Knocking sound from under car...
Discussion
cacatous said:
I get a knocking sound from the bottom of the car toward the rear passenger side when I turn right.
Sounds like a loose exhaust but not sure.
It is likely to be the brake pads as they clap against themselves. The spring mechanism to keep them away is not there in Cerbera. The front driver side is said to be different and should not sound like this.
The proof is that when you press the brake pedal lightly all noise disappears!
jonnie5 said:
I had this but only when I turned left . It was the exhaust moving slightly and knocking as the engine moved on the mounts (as it's supposed to).
A quick bit of persuasion with a crowbar* and the offending noise soon disappeared
* administered by Brian at Topcats not me!!!
Yep, mine was the same. Left turn and worse when off the gas. Off side exhaust touching chassis near gearbox.
Crowbar is the answer.
jonnie5 said:
I had this but only when I turned left
A quick bit of persuasion with a crowbar* and the offending noise soon disappeared
* administered by Brian at Topcats not me!!!
Exactly the same with mine, and again only on left turn at slow speed - and spookily also fixed by same 'TVR Official Procedure' by Brian!
Sound like Topcats should patent this fix....
cacatous said:
Do I bash the whole exhaust or what? Someone tell me please!!
Sorry, I left it to Brian and his hammer - as my action may have been a little too destructive.
Maybe worth giving Topcats a call - very nice bunch of people.
Cheers,
Michael
>> Edited by tommomic on Thursday 5th February 16:48
I'm not that familiar with the underside of the car (no pit at home!), but if you follow the line of the exhausts from the engine just behind the gearbox the two exhaust pipes almost meet - mine was banging the underside of the car there and just needed a bit of persuasion away from the tunnel in which the exhaust sat. This was a gentle lever not a bang
I hope that makes sense and helps, but you'll certainly need to have the car on a ramp or in a pit to get to it!!
I hope that makes sense and helps, but you'll certainly need to have the car on a ramp or in a pit to get to it!!
From what i have seen of mine whilst it was on a ramp, the exhaust drops down from the manifolds at the front, and is shaped to run along the sides of the gearbox and then narrows into the propshaft tunnel. The exhaust then widens at about the back axle point, (almost in a 'y' shape) and then through to what you see at the back.
There is from what i can see very little error in the position of the exhaust from front to back, where a slight mis-alignment or weak suspension point, will cause the exhaust to knock against bodywork,chassis,or gearbox, and i suspect that a 'crowbar' will, on its own, be at best a tempory fix for a knocking exhaust. Besides from obviously damaging the exhaust pipe itself, or something else in the process of 'levering' the exhaust,espcially if laid on your back with just a jack and/or axle stands, the car needs to be sitting on its wheels in the position it would be on the road. IMO the car needs to go onto a ramp, where the exhaust can be 'shaken' to see where its knocking and adjusting via the joint clamps or exhaust suspension parts.
This is where the guys such as Jools and co should assist.....
awaits to be told otherwise
There is from what i can see very little error in the position of the exhaust from front to back, where a slight mis-alignment or weak suspension point, will cause the exhaust to knock against bodywork,chassis,or gearbox, and i suspect that a 'crowbar' will, on its own, be at best a tempory fix for a knocking exhaust. Besides from obviously damaging the exhaust pipe itself, or something else in the process of 'levering' the exhaust,espcially if laid on your back with just a jack and/or axle stands, the car needs to be sitting on its wheels in the position it would be on the road. IMO the car needs to go onto a ramp, where the exhaust can be 'shaken' to see where its knocking and adjusting via the joint clamps or exhaust suspension parts.
This is where the guys such as Jools and co should assist.....
awaits to be told otherwise
Paddy, what you say makes good sense to me but when mine was 'adjusted' it literally moved about 2-3mm and that was it, and the noise hasn't come back since (at least 2 months!). There is so little room for movement under there anyway I guess this basically bends the pipe very slightly to stop the thing knocking.
I must confess that at the time I was amazed at how such a loud and concerning noise was fixed so easily!
I must confess that at the time I was amazed at how such a loud and concerning noise was fixed so easily!
Satman's pretty much got it sussed.
the most common point for touching is just as the manifolds turn around the back of the gearbox, it's where the secondary pipes join and there's a meaty weld which compromises the space for this Y piece junction. You can lever the pipes but I prefer not to, since stresses further up the manifold contribute to the manifold cracking issues that are all too common anyway.
making sure you get teh whole thing hung properly with no stresses is the only way to do it.
the most common point for touching is just as the manifolds turn around the back of the gearbox, it's where the secondary pipes join and there's a meaty weld which compromises the space for this Y piece junction. You can lever the pipes but I prefer not to, since stresses further up the manifold contribute to the manifold cracking issues that are all too common anyway.
making sure you get teh whole thing hung properly with no stresses is the only way to do it.
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