Knock upon braking

0375cdt · 9th October 2013, 11:09

Hello all,

Some advice please. Upon braking I can hear a knock from under the bonnet on my 75 CDT 2000

This happens only when braking.

It is quite quiet and can not be heard if the radio is on or there is another noise.

It is not a grating or a heavy knocking metal sound but is quite annoying and gives me the impression something is wrong, although it has been driven around France in the summer and since like it with no problems.

It had a service in June at the garage I always take my cars to, the noise was noticed since then. I took it back to the garage who looked all round the car and took it out for a drive. They heard the noise but said everything is where it should be and did not really no why although :
since June I have had replaced
Thermostat housing
OSF drop link
OSF CV Gaitor

When at the garage the mechanic let me go down the inspection pit with him and he showed around under the car.
He gave me his thoughts on a piece of paper :-
excessive brake judder - possibe warped brake discs?
NSF drop link knocking?
Knocking from OSF brakes?

Has anybody else had unexplained knocking like this before and can I have peoples thought on what it may be?

Cheers

First_damned · 9th October 2013, 11:29

I had this on my mondeo it was one of the drive shafts

Synchromesh · 9th October 2013, 11:51

Could be OSF drop link or wishbone bushes. Could even be NSF drop link if you fitted poor quality one. The OEM drop links on my wife's V6 lasted 80000 miles. The replacements I fitted only lasted 10000 miles. When I took them off and pulled back the rubber boots there was no lubricant on the ball/socket so they wore out prematurely. I greased the third pair of drop links before I fitted them.

rich17865 · 9th October 2013, 17:11

It could well be the bottom engine mount, certainly worth checking.

Open the bonnet so you can see the engine from the drivers seat, put it in gear and slowly release the clutch to biting point, if the engine moves a lot I would almost certainly suspect the mount.

0375cdt · 10th October 2013, 17:10

Many thanks for all replies.

rich17865 - The car is an auto. Could it still be a mount though?

Any other ideas as it is a real puzzler, hope it is nothing serious.

I keep thinking something is going to snap and it will break down.

Cheers.

rover10 · 10th October 2013, 17:41

I have the same issue,except in my car it is coming from the rear end.

rich17865 · 10th October 2013, 18:42

Quote:

Originally Posted by 0375cdt

Many thanks for all replies.

rich17865 - The car is an auto. Could it still be a mount though?

Any other ideas as it is a real puzzler, hope it is nothing serious.

I keep thinking something is going to snap and it will break down.

Cheers.

Yep, it could still be the lower engine mount, try the same test, but using drive and reverse and a tiny bit of throttle with the brakes on.

ProfDave · 10th October 2013, 18:52

Quote:

Originally Posted by rich17865

It could well be the bottom engine mount, certainly worth checking.

Open the bonnet so you can see the engine from the drivers seat, put it in gear and slowly release the clutch to biting point, if the engine moves a lot I would almost certainly suspect the mount.

as he says!! Mine was completely cream crackered when I got the car and it affected everything (a visual check will not show you so do as Rich suggests preferably with a mate!)

ProfDave · 10th October 2013, 18:53

btw mine is an auto; changing the mount improved shifts markedly too; done 30,000 miles since and its smooth and generally super!

rich17865 · 21st October 2013, 06:21

There are several reasons why you should replace the lower engine mount, improved driveability, smoother drive, no clonking etc. also with excess play in the lower mount it puts undue stress on the other mounts which will quickly fail too. Excess movement in wiring loom, fuel and coolant hoses, etc, etc.

Replacing it is easy, just two bolts accessible from underneath.

Options as follows, the new correct replacement part,

http://bit.ly/1ayU1V3

A modified performance part,

http://bit.ly/16lQy04

A used part,

http://bit.ly/16lQMVd

Or just ignore it.

There is plenty of information on them, use the search facility.

