Pointers

Pest · Post by **Pest** » Sat Jul 17, 2010 3:59 pm

I've just dropped the diff out of the Z and the gearbox is out next, both to be refurbished hopefully before the Coromandel run.

My question is, is there anything else I should be checking/doing/replacing while they're out? Stuff I wouldn't be able to reach with them in?

Anyone know what the heck the belt the goes over the nose of the diff is for? Seems pretty pointless.

Luke.

old_datto_fan · Post by **old_datto_fan** » Sat Jul 17, 2010 5:13 pm

The belt over the nose of the diff is to stop the nose of the diff lifting too much - that is what quite often creates the clunk you hear when accelerating hard. Make sure the strap is not damaged - if it is I have a few spares. The other option is to fit the R/T (Ron Tyler) diff mount which minimises the diff movement and replaces the strap. You need a special bracket and you can find details if you do a search on 240Z Ron Tyler Diff Mount.

The other things I would be checking are all the driveshaft universals, clutch plate wear and release bearing and the rear gearbox oil seal where the driveshaft goes in (probably worth replacing anyway). Also check for cracks in the clutch fork where it sits on the pivot mount, they quite often crack there.

Baker93 · Post by **Baker93** » Sat Jul 17, 2010 5:26 pm

Hi
Add to that list the drive shaft and half shaft universal joints. Check them for waer and give them a birthday with some new grease. Its probably a while since you have done them ! Check mostach bar and rear suspension hangers for cracks. These normally appear at the top where the metal is folded just behind the two mounting bolts. Much easier to see with all the stuff out of the way.

Andy · Post by **Andy** » Sat Jul 17, 2010 11:19 pm

Handbrake cable work is alot easier with drive-shaft out, check for normal signs of wear and adjust and lubricate.

Pest · Post by **Pest** » Sun Jul 18, 2010 11:08 am

Cheers gyus, will do.

old_datto_fan wrote:The belt over the nose of the diff is to stop the nose of the diff lifting too much

Really? The nose seemed to me to be bolted down pretty well. The mount is rubber, but surely it can't stretch enough to reach that belt? There's at least 3/4" between the diff nose and the belt.

BTW, Any recommendations of where to get the 'box refurbed?

Pest · Post by **Pest** » Sun Jul 18, 2010 11:11 am

Baker93 wrote:Add to that list the drive shaft and half shaft universal joints.

The half shafts are all looooobed up, I redo them about once a year. The drive shaft on the other hand, doesn't appear to have any way to lubricate. There certainly aren't any nipples on them like there are on the half shafts

and no apparent place to screw some in. Even looking at it closely now that it's out I can't see how to lubricate these.

us2 · Post by **us2** » Sun Jul 18, 2010 11:28 am

With age and use the diff mount rubber can degrade, allowing it to come apart, letting the nose of the diff move upward
under acceleration. The strap is supposed to prevent that if the mount breaks. Your driveshaft joints are sealed for life.
nothing to do unless they are loose.
I had a RWD Corolla gearbox rebuilt by a company in Takanini about six years ago and had no issues.
Gearboxes R Us. 327 Gt. Sth. Rd. Takanini. 296 1932. From memory they have been in business there about 15 years.

I wouldn't think an old Datsun gearbox would be much different than an old Toyota box, unless sourcing parts was a problem.

Pest · Post by **Pest** » Mon Jul 19, 2010 3:38 pm

I'm going to replace the clutch plate too. Is it worth replacing the pressure plate at the same time?

I'm not sure if the pressure plate is something you replace if it's not "broken".

us2 · Post by **us2** » Mon Jul 19, 2010 5:35 pm

I would say yes, replace the pressure plate. I replaced a clutch plate on mine 10 years ago and didn't
do the pressure plate. Of course the inevitable had to happen, and after a month, I was having
trouble selecting first gear. After a lot of headscratching I pulled the box again, and replaced the pressure plate
and no further trouble. Seems hard to tell if it's actually "broken" My 2c.

Pest · Post by **Pest** » Mon Jul 19, 2010 7:48 pm

Bought a clutch kit from Repco on the way home this afternoon. $263 for clutch plate, pressure plate and bearing.

They do a "performance" version too for $333.

asyado · Post by **asyado** » Tue Jul 20, 2010 12:43 am

Hi Luke, yes clutches are like wheel bearings, if you are gunna replace one while having gone to the trouble of getting the part off and the part isn't an easy fit. It always pays in the long run to replace all inline components eg pressure plate, clutch plate, release bearing and if fitted (can't remember on the Z, check ya maintenance book), renew spigot bush or bearing in centre of flywheel if looks dodgy. I've lost count how many times those little buggers suddenly seize up after having installed gearbox back in. Also check the flywheel's clutchplate surface contact point for cracks or grooves which will need attention if they are visable to eye. Last of all is a check of the flywheel ring gear, if it only has half teeth, good as time as any to replace now before hearing shredding metal when engaging starter motor, when I hear that sound it's like someone running fingernails down a blackboard( makes the hairs stand up on the back of me neck) and doing further component damage (starter motor drive), not to mention elevated stress levels from not having listened to the little mechanic on your shoulder when you convinced yourself you were going to save money by not doing it this time round. My motto is, if in doubt, throw it out, works for ex girlfriends too lol, saves alot of money. Nigel

nustad · Post by **nustad** » Tue Jul 20, 2010 11:26 am

Nobody has mentioned that fun job of cleaning everying so it is all sparkly.

Yours may already be clean but suprises lurk when you clean all the crud off..............

Pest · Post by **Pest** » Tue Jul 20, 2010 5:07 pm

Hahaha, I'm pretty sure the crud is the only thing holding it all together, I dare not remove it!

Pest · Post by **Pest** » Wed Jul 21, 2010 8:22 pm

Finally pulled the bung on the gearbox to drain it prior to transport and *surprise* there are ominous large chunks of important looking metal stuck to the bung magnet and the oil is all sparkly; I'd say it was pretty if it wasn't so catastrophic.

Looks like I made the right call to pull it out!

The metal looks like it might be the ball retainer from a bearing, so hopefully the gearing is still OK. I guess we'll find out

In the event that it's too far gone, anyone here got a gearbox they'd part with at a reasonable price?

us2 · Post by **us2** » Thu Jul 22, 2010 1:33 pm

Was it howling in 5th gear.

I had this in the old Corolla box
and it turned out to be bearing failure, amongst other things, by the
time I actually had it seen to.