New NABCO clutch rod too short???

[EricB]

Hey all

So a couple weeks ago my friction disk finally bit the dust.

I got another and at the same time decided to replace my clutch master cylinder and slave cylinder.

First I went to the import auto parts store in Pasadena and they sold me a no name brand Japanese made replacement set for my '73 240.

When I took them home and unbolted my original Nabco and got to comparing them I found the replacement's rod was something like 5/8~3/4" too short. Considering my original one was adjusted all the way out I figured this wouldn't work. I returned both and drove down to MSA.

MSA sold me a matched NABCO set which I assumed good and brought home. The threaded rod difference was something like 1/8 ~ 3/16". I figured I'd be fine... Re-assembled everything on the car the next day, fired it up, and couldn't get it in gear.... great... By this time it's 11:30pm on a sunday. I bit the bullet and got a rental car for the week.

This weekend thinking my problem was with the throwout collar (maybe it got cockeyed or something) I pulled the tranny off - found nothing wrong and re-assembled. Still wouldn't go in gear.

So I took a closer look at the clutch master cylinder rod. I adjusted it out even futher (it's now only held on by like 2 threads - doesn't seem safe to me) and I can BARELY get the car in gear. I feel like I would want to adjust it out a further two threads or something but can't....

What now?

The clutch master cylinder MSA sold me is indeed for a 73 240. How come the OE one I pulled off the car was longer???

Thanks as always.

-e

[panchovisa]

Eric, take the rod off the old cylinder (only the rubber boot holds it on). If that is still to short then thread a piece of rod and cut to the right length.

[EricB]

$&*%...

I did peel back the boot and thought I saw the rod being part of the ball/plunger assembly... so I tossed it... that was last week... trash's been picked up...

any other ideas?

is the longer rod specific to only certain months of HLS30 production - like late 73 240's only???

Enrique as far as modifying the rod itself... you're saying it's just threaded in behind the rubber boot... so I can get a 1' section of threaded rod with the correct pitch, cut to fit, and replace it... nice. Ok I guess I'll do that then... So much for bolt on replacement parts for our cars... hahaha

-e

[panchovisa]

If you don't have threading dies, then all-thread rod will work. If you can't find metric all-thred rod than SAE threds will work with SAE nylon-lock nut. Just radius end of rod that fits cylinder cup and shape nyloc nut to fit clutch fork. A hacksaw, file and emery paper is minium that you need.

EDIT: The threads should END before the boot. Boot just slips over smooth part of rod and grips it tight enough to keep rod from falling out. I would thread a smooth rod, but all thread rod could have threads filed off at boot. Leaving threads on at boot will wear rubber and allow crud into clutch slave.

Example: If you assume stock rod is 6mm (.236 inches), then I would use 5/16 all thread rod and file threads of from boot to piston cup (.25" approx diameter) which would give a slightly tighter fit for the boot to rod.

Enrique?

Regards,

Pancho

[EricB]

Sorry Pancho I don't know where the ENrique thing came from...

Thanks again though...

-e

[EricB]

Anyone happen to know the pitch and thread on the NABCO clutch rod?

I'm guessing M8 x 1.25pitch but I don't have it in front of me...

Was going to order some longer threaded rod from McMaster Carr as they have it in stock for $3.-

-e

[Curtis240Z]

Did you replace the pressure plate and throwout bearing too?

The 280Z pressure plate is thinner in height than the 240Z. If you put the throwout bearing on backwards that would also make your travel too long. Just some food for thought.

[EricB]

'81 F54 L28 block mated to an '81 5spd in a '73 240.

Last time I changed the clutch and pressure plate I got one for an '81...

The clutch master cylinder I replaced on my car was the original 73 one - other than having sprung a leak it worked fine - I replaced it with another 73 Nabco one as described above and found the new rod to be too short - thus the source of my problems...

-e

[EricB]

Pancho

I unbolted the clutch master cylinder from the firewall and pulled it through into the engine bay, peeled back the rubber boot and looked at the threaded rod... I tugged on it a bit but fearing to brake something I stopped when nothing seemed to budge. It really looks like the rod is held into the ball/plunger assembly by a circlip or some equivalent. You sure it will just pull right out?

I guess I need to see an exploded view to see how the parts go together...

-e

[panchovisa]

Eric. SO sorry. I was talking about the rod on your slave cylinder.

[EricB]

ok well glad we're all on the same page now...

yeah it's the threaded rod that's too short...

-e

[mdbrandy]

$&*%...

I did peel back the boot and thought I saw the rod being part of the ball/plunger assembly... so I tossed it... that was last week... trash's been picked up...

any other ideas?

is the longer rod specific to only certain months of HLS30 production - like late 73 240's only???

Enrique as far as modifying the rod itself... you're saying it's just threaded in behind the rubber boot... so I can get a 1' section of threaded rod with the correct pitch, cut to fit, and replace it... nice. Ok I guess I'll do that then... So much for bolt on replacement parts for our cars... hahaha

-e

I had exactly the same problem when I replaced the clutch MC on my '78 280Z a year or so ago. Bought an Autozone MC, installed it, and found that the pushrod was really short. Peeled back the boot on the original, and it didn't appear to be removable. So, I returned it, then went and bought one from Nissan (expensive, but they had it in 3 days), and it fit perfectly.