1981 280zx 5 speed

[Dave WM]

more researching on the topic of stuck hardware, massive sustained torque leads to shearing off the bolts.

Heat, seems to be popular as does impact tools. I have a hand held manual impact tool (whack with hammer on back) which seems the safest for starters if I go that approach. Also have electric impact driver, seems like I could go overboard with that. looking into nut splitter, challenge will be to find one that will fit. May end up getting the oxy/ace torch as I would like to have one of those anyway.

[EuroDat]

If your propane torch is enough for plumbing solder, it should have enough heat for the brass nut.

I would get as much heat I could into the nut and try to spread it by hitting it in the middle of one or two flats with a chissel. Hit it in the centre of the flat in line with the stud, not across. That will help spread the stud and create clearence.

No garantees you will get it off without breaking the stud. I had one come loose but lock up on the dirty threads on the way off.

Good luck with it.

[Mark Maras]

 After you've heated the stud and nut to smoking hot, Dry or wet ice applied to the end of the stud will chill it rapidly. My theory is the stud will shrink and the nut will stay hot. I've used this method a few time and it does seem to work better than heat alone. Be sure to wire brush any of the exposed stud threads. The nut can break loose and then jam because of the corrosion on the exposed threads.

[Dave WM]

I guess if I bust the nut, I will need to drill out and thru bolt it?

[EuroDat]

Yes. That is the risk you take when you remove the collector pipe.

There many opinons on how to go about this. Like Mark said, heat the nut red hot and cool the stud as much as possible. This will create clearance by shrinking the stud and expanding the nut.

Another way is to heat the stud red hot and then let it cool down again. Then heat the nut. This will cause the stud to stretch, expand and creap out where there is room. The tension on the nut relaxes a bit when the stud is red hot. When it cools it will shrink again, but not as much tension on the nut. Heating the nut will than expand the nut. When you try to undo it then the stud will be cool and at its strongest.

Another option you can try is heat the manifold where the stud is and get is really hot then try to screw the nut with stud out of the manifold.

 

[Dave WM]

got the nuts in today from Nissan 20602-S0600. Looks stainless.

Side note, wanting to get some highway miles on the Z today took a cross town trip at 65-75 mph. at the 1/2 way point (30 miles or so) while in traffic the brake booster went AWOL. Besides no power assist, everytime I applied the brakes it developed a massive vacuum leak (at least it only happened with brakes on). Ordered the booster from autozone should be here Tomorrow. Got the old one out ready to install the new.

[Zed Head]

Yep, you're on the new owner of old car path.  Expect more.  Study up on ignition modules.

[Patcon]

20 hours ago, Dave WM said:

Looks stainless

Take a magnet to them. They may attract but it will be weak if it's stainless

[Dave WM]

1 hour ago, Patcon said:

Take a magnet to them. They may attract but it will be weak if it's stainless

magnetic test negative (virtually no attraction to a rare earth magnet), so stainless they are (I sound like yoda).

[zKars]

I’m not sure if this is the best thread to add this information to, but it started out and generally speaks to rebuilding the 5 speeds, even though it ended with exhaust nuts….

I’m back rebuilding a few 5 speeds again this fall, and did an operation for the first time and thought I would record the “how to” here for posterity.

This relates to replacing the two shifter rod seals (o-ring and oil seal) in the upper rear case of 71B 5 speeds. I think it applies to the 4 speeds as well.

This requires removing the shifter rod which requires you remove the spindle pin like lock pin that resides in the rear case to detach the shifter rod from the finger that engages the shift forks. 

On the 81-83 trans, you have access through the reverse lockout thingy hole to bash it out with a punch or air hammer but on the 77-80 transmissions, there is no such reverse lockout do-hicky. We/I have given advice previously to drill a hole “in the right spot” then to plug when done. Until now, no one has documented exactly where to drill and how to plug. Well here goes.

[zKars]

I drilled a 5/16 hole, then enlarged it to about 3/8 and angled it to aim at the pin more directly.

When done I drilled it to 27/64 (just under 7/16) and tapped it with a 1/4NPT tap and plugged it.

The hole is 3.125 from the case face, and down 1.375 from the casting edge above. 

I’d likely use a plug with a recessed hex head rather than the square headed thing I show, it’s just what I had on hand. Locktight it in. 

 

[zKars]

You can move the rod in and out several inches so the front to back position is not very critical.

I made a simple plate jig to hold the end of the rod in place to support it while bashing the pin out. 17/32 bit for the rod I think. Hose clamp to hold the rod fully forward. This puts the pin head exactly 3-1/8 back from the case face.

I have used an air chisel tool with a round bit in the past to get this pin out, it works extremely well and is nearly instantaneous. Beating it with a punch requires more effort and unpleasant words.