Fast Ratio Steering Box Rebuild

[cwestra]

Any advice on rebuilding the leaking steering box on my Cuda?  How tough is it?  Any special tools needed?  Who has good kits for it?  Is the kit the same for Fast Ratio boxes?  Thanks.

[Chryco Psycho]

I rebuilt a PS box in High school & have not attempted it since , ,Omega makes seal kits for it & I bet it is the same kit for fast ratio as it uses the same housing

[Topcat]

Great episode on Musclecar TV this Saturday on re building a GM PS box. Internals are all similiar so it was a good video. You could probably buy that episode from their website. Another thing is the 70 or 71 Chassis service manual goes into great detail on re building them.

[Topcat]

[cwestra]

I rebuilt a PS box in High school & have not attempted it since , ,Omega makes seal kits for it & I bet it is the same kit for fast ratio as it uses the same housing

Thanks.  Is that because you haven't had to since or because it was a bad experience?  How tough it is?

[cwestra]

Thanks for the exploded view and feedback.  Much appreciated.

[Kapteenikosmos]

I did mine last summer and it wasn't that bad. Takes some patience and a good vice to hold the box in different positions while you are working with it. I also added one extra reaction spring (those disc shaped springs on the head & housing head explosion view) to both sides to firm up the steering. I got the extra springs from another steering box I had for parts.

The only real problem I had was that the larger spanner nut was very hard to break loose and I only managed to loosen it with some serious beating which resulted me using the spanner nut from the spare box when I reassembled it. On that box it came off pretty easy.

I changed all seals and one or two bearings. I didn't tear into the actual ball screw unit because it seemed to be fine and I have heard horror stories about the reassembly on those when all the balls drop to the floor.

I have a factory service manual on CD for my -73 Chal and the instructions there are quite good, I can send them to you via email if you need them.

[cwestra]

I did mine last summer and it wasn't that bad. Takes some patience and a good vice to hold the box in different positions while you are working with it. I also added one extra reaction spring (those disc shaped springs on the head & housing head explosion view) to both sides to firm up the steering. I got the extra springs from another steering box I had for parts.

The only real problem I had was that the larger spanner nut was very hard to break loose and I only managed to loosen it with some serious beating which resulted me using the spanner nut from the spare box when I reassembled it. On that box it came off pretty easy.

I changed all seals and one or two bearings. I didn't tear into the actual ball screw unit because it seemed to be fine and I have heard horror stories about the reassembly on those when all the balls drop to the floor.

I have a factory service manual on CD for my -73 Chal and the instructions there are quite good, I can send them to you via email if you need them.

Thanks for the detail on your rebuild.  I plan on just replacing the seals on my box since it seems to work fine but leaks.  Since I'll have it apart, though, I wonder if I should be considering the spring addition you mentioned.  How did you determine yours needed to be tightened up and what happens if it ends up too tight?  I know there is an adjustment that can be made to tighten or loosen so I suppose the added spring just shifts that adjustment zone to the tighter side.  Thanks, again for your information and your offer to provide me the service manual info.  I'll let you know if I need it.  Hopefully I won't have a similar problem with the nut.

Also, where did you end getting your rebuild kit from?  Thanks.

[Chryco Psycho]

rebuilding it was fine , as stated you may need some special tools & a good vice , I have found replacing the boxes with Firm feel type units is a better result than rebuilding a worn box

[UKcuda]

Thanks for the detail on your rebuild.  I plan on just replacing the seals on my box since it seems to work fine but leaks.  Since I'll have it apart, though, I wonder if I should be considering the spring addition you mentioned.  How did you determine yours needed to be tightened up and what happens if it ends up too tight?  I know there is an adjustment that can be made to tighten or loosen so I suppose the added spring just shifts that adjustment zone to the tighter side.  Thanks, again for your information and your offer to provide me the service manual info.  I'll let you know if I need it.  Hopefully I won't have a similar problem with the nut.

Also, where did you end getting your rebuild kit from?  Thanks.

The springs he is talking about are called "reaction springs" and not connected with the adjustment you are thinking of (the sector shaft adjustment). 

The reaction springs are what the steering column has to overcome before the spool valve moves to direct the high pressure fluid to the power piston.  Stronger reaction springs = more effort at the steering wheel and firmer feel.  "Firm Feel" boxes use stronger springs, the stock ones are quite weak which is why Mopar boxes are so light on driver effort.  That is except for the cop car boxes which got stronger springs.  I saw somewhere that you can order cop car type springs about $30 each.

