Mk2 Steering Box

Hello all, as part of a full restoration on my '64 Mk2 I turned my attention to the leaking steering box ( not PAS). Inside what little oil there was had turned brown in color with a thick residue residing at the bottom. I reasoned a wash out in petrol would do no harm and then see if there was any apparent damage. On removing the larger plate I noticed it was marked where something had been pressing hard enough on it to have worn two 20mm long scores side by side on the back of the plate, one of which is quite deep. I have never driven this car as it was purchased following an under bonnet fire caused by an electrical issue. Is it worthwhile rebuilding this box given the significant scoring.
If it is, any advice on procedure to replace the balls next to the worm drive and how to ensure it is set up central.
As always your response is much appreciated. Eugene

Post a picture so that we can asses the damage.

Thanks for getting on the case Robin. I will take a picture but may struggle to post it, will have a go.

The plate with the score marks should be able to be ground flat by any machine shop with a surface grinder, its natural wear pattern from the movement of the shaft.
Any engineering suppliers should have the correct sized ball bearings or google ‘loose ball bearings’ to find a supplier in your area.

Thanks Robin, are you saying it is due to worn ball bearings that as been the reason for the scoring and I would need to renew them all to cure the misalignment and restore thru running of the shaft

Robin I have just had a look at ebay for new ball bearings and there appears to be many advertised for slingshot/ catapult use. Is there a particular grade ie Stainless steel or Grade 100 of bearing I need to seek out which is appropriate for my use. I put my caliper to a random sample of 10 ball bearing from the steering box and they measured 5.41 to 5.42 mm ( 0.213 inch). Given mine are worn what size should the new replacement ball bearings be. I can purchase them in 5.5 mm on ebay from Aero Auto Components in packs of 20.These are AISI 52100 Hardened Chrome Steel. BTW SNG does the oil seal and the rubber O ring if anyone needs them. Thanks

I’m not sure what the original size of BB’s would be but I doubt that they have worn very much at all they with certainty would not have been 5.5mm (says he with the utmost confidence) as these boxes were pre-metric.
.213” is equivalent to 5.41mm which is a difference of .004”
Just to confound my own statement 7/32” is .218” so I might be talking through a hole in the top of my head. It might pay to use a micrometer rather than calipers to double check your measurements.
Failing that if the 5.5mm BB’s are not too expensive try them out making sure there is un-encumbered travel through the complete arc of movement.

Yes Robin well pre 1973, maybe someone else can come in and let us know what the original imperial size the BB’s would have been. The ‘Grade 100’ appears to be the industry standard so when I do purchase I will go for that. Will hold back buying any until confirmation comes in on what size they would have been originally.
Note : When you mentioned micrometer it made me think did I use an old digi caliper or my recently purchased one (approx 1 year plus) so I went out and checked. On my newer one the figures are 0.258" or 6.57 mm. Old one now binned. Still does not make it any easier to source replacements given they are on the upper side of even numbers.

Thats just a tad over 1/4” now I’m really confused :frowning:

Yes, one would have thought 1/4" imperial would have been the size they would have used.
Maybe the caliper is showing slightly on the high side.
If no confirmation of factory fitted size in next few days I will go ahead and buy the 1/4" BB’s.
Robin have you or anyone else any experience in fitting the BB’s. I would like to know the method/ sequence in fitting them to the shaft, presumably with grease, but mindful of having it set up to be central for left to right turning.

Did it about a year ago, its really a case of trial and error, as far as being central thats just a case of turning the input shaft one way and then fully the other and splitting the difference.

Has anyone thought of adapting a 2204-2006 S type electric steering to a MK11?

Do the scores need to be machined out ?
Once adjusted right , the 2 parts that made the scores will not be making contact , scores or no scores !!

My feeling to Ian. I ran a ‘flappy disc’ over them to remove any possible sharp edges and I am happy with the result.
Any idea on the original size of the balls ?

It’s my belief that the scores are from general wear and tear not mal-adjustment. The major wear is in the straight ahead position where the car is spending most of the time, at full lock area there is very little wear. I would be very inclined to make sure the plate is flat across the complete area as I think it will bind on any high areas.

Well worth a check Robin.
I will give a light coat to the inner surface tomorrow and lay it flat on some new 1/4" steel plate I have to check for flatness. Will also give it the steel rule check.

Sorry Robin , but I beg to differ , the scores are damage , not wear , put the fault right your get no damage , so a waste of time and money machining the scores out , only metal to metal contact on the top is a spring and the roller , anything else is poor adjustment or wear !
As for ball bearing size , I don’t know , but would not pay the £75 odd , that well known dealers want for a set .
I would take the old ones to a bearing supplier , I have a good one close to me , who supplied the oil seal .

Always worth doing a search on the net , I found this !

Hi Ian, I found this blog on the internet and saved it. Actually asked poster a question on it.

Right, I have result on the diametre of the balls in the steering box
9/32” however to be honest I don’t think they will need replacing.
I have just taken one apart and measured them with a Mic.
I think the problem thats going to arise is the galling on the two thrust races on the input shaft.
Also this has the same wear pattern on the top:

I still believe this is normal wear and tear due to the action that the steering box goes through from lock to lock.