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Any tips for starting 620 after sitting for 7 years?


JohnnyBlaze

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11 hours ago, datzenmike said:

I'm not convinced the arm is stuck at all. Takes a lot of force to move it back.

New clutch master, hose, and slave cylinder in now. When pushing the clutch in the slave is leaking from where the hose screws into it. I believe this is happening because the clutch is frozen/rusted and the slave can’t push the arm. I tied starting it in gear to break it loose a few times, but that hasn’t worked. I’ve seen videos of people lifting the back of the truck with a jack and starting it in gear. Then releasing the jack and the wheels grabbing the ground can break the clutch loose, but idk. Any other suggestions?

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The throwout bearing sleeve could be rusted to the collar on the front cover of the trans. I do not know of any way to break this free without removing the trans from the truck. You could use a large pry bar and try fitting it in the access hole, but you might risk damaging other parts.

 

You could always try squirting some WD40 in there and let it sit for a couple days before trying again. But even if it does break free, if it were rusted enough to cause sticking, it may have junk left over inside the collar that will cause it to stick.

 

So to clarify, you installed all the new hydraulic parts and you cannot push the pedal? Does the pedal move at all? If what you say is true, don't force it.

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It shouldn't leak. If the clutch arm was not moving the pedal would be solid and not move. Check you are not cross threaded. These are re manufactured or rebuilt with extremely poor quality control. May have been traded in damaged as a core or made wrong. Dealership ones are $60-$80. Try plumber's tape on the threads.

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3 minutes ago, Stoffregen Motorsports said:

The throwout bearing sleeve could be rusted to the collar on the front cover of the trans. I do not know of any way to break this free without removing the trans from the truck. You could use a large pry bar and try fitting it in the access hole, but you might risk damaging other parts.

 

You could always try squirting some WD40 in there and let it sit for a couple days before trying again. But even if it does break free, if it were rusted enough to cause sticking, it may have junk left over inside the collar that will cause it to stick.

 

So to clarify, you installed all the new hydraulic parts and you cannot push the pedal? Does the pedal move at all? If what you say is true, don't force it.

 

 

I have seen one steel cover plate from an '85 Diesel. By far all the other cover plates I have are cast aluminum and won't 'rust'.   

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6 minutes ago, Stoffregen Motorsports said:

The throwout bearing sleeve could be rusted to the collar on the front cover of the trans. I do not know of any way to break this free without removing the trans from the truck. You could use a large pry bar and try fitting it in the access hole, but you might risk damaging other parts.

 

You could always try squirting some WD40 in there and let it sit for a couple days before trying again. But even if it does break free, if it were rusted enough to cause sticking, it may have junk left over inside the collar that will cause it to stick.

 

So to clarify, you installed all the new hydraulic parts and you cannot push the pedal? Does the pedal move at all? If what you say is true, don't force it.

I installed all the parts and everything went together easy. The pedal was firm and the slave rod moved a little, but the arm wouldn’t move. Now the pedal is softer because the fluid is leaking from where the hose attaches to the slave when I push the pedal in. The rubber boot is torn bad that goes around the arm, so who knows what kind of elements got in there like water or mice. 

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10 minutes ago, datzenmike said:

It shouldn't leak. If the clutch arm was not moving the pedal would be solid and not move. Check you are not cross threaded. These are re manufactured or rebuilt with extremely poor quality control. May have been traded in damaged as a core or made wrong. Dealership ones are $60-$80. Try plumber's tape on the threads.

It definitely isn’t cross threaded since it went together easy. The slave and hose didnt come with a washer, so I don’t think there is supposed to be one, but idk. I can try plumbers tape and see if that helps.  If the tape doesn’t work I guess I could send it back to Rockauto and order one from the dealer. I really do feel the clutch parts are frozen since I’m sure lots of moisture got in the torn(almost missing) boot in the years it was sitting. I might just have to buy a clutch kit earlier than I was planning to ?.

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Some of them did have a crush washer type seal, but more than likely it's an inverted flare fitting. The easiest way to tell is to remove the hose and look at the end of the threads. Is there a convex surface at the end? Does the inside of the slave (at the bottom of the threads) have a similar corresponding bubble? If so, then it's an inverted flare fitting. Another way to tell, does the fitting bottom out all the way to the "nut" on the hose? If so, then you may need a crush washer.

 

Mike, I think the aluminum covers were generally used on later model transmissions. I have seen plenty of 4 and 5 spd Datsun transmissions with cast steel or iron covers. I have never had one rust like that though.

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Had a '78 620 5 speed, '79 620 4 speed traded for a Z24 5 speed, '79 280zx, '80-'83 280zx, '80 200sx, '85 CA18ET,  Z24 shorty 4x4... all 5 speeds, maybe 1 or 2 more? all aluminum. I thought they all were.  

 

The cavity inside the release collar is packed with grease so rust can't be it. There would have to be something broken inside the clutch diaphragm jamming it. 

 

 

If spraying fluid you aren't getting full release pressure.

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The Napa Auto by me had a slave cylinder in stock, so I went up and got that. There was a washer on the original slave I took off, so I put that on the Napa one. I also sprayed a bunch of brake cleaner in the trans opening. No luck and there is still fluid leaking from where the hose screws in. I think the clutch components are just too rusted or something is broken like you said.

 

I guess I’ll just order a new clutch kit and put that in. Should I replace anything thing else while I’m in there, rear main seal...? I’ll check prices online, but any suggestions for clutch kits? I was thinking just getting an oem style one from Rockauto or Partsgeek...something like that. 

