knock sound

[Stubonez]

Hi guys, i seem to have acquired a knock from underneath the car (sounds like under driver seat) It only happens once when turning out the bottom of my road and when turning back into my road. It's a sharp corner on a hill so a lot of the weight transfers from one side to the other when turning in. It's quite a hard, deep sounding knock like something moving when turning it. I can't seem to make it knock anywhere else but there? I recently had the gearbox done so could it be anything that was not tightened up correctly? Any ideas? thanks

 

[nutnutwelshman]

Had a knock on my meg which was at low speed re parking and out of junctions turned out to a lower ball joint

 

[Chris]

Ball joints, which is usually at low speeds and a more screeching sound, engine mounts, gearbox mount (wouldn't usually say this bu being as you've had it done) could be top mounts.

 

[nutnutwelshman]

Mine was a knock [MENTION=29138]Chris91[/MENTION] definitely buddy

 

[Chris]

Yeah kev didn't say it wasn't, just said they usually make a creak/screech at low speeds

 

[nutnutwelshman]

Yes but done under warranty

 

[Stubonez]

Somewhere i was just reading about a chap who had a similar problem and it was a loose subframe. Popping to my local garage tomorrow & we'll get it up on a ramp and have a look! Cheers for the suggestions though guys!

 

[peter]

when i had my gearbox replaced, one of the bolts of the subframe broke. well, it broke the first time i drove through a pothole (at low speed, in a corner).

 

[Stubonez]

It usually happens when the car has sat for a couple hours. If I accelerate a little harder than normal in 1st there's a clunk/knock sounds like it's from the engine and then it's pretty hard to get it to do it again.

 

[john_walker74]

After clutch change I had a loud constant rattle due to a subframe brace being put back on the wrong way round. Won't be that.

Does it drive ok? I had a clunk and a move left / right due to a loose wishbone bolt. Took two attempts to get it tight enough! Did Chris have the wishbones off?

 

[peter]

after that initial knock, i felt it knocking really hard whenever i braked hard. it was as if i could feel it through the pedals. maybe yours has just come loose.

 

[Stubonez]

After clutch change I had a loud constant rattle due to a subframe brace being put back on the wrong way round. Won't be that.

Does it drive ok? I had a clunk and a move left / right due to a loose wishbone bolt. Took two attempts to get it tight enough! Did Chris have the wishbones off?

Drives perfectly. Just this one knock sound when i accelerate and that's it. Sounds like something sliding backward and knocking then it doesn't do it again. Leave the car for a couple hours and i heard it again when i accelerate of turn out my road. It has to be something loose. Can't see what else it could be. I have no idea what Chris had off. >.<

 

[skny]

Could it be the clutch master cylinder? it makes a little knock everytime you start the car and set off, never heard it doing it again in any other gears than just when setting off, but had it on my previous 197 and have it on the current one, if thats the case then you shouldnt worry, its not a loud knock as if from the suspensioin though so you should be able to tell the difference.

 

[Stubonez]

We went over all bolts and managed to get half a turn out of just one of the subframe bolts and it's stopped knocking. Find it hard to believe that would stop the knock but it has.. Will see if the knock comes back over the next few drives.

 

[R27#239]

The sub frames like to move. I work with a lad who ran a couple of cup race cars. His advice for when I removed my subframe was to hang off the bolt to tighten them. If they work loose again I'd recommend applying thread lock