Constant knocking noise

[benfell100]

I am getting an annoying knocking noise (not actually constant) from behind the driver position. Going over bumps, round bends it is driving me bananas!. I've checked pretty much everything I can think of including the ECU, chassis bolts (took the carpet up and inspected the bulkhead wooden thing, fine) twiddled everything in the engine bay. Can't work it out. It may be suspension as I haven't got theat far yet but it sounds too close to the driver. Any ideas?
Dom

>>> Edited by benfell100 on Tuesday 12th April 07:41

[hilly]

It will be the chassis bolt through the bulkhead. Mine was the same, the clonking drove me nuts until I tightened them up which fixed it.

Andy
1981 S3

[toyroom]

I've had the same proble with my V8 for years. It started after the original dealer changed the power steering pump. Ever since then, I've had a loud clonk every now and then from somewhere behinf=d the passenger's head. I've tightened the chassis bolts, taken the seats out, disconnected the tailgate gas struts, packed rubber between the radiator return pipe and the bulkhead, tried sitting backwards in the passenger side without the seat while someone else drives to see if I can pinpoint the source and.... finally given up and got used to it ! I am assuming that it is a creak as a result of tiny movements of the bulkhead joint with the body.
I'll never forget the first time I drove the car with the engine cover off however. I remember looking back as I blipped the throttle to cause the noise to occur. It's absolutely amazing how much the engine jumps about !!!!

[Skerd]

A blown out shock absorber caused a similar noise on a different type of car of mine years ago.

[benfell100]

After a lot of frustrated tinkering I seem to have found what may be the problem. One of the chassis bolts in the boot (not the bulkhead ones, the ones under the carpet) has pushed through. There is a crack in the fibreglass, a little white powder and the boot floor, the sidewall and the upright part are not as one. After looking underneath it also appears that the top of the exhaust mounting bracket that has the rubber insert is rubbing on the bottom of the boot. I expect this is connected with the fibreglass failure. I have also had these bolts fixed before and that time the back end felt like it was unstable going round corners. Steve at SJ noticed it when the engine cover was rubbing on the dump valve t-pipe and looked like it was sittng too low.
Another trip to Geoff is in order and hopefully not too big a bill...
Rant start.
Incidentally, what the hell possessed Lotus to fit bits of mild steel/nuts/bolts that just rust to dust!!!!!
Rant finished.

>> Edited by benfell100 on Wednesday 13th April 16:14