Haven't seen this before!

[Logical1]

I live way up in the middle of nowhere while not working and love it. Do to force majeure I was away from my place for over a year and a half. I recently got back home and was happy to find most of my place unmolested from humanity, but nature took its toll. MY 85' 720 had been sitting for over a year and besides the small packrat nest in the engine bay and a slightly low tire she fired right up and ran great!

 

 

She has been running great for the last two weeks and I have been super happy. On my way back from town (a 15-20min trip) she got quite a bit louder. She has had an exhaust leak for a while because some of the exhaust bolts were stripped. I haven't worried about it to much, as its a country truck. well halfway home I went to shift and the clutch pedal hit the floor. I am in the middle of BFE on a sunday and know there is no help available. I leave it in 4'th for the most part and do some rpm gear shifting to take some turns. I get to my turn and was able to get it onto my road (dirt) without it dying and nudge it into 2'nd. 

Edited December 23, 2024 by Logical1

[Logical1]

I live down a crazy ass 3 mile driveway that the last part is 4x4 only and I am thinking of a way to keep it moving so while going down the last downhill I slow it down as much as possible and then pull the transfer case into 4 low. I dont truly need all 4 wheels to grab but I do need the low gearing to keep me going slowly through some serious bouldering. Amazingly I get it back to my property and I am so grateful! I get out and open the hood because I am so curious as no clutch has died on me like this in a Datsun. It turns out my exhaust manifold had rocked/vibrated loose and was blowing ultra hot exhaust gasses over my master cylinders! luckily the break master is tough and lived!

[datzenmike]

Problem identified.

[datzenmike]

Degrease the stud holes with brake cleaner. Put some JB weld in the bolt holes and screw new studs in without the manifold till set. 12-15 ft lbs should do it.

[Logical1]

 

1 minute ago, datzenmike said:

Degrease the stud holes with brake cleaner. Put some JB weld in the bolt holes and screw new studs in without the manifold till set. 12-15 ft lbs should do it.

That was my thought for s short term solution as well. 

I have another head down here but its off a 80's A10 wagon and I dont have the time to get really deep as I am leaving to go back to work shortly.

 

What I am curious about and would like to document is the thermal resistance of original parts Vs newer. I had replaced the clutch master with a new version as NOS are tough to get these days. that being said, the OG brake master took the heat without issue. I think its worth noting. 

[datzenmike]

The brake master is way to the front and missed most of the heat.

 

The Z20 head will work. The only difference is the intake ports are round where your Z24 are square with rounded corners. I guess use the round Z20 intake gasket.

 

Also the Z20 head will have a hole in it for a mechanical fuel pump. (on the 720 it might have a block off plate) On the Z24 it's not used for that but for the power steering pump.

 

[NC85ST]

What a way to lose the clutch master cylinder! Never seen an exhaust manifold come off like that.

[datzenmike]

It's probably just the reservoir that's failed and lost all the fluid. Get one off a spare brake master. Warm it in hot water, dry and then quickly put the clamp on.

[Logical1]

Luckily I brought my parts stash when I moved from Seattle and have a good working original clutch master from another 720 I parted out! Also lucky I have a big bottle of dot 3 stored tight and dry. I also have some JB weld for the head! I live about 18 miles from town and haven't really made any friends here yet. That is a long walk and its xmas week, which means in this town most everything will be closed all week. Living in the mountains, out in the woods is not for the faint of heart!

[banzai510(hainz)]

iF your real good or someone use steel keenserts if it pulls out again