Technical Steering / Wheel alignment

[ajw888]

Hi, first post.

I have a 64 500D and slowly bring it back to life before I stick a 2014 Moto guzzi 750 engine in it.

While replacing the brakes I found the kingpins where worn, so I decided to do the seals on the steering box as it leaks and all the arms & ball joints and idler bushes.

What I found with the original set up was that the steering wheel when centred (equal turns to L & R) to drive straight it is turned about 33 degrees to the left. The original arms where RHS 368mm, LHS 361mm and tie rod 360mm long.

The new tie rod is 392, that fine, the steering rods initially set to 360mm both sides. Looking at the wheels, they are pointing about 5 degrees to the left (same on both sides). So I am guessing this is why the original arms were such different lengths.

Finally my question. how many splines are there on the steer box output shaft? I am wondering if the drop arm on the steering box was 1 spline out, I don't really want to dismantle it all to test. I could work out the amount 1 spline might do.

 

[Goldnrust]

I cannot tell you exactly how many splines there are on the steering box output, but I’d be fairly confident the spline will be too coarse for the adjustment you’re looking for.

I would question the difference in tie rod length, 360mm old vs 392 new. A change in tie rod length would change where their straight ahead position of the steering box arm needs to be?

 

[smart51]

If I suspected the steering arm was fitted to the steering box one tooth off, I'd steer to full lock in each direction and look under the front of the car. If the arm is measurably closer to the bulkhead at one side than the other, it is probably off. Otherwise it is OK.

Another check you could do. set the steering to the centre and measure diagonally between the pivot points of the steering arms. The two diagonals should be the same. Move the steering so that the diagonals are the same, then measure from the steering box to the idler arm and from the centre track rod's pivot points. They should be the same. If not, the steering arms are not parallel. You then know if it is off by a tooth or two.

 

[ajw888]

Edit.

Original drag link length is 383mm not 360 as above. Still ~9-10mm difference

 

[ajw888]

If I suspected the steering arm was fitted to the steering box one tooth off, I'd steer to full lock in each direction and look under the front of the car. If the arm is measurably closer to the bulkhead at one side than the other, it is probably off. Otherwise it is OK.

Another check you could do. set the steering to the centre and measure diagonally between the pivot points of the steering arms. The two diagonals should be the same. Move the steering so that the diagonals are the same, then measure from the steering box to the idler arm and from the centre track rod's pivot points. They should be the same. If not, the steering arms are not parallel. You then know if it is off by a tooth or two.

Thanks, will check. Note I also used the wrong original drag link measure - it is 383mm

 

[the hobbler]

Thanks, will check. Note I also used the wrong original drag link measure - it is 383mm

There is a fair chance that whoever adjusted the steering previously did a bum job! When the toe-in has been adjusted to the correct setting (0 degrees with a fair bit of weight in the front of the car) the track-rods MUST be the same length. As has been pointed out on previous query, on many occassions the "proffessional" doing the adjustment just adjusts 1 track-rod to get the toe-in adjustment---lazy bugger! It IS fiddly getting the lengths the same, but it is worth the effort. The steering wheel alignment can then be checked/corrected---1 big nut inside the hub of the steering wheel. The splines are fairly fine for the steering wheel, but don't forget to just undo the nut a couple of turns, then loosen the steering-wheel before you take the nut and wheel completely off.
The splines for the steeting arm (on the the steering box) are coarse, and moving the arm even just 1 spline makes a big difference.