Thorpeado Posted July 18, 2014 Report Share Posted July 18, 2014 Hello Ratsun members, I have a 1974 620 pickup that is my daily driver. My question is this, the truck has been lowered a lot by the previous owner and it has beat up the old king pins tie rod ends etc. quite a lot and now there is a bit of play in the front end, so I have heard that it is possible to swap the ball joint front end off of later model dat suns or possibly a hardbody. I like the idea of this rather than dealing with rebuilding the old king pins. I would like to keep the truck lowered as well, are there aftermarket lower profile bumpers that allow for a little more suspension travel? any help would be great as far as years of trucks that will work for a swap. Sorry for no pictures, I haven't taken any of the truck but will try to soon. - cheers Quote Link to comment
flatcat19 Posted July 18, 2014 Report Share Posted July 18, 2014 720. If I wasn't on my phone I'd C/P the thread. Quote Link to comment
wayno Posted July 18, 2014 Report Share Posted July 18, 2014 It will not just bolt in, you will have to fabricate parts. 1 Quote Link to comment
orangie Posted July 18, 2014 Report Share Posted July 18, 2014 If you look at a later 620 frame, you can see the upper control arm mount is rotated back slightly. In other words, it's not built the same so all the later parts don't necessarily align. They will bolt up, but the upper control arm will be about an inch to short. You have a couple of options. Change the frame to either the later 620/early 720 or get a set of custom upper control arms. I made my own, a user by the name of Beebani makes some. My gripe with Beebani's design is there is no tilt added to the ball joint. If you look at the lower control arm it has about 20 degrees of tilt. The stock upper control arm also has about the same amount of tilt. Beebani's has no tilt, so you lose over 70% of your ball joint range (30 degrees is a typical ball joint tilt range). Is it that critical? I don't know. I haven't ran the control up and down in its range to see how far the ball joint actually rocks. Quote Link to comment
flatcat19 Posted July 19, 2014 Report Share Posted July 19, 2014 If you look at a later 620 frame, you can see the upper control arm mount is rotated back slightly. In other words, it's not built the same so all the later parts don't necessarily align. They will bolt up, but the upper control arm will be about an inch to short. You have a couple of options. Change the frame to either the later 620/early 720 or get a set of custom upper control arms. I made my own, a user by the name of Beebani makes some. My gripe with Beebani's design is there is no tilt added to the ball joint. If you look at the lower control arm it has about 20 degrees of tilt. The stock upper control arm also has about the same amount of tilt. Beebani's has no tilt, so you lose over 70% of your ball joint range (30 degrees is a typical ball joint tilt range). Is it that critical? I don't know. I haven't ran the control up and down in its range to see how far the ball joint actually rocks. That's not what this guy says... Quote Link to comment
orangie Posted July 20, 2014 Report Share Posted July 20, 2014 You can see it on my car. The lower control arm required a longer bolt (from the early 720). The upper control arm spindle is the same for the 620 and early 720 even though the control arm is different. Quote Link to comment
wayno Posted July 20, 2014 Report Share Posted July 20, 2014 That's not what this guy says... OK, let us understand something here about this link you provided, this guy bagged that truck, he has no way to properly align his truck, he has negative camber in ample supply, and he likely wants his front tires to tuck into the fender wells when dropped, so it worked out perfect for him. This may be a bolt on, but it's not alignable unless the upper control arms are lengthened. Drilling out the upper control arm mount holes and tapping them to the 720 bolt size is smart, very smart, also using early 720 lower control arm bushings is also smart, as one doesn't have to add washers to take up the slop, but the upper control arms are about 5/8ths of an inch short to be able to have it properly aligned on a stock height or slightly dropped truck. Quote Link to comment
flatcat19 Posted July 20, 2014 Report Share Posted July 20, 2014 I missed that that guy bagged his truck. Touche'. Quote Link to comment
wayno Posted July 20, 2014 Report Share Posted July 20, 2014 I missed that that guy bagged his truck. Touche'. Don't take me wrong, that guy did a lot of things right, and it worked for what he was doing to the truck. I get kinda touchy on this subject, I did all this back in about 2005, and I did not figure everything out right away, it was kinda scary for a while, and until a couple years ago I had issues, so when I read incomplete instructions that don't cover everything, I go crazy. You should have seen the complete reply I wrote, talk about rants. :lol: Quote Link to comment
