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Thread: Direction Finding

  1. #1
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Direction Finding

    So I have been slowly improving the calibration accuracy of my speedometer and Nav odometer, zeroing both and using an 8.7 mile test loop to check both the absolute calibration and the relative difference between the two. I had got it down to a 2.5% error, but as I pulled into the drive on full right lock the steering wheel suddenly felt “odd”, with lots of lateral movement pivoting around the upper steering column support.


    A quick look in the drivers side footwell confirmed my worst fears – the plastic bush that supports the steering column as it goes through the bulkhead had broken up. In fact, I only found half of the bush intact, the rest of it was reduced to plastic shavings on the floor.


    As I knew I would have to replace the bush before I could use the car again, I ordered a replacement from Rimmer Bros at 11:30am on Friday morning, and the part arrived exactly 24 hours later! Amazing service, you can understand why there are so many classic Triumphs and MGs still on the road…


    The new bush appears to be made of a material similar to urethane, quite hard but with a bit of give in it. Rather like a bodywork grommet, it is intended to be pushed through a hole in a retaining plate, which is then bolted to the bulkhead. The splined end of the steering column then passes through the bush and into the UJ on the other side.


    So the plan of action was simple – disconnect the steering column from the UJ, withdraw the column from the support plate so that the latter could be removed, press the new bush into the support plate and reassembly is the reverse of removal, as all the best manuals would say.


    Sounds simple, but the reality was a long hard slog. First the dashboard had to come out (top cover, RH closure panel, centre support moulding, instrument panel and wiper contact plate), then undo the UJ pinch bolt from inside the front wheel arch, then pull the splined shaft out of the UJ from the drivers footwell. Here’s a few images I took along the way...





    Front brakes. M16 calipers with Ferodo fast road pads and my new anti-rattle springs installed, courtesy of Bigg Red. Solid grooved rotors from Burton Power, alloy hubs from Hi-Spec. Only the upright betrays its Ford origins and even this has been modified for screw-in spindles courtesy of Randall Motorsport, who modify Ford uprights for stock car racing.





    My old SPAX dampers will soon be replaced with AVO double-adjustable dampers with spherical joints top and bottom. I have the same same set-up on the rear suspension. Wishbones are from Lee Noble, fully Rose-jointed and still holding up well after all these years…





    I can’t show you a picture of the upper UJ because I just couldn’t get the camera in there. Here’s a picture of the fuel flow sensor instead





    Actually, you can just about make out the UJ pinch bolt above the roll-over valve on the fuel tank. Accessibility is poor because the steering column was one of the first components installed in the chassis and hasn’t been removed since


    Part of the problem is that the Rover SD1 steering column is designed to collapse in the event of a head-on crash, so the splined shaft is only held in place by a sacrificial plastic pin designed to shear on impact. So even though the UJ was loose I couldn’t simply pull the column out without breaking the shear pin. Plus there is a fair amount of wiring attached to the column as well…





    So after 4 hours of teasing, cajoling, tapping and wiggling, the splines finally gave up their grip on the UJ and the column was free! Now onto the support plate – this lozenge-shaped piece of steel is held in place with two bolts, but one of them was glassed over. A bit of surgery later, and the support plate was free as well. The plate was quite badly distorted, so I bashed it back into shape before pressing in the new bush. Then it was bolted back into place on the bulkhead, the splines were well-greased and popped through the bush and into the UJ behind.





    Yes, it’s that little bit of grey plastic. What a lot of effort for such a seemingly insignificant part...


    More cajoling was required to get the splines to fit completely into the UJ, but eventually the pinch bolt was reinserted and tightened, the wheel was roughly aligned and the re-assembly could begin.





    First I thought I better clean up the carpets a bit. This is the passenger side. All the plastic shavings were vacuumed out of the drivers footwell and then it was back on with the main dash panel, followed by the instrument panel…





    The black box on the right of the panel is the SGI-5 signal converter. The speedometer is just in front and has 2 DIP switches for calibration. I left the top cover unsecured so I can change the calibration settings more easily.


