Possible help with small issues with my 5 speed in my 72 240z....

[dogma420]

Wondering if anybody has any ideas about my issue below...then I'll list what I've replaced.

When driving down the road, the gears shift pretty smoothly from gear to gear. I'm really happy with my 5 speed tranny conversion. I opted for a 77-78 5 speed, so my 1 through 4 gears were essentially the same...I know, I know...they are not exact, but I liked that they are very similiar. Please don't say get a ZX 5 speed...I'm not going to do this, I intentionally got the 77 5 speed on purpose.

To me, it feels strong, I can spin the tires if I dump the clutch, so it is engaging correctly I believe...

Problem:

When I am going 5 mph or under, or I am sitting still, gears are hard to shift into (with the clutch pedal pushed in all the way)....

IE. when completely stopped and I'm in 2nd gear, and shift into 1st gear while waiting at the stop, its too harsh most of the time. It isn't just a smooth movement from 2nd to 1st...I don't expect it to be as smooth as when the motor is turned off, but it's harsher than anything I've driven before.

IE. shifting into reverse with motor running at a complete stop is tough...since my 5 speed is the one that the reverse fork shares the 5th gear, I get a little grinding sound about 40% of the time when shifting into reverse.

It's almost like I don't have the clutch pedal all the way down to the floor, which I do, or that I'm trying to shift without the clutch.

The problem seems to be that the clutch isn't disengaged 100% but don't know what to do next to alleviate the problem. It shouldn't be like this.

Here's what I've done:

1977 5-speed...came with clutch fork and throw-out bearing already installed, and this was directly pulled out of a 77 280z for my purchase, so the clutch fork and throw out bearing are stock 77 parts. I never did check, so it could be the PO screwed me here...possibly the next step would be to get a new replacement 77 clutch fork, boot, and throwout bearing...I noticed the other day that the boot is cracked, so it could use replacing. If I pulled the tranny to do this, it would also give me a reason to replace my leaking rear main seal.

Clutch Slave AND master cylinders ordered from MSA for a 1977 280z with 5 speed. So I have the automatic adjusting clutch slave cylinder.

Steel braded clutch hose where the flexible hose goes right before the slave. Bought at MSA.

Complete OEM style clutch kit for a 1977 5 speed 280z. Pressure plate and clutch disc for a 77 5 speed.

My stock 1972 flywheel resurfaced.

Used a 77 positioning tool when installing the tranny last summer. Have driven car approximately 10,000 miles since.

Clutch pedal is original 1972. is this different for the 77 5 speed car?

The adjuster that attaches to the clutch pedal (that goes into the clutch master cylinder) is adjusted all the way out. If it isn't adjusted all the way out, the car doesn't go anywhere...just sits there like the clutch pedal is pushed in all the time whether it is or not. if it isn't adjusted all the way out, you can sit with the motor running and shift through all gears while it is running and the clutch isn't pushed in.

What I'm wondering is, the actions I'm experiencing can't be the norm for a 5 speed...my 4 speed was very smooth when stopped and wanting to shift from 2nd to 1st or shift into reverse.

Is there something I'm missing? Like the pedal being different or has anyone had any issues like what I'm saying? I'm stumped.

I also got the 77 5 speed because I was interested in the 60% reduction in shifter throw action with MSA's short shifter kit. I am getting this next week....can't wait. I'm going to cut the top of the shift linkage down 1.5 inches and get the threads put on down 1.5 inches, so the shifter is lower and even more reduced on throws.

Besides this problem, the 5 speed conversion is awesome! I've loved the 5 speed overdrive...I can go 70 mph at about 3300 rpm, where as before I'd be way over 4000 rpm. I'd say I'm getting 2-3 miles per gallon better on the highway than before.

? Anybody? Help!

[Arne]

I guess I'd start with the simple stuff - are you absolutely certain that ALL the air has been bled out of the line?

[dogma420]

ya know, that's a possible other issue; logically, my brain just doesn't understand how clutches can be bled...it doesn't follow the same procedure as brakes in my head, because there isn't a point of 'pressure' where you push the brake pedal to.

What I did to blead the clutch line was this:

push clutch in like 10 times, hold it in, and while it is held in, release nipple at the slave. All that comes out is hydraulic fluid however. Then seal back up.

