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JohnnyBlaze

1978 620 Brake, Suspension, Engine, etc... Update/Upgrade?

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I have been searching through here and google and not finding all the answers I need...Help my brain is melting from all the searching ?.

 

I just bought a 1978 620 5speed that has been sitting for years.  This will be a project that may take quite some time, but I'm anxious to get start and look forward to learning and getting it road worthy.  Hopefully I can find ways to save money and not have this project become a money pit ?.  I will be going through the whole truck since I'm sure most or all of the major parts need help.  I already plan to get the truck glass blasted and will have rust areas fixed ( there are a lot) and do a cheap paint job.  I plan to do a KA engine swap and have been learning all I can about that.

 

I will most likely keep it rear drum brakes with new components and will replace or upgrade the front disks.  I read that I can swap the D21 front brakes and get Belltech drop spindles since I do plan to lower the truck.  Can I use the 2wd D21 front brake components or do they have to be 4wd like the post I read?  There are usually a few 2wd hardbodies at my local parts yard and hope to source what I need from them.  I also have Belltech 3" lowering leafs and was curious if I could put them on the 620?  I believe someone on here did that and just redrilled the plates to bring them in line with the 620 axle...Is that correct?

 

In short my question now is..

 

--Can I use 2wd Hardbody front brake parts to upgrade my factory disks?  I will probably do drop spindles for a better ride being lowered which is why D21 brakes would be used.

--What parts do I need to source from the hardbody?

--Can I use 2wd Belltech lowering leafs on my 620?  Redrill leaf mounting plate to line 620 axle up?

--What shocks do I need for the above set up if I can do those upgrades?

 

Thank you and sorry for the long post.  I know I will have more questions throughout this journey.

Hopefully I'm adding these pics correctly below..haha

 

 

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6808E22F-E31B-49BE-8DD1-04260B8D41D0.jpe

 

44223096-819C-405A-B4DB-C2B9B9C1B3DE.jpe

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Holly crap that's a lot of rust.

 

Yes 2wd well work. Just pick a year and use all components. I used 1990 d21 2wd.

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Awesome, thanks for the reply Farmer.

Yes, unfortunately there is a ton of rust.  I'm not sure the bed will be salvageable, but I'll see once I get it to my house and start going through it.  I already bought the rocker panel patches from Tabco. These trucks are rare to find around me and this one came up as a parts truck.  He had the title and it's a complete truck, so I made him an offer and took it off his hands for a few hundred bucks.  I could have driven several hours and got one for close to $3k that still has rust and I'd dump more money making it the way I want.  I was thinking this way I got it cheap and will basically rebuild it the way I want and will probably be around the same cost or cheaper...hopefully.

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You can bolt up any brake upgrade you want, you just unbolt the ball joints from the upper and lower control arms from the doner truck and bolt the assemblies onto your control arms, connect the brake lines, bleed them and you are good to go.

Now if your going to piece it together, get the drop spindles, pick any year after mid/late 1986 preferably, use your 620 hub and buy all the same year parts(rotors/calipers/brake lines) and bolt them on, bleed the system and your good to go except for the modifications to the tie rods, and you will have to get 15 inch wheels/rims unless you cut the end of the lower control arms off, then you can use your 14 inch wheels, at least I believe that is what needs to be done.

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Can you really? I do know that there is a geometry difference between the 620 and 720, but I don't know if the difference is limited to the suspension components, or if the frame has differences too.

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10 hours ago, Stoffregen Motorsports said:

Can you really? I do know that there is a geometry difference between the 620 and 720, but I don't know if the difference is limited to the suspension components, or if the frame has differences too.

If the 620 is a ball joint truck as it should be if it is a 78, then everything between the ball joints is interchangeable, I even put the 1990 Nissan hardbody V6 dual piston caliper brakes on my work truck that had 620 non-vented type disc brakes on it, I just bolted them in and bled the brakes and I was good to go.

It is easier to unbolt the ball joints than to remove the spindles from the ball joints, that is why I say to remove everything between the control arms and transfer them to your control arms, I figured all this out when I bought a set of V6 brakes from Yello620 several years ago, since I already had early 620 disc brakes in the truck the better V6 dual piston type brakes bolted right in.

I believe that everything from 1978 thru to when they put the lower ball joint into the lower control arm will interchange, I do not know what is interchangeable after that ball joint is put in the lower control arms, I do know that the 1990 Nissan Hardbody V6 dual piston calipers are the same as what the Pathfinders have.

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'78-'79 were ball joint, '77 and older were king pin.

