AC Ace steering box?

[Michael Trotter]

Good morning Jonas

When you started this topic in June you were seeking a replacement steering box. A month later (#11) you told us 'I don't think there is anything very wrong with my steering box'. Was this a change of mind about the original or were you talking about a replacement? I hope the former as the latter might well have cost you a lot in time and cash for a box no better than your original low-mileage one. You reduced the toe-in from 5/32" or more to 1/16". I hope you noted my reservation re following Trackace pre-measurement procedure. I shall be more confident when you have taken AEX31 to a drive-over gauge which shows it spot-on. You reported (#32) that 'the steering and stability were better' but, presumably not as good as you hoped for, since you said you would then adjust the steering box. Later (#44) you say you have been adjusting it over time and it is disappointing  that you still have 14 or 15 mm free play which is no good. I feel  cautious about assuming , as I think you do, that better adjustment will get you to slightest drag and no free play and the instability problem will be completely cured.

Forgive me for being blunt but I think you need to bring to your instability / steering box problems clarity of thought and decisive action as dished out by Napoleon. He always had a battle plan - only failed once near a village in Belgium called Waterloo. Firstly I advise you to carry out the procedure (the 'drop arm test') which I suggested to Greg (wonder how he is getting on). This will confirm whether or not the free play is all a steering box issue. Note this test only provides evidence about the box and the linkage. It will tell you nothing about the bearings, king pins, suspension bushes etc. which I listed (#15) as 'baseline certainties', being factors which could contribute to instability. You said you were 'somewhat confident these were all fine'. You may need to reconsider this later if you think the stability is not as good as as it should be.

Now to the steering box. I suggest the following: 1. We haven't mentioned the possibility of axial movement of the cam - unlikely but best be sure. Push the wheel towards the dash and then pull away from the dash. There should be no axial movement of the column. If there is the box must be re-shimmed before adjustment.  2. Do not waste your time adjusting it at the side of the road - follow AC's instructions.  3. Experiment and get used to the feelings of drag - nil, slightest, slight and too much. This is not adjusting. It is getting a 'feel' for different drags and the relation of movement of the screw and the resulting effect on drag.  4.If you despair of distinguishing different degrees of drag I suggest you separate the drop arm / draglink ball joint and tie up the draglink out of the way. This will eliminate the background drag from the balljoints, idler and king pins. This drag should be little (but when did you last grease them?). You will now only feel peg to cam drag and can continue with the wheels on the floor.  5. Repeat 3 above if you have done 4 above.  6. Now to adjustment. When you you have slightest drag hold the screw with your best screwdriver and tighten the locknut.  7. If, as I expect, the drag has changed  your knowledge of the feel of drags and the related rotation of the screw will tell you the direction and extent of the change. Re-adjust with an allowance for the 'locknut effect'.   8. It may take several trial and error re-adjustments but by lunchtime you will have got the hang of this Burman lark and have slightest drag and no free play. If all else fails, slight free play is better than too much drag.  9. Remember to refit the ball joint!

I hope your further reports will tell us that AEX31 now drives as well as it did when it left that little factory in Thames Ditton 68 years ago.

Michael

[Michael Trotter]

Jonas

A footnote to my above post. I expect you realised, but I forgot to remind you that the column/cam axial check must be done with the wheels off the floor.

Michael

[59 Aceca]

Michael,

Thank you for your continued contributions to this thread.  I did the drop arm test a while back and, from what I can tell, my grossly abundant free play is related to the steering box.  Since performing this test weeks ago, I've simply been waiting for my turn with my busy mechanic.  Seeing your most recent post regarding the axial check, I performed that test today and noted no axial play.  I will be sure to report back once the steering box is evaluated.

Greg

[AEX 31]

Dear Michael,

Again thanks for your valued input concerning the steering of our beloved Ace’s and Aceca’s. The first snow has fallen in southern Sweden so I fear any more driving, and testing will have to wait until spring is here.

