408: rear suspension adjustment. What is the procedure?

[PEU186F]

I very much endorse the other recommendations to look at the front end before adjusting the back, particularly as your front sounds to be lower than it should be.

Having got the front ride height right and level it is relatively straightforward to adjust the back - all that you’re aiming for at that point is to keep the main fore and aft chassis rails parallel with the floor. To answer your specific question about the rear torsion bar adjustment point, it is indeed at the front of the bar at the point you’ve identified, all you need to do hopefully is to loosen the lock nut (which is likely to be extremely tight and you’ll need the correct size ?Whitworth? Spanner) on the bolt that acts on the arm that is splined on to the front of the torsion bar and screw the bolt in or out to suit the rear ride height that you want to achieve. I’d advise a good soak with penetrating oil before you start.

You may find that the torsion bars have sagged beyond the range of adjustment available, if so you’ll need to have the car on a lift on the chassis and a friend with a large Stilson wrench. First screw the bolt right out so that there is little or no tension on the torsion bar. You might need to remove the axle rebound retaining strap to achieve this happy state of affairs. You then need to dismantle the torsion bar mounting, which will allow the torsion bar to drop to the point where the adjustment arm can be taken off and moved by one spline. You’ll then need the friend with the stilson to pretension the torsion bar slightly so that you can reassemble the mounting. That needs some strength on the part of your friend but by no means a great deal of brute force. This might all sound rather alarming but in my experience it is all very well made and comes apart and goes back together again easily - given a good previous dose of penetrating oil.

Roger

[dwomby]

Thanks, Roger.

I assume the only thing that will raise the front end to specification is new springs?

David

[Kevin H]

Originally Posted by dwomby

Thanks, Roger.

I assume the only thing that will raise the front end to specification is new springs?

David, that's not necessarily the case. Some of it maybe down to modern tyres which don't have the same side wall height as the original tyres and it's possible the "distance pieces" as Bristol refer to them have disintegrated, which they do eventually. I mentioned these earlier in this thread and supplied links to more detail. The two combined could add up to 1.375". I would certainly check that before you start getting springs made. Either way you are going to have to dismantle the front suspension.

While you are at it I would consider replacing the wishbone bushes if they haven't been done already.

[dwomby]

Thanks, Kevin.

I'll investigate and, if needed, get to grips with the work on it later in the year when it cools down again. I am committed to finishing the servo replacement I am doing now but it's gone to 35C and 100% humidity a bit early here this year so this will be the last heavy job for a while.

David

[AndrewA]

Or A/C in the garage?

Did the revised air filter arrangement quieten things down to your satisfaction btw?

[dwomby]

Originally Posted by AndrewA

Or A/C in the garage?

Did the revised air filter arrangement quieten things down to your satisfaction btw?

Hi Andrew,

I did have a window AC in the garage but didn't replace it when it failed a few years ago as we spend summers in Canada! However, it's heated up a bit early this year so I may indulge in a new one for next year.

The air filter has helped a bit but I would still like to try a fully silenced (snorkel-type) unit if I can get one for a reasonable price and that will fit. Probably not before the autumn either though.

David