Steering Box 620 truck

[Stinky]

I've got a friend that is working on a 78 620.  He needs a steering-gear box.  Are there any other vehicles that have a compatible steering-box?

 

Can a 720s box be rigged up to work?

 

Is there a place that works on them?

[datzenmike]

Unfortunately the 620 are one piece column and box. The 720 are separate column and box. The 521 and 620 are similar.

 

If leaking, remove the pitman arm and use a wood screw driven into the sector shaft seal to pull it down and out. A greased new seal can be lightly driven into place using a suitable length piece of pipe. The steering box also has a play adjustment bolt on top. Loosen the lock nut and turn bolt to remove excess play while the wheels are off the ground. There should be no tight spots when turning from lock to lock. Tighten the lock nut! Check you adjustment.

 

Extreme looseness in the steering can also be a combination of all the wear in all the steering ball joints, idler arm, box itself, wheel bearing pre-load and if a '73-'77 it has king pins which if also worn will contribute to the slack. 

 

With wheels on the ground, have someone wiggle the steering wheel back and forth while your watch for looseness on these parts. Sometimes if holding the ball joint you can feel they are loose. 

 

If there is accumulated wear of replaceable parts, replacing the steering box won't fix this. 

 

[iceman510]

This place can rebuild steering gearboxes.  They don't list Datsun, but many guys have had them rebuild 510 boxes.  I would check with them if it comes to that need after checking some of the other suggestions.

 

https://www.redheadsteeringgears.com/

[EDM620]

On 5/6/2026 at 6:44 AM, datzenmike said:

The 720 are separate column and box

BTW, the 720 box also bolts to the other side of the frame

[datzenmike]

Yup. Put a '79 280zx power steering box in my 620. Had a D-21 pump with the external reservoir and home made mount below the distributor. 

 

 

Eventually an SAS so no idler arm. 720 steering PS box (outside of frame) and column and a 720 dash to make it all work. Then eventually a Z24 with the one piece PS pump and reservoir.