flatcat19 Posted July 20, 2014 Report Share Posted July 20, 2014 I've read you saying that a few times. I even talked to you about it the day we met. I'm gonna go back and read that thread. Better this time though. Not just want I want to digest. Quote Link to comment
Thorpeado Posted July 20, 2014 Author Report Share Posted July 20, 2014 Thanks guys for the tips guys, from what it sounds like upgrading the upper control arms to beebani's might be the way to go and using 720 lower arms and hardbody spindles with disc brakes might work out the best. I assume that I would need to get the booster and master cylinder from the same truck to supply ample braking. The truck now has been converted to disk brakes up front using the honda passport conversion, however it requires a lot of pedal pressure so I'm guessing the previous owner did not upgrade the master cylinder and booster. I will PM beebani and find out whether the ball joint angle is within tolerances. heres some pics of the lil' datsy 2 Quote Link to comment
orangie Posted July 21, 2014 Report Share Posted July 21, 2014 I haven't found a nice big brake kit for the 720 spindles. I'm using stock 720 rotors and they seem pretty small compared to the passport ones. I like those steelies you got on the truck. Are they original Datsun's? Quote Link to comment
JNHEscher Posted July 28, 2014 Report Share Posted July 28, 2014 I missed that that guy bagged his truck. Touche'. Bagged indeed! My camber is actually correct at ride height, but that's because I cut and bent the upper arm towers. Not the thing to do if you're not comfortable with it. Purchase or build adjustable upper arms. All else should work well. Quote Link to comment
datzenmike Posted July 28, 2014 Report Share Posted July 28, 2014 Cut the 720 frame off just ahead of the cab and weld it on. Quote Link to comment
redskunk Posted July 28, 2014 Report Share Posted July 28, 2014 Thanks guys for the tips guys, from what it sounds like upgrading the upper control arms to beebani's might be the way to go and using 720 lower arms and hardbody spindles with disc brakes might work out the best. I assume that I would need to get the booster and master cylinder from the same truck to supply ample braking. The truck now has been converted to disk brakes up front using the honda passport conversion, however it requires a lot of pedal pressure so I'm guessing the previous owner did not upgrade the master cylinder and booster. I will PM beebani and find out whether the ball joint angle is within tolerances. heres some pics of the lil' datsy Truck look good man! Keep us updated with pics of the suspension upgrade. I'm in the process of deciding to lower and modify the suspension on my truck too. Quote Link to comment
stormsinger54 Posted August 5, 2014 Report Share Posted August 5, 2014 ahh im looking at converting mine within the year also and was almost given a pair of hardbody drop spindles a couple weeks ago and turned them down haha i believe they were drop spindles tho...what year hardbody spindles are yall thinking of?i have a 77 kingpin and im gonna be swapping to discs soon! Quote Link to comment
orangie Posted August 5, 2014 Report Share Posted August 5, 2014 I have a set of drop spindles and am currently trying to sort out which, hub, rotor and caliper combination will work. Quote Link to comment
hosestop@msn.com Posted August 5, 2014 Report Share Posted August 5, 2014 Hey I did the disc brake conversion on that truck , was owned by the guy with air bagged Toyota truck , and has a stock master I think , anyway was a decent truck as a starter project . Quote Link to comment
orangie Posted August 9, 2014 Report Share Posted August 9, 2014 This is the combo I found that looks like it's going to work. I have and 83 hub, 83 caliper and an 86 rotor. Note the spacing difference with the 83 rotor. There's about a quarter inch gap between the caliper and the drop spindle. This is remedied by using the 86 rotor. Just for reference I put a picture of three different rotors. From left to right 83, 86 and 82. The hubs for the 83 will bolt on to the 86 rotor. The added height makes up the difference in the previous picture. 1 Quote Link to comment
mklotz70 Posted June 19, 2022 Report Share Posted June 19, 2022 Super old thread.....sorry. If anyone else comes across is like I did.......the reason for the gap and having to use the '86 rotor is because of the dropped spindles. All dropped spindles are Hardbody units. When you buy them new, you'll probably get the spacers that go in that gap. They allow the 720 rotor to be used so they can sell the spindles as 720/HB units. There's no advantage to using the 720 rotor with the spacers.....in fact, it makes wheel fitment a lot harder. Just use the HB rotor with no spacers on the dropped spindles. The calipers are the same and the hubs are very similar....the nose diameter for the center hole on the rim is the only difference. Okay......it can go back into hibernation again. :) 5 Quote Link to comment
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