Jaguar S-Type Front Suspension Knocking
On the S-Type a knock from the front over small bumps is most often the front anti-roll bar bushes or the drop links, both cheap. The original bushes were undersized and Jaguar later revised them. I'd check the bar first, then the ball joints, and only then the wheel bearings and shock bushes.
How bad is it · Garage, carefully
Fine to drive gently, but get it found
Worn bar bushes and drop links are a noise, not a danger. A worn ball joint or wheel bearing is a safety item, and it wears the tyres while it waits.
Which one applies to yours depends on your symptoms, your model year and what has already been done to it.
Likely causes, most common first
Read the check cost before the odds: a free check that rules a cause out beats a likely guess that costs money.
Front anti-roll bar bushes
The bar is clamped to the subframe through two rubber bushes in brackets. The first bushes were too small for the job and wear quickly; once there is a gap, the bar knocks in its brackets on every bump. Rust under a tight solid bush can squeak or knock as well, and a bracket a millimetre out of size ruins new bushes early.
A hollow knock or clonk over potholes and rough surfaces, worst at low speed, often with nothing found at the annual test.
The bushes can be seen from above under the bonnet. To tell them from a ball joint, take a bump while turning: the turn preloads the bar and a bush knock goes quiet, while a ball joint still thumps once.
Replace both bushes with the revised type that has a felt lining; Jaguar bulletin S204-08 covers the redesign. On the heater valve side, take out the two 10 mm bolts holding the valve bracket and lift it aside, hoses still connected, to reach the clamp bolt; the undertray comes off too. Allow about an hour and a half for both. If the knock comes back, renew the brackets as well.
Front ball joints, upper and lower
These ball joints wear without much play you can see, so a joint can pass a lift inspection and still rattle. Jaguar supplies the lower joint only with its arm or vertical link, which makes the factory part dear; press-in joints are sold separately.
A single thud rather than a rattle, a knock when turning onto a dropped kerb, a clonk when braking on full lock, or wear on the inside edge of a front tyre.
With the wheel off the ground, rock it top to bottom, then compare how easily each joint turns against its partner on the other side: the easier one is usually the worn one. Split rubber boots fail the test on their own.
Replace the worn joint; the upper one comes with its arm. Match the stud size: cars up to VIN M44997 (to 2002) take M14 joints, cars from M44998 take M16. Have the alignment set afterwards. Early cars were covered by recall bulletin S204-R136, a torque check of the lower ball joint fastener, not a free joint.
Anti-roll bar drop links
The short vertical links from the bar to the struts have ball ends that wear and rattle over small bumps. Jaguar changed the link design several times, so the part has to match the VIN.
A light rattle rather than a knock on every small bump at low speed, or a knock that returns soon after new bar bushes.
Keep both front wheels on the ground, or lift both: jacking one side loads the bar and hides the play. Hold the ball end while someone bounces that corner and you'll feel it knock.
New links on both sides, ideally together with the bar bushes.
A worn front wheel bearing
A front bearing can start with a knock at one corner over bumps, or a light clonk when braking on lock, well before it begins to hum.
The knock stays at one corner and the bushes and links are sound; months later it turns into a rumble.
Lift the wheel and rock it top to bottom: play there is the bearing or a ball joint. Spin it and listen.
Worth checking before a second round of suspension parts; the bearing is sold with the hub.
The order to check them in
The point of the order is money: each step either rules a cause out or makes the next one worth doing. Green is free, amber costs a little, red is the one to arrive at last.
When does it knock
Straight over bumps, turning, or braking on lock; one corner or both. A rattle points to links, a single thud to a ball joint.
freeAnti-roll bar bushes
Look at the bushes and brackets from above, under the bonnet. Take a bump while turning and listen.
freeDrop links with the wheels loaded
Both wheels down, hand on the ball end, someone bouncing the corner.
freeBall joints and bearings
Rock each wheel top to bottom, compare the joints side to side, and check the boots.
free on a liftShock bushes and mounts
If it still knocks, the lower shock bush is sold on its own and costs far less than a shock.
a lower shock bushAlignment
After any arm or ball joint work, set the alignment before the tyres wear.
an alignment checkWhat it usually isn't
Don't spend money here first:
If none of this finds it:
On jagaux.com
- Jaguar S-Type Gearbox Fault, Transmission FaultIf the clunk comes with gear changes rather than with bumps.
- Jaguar S-Type Parking Brake FaultIf a rear brake drags or the parking brake warning is on.
- Jaguar VIN decoderConfirm your exact model year, engine and factory options before ordering parts — free.
Ratings, fuse numbers and torque figures vary by model year and market. Read the legend on your own car before pulling anything, and use the figures in the manual for your car, not the ones in a video.
Check your VIN: exactly which car you have and which bulletins apply to it.