Rear coilovers on a 620?

[TenaciousTiger]

I know this may sound a bit unconventional, but would it be possible to run single leaves to hold the axle in place, while replacing the shock absorbers with coilovers? I'm not able to exactly afford the 4-link kit for this truck, but I'd like to get some more adjustability out of the rear suspension. A friend did the same with his hilux, but that's a 2-link. Any help would be appreciated!

[datzenmike]

Even a double leaf won't be enough to prevent the rear end from shifting laterally on turns. You may be able to get away with this if you install a panhard bar to locate the axle longitudinally. Unless you plan to raise and lower your truck once a week, coil overs are an expensive waste of money. Get lowering blocks and keep the leaf springs. You don't want a softer spring, if anything you want it stiffer to reduce the chances of bottoming out now that you are closer to the ground. In addition raising or lowering disrupts the drive haft angles causing vibration and wear of the U joints. Lower to where you like it, correct for driveshaft angles and enjoy the ride.

[TenaciousTiger]

7 minutes ago, datzenmike said:

Even a double leaf won't be enough to prevent the rear end from shifting laterally on turns. You may be able to get away with this if you install a panhard bar to locate the axle longitudinally. Unless you plan to raise and lower your truck once a week, coil overs are an expensive waste of money. Get lowering blocks and keep the leaf springs. You don't want a softer spring, if anything you want it stiffer to reduce the chances of bottoming out now that you are closer to the ground. In addition raising or lowering disrupts the drive haft angles causing vibration and wear of the U joints. Lower to where you like it, correct for driveshaft angles and enjoy the ride.

I'm already riding on 2.5" lowering blocks, my suspension is too soft and bottoms out in the rear when both sides compress simultaneously, rubbing the bed fenderwells with poorly fit tires/rims. I bought the truck this way, and now I'm finally getting around to dealing with the issues from the last owner. I don't mind the rear shifting laterally, that's to be expected with the layout. How should I go about getting a comfortably set up pair of leaves?

[datzenmike]

Shifting sideways is really wrong. The leaves can curl and be damaged not to mention the tires ground into the inner fenders. It bottoms out because you are closer to the ground. Add an extra over-load leaf to the pack. A coil over is an expensive way to prevent bottoming out. Once you get what you want the adjustability and expense is just along for the ride. It's really a stiffer spring being added that you need, adjustability has nothing to do with it. There are over-load coil springs you can clamp to the stock shock. They have no effect on ride till the leaf spring begins to flex and weight is transferred to them.

 

 

 

[TenaciousTiger]

1 hour ago, datzenmike said:

Shifting sideways is really wrong. The leaves can curl and be damaged not to mention the tires ground into the inner fenders. It bottoms out because you are closer to the ground. Add an extra over-load leaf to the pack. A coil over is an expensive way to prevent bottoming out. Once you get what you want the adjustability and expense is just along for the ride. It's really a stiffer spring being added that you need, adjustability has nothing to do with it. There are over-load coil springs you can clamp to the stock shock. They have no effect on ride till the leaf spring begins to flex and weight is transferred to them.

 

 

 

The axle does not move in the leaves at all, but the inner wheel sticks out further when cornering. That's normal, correct? If not, should a panhard bar be my next consideration to correct this?

[datzenmike]

 Stock springs are fine for positioning the rear axle laterally and it shouldn't move. The wheel will project slightly when cornering but it's not the rear axle, it's the sidewalls on the tires flexing. A panhard bar is not needed as it is. What you need is stiffer springs to prevent bottoming although this may stiffen the ride all the time and be uncomfortable...or an add on spring like pictures above. The suspension rides lightly on these springs and only when the suspension flexes does it resist movement.

[TenaciousTiger]

Alright, I'll look into those over-load springs, they seem like they'd give the best ride, similar to having a progressive spring rate. Thank you very much!

[datzenmike]

Progressive, that's the word. There is some adjustability with them. They can be somewhat lose so you are riding mostly on the stock leaf springs but past a certain movement these begin to add support. Or they can be slightly compressed so they are acting all the time.

[TenaciousTiger]

Then that's absolutely what I want. Now comes the issue of finding them, googling what you told me comes up with nothing of help.

[datzenmike]

The picture was grabbed from Amazon. Try there. "rear load control  coil springs"

[klam07]

On 11/10/2020 at 12:56 PM, TenaciousTiger said:

I'm already riding on 2.5" lowering blocks, my suspension is too soft and bottoms out in the rear when both sides compress simultaneously, rubbing the bed fenderwells with poorly fit tires/rims.

 

Maybe something else to consider is using air shocks in the rear. Gets you ~1" of ride-height adjustability by airing up or down, and in my opinion makes the rear a decent bit stiffer even despite running it at the minimum psi rating (~30psi). Will get more stiffer (and taller) when you air up.

I also have Datsun/Nissan 720 4x4 leaf springs which is a common thing that alot of people do, plenty of info online about it. It'll drop the rear a bit but theyre also stiffer leafs as I've read. Lastly for what its worth, Im also on 2" blocks in conjunction with all this.

 

Ultimately, it depends on what you're after. I wanted a daily'able truck with the ability to air up a bit if I need to carry a load - thats its only real function and it does it decently. Still rides like a 40 year old truck but its not bouncy or 'loose' to say the least, quite stiff actually. A good ~$100 bolt-on compromise as opposed to the coilover route.

I have a thread somewhere on here that talks about it pretty in depth - if you decide this is something to consider I can dig up the link