I think that you in a very clear and systematic way put light on the importance of being thorough and meticulous when trying to find out a mechanical problem. I will certainly start over from “scratch” when the temperature allows.

To answer some of your questions I have carried out a number of the procedures that you suggest and the results have all seemed satisfactory. But since I’m taking the track rods off the car soon for repainting, I will have the opportunity to go about this in a precise way when reassembling again.

I haven’t tried or tested the column/cam for axial birthday lay since the box was restored by a professional, but I will do this as soon as have time and I will post my findings.

On a slightly different note I would argue that Napoleon did loose big time at the battle of Leipzig in 1813. Important as a Swede since this was the last time Sweden was at war on the continent, but Napoleon did indeed have a battle plan!

Thanks again from at the moment a white Copenhagen.

Jonas

[59 Aceca]

All,

I had some further delays to getting my car to my mechanic so I ended up pulling the sector shaft myself.  The most difficult part was finding a suitable puller to engage with the angled "ears" on the drag link.  The shaft seems to be in good shape and to the naked eye and fingers the pin seemed unworn.  I did, however, devise a rather crude way to check wear on the pin by stacking washers incrementally and measuring with my micrometer at each level and did note a small amount of wear.  It's hard to believe the fractional amount could amount to much play but I'm going to have the pin turned 90 degrees just the same.  Here are my findings:

Wear sides
Base = 13.88mm
1 washer = 11.88mm
2 washers = 10.80mm
3 washers = 10.24mm

90 degrees to wear sides
Base = 13.90mm
1 washer = 12.02mm
2 washers = 10.92 mm
3 washers = 10.28mm

I think I will ultimately remove the steering assembly for rebuild.  Checking my tattered AC manual, it states that the offside shock absorber must be removed.  I've not had any experience with this.  Are there any precautions to take into consideration?  Don't want a loaded spring/shock to release suddenly and cause an issue.

Thanks in advance for any advice on this,
Greg 

[Michael Trotter]

Good morning Greg

Impressed by your measurements of the peg. You have identified slight wear (a bit over 5 thou on diameter) and there will be corresponding slight but acceptable wear on the cam. Just as Bishop expected and for which they provided compensating adjustment. You will rotate the peg which will have long-term benefit but will not, I think , do much  for 5"+ of free play. You say the shaft looks fine and diameter measurements would confirm this.

You are now intending to remove the steering box to 'rebuild' it. The implication is that you are of the opinion that the cause of the free play is in the steering box rather than in the adjustment of it. But where is the evidence? No opinion is worth holding unless it is supported by evidence. The only evidence I am aware of is your confirmation of no axial movement of the column (hope you had the wheels off the floor). This suggests there is nothing much wrong with the cam/column assembly, the upper and lower bearings or the shimming. Now this is not decisive evidence but it is negative rather than positive and supporting your opinion. And what would a rebuild involve? A new cam and new bearings? Hardly 'off the shelf' stuff. I think Jonas may have researched this, or have knowledge, and his advice would be helpful. I have in mind a lot of time, a lot of dollars and replacement parts of questionable quality. Sounds to me like a high cost to benefit ratio. But it is your car, your time and your cash..........

And what about adjustment? Seems to have gone out of the window. With respect Greg, I think you are going the wrong way at the fork in the road. If I were you I would refit the rocker shaft in the straight ahead position, crank and peg at 90 degrees to the axis of the cam. No need to replace the drop arm at this stage. Fit the Bishop cover plate and adjust the box, wheels on the floor. Somebody banged on about this at great length above. Only if careful adjustment failed to eliminate the free play would I think 'rebuild'. If you take the other road at the fork - rebuild, fit the Bishop cover, adjust and eliminate free play you will never know whether all those dollars were wasted and you will have concerns, perhaps, about the quality of the replacement parts. If you doubt the wisdom of my advice, ask your wife for her opinion as she is clearly a member of 'Team 59 Aceca'. 

Now, to cut to the chase (I do go on a bit). You asked for advice about removing the steering box. Unless you have evidence (sufficient, relevant and reliable) that it is broke don't fix it. My advice is to leave the steering box where it is and adjust it.

