just wondering if anyone has done a brake upgrade on their 620, mine is drum brake all round, fitting a v8 and need to upgrade, would also like to change to 5 stud, any help would be great
Thanks

Am I correct when I say the 620 has a wishbone front suspension with torsion bar?
If so, the front hubs would probably have to be retained unless someone knows of a disc brake type hub that would bolt up to the stock suspension.
I certainly don't

What I would do in this instance is measure the offset between the drum brake backing plate surface on the hub to the drum brake axle flange surface.
That will give you the ballpark dimension of the disc rotor "hat" measurement [dimension B in the diagram]
Then you need to measure where the calliper needs to be and see how that lines up with the backing plate face.
If the calliper mount is not too far away from the backing plate plane then a custom calliper mount with spacers is designed to centre the calliper over the rotor.
I've done much of this for a disc brake conversion to the drum brake struts on my B120 Ute.
It uses Datsun 260Z rotors and 810/200B callipers mounted on a 6mm thick calliper plate.
The DBA Cattledog is very handy to use as a reference when planning something like this
Years ago I built up an Excel spreadsheet of all the disc rotors that DBA listed.
All you need to do is enter the critical dimensions into the SORT box and VIOLA! the appropriate disc types are output
Then I short list what is the practical choice.
The dimensions listed below are lifted from the Disc Brakes Australia cattledog.
A = Diameter
B = Original Height
C = Original Thickness
D = Min. Thickness, i.e. Replacement
E = Centre Hole
F = No. of Bolt Holes

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Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

hey 510psi,
I have a 76 model 620 ute and have been wanting to do the same thing too, the closest thing I can find that any one has done to a 620 is an American forum http://www.nwde.org/extras/forum/forum_ ... p?TID=2005
The thing is they fabricate the bracket that holds that disc calipers.And they use American car brand for disc conversions and I don't know what the Australian equivilant would be.What i do know is that the 720 ute hubs won't fit the off set is too big.unless you could use the 720 hub and put a different disc on it.Probably wrong though.But if you do find a combination 6 or 5 stud pattern i'd be one of the first that would greatly appreciate the info.
Cheers
Pete

After some research in trying to find front hub combo's and disk offsets,I rang a couple of mechanical inspection shops up here in Toowoomba,so what I am about to say applies for QLD but I don't know for the rest of Oz.What they both said was:If you make/fabricate any brake conponent,ie:Caliper mounting bracket,than you need to make three off and send them away to Brisbane to get engineered certified.(very costly in the thousands )
Why three? They test (destroy )in different ways the quality of the manufacture.This certification alows you to be classed as a manufacturer under the Dept of Transport,then with this certificate any inspection station can do the mod plate without putting there arse on the line.
I also enquired about just changing the chassis form a 720/Navara and put a 620 cab on it,they were a lot more comfortable in passing this for the brake upgrade than using any fabricated part on the braking system as this will not alter any wheel alignment measurements and steering measurements.
Thus I pose this question to you out in Datsun land.Would the 620 cab fit a 720 chassis,and can any body foresee any nasty supprises that might be encountered?Or does anyone have or know of the cab mounting dimensions ?

Cheers
Pete

Back tracking a bit, I was under the impression that the late model 720 complete disc brake assemblies (possibly knuckles and wishbones, hubs, rotors etc) fitted on a datsun 620.

Not a massive upgrade but sure beats drums, and I doubt you'd have many hassles getting it certified.

Look up a project thread by greiggy, maybe just his posts and you'll find what i'm talking about. Here is a link to his project thread that should get you started --> here

Yeah I've read through Greiggy's project page a couple of times,fortunatly for him,he seems to have scored himself a 78-79 model 620 which came out with ball joint front end and the same stub axle as the 720,lucky bastard ,mine is a 76 model with the king pin front end and different sized stub axle (front wheel bearings are not interchangable different part numbers),Still trying to find a way though,got in contact with a guy who's an engineer certifier in Brisbane and does a lot of hot rod mods,he said it is ok to fabricate a caliper mounting bracket so long as it is one piece (definetly no welds) and no thinner than 12mm at any part of the bracket,but the vehicle will need to be sent to Brisbane to have a brake fade test and part with around $350 for the privaledge to have it certified.Oh also you need to draw up the bracket and show him first before making it.Then you need to go and get the mod plate done which is another $150 or so.So this may be a very costly exercise.I talked to him about changing chassis and he said that this mod will also need to be certified by an engineer before mod plating.Which is a little different to what I was told by the first mechanic/inspection station.So I think some inspection stations may have different ideas as to whats legal or not.
Though a chassis change if possible would give you a balljoint front end as well.Hope this info is helping some one out there.
cheers
Pete

i have had the same problem with my 78 620. the 79 models came out with disk fronts but i know from 76 onwards you can use the 720's to create your own conversion. But if you want to change the stud pattern....(why these are great with 20's) that becomes a little bit harder.

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71 1200 sedan! now a a14 turbo project

yeap correct in saying mine is a 78 chassis . therefore it has a ball joint front end and will accept any front hub assembly up to D22 navara.

if you really want to go low, the drop spindles from d21/d22 will run and fit fine.

Hi,
just wondering if anyone has any more info on this subject,(shame if this thread just dies)or knows anyone who's done a 720 chassis/620 cab swap legally.The closest thing to disks I can get for my 76 620 is purchasing a 78 model ball joint front end fubar from the wreckers for $750.


What a f*%king rip off.

dude thats cheap i went looking ages ago for the front disk bakes and come up with nothin and gave up and now my utes up for sale, you have to be careful with the 620's as mine is a 78 model and doesnt have the disks, it is only the later models the late 78 and 79

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71 1200 sedan! now a a14 turbo project

True,some did come with ball joint/disks,but some came with balljoint/drum which is compatible with the 720 disk front axles with some parts changing.
Ebay seems to be the place to pick 620's up as the wreakers around here in Toowoomba have only one.

I have a couple of ball joint style 620 chassis, which combined with 720 or Navara spindles will give you the basis for disc brakes. Also makes it easy to bolt in L series engines using 720 engine mounts and sump and stumpy gearbox. Unfortunately I'm in Adelaide, so shipping could be a problem.

Make me an offer on a chassis if your interested, it may get the wife off my back a little.

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Trev

There's something about twin webers at full noise.

I also did a conversion on my race ute using Holden Shuttle hubs, discs and calipers. Found bearings which fit the king pin stubs and Shuttle hubs, from memory had to machine up a spacer to get the bearing nut to clamp it all up properly. As has already been suggested, had to fabricate some brackets to mount the calipers, but no problem with Roadworthy's and engineers on a race car so welded bracket was OK.

Trev

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Trev

There's something about twin webers at full noise.

Murphy's Law #620 ,
The part your chasing is always going to be at the other end of the country.

In saying that, I'd make you an offer but logistics are gonna be a wee problem!
Talked to another mob that does approvals for RWC,(Paramount Performance in Toowoomba), about 720 chassis swap.Basically the owner said if I just say my chassis was rooted and needed changing to DOT (if they ask) ,as long as I go up in years and not backward and mounting holes in the cab are the same which I'm pretty sure they're close enough ,it should be OK.He said this mod will need two compliance plates,$110 each,no need for engineering.I think (don't quote me)one plate would be for cab/chassis/suspension and the other for engine/gear box and steering column.Also I think emissions controls will have to be at the 720 standard.

Cheers
Pete

You might need to use the 720 steering box and column as well if you go that way, because the 720 box is on the outside of the chassis, 620 on the inside with the spear type column.

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Trev

There's something about twin webers at full noise.