steering box related

[SteveO_71]

As part of added improvements to my 71, I wanted to address the loose steering by replacing rag joint and doing something with the steering box.

I dont want to get into rebuilding it myself so i'm doing internet searches both to educate myself and see whats available. Of course, as a result of all this I have some questions i hope someone with more experience than me can answer.

I have an SPA-T variable ratio box in the car and I'm trying to decide between buying a rebuilt/remanufactured or sending mine in to get rebuilt.

For example, CarSteering.com has the SPA-T as well as a quick ratio 2.5 turns LTL that can be bought and my core sent in.

Powersteering.com will rebuild a sent in box and can also upgrade to a quick ratio.

Is there one advantage over the other... buying existing and returning core or rebuilding original?

Is it worth getting the quicker ratio over variable ratio?

I can understand replacing seals etc as part of a rebuild but what happens if gears are physically worn down i.e. sector shaft ? Are these even replaceable. especially a variable ratio one or would the internals be replaced with something totally different?

Sorry for all the questions but hopefully someone thats been thru this can educate me!

thanks!

 

[73pony]

I had mine rebuilt by powersteering.com and upgraded to the quick ratio. They did a fantastic job, quick turnaround and I could not be happier. It is night and day different.

 

[Hemikiller]

I've driven both the upgraded quick ratio and the factory variable ratio. I found the variable ratio easier to drive and less "twitchy" on center. The quick ratio definitely takes time to get used to.

If you just do a lot of cruising and general driving, I'd go with the variable ratio. If it's corner carving, a track day or two - maybe upgrade to the quick ratio.

IMO, I wouldn't send in your VR box to have upgraded to QR, get a regular box, send that in and sell the VR unit.

 

[mustang7173]

I also had the quick steer ratio installed and it is a bit touchy. As Hemikiller stated, " The quick ratio definitely takes time to get used to! "

 

[73pony]

Odd. I don't find the steering twitchy at all. In my experience it is smooth and certainly makes the car handle more like a modern car. I also upgraded all of the front suspension at the time.

 

[Stanglover]

I like what Hemikiller said, find a regular box. By that I think he means a 17.5:1 ratio SPA-S,U, AC or AE and send that in for QR upgrade if that's what you want.

My thoughts are to keep the VR. For ordinary driving, it's all you really need. Get it rebuilt.

 Rebuilding a box properly is far more than just replacing seals. Although in some cases, that's all that may be needed, it's far more likely that the sector shaft will be badly worn at the lower seal area from dirt that has scored the shaft to the point were it leaks like a sieve and will need to be machined, hard chromed and ground to size. I think most of the larger rebuilders will have these already done and on the shelf. Another area that tends to wear is the rotation valve bore. This is from the Teflon seals and depending on how bad, the casting my be scrap although I believe some rebuilders can sleeve them. Then there is the ball screw and balls. Ford listed 5 different size 'kits' for the balls, but are no longer available. They were dimensioned to 5 decimals with very small increments between the 'kits'. However, the rebuilders can buy appropriate sizes from ball bearing manufacturers, but are quite expensive for the home rebuilder to buy, like $2.50 a piece and you need 24 of them for a VR box.

So, yes, if you're not up to doing your own, then send it away for rebuild. However, do your homework first. I learned the hard way by trusting a local brake and steering gear rebuilder who totally F'd up my box to the point that it could have injured me or worse. Now I do my own and being a machinist helps.

Another company that has helped me with parts and information is Steer and Gear in Columbus Ohio, www.steerandgear.com.

Geoff.

 

[72Mach168Cam]

When I looked into it, the best option for me (haven't bought one yet) was rockauto.com; a Lares Manufacturing, there is both standard(183.79) and quick ratio(239.99) available. There is a $200 core charge. Remanufactured in the USA.

 

[Stanglover]

When I looked into it, the best option for me (haven't bought one yet) was rockauto.com; a Lares Manufacturing, there is both standard(183.79) and quick ratio(239.99) available. There is a $200 core charge. Remanufactured in the USA.

 A good price for sure, but on the Lares 806, it does NOT say if it's standard ratio or variable ratio, so I'd guess standard with 4 turns LTL. Still not terrible, but will be a lot softer feel when driving. The input torque rod will be smaller than in a VR, therefore lees effort to steer the car. If you're good with that, go for it. While at it, order a Lares 201 coupler.

Good luck with it,

Geoff.

 

[Hemikiller]

Lares 806 is the constant ratio box - 4 turns.

