Clicking or thumping from rear S2 Coupe

I have read some of the threads here about a noise coming from the rear drive splines and I’m not sure if that’s the problem I am having.

It doesn’t seem to happen until the car is heat soaked from driving on the highway then as I lightly apply the brakes to start slowing down for a stop, I get a staccato thump sound which I think is coming from the right rear of the car. The frequency of the sound is in direct proportion to the speed of the car and it goes away as I press harder on the brakes to come to a stop. The car has about 1800 miles on it since a complete ground up restoration which included a complete rebuild of the rear suspension/ drive line assembly with all new components.

Does this sound like the problem encountered from the movement of the drive line splines? If not, any suggestions on a possible cause?

FWIW, I had a similar noise when I first started driving post-restoration which was caused by the large rubber bushes in the radius arms failing (new during restoration) so I replaced both the large and small bushes with new poly bushes.

Any insight appreciated.

The spines moving in the hubs causes a clicking noise more than a thump, like loose wire wheels cause, and IME doesn’t occur in the circumstances like yours. I’ve had the problem on both my cars. I’ve also got a significant clunk/thump from somewhere in my drive line on my coupe. It’s getting worse as I drive. Every thing in the car including the diff has been rebuilt, except the drive shaft which has 25k miles on it and shouldn’t have failed.

There has been some problems with the big poly bush for the trailing arm separating where it joins the inner cup. Check there first.

Sounds like brake related noise. Warped rotor? Rust build up on edge of rotor? Pad separated from the backing? I have experienced those but, not on the Jag

I would check the pads in the rear brakes. One could have separated from the metal backing, or a retaining pin could have come adrift. Any issue with the splines or U-joints would more likely happen under acceleration, not braking.

Do you have the mud shields fitted to the driveshafts?

Terry, thanks for the tip. It is definitely a thump and not a click. I will check the poly bush which is new after the rubber ones failed. It surprises me that there is that much vertical movement of the big end bushes to cause a failure like that.

Bill, I don’t think it’s a warped rotor as the brakes work smoothly with no pulsing in the pedal. I will check the pads as that is a possibility.

Jack, thanks for the tip, I will check.

Andrew, I do have the shields but I don’t see anywhere that they are rubbing.

The problem I’ve had with seperation on a poly bush comes from the install. Typically they get bolted up to the pylon on the underside of the car when the suspension is in full droop, and this causes a lot of strain. The metalastic bushes are more flexible and weren’t bothered by this. Not sure that the poly bush is right for this application, because there is a big strain each time the car is jacked up or put on a two post lift. I’ve got them in one of my cars and am somewhat worried about it.

I have this condition as well. All new/rebuilt. I have a set of “chassis ears” that I was going to use to pinpoint the location of the noise. Just have not yet.

Terry, I checked the bushes and they are fine. Fortunately, I installed them with the car on my 4 post lift so the suspension was fully loaded.

Michael, That seems like a great way to isolate the problem. I’d like to hear what you find when you do it.

They are notorious for making noise. If all else fails take them off and see if it improves things.

I’m going to pull the driveshaft and check the u.j’s Last resort, but my problem is just getting worse and something needs to be done.

If all the other myriad possible sources have been examined, tight UJs can create odd noises.

The odd thing to me is that the problem generally doesn’t occur until after the car is completely heat soaked from a highway run. Then once it starts it’s constant every time I come to a stop.

Terry, you realize removing the driveshaft means either pulling the engine or dropping the irs?

Oh yeah. With some experience, and a 2 post lift irs is out in 30 - 45 mins and the drive shaft is a Medatronics one connected to their 5 speed, so it just pulls out of the back of the gear box without disconnecting it at the gearbox. (drive shaft spline is internal in the gearbox.) Easy really.

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Nice! Nothing beats experience.