84 720 kc project

[mattmctree@gmail.com]

so i went to a local clutch supplier on the off chance they might have one and they had it. i used the tool and got the transmission on in about 20 minutes! live and learn. when i put the front diff back in the breather tube was rotten and came right off. any way of replacing these? the exhaust system is off up to the engine and need to get welded back together. can i still run the truck with no exhaust or will the lack of back pressure from the exhaust system make things wonky?

[datzenmike]

The diff vent hose ids just to prevent water being sucked in. Any oil resistant hose will do.

 

Truck should have a few feet of pipe to direct hot exhaust away from torsion bars and tranny.

[mattmctree@gmail.com]

ive been putting an 84 4x4 back together to get mobile. when i bought it everything looked ok. the frame seems alright but after scraping away some of the undercoating and tapping with a hammer i have found a hole in the frame that i can stick 2 fingers in. its right under where the cab meets the box just above the front perch for the leaf spring? i got the truck for 800 as a learning experience and would like to get it road worthy again. is this a deal breaker? are there any ways of repairing a frame or will i have to try and locate another frame. to look for more rot i will have to take the box off and scrape down the frame which will likely help. 

thanks

[datzenmike]

My 620 frame rotted away from the driveshaft side where you don't notice it. Eventually someone told me that the front of the leaf spring as moving. It had rotted away and explained a clicking sound. I had a couple of feet of U shaped 1/8" steel bent up. Slid it up from below over the old frame and welded it along the two top edges. Had to do the other side as well. This was extreme but it can be fixed. When done I poured motor oil in the frame ends for rust proofing.

[DanielC]

I see two options.  Replace the frame, or repair the frame.

finding a 720 4x4 framne might be easy, or not.  I do not know where Burlington Canada is, forgive my USA lack of knowledge, but if they salt the roads where you live, other frames might be just as bad.  Also there is the issue of the frame legally being the truck, that is the VIN is on the frame, and that is the one on the title.

 

Other option is repairing the frame.   Cutting bad parts away, inspecting what is left, welding in new parts.

 

Unless you are really handy, and sentimentally attached to this truck, you probably want to look for another truck.

[datzenmike]

Burlington? Ha I missed that, I lived in Binbrook as a kid just to the south up on the escarpment. Yes they most certainly salt the roads. Burlington is on the outskirts of Hamilton at the very western corner of Lake Ontario.

 

Last time I was in Ontario with my 620 I needed a gas tank. There were no Nissans before '92 ish. I tried from Windsor to Kingston... nothing. Very rare to hear of a 720 out there and it mist be a nightmare finding parts.

[nsackett]

my 83 720 had a small hole in the frame right under the drivers side leaf spring mount. the hole was about the size of two fingers, i just cut all the rust away from the area and welded a patch in. i just used regular 90 wall steel. (that's 90 thousands of an inch thick, just to clarify) grind the welds flush when you're done and throw some undercoating over it, you'll never know it was there,.

[mattmctree@gmail.com]

yeah they are like hens teeth! damn salt. i wish they used sand. i recently got a millermatic 211 mig welder and am fairly handy so i think i will try to repair it as i got it for a learning experience, plus to maybe i can make it into a bush truck.

[mattmctree@gmail.com]

im going to start scraping and then brushing and grinding my truck frame to see what ive got to work with. does anyone know of a good rust neutralizer/converter product to use before painting?

[mattmctree@gmail.com]

so i picked up an alignment tool from a clutch shop in town and that was my problem. i re hung the clutch disk and the transmission went in second try with no swearing. i drained and filled the tranny , transfer case and both diffs. its still up on blocks as i have to get the shafts back in but i wanted to see if it would turn over. it started with some coaxing but runs like a bag of shit, tranny fluid started poring out the tail stock which i am assuming is normal since the primary drive shaft isnt in or do i need a new seal in the transmission? also i put a starter in that i rebuilt and it will catch the ring gear for a few seconds and then fall back and just spin? i put a new solenoid in it. could it be a bad bendix or a bad ground. im a bit confused why its doing it.

 

thanks for all the help here

 

this site is great

[datzenmike]

The transmission should hold about two quarts. If off the ground it may be tilted and over full. Yes running it without the driveshaft could do this. ALWAYS replace the $5 rear seal... it's easy and cheap insurance against leaks.

