[BAMBER]

Hi all.
Is the underbody on the MK4 the same as the MK3? If so, I had a MK3 some years ago and it developed a metallic knock coming from the rear (round about the rear seat area). No amount of investigation could pin it down until I had it in a garage for the second time. When I went to collect it, the owner told me that he and a young mechanic had been on it for four hours with no luck. On the road they could hear it, but in the workshop no amount of bouncing the car could replicate the knock. They were giving up when the young lad, who was very well built, grabbed the tow-bar of the car, which was up on the lift, and yanked it up and down with frustration. On the upward stroke they heard the knock and traced it to a sub-frame type pressing, which had some studs and rubber bushes fixed in. Needless to say, the bushes were not replaceable and the whole unit needed to be replaced.
Now I have a 2010 Mk4 which has developed a similar knock and the mechanic couldn't find it. If the underbody is the same, I might point him in the direction of the area, although I think the price might be high (as was the Mk3 in 2006/7).
Thanks in advance.
Bamber

 

[BlakeS94]

Can you provide more information about your current cars issue and not a previous car?

I don't think the subfrsme bushes are known to go bad on MK4s. I had a knock on my own a year ago that was the exhaust backbox hanger had snapped off due to rust so the box was hitting the boot floor from underneath.

Outside of that, a knock can be several different issues. Please tell us more, is it front or back of the car knocking, is it easy to replicate when driving and/or with car idle and bouncing on it.

MK4s (and other fords) rear trailing arm bushes are a weak point which will cause rear end knocking.

Strut top mounts on the front are also a common enough thing to go.

 

[riikomi]

Have someone else driving the car and sit on the backseat. If you hear knocking coming underneath your feet, the problem is the retainer of the hand break cable.

 

[TheAntman]

No. The MK3 shared the same CDW27 as the Mk1 and Mk2 whereas the MK4 was a completely new platform - the EUCD and was shared with S-Max, Galaxy, Volvo S60, V60, XC60, S70, V70, XC70, S80 and the Land Rover Freelander 2

 

[tellmah]

It may help, but mine had a knock if i went over low bumps or reversed onto my drive over a "1" concrete lip. Handling was washy on roundabouts too.

It sounded like the shocker had gone.

I changed every bit of the the rear suspension.

I was sure it was the trailing arm bushes which were replaced 4 years earlier because it was coming from that area and there was nothing left to change, but two MOT's later and despite going to a garage to have them checked, they said they were fine and suggested it was the exhaust banging (i knew it wasn't).

Anyway long story short, I sold the car and went to put a 12 month on it, guess what failed on the trailing arm bushes. New ones were fitted, all the above problems disappeared.

 

[BAMBER]

It may help, but mine had a knock if i went over low bumps or reversed onto my drive over a "1" concrete lip. Handling was washy on roundabouts too.

It sounded like the shocker had gone.

I changed every bit of the the rear suspension.

I was sure it was the trailing arm bushes which were replaced 4 years earlier because it was coming from that area and there was nothing left to change, but two MOT's later and despite going to a garage to have them checked, they said they were fine and suggested it was the exhaust banging (i knew it wasn't).

Anyway long story short, I sold the car and went to put a 12 month on it, guess what failed on the trailing arm bushes. New ones were fitted, all the above problems disappeared.

Thanks to all for your replies. Bouncing down on the suspension doesn't cause the knock to happen, but driving over rumble strips (raised lines in series a few inches apart) makes it sound like a mad drummer. The noise generally seems to come from near the back, but there seems to be no problem with the exhaust at all. I really need to get it up on a ramp and spend some time underneath it. Although I don't think I'm old, my body tells me that I shouldn't be creeping around underneath a car, especially when I try to get up. I'll see if the garage will oblige. Thanks again.