    Finally all back together, a quick test drive confirmed that (a) the steering was back to normal (maybe even a bit more direct than before) and (b) the wheel was off-centre by a couple of splines. Fortunately I had greased the steering wheel splines after all the trouble I had removing the wheel last time, so getting it re-aligned was straightforward.


    Phew! Back on the road, and only 30 hours after the problem had first manifested.


    Lauren
    only Pythagoras can save me now!

  2. #2
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    Glad you are back on the road. It is amazing how some relatively simple and cheap repairs can become a right nightmare.

    Dirk

  3. #3
    Sometimes a simple plastic fitting can cause a whole lot of work.I fitted polyurethane mounts on the gearbox thinking that they would last forever, well they did, if "forever" is 15 years of none use. they just crumbled away meaning the whole lot has to be replaced which basically means,' engine out ',

    Nice set up on the front end.



    The opinions expressed in my posts may not be made in a sound mind and should be taken in the spirit intended, Jack Daniels is fine.
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  4. #4
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    Lauren, Your use of zip-ties and molex connectors in your wiring makes me feel better about my use of the same. As always, love your build updates.
    Thanks,

    Nic.
    http://s93.photobucket.com/albums/l61/quikniq/
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  5. #5
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Quote Originally Posted by Nic View Post
    Lauren, Your use of zip-ties and molex connectors in your wiring makes me feel better about my use of the same. As always, love your build updates.
    Thanks Nic - well, you know what they say, "a place for everything and everything in its place". It's a lot neater than the rat's nest that it replaced, if you look carefully you can see that all of the instrument panel interfaces (sensors, warning lights, power) are on just 3 Cannon D connectors (2 x 25-way and 1 x 9-way), so it is really easy to hook up all the instrumentation in one go

    Besides, you should see our spacecraft wiring harnesses - apart from the Kapton insulation and Teflon dielectric, its all zip ties and multi-way connectors too!
    only Pythagoras can save me now!

  6. #6
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    Quote Originally Posted by Spacenut View Post
    all of the instrument panel interfaces (sensors, warning lights, power) are on just 3 Cannon D connectors (2 x 25-way and 1 x 9-way), so it is really easy to hook up all the instrumentation in one go
    WOW! I had noticed them but not really NOTICED them the first time. Are you running solid or stranded wire and what gauge/size wire? It looks like its somewhere around 20-22 gauge. If so, and it can take the power, I have WAY over-sized my wiring at 14-12 gauge. Aww, man... I don't want to have to rewire everything... again.
    Thanks,

    Nic.
    http://s93.photobucket.com/albums/l61/quikniq/
    CCC Sterling # 416

  7. #7
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Hi Nic - I'm sure you don't have to re-wire anything. The cable I used was multi-strand thinwall automotive stuff with rating from 8 Amps to 22 Amps from memory. I used the 8A wire for all the instrument wiring as the on-board fuse is 5A, so there is a bit of margin. I couldn't go above 8A anyway, as the wire was too thick to fit into the Cannon connector solder buckets.
    only Pythagoras can save me now!

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    I hadn't noticed the D connectors either, do you have a way of locking them once in place (small nut and bolt)?

    Dirk

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    Quote Originally Posted by Spacenut View Post
    Hi Nic - I'm sure you don't have to re-wire anything. The cable I used was multi-strand thinwall automotive stuff with rating from 8 Amps to 22 Amps from memory. I used the 8A wire for all the instrument wiring as the on-board fuse is 5A, so there is a bit of margin. I couldn't go above 8A anyway, as the wire was too thick to fit into the Cannon connector solder buckets.
    Of course I don't HAVE TO rewire anything, but knowing how much it would tidy up under the dash it would set my slightly OCD tendencies at ease.
    Thanks,

    Nic.
    http://s93.photobucket.com/albums/l61/quikniq/
    CCC Sterling # 416

  10. #10
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Quote Originally Posted by Dirk View Post
    I hadn't noticed the D connectors either, do you have a way of locking them once in place (small nut and bolt)?
    Normally the male connector has captive screws and the female has threaded posts to lock the connector in place, but the connectors are a very tight push-fit anyway so I didn't bother with the locking screws...
    only Pythagoras can save me now!

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