JUPITER STEERING BOX

Drummond Black · Post by **Drummond Black** » Wed Sep 13, 2006 8:15 pm

One job that I intend doing over the Winter months is a complete rebuild of the steering box on the Jupiter. A small unacceptle ammount of wear has been observed during the season which make the steering accuracy occasionally dificult to to control. The wear is in the usual straight ahead position.

I intend to replace the rack and pinion. The hardy spicer is perfect, but may be replaced as a matter of course.

My main concern is the condition of the alloy steering box casting. I envisage wear in the rack bore. I have no spare so will have to reclaim my one and only casting.

HAS ANYBODY CARRIED OUT ANY WORK IN THIS AREA, ie. Rebushing the ends of the box, TIG welding and reboring, any other ideas.......

I have a NEW Left Hand Drive Jupiter steering box casting which can be used for dimensions however it is not interchangeable with a Right Hand Drive car.

I would welcome ANY advice Thanks Drummond

TedAllen · Post by **TedAllen** » Sat Sep 16, 2006 12:09 am

Hi buddy
You did say ANY advice...........I think you're too old to have a nice little red sports car and you should buy a nice little beige automatic Micra and a pipe !....suit you ,sir ?

Good luck.

Keith Clements · Post by **Keith Clements** » Mon Sep 18, 2006 7:27 am

Change the car to left hand drive for some continental motoring and balance the wear on the bench seat!

Drummond Black · Post by **Drummond Black** » Tue Sep 19, 2006 7:33 pm

Trying to get sensible technical advice is like drawing hens teeth. Somebody must have come across wear in the casting. Lets have some feedback

Keith Andrews · Post by **Keith Andrews** » Wed Sep 20, 2006 7:29 am

Trying to get sensible technical advice is like drawing hens teeth.

IMAO!!
What do u expect...Poms m8...they are worse than Okers, not as bad as yanks thu

Is it a worm box like the bradfords have?
anything outside a 1st gen camaro, sb chevy and braddy I realy have no idea lol
If so check out
http://jowett.net/forum/viewtopic.php?t=215
This is work in progress
maybe of some help

Post by **Forumadmin** » Wed Sep 20, 2006 9:55 am

I had wear in my casting and as I did not know better when a student I used a flattened tin can to get rid of it- satisfied the MOT man for many years!
Seriously though, without resorting to rebushing and the problems of line boring across such a long distance, I would attempt to add some ally weld to the hole and then file down until the rack slid through.
No doubt good engineers will decry this.
I could suggest making a bush to sliding fit over each rack end (assuming it is not the rack which is worn; bore out the casing to give a slack fit to allow take up of any axial misalignment. Set the bushes into the casting with the rack installed using a bearing fit Loctite, and make doubly sure by putting some tiny lock screws at the join of casting and bush.
Not tried this mind; but may have a go on my old casting.

geoffwills · Post by **geoffwills** » Thu Sep 21, 2006 9:05 am

Hi Drummond,
Cast ali is in my experience an Ok bearing material, but is likely to wear in high load conditions. If you want to sleeve with a similar material Duralamin (Dural is an alloy with copper content) would probably be the best 'off the shelf' option. Phosphor Bronze is worth considering, but again will suffer some wear in the load conditions. I would seek Cast Iron bushes which should be available from a bearing supplier.

The process I would use is: Line bore the casting to accept the bushes; Warm the casting to approx 100 degrees centigrade; Press in the bushes.
You can if you wish leave say 5 thou inside the bushes for line reaming on assembly.

Notes: The bush should be one thou per inch in diameter larger than the bore that it is to fit; Provide a lead diameter on the bush one thou per inch in diameter smaller than the bore that it is to fit, for one eigth of an inch of its length to enable good alignment on insertion. DO NOT use loctite, but lightly grease both bush and bore before pressing home.

Drummond Black · Post by **Drummond Black** » Thu Sep 21, 2006 9:40 pm

Geoff / Keith, Good information thanks all, I had considered Dural or Phos Bronze, but not CAST IRON. Worth thinking about. As the labour cost of the renovation will be the greatest figure, the choice of bearing material will be insignificant compared to the overall job.
Good food for thought and planning. THANKS

Drummond Black · Post by **Drummond Black** » Sat Sep 23, 2006 7:51 pm

Geoff The maximum wall thickness of the sleeve can be no more than 2mm. This would leave a casting wall thickness at the undercut area at the ends of the steering box of 4.5 mm. Anything less may weaken the steering box casting.