Arne, or anyone else, is there a better way to do it?

I've pissed at this problem so much that I might even go to a clutch mechanic and say 'please adjust and bleed my clutch system' and tell him what I told everyone here in my posting (#1 post).

But I enjoy knowing how to do everything on my car, and this is frustrating!

Let me know Arne if this is how you do it....would one of the 'one man brake bleeding systems' work better?

Thanks for bringing up the idea of making sure there is no air.

[Arne]

From my prior experience bleeding clutches (on other cars, granted, my 240 still has an automatic in it), I'd do it differently. First, make sure that the bleeder screw is pointing up. (I don't think this is a problem on a Z, but other cars I've done have had to have the cylinder unbolted from the transmission to bleed properly.)

Second, don't pump it up - that may force the air past the bleeder. Instead, open the bleeder and push down once on the pedal and hold it down. Tighten the bleeder, release the pedal (slowly) and repeat.

[dogma420]

I will try that tomorrow, thanks Arne.

I have always felt that this wasn't an issue, and that may just be the issue!

It sure doesn't appear that there is anything else I can do, so I hope this works.

Thank you Arne.

[ktm]

Wow. I am having the exact same problem in my 240 that I just picked up, except I grind 2nd, 3rd and reverse about 50% of the time. I figured that the clutch was not being fully released but did not have any idea where to start.

I know that the previous owner replaced the clutch slave cylinder recently (a DIYer) and may not have properly bled the system.

[rztmartini]

that exact problem happend to me. i was leaking clutch fluid...had to fill it back up again after about 10 miles driving around town, kept having to pump it up to regain some pressure. so a airy hydraulic system may be the culprit.

[dogma420]

Yes, I think Arne and you are correct, Martini....I just haven't had a chance to bleed it....all clutch parts are about 5k old so hopefully I'm not leaking yet.

[Dtsnlvrs]

You can "gravity" bleed the datsun clutch. That is, fiil the master res, then open the bleeder screw...thats it...make sure to keep the master full and just let it run. Also check the pedal height as well as the slave piston slack. If you do not have the proper pedal height, you will either have too much "throw" which will bottom the master and damage it, or too little "throw" which will cause the clutch slave to push "short." Also check that the master piston attaching pin (to the pedal) is not overly worn....if it is you can remove the slack in the sys but it is just as easy to replace the pin. As far as the slave piston slack goes, I cannot remember the exact measurment or number of turns, but I set mine like this. Once the pedal height is checked and corrected as needed (good info in Haynes manual), I remove the spring between the slave and the clutch fork. I then try to "force" the fork with my hand, that is I make sure it is positively engaging the throwout collar thereby engaging the bearing to the pressure plate. I then adjust the slave "piston" to touch the clutch fork, then back off 1.5 turns....like I said I do not know if that is the proper number of turns....then re-attach the return spring...I know some of the later cars did not have the spring. On a side note, I do not have a tranny book out right now, but IIRC there is no syncro for 1st or Reverse, you should always engage the clutch and wait a sec or two before engaging either gear...for reverse, I usually go thru 3rd gear real quick to stop the tranny before engaging reverse....been doing that in All my cars since 1985 (its a jeep thing)

[yukonharry]

I have a 77 with an 78 5 speed and love it. I had the same problem as you do. I had a bad slave cyl. I have to agree with Dtsnlovs. The clutch pedal height is critical. I forget the measurement and what points they are taken from. The FSM should tell you. I tried the gravity feed, but it took too long. So I did the old pop bottle and hose thing. After this was done, it's a sweet ride and shift.

[dogma420]

yeah, thinking it might be a doa slave....but I'm bleeding the system tomorrow (it's been raining out here too much and the z lives outside).

The newer D30 slave cylinders, such as mine, aren't adjustable like my original 4 speed slave....it's self adjusting with an internal spring.

[sjcurtis]

I had a problem very similar. After a workshop changed out my slave cylinder complete, I drove home just great. parked in the garage nose first had to get reverseto get it out, no deal, all attempts failed could not engage reverse. Found the gasket to the flex line was sucking air with operation of the clutch sys required a full re-install and bleed to clear.

cheers

steve