 

I've been searching and I can't find anyone selling a flywheel for this things.  I'm looking to get the Exedy oem style clutch kit, but can't find a flywheel.  Does anyone know where to get one?  Thanks

Edited by JohnnyBlaze
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Just now, Stoffregen Motorsports said:

Though Datsuns are the Chevys of the import world, parts aren't as readily available. You likely won't find a good stock replacement flywheel, and a performance flywheel isn't needed on a stock build.

 

What's wrong with yours? Can it be re-surfaced?

I’m not sure that anything is wrong with mine. I just figured it may be a good idea to change that when I do the clutch, but I’m sure I can resurface the original. Would you recommend anything else to replace while I am doing the clutch kit? Should I reuse the flywheel bolts or get new ones? Thanks!

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One saving grace about Japanese cars is the quality of the components. The stock flywheel bolts are very strong, and if they are in good shape, they should not need replacing.

 

Note - there are about 4 different flywheel bolts for the L motors. The strongest being the ones from the 280ZX turbo. You likely have the bolts marked with a "T" which came in the late 70's and are still very good bolts.

 

I can't think of anything else to replace, except maybe the trans front seal, but if it's not leaking, maybe just leave it alone. I wouldn't do the rear main on the engine either. The factory ones were vary high quality, and again, if it's not leaking, leave it alone.

 

One last thing. Use red loctite on the flywheel bolts when reassembling it. Use it on the clutch cover bolts too. People will say that red loctitie is toostrong and recommend against it, but they are wrong. It's all I use. Better safe than sorry.

Edited by Stoffregen Motorsports
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My first question would be are you actually seeing with your own eyes the slave/hose connection leaking, or are you just seeing fluid on the ground and in that slave/hose connection area?

I would check to see if the hose connection above where it is connected to the hardline is leaking and make sure fluid is not just draining down the hose and that other connection is where is is dripping from as that is the low spot.

There is a flat copper washer between the hose and the slave, it needs to be tight!

I myself have only seen diesel 5spd transmissions with steel from covers, but I heard that a few of the Zcars had steel covers also, I have never seen one myself, but I have not been looking at Zcar transmissions either, I mostly deal with 720 truck transmissions.

 

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2 hours ago, wayno said:

My first question would be are you actually seeing with your own eyes the slave/hose connection leaking, or are you just seeing fluid on the ground and in that slave/hose connection area?

I would check to see if the hose connection above where it is connected to the hardline is leaking and make sure fluid is not just draining down the hose and that other connection is where is is dripping from as that is the low spot.

There is a flat copper washer between the hose and the slave, it needs to be tight!

I myself have only seen diesel 5spd transmissions with steel from covers, but I heard that a few of the Zcars had steel covers also, I have never seen one myself, but I have not been looking at Zcar transmissions either, I mostly deal with 720 truck transmissions.

 

I just double checked and it’s definitely leaking from where the hose screws into the slave. The hardline and hose connection is dry. I’m not going to mess with that anymore right now. I’m going to order the clutch kit and replace all that and hopefully that will give me a working clutch and none leaking slave. I’m going to order all my front and rear brake components too since they are old and at least one rear drum is frozen.  Thanks!

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21 hours ago, banzai510(hainz) said:

This is just me.

On the brakes I would only replace what is needed. The new Hydralic stuff is not as good as the Japam made orginal. I only get 5 years outof the Taiwan,Chinese,Italy made units.

 

One could always shooh PB Blaster in thru the trans hole if you think the T/O bearing is stuck

Then don't get cheap Chinese stuff. OEM parts are still out there.

 

I disagree on replacing only what's needed. Brakes are one system I don't roll the dice on. Besides, what's involved in a brake system? Two wheels cylinders, two calipers, three hoses, and a master cylinder. Hard lines if they are badly corroded, and maybe a new tube nut here and there (if you're careful with disassembly, this shouldn't be a problem).

 

I have seen clutch slaves that were not spot faced where the hose connects, so even if a crush washer was installed, it wouldn't seal on the rough, as-cast surface.

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Stoff

Going to the Nissan Dealer unless you know the person and delt with them is now just a heartache away from me punching them.

1St thing is that vehicle is so old, is the 1st thing they say. I have to guide them thru the microfisch or computer to help them looking up the parts. Just tired of them. 6 months earlier they were at the Ford Dealership.  if I can find Jap made parts believe me Im on it.

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Reminds me of our cross country road trip in an MGB about 20 years ago. At a NAPA auto parts in Iron River Wisconsin, told the guy we needed NGK B6ES spark plugs. He asked for what. I said never mind. He persisted so I said MGB. He said do you mean GM?

 

I get it. I know it's a pain. You don't have to go to the dealer though. Go through one of those online guys like http://www.new-datsun-parts.com/

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MIke I know about the part numbers. But still they say NLA or cop a attitude at the dealer cause they don't want to deal with you and then the price is a killer when one used to be able to find the same Jap part(just repackaged) at a good import place but they all have gone defunct now.

All my 510 stuff I got long time ago from Nissan when I had a person there I trusted. Now I just Rockauto it for my 521 and sometimes its good and sometimes bad. But usually I tried the Autozone , O Rileys parts as my 521 was a daily driver and needed the parts like NOW , but then learn the Taiwan mastercylinder only last 5 years. Now the OEM Nissan are NLA so unless seombody has a good stash its the 2nd rate stuff I get now unless by chance it says Nabco Tokico ectt......

 

Last time I went to dealer was for 521 heater hoses esp the S shaped one for the head. and throttle cable, speedo cable all NLA for the 521. Lucky I had spares. but found some cheezy spares on Rockauto.com but we will  see if they really even work. esp the speedo cable(Pioneer brand)

 

Even that link you posted most are just aftermarket Cheap stuff. the Nissan stuff is $$$$$ or NLA

 

 

Edited by banzai510(hainz)
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