Another "Clonk" question

[PaulM]

Today I have a new, unnervingly loud clonk from the front of my car.
It doesn't happen when just driving along a road. It happens when manoeuvring, at junctions and at roundabouts.
More power or speed (so tendency to roll??) = clonk more likely
Tighter turn = clonk more likely.
It's just one or two clonks each time, not a continuous rattle grind or squeak.
It very occasionally happens over potholes but it's really not an issue on the open road. I haven't driven the car hard since I first heard the clonk, obviously.
I THINK it's more likely to happen when straightening back up rather than when initiating a turn but I might be wrong.
I can't tell whether it's coming from left or right - middle seems most likely if that's possible.
I've checked the wheel nuts. All tight.
I just got the car back from a garage where a coolant leak was being fixed. I believe that's irrelevant/coincidence because the leak didn't require steering or suspension to be touched.
Any ideas???
I'd really like to drive the car this weekend (Lotus On The Pier, Whitby, North Yorks) and worry about clonks next week but it would help with that choice if I had some idea where the clonk might be coming from.
Any help gratefully received! Thanks.

[dapinky]

It is something which is impossible to identify from words alone, but I can tell you what I would look for, and in what order.....

.... if wheel bolts are correct I'd first jack up the front of the car onto axle stands and chock the rear wheels. Rotate each wheel forwards, then backwards a few times (to see if there is play in the driveshafts/bearings).

Get an assistant to move the steering from lock to lock whilst you lie under the front and see if you can hear the same noise...... then do the same by holding a wheel and moving it through it's full movement (then the other one). The theory being that you should see/hear a movement in any of the moving components if there is a problem in the steering system.

Then take the front wheels off and check the brake callipers are tight to the uprights.

Put a jack under the hub and lift it until the weight is just transferring to the jack from the axle stand - repeat the other side. (this should show any component in the suspension).

Put the jack under the right-side of the sump (with a bit of wood to spread the weight!) near to the drain plug..... see if there is any vertical movement which could indicate a duff mounting/damper ....... DO NOT TRY TO LIFT THE WHOLE CAR - just take the weight off the mountings.

If none of this gives any results, and only if it is safe to do so, start the car, engage 2nd or 3rd gear, release the clutch and allow the front wheels to move - turn the steering, and see if you can replicate the noise.... apply the brakes both with the engine driving the wheels, and with the clutch depressed (one will put strain on the shafts in one direction, the other in the other direction) - repeat in reverse gear.

If none of this helps, then it is a case of looking for absolutely anything that is loose and rattling around, either in the engine bay, or behind the wheel arch liners (vacuum reservoir/horn?????)

However, I would also throw in a wild-card suggestion that I'd stick my arm along the right-side driveshaft and feel the bracket that holds the jack-shaft bearing to the engine block..... they don't work loose very often, but if they do it can do exactly as you describe, and can be hard to find!

Hopefully, it will be something really obvious and there will be no need to perform all the tests described....... and although that is the order I'd do it, it doesn't really matter.

[Tuga2112]

im not reading pinks message and there is a chance he mentioend it. but given the description i would be checking very carefully with a crowbar for leverage the lower and upper ball joints as well as the anti roll bar joints.

and ideally you will try to wiggle those both with the suspension under load as well as withtou any load.

jack the car up on the jacking points and test. and then also put the car on ramps (or lift the jack under each wheel till the point where theres good tension... if you are brave/suicidal enough) to check again.

i have experienced a similar set of symptoms a few years ago and it turned out to be the lower ball joint on the passenger side nut was halfway up, the whole thing was not noticeable when the wheels were off the ground. but as soon as the car was on a 4 post lift at the mot station and they made the shake mechanism work it was very obvious that i needed a new lower ball joint

[PaulM]

Wow Dave - many thanks for such a detailed reply.
I'll work my way through that lot as best I can.
The car only passed its MoT a month ago so hopefully I won't find anything too bad.

Update - it turns out that it's one of the joints at the end of the anti-roll bar. An easy, inexpensive fix.

[PaulM]

And thanks also to Tuga! Your suggestion to look at the anti-roll bar joints turned out to be spot on!