By the way, I take issue with your description of the Burman steering box as 'antiquated' (OED = old fashioned, out of date). It was good British engineering in the 1950's and still is in 2023. (Pause for 'Rule Britannia'!)

Regards and a Happy New Year to you. May 2023 be the year you get your Aceca steering safely, indeed as it did ex-Thames Ditton in 1959.

Michael

[Michael Trotter]

Greg

For 'Burman' read 'Bishop' !

Michael

[59 Aceca]

Dear Michael (and all),

First, thank you for your comments and suggestions.  Some interesting developments to share...  After a referral and a couple of additional phone calls, I was able to find someone to rotate the pin on the sector shaft 90 degrees.  It was mere minutes from when I explained what I wanted to have done to when it was brought back out to me with the operation completed.  After a quick back and forth between the brothers that owned the shop, it was handed back to me at no charge.  I returned their generosity with a couple of bottles of wine later that day and everyone was happy (Merry Christmas to all).

I had every intention of pulling the steering box assembly for rebuilding but first wanted to see what effect, if any, the rotated pin would have.  During the Christmas Holiday, and with the help of a friend, I reinstalled the sector shaft and put the original top plate back into service.  We initially lowered the adjustment screw only checking the slightest side to side motion on the steering wheel for drag but quickly discovered that things tightened up considerably when the wheels were turned much more than that so we jacked up the front end of the car, made some additional adjustments which allowed the wheels to more comfortably achieve lock in either direction, and went for a ride.  What's odd is that the alignment seemed off, with the car pulling a little to the right.  Looking at the wheels, it seems as though the right front wheel is turned out slightly.  This has me scratching my head because, other than rotating the pin, nothing was done to the tie rods.  I need to look into this further and I also want to look at some further fiddling with the pin adjustment screw depth.  What's really interesting what has happened to the free play.  It's gone from 5+ inches down to 1 inch or maybe 1.5 inches (see attached official Q-tip test photos).  And looking at the drag link arm when the steering wheel is being rotated shows immediate movement of the sector shaft, with that 1 to 1.5 inches of free play being absorbed into the steering linkage.  Amazing!  Needless to say I don't have any plans to pull the steering box assembly now.  Could the alignment have been thrown off by things tightening up so much?  You would think that any effect would have been uniform given the whole steering linkage is locked together.  Regardless, I'm hoping a trip to the alignment shop solves things.  More to come once our much-needed California rains subside.

Best,
Greg

[Michael Trotter]

Good morning Greg

Pleased to hear that Plan B is progressing - I think you are well on the way. Not entirely clear to me but I think you have eliminated the 4" of free play coming from the steering box and are left with 1"+ coming from ahead of the drop arm. Greg, I am not writing a workshop manual - I just make this stuff up as I go along. However, as you would expect, I have some observations which you may find helpful.

1. A full repeat of my 'drop arm test' should confirm that 1"+ is nothing to do with the steering box but comes from beyond the drop arm. 2. Your description of the RH front wheel sounds like toe-out. This will not have happened overnight but will have been lost in the excessive play. Probably arises from the cause of the 1"+. Driving a few feet in reverse may change this 'alignment'. 3. Don't rush to your alignment shop. When you have got rid of the 1"+ you will want an alignment check then (12 to 13 minutes included angle between the wheels - 12.37 to be exact). 4. Read all the above in this thread and note what is relevant to you. 5. A word of caution. The danger in adjusting is overtightening the screw. You may have done this in trying to get rid of the last of the free play. When you have got rid of the 1"+ I think you should follow in detail the AC adjustment instructions. Back off the screw and go through the full procedure, noting that 1/8" free play is better than too much drag at straight ahead. Check for free, easy movement lock to lock with increasing free play away from straight ahead.

I think you are nearly there but let me know if you have problems/questions. Keep me posted on your further progress - I feel a personal involvement and will not be satisfied until you can report 'rock steady at 100mph' (you pay for the speeding ticket!).