9th October 2013, 11:09	#1
0375cdt Newbie Rover 75 CDT Join Date: Jun 2012 Location: Kent Posts: 23 Thanks: 0 Thanked 0 Times in 0 Posts	Knock upon braking Hello all, Some advice please. Upon braking I can hear a knock from under the bonnet on my 75 CDT 2000 This happens only when braking. It is quite quiet and can not be heard if the radio is on or there is another noise. It is not a grating or a heavy knocking metal sound but is quite annoying and gives me the impression something is wrong, although it has been driven around France in the summer and since like it with no problems. It had a service in June at the garage I always take my cars to, the noise was noticed since then. I took it back to the garage who looked all round the car and took it out for a drive. They heard the noise but said everything is where it should be and did not really no why although : since June I have had replaced Thermostat housing OSF drop link OSF CV Gaitor When at the garage the mechanic let me go down the inspection pit with him and he showed around under the car. He gave me his thoughts on a piece of paper :- excessive brake judder - possibe warped brake discs? NSF drop link knocking? Knocking from OSF brakes? Has anybody else had unexplained knocking like this before and can I have peoples thought on what it may be? Cheers

9th October 2013, 17:11	#4
rich17865 This is my second home Transit Connect Join Date: Feb 2011 Location: Crewe Posts: 9,532 Thanks: 868 Thanked 1,619 Times in 1,095 Posts	It could well be the bottom engine mount, certainly worth checking. Open the bonnet so you can see the engine from the drivers seat, put it in gear and slowly release the clutch to biting point, if the engine moves a lot I would almost certainly suspect the mount. Last edited by rich17865; 9th October 2013 at 17:29..

9th October 2013, 11:29	#2
First_damned Posted a thing or two Rover 75 Connoisseur CDTi Join Date: Aug 2013 Location: Birmingham Posts: 1,272 Thanks: 267 Thanked 100 Times in 93 Posts	I had this on my mondeo it was one of the drive shafts

9th October 2013, 11:51	#3
Synchromesh Gets stuck in Rover 75 Saloon Join Date: Jan 2010 Location: Preston Posts: 626 Thanks: 50 Thanked 44 Times in 32 Posts	Could be OSF drop link or wishbone bushes. Could even be NSF drop link if you fitted poor quality one. The OEM drop links on my wife's V6 lasted 80000 miles. The replacements I fitted only lasted 10000 miles. When I took them off and pulled back the rubber boots there was no lubricant on the ball/socket so they wore out prematurely. I greased the third pair of drop links before I fitted them.

10th October 2013, 17:10	#5
0375cdt Newbie Rover 75 CDT Join Date: Jun 2012 Location: Kent Posts: 23 Thanks: 0 Thanked 0 Times in 0 Posts	Many thanks for all replies. rich17865 - The car is an auto. Could it still be a mount though? Any other ideas as it is a real puzzler, hope it is nothing serious. I keep thinking something is going to snap and it will break down. Cheers.

10th October 2013, 17:41	#6
rover10 Avid contributor Rover 75 v6 Join Date: Sep 2013 Location: London Posts: 174 Thanks: 0 Thanked 7 Times in 6 Posts	I have the same issue,except in my car it is coming from the rear end.

10th October 2013, 18:53	#9
ProfDave This is my second home ZTT, Contemp Saloon, Duotone Tourer Join Date: May 2012 Location: Llandeilo Posts: 4,192 Thanks: 290 Thanked 387 Times in 333 Posts	btw mine is an auto; changing the mount improved shifts markedly too; done 30,000 miles since and its smooth and generally super!

21st October 2013, 06:21	#10
rich17865 This is my second home Transit Connect Join Date: Feb 2011 Location: Crewe Posts: 9,532 Thanks: 868 Thanked 1,619 Times in 1,095 Posts	There are several reasons why you should replace the lower engine mount, improved driveability, smoother drive, no clonking etc. also with excess play in the lower mount it puts undue stress on the other mounts which will quickly fail too. Excess movement in wiring loom, fuel and coolant hoses, etc, etc. Replacing it is easy, just two bolts accessible from underneath. Options as follows, the new correct replacement part, http://bit.ly/1ayU1V3 A modified performance part, http://bit.ly/16lQy04 A used part, http://bit.ly/16lQMVd Or just ignore it. There is plenty of information on them, use the search facility.