Convert to manual steering

Duke davis

New Member
May 27, 2022
9
Hello I have a 1970 with p/s and has a bit of slack in the steering box. So I'm considering changing to manual quick ratio 16:1 gear box. Has anyone made this change or information about it. Your help is greatly appreciated. Thanks
 

Twisted_Metal

Administrator
Staff member
Lifetime Gold Member
Feb 26, 2004
31,681
Bloomington, MN
Are you sure it's the box and not the rag joint?

It's possible to tighten up the steering box but I've never touched the adjustment so I can't provide instructions.
 

Duke davis

New Member
May 27, 2022
9
The rag joint is good I Replaced it and Replaced the boot and bushing thing and packed it with grease at top of the steering shaft. It has about 2in of play.
 

70lt1z28

Veteran Member
Gold Member
Oct 3, 1999
4,951
Beavercreek, Ohio, USA
The power steering and the manual steering uses the same LENGTH (~8 inches) pitman arm, but the spline diameter is smaller on the manual box. To make it even more confusing the pitman arms even have the same number on them (3964881) but the power steering arm has a "P" stamped near the splined hole. The manual arm is hard to find as it was only used on the Z28. There may be aftermarket arms out there by now, but I do not know so this info may be obsolete. Non Z28's with manual steering used a shorter arm (~6-3/4) and the steering linkage made up for this arm with an offset in the linkage where it attaches to the arm. If you change to the more common short arm, you will have to change the steering linkage.

Here is the difference in the spline shaft diameter. This is a manual box and the calipers were set to the diameter in the PS box shaft:
1668183212402.png
 

Rosster

Veteran Member
Gold Member
Mar 1, 2020
1,058
This is my 2nd 70 z28 with manual steering and had an 70 SS with. Although faster than std manual they are still really slow compared to PS. I decided to convert to PS and put the original parts on the shelf.
 

70lt1z28

Veteran Member
Gold Member
Oct 3, 1999
4,951
Beavercreek, Ohio, USA
Here is an image from the Fisher Body book:
1668186107125.png

Notice that the 6 cylinder and the Z28 have the same gear ratio and that the overall is different. So the steering box is the same on the 6 and Z28. This was accomplished by the pitman arm length difference I mentioned in my first post.
Also, the rag joint is different from PS to manual. The input splined shaft size is also a different diameter. Things also change in I think '77 or so as they went metric on the hose fittings.
 

Duke davis

New Member
May 27, 2022
9
I have to replace it I don't like the 2in or so of slack in the steering I'm considering manual steering box for a little hp gain and weight loss of the ps box & pump.
 

mikelstudy

New Member
Nov 24, 2022
8
Hello I have a 1970 with p/s and has a bit of slack in the steering box. So I'm Showbox jiofi.local.html tplinklogin considering changing to manual quick ratio 16:1 gear box. Has anyone made this change or information about it. Your help is greatly appreciated. Thanks
It's possible to tighten up the steering box but I've never touched the adjustment so I can't provide instructions.
 
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