I think Kapteenikosmos is saying he doubled up some stock springs to get a similar effect.

I only know all this because I had to figure it all out before I finally sussed what's wrong with my own steering box - one of the reaction springs is collapsed, broken or missing !

[Kapteenikosmos]

The reaction springs are what the steering column has to overcome before the spool valve moves to direct the high pressure fluid to the power piston.  Stronger reaction springs = more effort at the steering wheel and firmer feel.  "Firm Feel" boxes use stronger springs, the stock ones are quite weak which is why Mopar boxes are so light on driver effort.  That is except for the cop car boxes which got stronger springs.  I saw somewhere that you can order cop car type springs about $30 each.

I think Kapteenikosmos is saying he doubled up some stock springs to get a similar effect.

I only know all this because I had to figure it all out before I finally sussed what's wrong with my own steering box - one of the reaction springs is collapsed, broken or missing !

Yeah that's correct. The stock springs are very flimsy and I just tested how it would work if I just double the number of stock springs. Seems to work fine and the steering feels quite good. I don't have a comparison for a stock box because I've never driven my car with the stock reaction springs but if compared to my parents -59 dodge, the steering is much firmer. The -59 they have has a power steering box  (not original) and the box looks quite similar to the one I have in my Challenger.

As a side note my own box just shows the quality control during those days. I had double springs on the other side and one spring on the other. Must have been blast to drive when the steering wheel is firmer when rotating to one direction than the other 

Anyway, if the ball screw assembly is worn out or the sector shaft / ball screw assembly gearing has bad slack, there is no point in rebuilding the old one. Mine seemed to be in very good condition when compared to the one I bought as a spare parts.

UKcuda, I also scratched my head for some time before I understood how that damn thing was supposed to work. For the starters, it was bit hard to understand, that those flimsy steel shims were the actual springs. Also because the parts are quite heavy and bulky, the testing was a bit of a pain.

[UKcuda]

As a side note my own box just shows the quality control during those days. I had double springs on the other side and one spring on the other. Must have been blast to drive when the steering wheel is firmer when rotating to one direction than the other 

Lol, and imagine how tricksy mine drives with only one spring at all.

If I can get some stiffer reaction springs and a seal set I might try stripping and upgrading myself.  The rest of the box seems basically OK and it is quite a lot of $$$ to ship a recon. box to the UK, especially after adding import duty and other taxes.

Have you got any DIY tips for pulling out the guts far enough to change the reaction springs ??

[Kapteenikosmos]

Lol, and imagine how tricksy mine drives with only one spring at all.

If I can get some stiffer reaction springs and a seal set I might try stripping and upgrading myself.  The rest of the box seems basically OK and it is quite a lot of $$$ to ship a recon. box to the UK, especially after adding import duty and other taxes.

Have you got any DIY tips for pulling out the guts far enough to change the reaction springs ??

I was first thinking to get a firm feel or similar unit but after checking out the import taxes and shipping costs to Finland, I decided to try to improve my own box first.

I'll check my pics from the rebuild and try to recall what I did to pull out the guts. Atleast I did it kind of a wrong way on my own box and tried different method on the spare box and it worked better. I just can't remember how it exactly went but I will probably remember when I go through the pics.

[UKcuda]

I was first thinking to get a firm feel or similar unit but after checking out the import taxes and shipping costs to Finland, I decided to try to improve my own box first.

I'll check my pics from the rebuild and try to recall what I did to pull out the guts. Atleast I did it kind of a wrong way on my own box and tried different method on the spare box and it worked better. I just can't remember how it exactly went but I will probably remember when I go through the pics.

Thanks, I've been looking at the way it all fits together and it looks like it could be possible to change the reaction springs without removing the power piston and sector shaft.  So I am wondering how many parts come out with the top cover and how much else can then be lifted over the input shaft/bearing etc.  It looks like the upper spring will come out with the cover.

I know there's a staked nut on the input shaft but that looks a fair bit smaller than the spacer and lower spring, but I can't see for sure whether the lower spring and spacer will just lift out.

[boydsdodge]

Mopar Action did a story on the springs last summer.
I'll try to find it.