 

Low battery can cause the solenoid to jump out early. Also bad connections. Make sure the ground cable on the intake is clean and tight as are the battery terminals.

[mattmctree@gmail.com]

is the seal easy to change with the transmission in the truck?

[datzenmike]

Awkward to get at but totally do able. Certainly easier than taking the tranny out and back in....

[mattmctree@gmail.com]

on my 84 720 which i got running and driving after sitting for 15 years in a barn needs a new fusible link on the positive battery cable. the one on there is melted slightly and i have to wiggle it to make a connection. what would cause the link to go? i am in ontario canada and am having a hard time finding where to buy a new link, most auto parts stores and nissan dealers say that they arent available . any one know where to get one?

 

thanks

 

[datzenmike]

The fusible links protect the power wires going to the fuse box and the ignition. In the event of an accident these wires could be crushed and pinched to ground causing a fire. They are NOT regular wire and have a special; Hypolon coating that resists catching fire.

 

 Fusible links are color coded with Black handling 80 amp and Green 40.

 

You could replace with a large fuse from some modern vehicle. I've seen 30. 50 and 60 amp fuses that clip in line. Just take a walk through a wrecking yard and grab some and some extras.

[Dawa]

the fsm will call out what amp fusible link youre supposed to use. or if you do like mike said you just take one from another donor and youre all good!

on my 620, i replaced my fusible link with an inline 30amp fuse. 

ive read a lot on battery relocations for multiple different cars and it seems like 30 amp is the highest you might wanna go. 

[Hyspeedz]

I ordered a fusible link from my local Nissan dealer and had it in three days. I too have an '84. Best of luck.

[Z-train]

I've replaced my FL's with 30 AMP circuit breakers.They just plug into a spade fuse receptacle.

[KELMO]

24022-10W00 should be your part # through Nissan (at least for a Federal model (USA), could be a different # for Canada but I don't have a Canadian catalog.  Any counter guy worth his salt should be able to find the right # based off of this one.

 

My $.02 worth

[mattmctree@gmail.com]

Finally after a long time of not being able to work on my truck I got the clutch and transmission back in and have taken the truck up and down the laneway. First time its been mobile in 15 years. As a novice shadetree mechanic I've got a couple issues I wanted to ask questions about. 1 i rebuilt the starter and put it it however when I turn the engine over it will engage the ring gear and then drop out imediatley. The solenoid is new. Could this be a grounding issue? I noticed a small steel braided strap (grounding strap?) That is on the firewall but it is not connected to anything. I replaced the fusible link on the battery yesterday but the one I got from nissan has 3 connectors and the old one only has 2. Curious as why and whether I can just tape up the other connector? I was under the truck and found a hole in the frame. ( Shit!) Iam I better to patch it or gusset and plate the frame? The whole frame looks like it was zeibarted originally so its tough to tell if there are any other holes until I have time to strip the frame. Has anyone heard of aftermarked beefier frames? I'd rather try and repair it but we will see.

 

I appreciate all the help.

 

This site is great.

[mattmctree@gmail.com]

i got o ne the other day from nissan. when i went to put it in i noticed that the old one only had 2 connectors and green and black wires. where the new one had 3 connectors and green black and red wires? am i able to use this? can i tape up the third harness? im guessing that the third connector is for an efi model?

[datzenmike]

Should have two Greens and a Black.

 

One Green fusible link is connected to a large RED wire. The red wire goes directly to the lighting switch.

[millican]

You don't literally mean to "tape" anything on the harness, do you?

[millican]

Congratulations on reviving the truck from the dead!

I recently had a similar issue (among others) with the starter. If you have the same problem, it's an easy fix. The bolt that holds the linkage in place to move the gear in and out was missing on mine. I think the torque of the motor spinning would move the gear, but it wouldn't stay engaged without that bolt. I have an image posted in a recent thread about part numbers for the solenoid.

For the holes in the frame, I just don't leave small items in the floorboard. However, I did find an unspent bullet in the floor recently and wondered what would happen if it hit the pavement while driving along the highway. Who knows how long it had been there or if there are more. I didn't put it there.

[millican]

The Allen wrench indicates where the bolt should be.