Michael

P.S. Do you think the mileage (?88,000)  is genuine and what is the chassis number?

[Aceca289]

I live in the same town as Greg and have been at his house a few times to help sort out his steering woes. When I heard that rotating the peg 90 degrees (to the virgin side of the peg) eliminated most of the 5 inches of play at the steering wheel, I had to get my head around how this could be… Being an engineer, I drafted the attached exhibit in CAD to illustrate the relationship between 5 inches of play at the steering wheel vs. the travel of the worm drive at the peg. Pretty simple geometry here…”a picture is worth s thousand words”. Based on the exhibit, you can see that the worm drive (groove that the peg rides in) only has to move 1/4 inch in each direction (1/2 inch total) to account for 5 inches of play at the wheel.  I guess that the wear on the peg accounts for most of this movement.

I hope this helps everyone visualize the situation better.

John
AEX521

[Michael Trotter]

Greg and John - Good morning

John : Liked your drawing and I agree all the data therein. Not so keen on the title - we don't have worms in our steering boxes (see my #15 above). Just pulling your leg and reminding you that pedantry is alive and well and living in Hampshire UK! Perhaps another example of 'Two nations divided by a common language'?

As I understand it the 90 degree rotation of the peg and the replacement of the Revington cover with the (adjusted) Bishop cover combined gave a 4" reduction in free play at the steering wheel. You say 'I guess the wear on the peg accounts for most of this movement'. My guess is at the other end of the range and I estimate that about 1/4" of the reduction is attributable to the peg rotation and the rest of the 4" is attributable to the Bishop cover.

Greg : Hope you have not been affected by the flooding in California. I have to apologise to you. I led you into breaking the Golden Rule - only change one thing at a time. If you want to add to the body of AC knowledge you could refit the Revington cover and see how much the rotated peg alone does for the original 5"+ free play. Wouldn't take long and wouldn't affect the current Bishop adjustment setting.

Now to the remaining 1"+ of free play. As I have said I think this comes from the linkage ahead of the drop arm (think six balljoints and the idler for starters). A careful repeat of my drop arm test should confirm or deny this. 'Looking at' and 'Starting to move' is relevant, but not reliable, evidence.

With our different terminologies we get into tom'ay'to / tom'ar'to territory as  the song goes. But we both are lucky enough to own 1959 Acecas and want them to drive as they should.

Michael

[Michael Trotter]

Good morning Jonas and Greg

Jonas : The Times today tells me that yesterday Copenhagen was 14C and sunny. Have you been able to get AEX31 out on the road again? And you were quite right about the Battle of Leiptzig!
Greg : Long time, no hear. Have you been able to progress the elimination of that last 1"+ of free play at the steering wheel rim of your Aceca?

Michael

[AEX 31]

Michael,

Even if I live in Malmö (Sweden) I’m actually in Copenhagen at the moment and I’m pleased to tell you that it is closer to 19 degrees, rather lovely!

I have done most of the things I set out to do with 31 over the winter but an electrical problem has made it impossible for me to try out the steering at any higher speeds. I am hopeful this can be cured soon so that I can report on progress regarding the steering.

Best regards

Jonas

[AEX 31]

Dear all and especially Michael,

I’m sorry for my delay in replying but moving my office and other time consuming chores postponed high speed testing of the steering until this last weekend.

The result was very positive and the steering felt better than it ever has since 31 was restored some 6-7 years ago. I’m very sure now that 12-13 minute degrees in total toe-in is what it should be. I should also mention that I have gone through and adjusted all the steering components and I also changed the tie-rod ends to have the best possible preconditions. It did make a big difference.

Thanks to everybody, especially Michael, that’s been supportive and helpful in this process.

Best wishes

Jonas

[Michael Trotter]

Good evening Jonas

Very pleased to hear that you have been able to do high speed testing of AEX31 and that it steers well and feels stable. Are we into 'rock solid at 100 mph' territory?

Regards
Michael