[datzenmike]

OOps, sorry clutch master my bad. :blush:  Did you see the Super Moon last night?

[LenRobertson]

OOps, sorry clutch master my bad. :blush:  Did you see the Super Moon last night?

 

I figured you were just testing my mental powers (such as I have remaining) with the power booster mention. :D That is why I needed to make a second trip out to the SX last night, just to be sure there wasn't a booster on the clutch.

 

I didn't see the moon while I was wandering around out there. Either it hadn't come up yet or it was cloudy. It is probably going to be clear (and cold) here tonight so maybe I'll see it if I remember to go look.

 

Len

[OmahaJames]

Thanks Len, I will look into that. I already have a cheap flare nut wrench set from Harbor Freight, so I guess we will find out the quality on them. I already got the factory service manual for the 200SX on eBay too, cost me a grand total of $12 shipped. The fluid level is okay, but I had not thought to verify there wasn't any leaking into the cabin. I'll take a look this weekend and probably try to bleed it at the slave cylinder, I just need to be able to drive it a few miles to be able to get it inspected by the local sheriff to get the title in my name.

[LenRobertson]

I believe years ago when my clutch hydraulics suddenly quit working (luckily just a few blocks from home) the fluid level was up pretty good. My theory at the time was maybe the slave cylinder had been sucking in a little air for years and the fluid level had been topped up to compensate. Then one day it sucked in a last gulp of air and I had no clutch. Anyway rebuilding the slave cylinder solved the problem. I seem to recall the bore of the cylinder was rather pitted.

 

I imagine if you bleed your system you should have a good clutch for awhile. Long enough to get your inspection done anyway. But a new cylinder will be a better long term solution.

 

Does that seem to be the stock factory color on your SX? If so it isn't a common SX color which makes it quite cool.

 

Len

[hobbes_the_cat]

I had a 510 that was doing the same thing you mentioned. After a few min. use I would loose pedal but once cooled down it would return. As it got worse I would have to bleed the system to get pedal back and eventually the slave cyl. completely gave out. I assume it was sucking air into the system when it got warm as that's when the symptoms would return. New slave cured the problem.

[OmahaJames]

I *finally* got around to messing with this thing, bleeding it did nothing for it so I replaced the slave cylinder and it seems to be working fine now. I drove it across town today. Thanks for the help guys.