I ran across a post where another guy was quoted $284 for a rebuild and fast ratio conversion last year by www.powersteering.com

 

[Bentworker]

Variable ratio vs 12.7:1 quick ratio is personal preference.  I have 12.7:1.

If I were in your shoes I would call up the different rebuild shops and have a conversation with them. 

The thing I would talk to the steering shop about is if they offer T-bar upgrades.

Sure- quick ratio is cool- but a larger T-bar is what is going to give you steering feel and feedback like a modern car.

Below is a picture of what I am talking about.  Basically the T-bar is a torsion spring that connects your steering column to the ballscrew inside the steering box.  The smaller it is, the easier it deflects.  Smaller T-bars offer very little feedback to the driver, and give that “pinky finger” over assisted feeling to your steering.

Getting a competent steering shop to swap it out to a .210” or larger is going to give you a much more modern steering feel and give you better feedback.

My box is 12.7:1 with a .210” T-bar.  It feels

https://www.hotrod.com/articles/ccrp-0901-gm-steering-box-upgrade/



I

 

[cwalker509]

Related to this....since many of the folks here are inclined to tackle things like this at home....who can offer advice on doing a steering box rebuild at home? Are there numerous specs to check (material wear) or other things that may require setups beyond most of us? i have the Ford shop manuals but am looking for personal experience? I have rebuilt a t-loc rearend and a C-6 tranny (and a few engines). Any info appreciated.

 

[Don C]

Bentworker did a good write-up:

https://www.7173mustangs.com/thread-playing-with-steering-boxes-spa-s-fixed-ratio-spa-af-variable-ratio-firebird-12-7

you can find just about anything you need, related to 71-73 Mustangs< by using the forum search function.

 

[Stanglover]

There are numerous post on this subject in "search". Also there are many video's on YouTube, some good some not so much. 

There are specs that need to be used for proper adjustments and there are rebuild kits available on RockAuto as well as most vendors. 

I don't want to get to far into my experience with rebuilding as others are far more experienced and knowledgeable on here.

Recently there was a post on PS boxes that may offer good insight.

Basically, it comes down to the condition of the casting you have within the bores, the condition of the sector shaft, worm screw, input shaft and rotator valve assembly. If it all look good without excessive wear, then they're not that hard to do. It just take a lot of care during assembly and follow the steps.

Geoff.

 

[SteveO_71]

Variable ratio vs 12.7:1 quick ratio is personal preference.  I have 12.7:1.

If I were in your shoes I would call up the different rebuild shops and have a conversation with them. 

The thing I would talk to the steering shop about is if they offer T-bar upgrades.

Sure- quick ratio is cool- but a larger T-bar is what is going to give you steering feel and feedback like a modern car.

Below is a picture of what I am talking about.  Basically the T-bar is a torsion spring that connects your steering column to the ballscrew inside the steering box.  The smaller it is, the easier it deflects.  Smaller T-bars offer very little feedback to the driver, and give that “pinky finger” over assisted feeling to your steering.

Getting a competent steering shop to swap it out to a .210” or larger is going to give you a much more modern steering feel and give you better feedback.

My box is 12.7:1 with a .210” T-bar.  It feels

https://www.hotrod.com/articles/ccrp-0901-gm-steering-box-upgrade/



I

How does the torsion spring you mention relate to what I was reading at a rebuilding site that mentions "valve weight"? Basically, are they referring to the same thing?

Some have mentioned on here that after switching to a quicker ratio, that the car takes getting used to and can feel twitchy at high speeds.

"The actual effort it takes to turn the wheel and engage the power assist. Although it is true that the larger the torsion bar, the stiffer the feel, it is the sum of all the valve parts that equate to the final result. Most stock Saginaw gearboxes (especially slower ratios) are spec’d with a lightweight valve, typically around 20-25#’s. This lightweight valve results in an effortless (one finger) steering feel. This super easy steering effort also means that you have very little road feel and can feel twitchy at high speeds. When upgrading to a faster ratio power steering gearbox, it is highly recommended to increase the valve weight to match your application. Our most common gearbox ratio/valve weight pairings are listed below.

Classic Cars

• 12:1 – 35-40#
  
• 14:1 – 30-35#
  
• 16:1VR – 30-35# "
  

 

[Bentworker]

Yes- I believe those numbers they are tossing out there indicate how many inch pounds of force it takes to deflect the torsion rod, which then allows the valve to port oil for assist. The bigger the rod the more inch pounds it takes to deflect it.

I can tell you mine does not feel twitchy with the .210” T-rod.

 

[EdM]

Ditto here along with a SoT coil over system and it is fantastic. Nothing twitchy about it for me.