Bear in mind that at the pinion end of the rack the bush length is over 4 inches and at the other end the bush length would be 2 inches. I feel that this would rule out cast iron due to its brittle construction and difficulty of manufacture. How about PTFE or similar

Thoughts please. Drummond

geoffwills · Post by **geoffwills** » Tue Sep 26, 2006 10:25 am

Cast Ali comes in many styles. We cam assume that JCL would use the knowledge gained from crankcase development to select a suitable alloy. Work hardening occurs when the marerial is worked, which means changing shape when cold (as in bending for example), so this will not feature in the steering box - although some age hardening may have taken place in the few weeks after manufacture. When refurbishing we have an opportunuty to fit bushes - something that Jowetts would have avioded on a cost basis. Cast Iron bushes are most certainly centrifugally cast - - better bearing qualities than a piece off a rod stock - - this makes them more dense.

Keith Andrews · Post by **Keith Andrews** » Tue Sep 26, 2006 9:06 pm

This alloy thing is a bit over my head, but, when I have been chatting to guys in machine shops, metolgists, Neil Moore (who from chatting to and learning his Navy background I have a lot of respect) re the braddy issue with steering box wear...(Braddy section) This is the general line of thought.
Wear occurs mainly on the hardened part not the bush eg a gudgen rather the the bronze bushing/piston
Also the sterring box orginally had the cast box with a harder shaft, the wear was mainly on the shaft not the casting box.
Also they cold sprayed the steering box shaft with a Al/bronze alloy. when they ground this they had 1 shot at it. This was because when the surface was worked, it became very hard, then the box its self was then honed to size. If the alloy also has traces of boron, this acts like little ball bearings on the surface creating less wear and a sort of self lunrication.
I think this principle applies to the above disscussion????

Drummond Black · Post by **Drummond Black** » Wed Sep 27, 2006 7:41 pm

As I raised this discussion, I find all the comments and advice very interesting and it is all being logged.
I am currently having communications with Leo Bolter regarding reclaimation proceedures for the Jupiter steering box and some of his ideas are deffinately worth considering. Once I have analysed all the factors I will outline my intentions. But in the meantine keep the advice coming. The subject is far from over.

Drummond

Post by **Forumadmin** » Wed Sep 27, 2006 7:52 pm

Try and get Leo on JowettTalk!

Mike Allfrey · Post by **Mike Allfrey** » Tue Oct 03, 2006 12:43 am

Dear Drummond,

Many years ago I fell into the trap and ordered a new rack and pinion set from JOAC. I, completely unaware of the pitfalls to come, handed the whole assembly to a toolmaker friend who was to clean out the bores in each end of the rack housing to accept the new components. He soon discovered that the rack was severely bowed, due to the steel bar 'relaxing' after the tooth cutting operation. This took some considerable time to get perfectly straight. The whole exercise was time consuming and expensive.

Before your winter project commences, I would suggest that the shims in the steering rack ball housings, 52872. I have found that thes pad shims wear (disintegrate) in conditions where wheels are run out of balance or if the wheels are bent. On my car, the LHS wheel was bent for quite a while and completely demolished the shims. This felt like rack and pinion wear.

I feel strongly that, in the case of the Jupiter, wheel balance and truth are vitally important.

I am pretty sure that the bores in my housing were in good condition, the wear was at the rack itself. I think that next time, whenever that may be, I would seriously consider reclamation by metal spraying.

Has anyone tried that yet?

Just one point, Jupiter owners are never too old to own and drive a Jupiter!

All the best with your project,

Mike Allfrey.

E0 SA 42R

Drummond Black · Post by **Drummond Black** » Tue Oct 03, 2006 7:06 pm

Thanks for the tip, Mike, I have examined the New Rack and to the naked eye it lookes straight, however now that you have raised the valued point I will get it onto the surface table and check it properly.

With regards to metal spraying I have experience in this area. When I rebuilt the car I had to build up the three " straight ahead teeth on the rack and hone then back to the correct profile. I built it up with bronze and this has worked very well for the last ten years. This was done using a fusion type metal spray ( same temperature as brazing ). If you are talking about reclaiming the rack diameter then a " cold type metal spray " would be best.

Once I get the box out and stripped then I will let you know the findings.

Thanks for the input Drummond

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