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It's a good idea to upgrade you master cylinder to a 15/16" or 1" bore.
You will also want to make sure the master is set up for disc/drum or disc/disc depending on what you do in the rear. 

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If running rear disc, any disc brake residual valve from a front disc brake car will work. 

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2 hours ago, ]2eDeYe said:

It's a good idea to upgrade you master cylinder to a 15/16" or 1" bore.
You will also want to make sure the master is set up for disc/drum or disc/disc depending on what you do in the rear. 

 For front discs and rear drums, do you recommend a specific master cylinder to get? Would it be a universal one or get one for a certain vehicle that bolts right up?

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When in doubt, get the master cylinder designed for use with whatever brake system you are running. ie- if using D21 brakes, get the master for that application.

 

This isn't a rule. It just helps make sure everything is happy together.

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The 1979-1982 (I think) Z car master bolts up to the booster and comes in 15/16 disc/disc. The front brakes on this are essentially the same as the d21. 

You can change the rear residual valve from your 620 master to the Z master to set it up for disc/drum.

These masters are getting hard to come by, just FYI. 

There is an aftermarket 1" upgrade that is a bit easier to find, it will show up in a search for the 79-82 Z. You may need to do the same valve mod to run drums in the rear or maybe you can specify during ordering.  

 

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Steve's right the ZX 15/16" master you want is identified as having vertical mounting bolts and will fit right onto the 620 booster. I found one and NAPA found me a rebuild kit. The counterman said it was the only one he could find and also that he's been doing this for 20 years and had never seen this style of art work on the box. It was really old looking.

 

I think the 810 (but not the Maxima) used the same 15/16"... and good luck finding one of those.

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The entire spindle from 2002 2wd V6 D22 will drop straight in from ball joint to ball joint. The steering link is different though. I used a 720 steer arms and a 5mm spacer under one mount bolt. Other options may work. Geometry would be within a few mm from memory. 270mm discs twin piston alloy calipers. 

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17 hours ago, ]2eDeYe said:

The 1979-1982 (I think) Z car master bolts up to the booster and comes in 15/16 disc/disc. The front brakes on this are essentially the same as the d21. 

You can change the rear residual valve from your 620 master to the Z master to set it up for disc/drum.

These masters are getting hard to come by, just FYI. 

There is an aftermarket 1" upgrade that is a bit easier to find, it will show up in a search for the 79-82 Z. You may need to do the same valve mod to run drums in the rear or maybe you can specify during ordering.  

 

Doing a quick search online and it looks like I'll have no trouble finding the master cylinder for the Z.  Thanks

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I'd pass if it's a $40 re-pop from China.

 

Certainly disassemble it and check for metal shavings and that the seals are there and put in correctly and lube with brake fluid so it doesn't start up dry.

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My 620 is getting delivered today and besides cleaning and looking over it more I want to see if I can get the engine running soon.  As stated before it has been sitting for years.  I have read several posts about steps to take before trying to start it, so I plan on taking those steps.  I searched and didn't see anything about specific tune up parts that the stock engine likes and where does everyone get your tune up parts from? I have typical auto parts store around me and I'm sure they don't stock anything for these trucks.  I'm thinking plugs, wires, cap, rotor, and any items like that.  This is my first carbureted vehicle, so any help on the carb side would be helpful too.  My Haynes manual should be here any day now also.

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rockauto.com or local parts places. 

ebay and amazon work too. I even got a repop rearview mirror on amazon. Never had one that wasn't crumbling til then lol. 

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2 hours ago, ]2eDeYe said:

rockauto.com or local parts places. 

ebay and amazon work too. I even got a repop rearview mirror on amazon. Never had one that wasn't crumbling til then lol. 

Yeah, I was looking on Rockauto today. I was thinking plugs, wires, cap, rotor, ignition coil, and thermostat right off the bat. I’ll look at coolant hoses, belt, and fuel lines and filter to see if they are dry, cracked, or dirty too. I was searching for “tune up” on here and didn’t find what I was looking for, but after searching for individual items I found info on plugs and wires these engines like. Thanks!

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Coils don't wear out, they work or they don't. Likely you will get an inferior product if you replace it. Stick with the original if you have one. Everything else is replaceable.... certainly ANY filter.  

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5 hours ago, datzenmike said:

Coils don't wear out, they work or they don't. Likely you will get an inferior product if you replace it. Stick with the original if you have one. Everything else is replaceable.... certainly ANY filter.  

False. Windings within the coil can fail from vibration/heat/short and reconnect internally significantly changing the resistance value and spark output. They can also have a broken wire that makes connection when cold but after heating and expanding shows up as an open. 

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Very rare on a stock Nissan coil, they're that good. Replace when needed. Don't fix what ain't broken.

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On ‎9‎/‎25‎/‎2018 at 2:00 PM, ]2eDeYe said:

The 1979-1982 (I think) Z car master bolts up to the booster and comes in 15/16 disc/disc. The front brakes on this are essentially the same as the d21. 

You can change the rear residual valve from your 620 master to the Z master to set it up for disc/drum.

These masters are getting hard to come by, just FYI. 

There is an aftermarket 1" upgrade that is a bit easier to find, it will show up in a search for the 79-82 Z. You may need to do the same valve mod to run drums in the rear or maybe you can specify during ordering.  

 

I'm getting ready to order a clutch kit and I planned to order front and rear brakes too since mine are old and are kind of frozen.  I'm going to order everything for the rear drums and was going to get everything for the front.  I figure it makes sense to get everything for running D21 drop spindles now since I figure that is the best route for lowering the truck and will save money in the long run getting it now.  I need a master cylinder and figured I should upgrade that to the 15/16 like you suggested.  I have seen the mid to late 70s Z cars have the vertical mounts, drum rears, and 15/16 size.  Do you know if this is a correct application for me?  I was going to get the drop spindles, D21 calipers, rotors, and pads.  Do I order brake hoses for the 620 or D21?  I guess I should get new ball joints too, so do I get those for the 620 or D21?  Is there anything else I need with this swap, like someone above mentioned modifying the tie rods...is that true or will everything just bolt up?

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On 9/25/2018 at 2:00 PM, ]2eDeYe said:

The 1979-1982 (I think) Z car master bolts up to the booster and comes in 15/16 disc/disc. The front brakes on this are essentially the same as the d21. 

You can change the rear residual valve from your 620 master to the Z master to set it up for disc/drum.

These masters are getting hard to come by, just FYI. 

There is an aftermarket 1" upgrade that is a bit easier to find, it will show up in a search for the 79-82 Z. You may need to do the same valve mod to run drums in the rear or maybe you can specify during ordering.  

 

Sorry to bring this up so many months later, but I believe that I'm in need of upgrading my master cylinder due to the fact that I don't really have much initial pedal.  When I first press it, it basically goes down to the base of its travel, and then if I let it out about half way and press again a couple more times it tends to build up some pressure and holds fairly well.  Once I get rolling again, I have to go through the same process even if it's only about a block of driving.  Currently I don't think that the rear drums are biting at all, as it feels as though all of the braking is coming from the fronts only, and the emergency brake doesn't hold at all when I pull it out.  I did get an emergency brake cable kit that I ordered from ebay, but it's only for the rear half of the whole setup.  I know when we did the engine swap and various upgrades about a year ago the parking brake cable was not the best as it wasn't really grabbing until it was a few notches from being all the way out.  I've read somewhere in the forums that for the rear drums they need to be adjusted often, but I thought that they were self adjusting cylinders.  If not, then how often should they be adjusted?  I'm guessing that the adjustment is simply moving the notched wheel adjustment ring on the rear cylinders until you start feeling resistance when trying to rotate the wheel as it's raised off of the ground?

 

So will this 15/16" 1979-1982 Z master cylinder work for any year of 620, or does it only apply to the same years?  I've got a 1977 620 so I'm hoping that the Z master cylinder will work for all years of 620.  In addition, I've got Beebani's front disc conversion but still having rear drums I'm not sure if just swapping to the Z master cylinder will be sufficient or overkill.  I do have a rear disc conversion kit somewhere stashed away to install, so I'm thinking that it should be alright to run with.

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Adjust the rear drums! If they have to move too far to start braking it will eat up huge amounts of pedal travel. Try this.... pull the emergency brake out so slightly dragging while driving and then try the brakes. If improved, they are in need of adjusting.

 

Self adjusting rear brakes started in around '81 on the next generation 720 truck. YOU will need to adjust them every 3-6 months depending on use. Don't forget the fronts.

 

'Soggy' brakes can also be air trapped in the system but if initially bled properly air can't get in and it's likely in need of adjusting. It can also be from an increase in caliper size. Larger caliper needs more fluid to activate them. In this case going to a larger master will help, but it won't help if the rears need adjusting or there is air in the system. to begin with. Check these first.  

 

The emergency brake should always be adjusted or checked after setting the brake adjustment. It your last chance to get stopped if something should go wrong with your brakes. Think of it as a reserve parachute.

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