braking vibration & clacking noise
1995 E220 .......
TWO problems to test your grey matter with.........
Number ONE..has been with me for about a month.
A very, very slight vibration somewhere at the front when the brakes are eased on slightly. It is noticed more as a sound (slight soft rumble) than the actual vibration.
No vibration is noticed during a test "crash stop".
....Have stripped both shoe assemblies, and tracked the rotors for warping. Have swapped tyres back to front.
.....Have had all steering bushes with slackness changed, now goes as straight as an arrow with "look no hands Mom".
....the thing is still with me... ???
The brake peddle does not vibrate violently like ABS kicking in, and the ABS tests OK on slippery surface.
Number TWO ....noticed this morning.....
An irregular clacking noise from somewhere at the front of the engine ......noticed at idle...cannot hear at reasonable rev's or inside the car.
I decided to do a check around this morning...before coming to work....noise located with trusty screw-driver and right ear-ole., seems to come from what looks like the thermostat housing which sits just to the right of the front of (and is level with) the valve gear cover.... Is this the thermostat.?? and has anybody ever had a CLACKY Thermostat..??????
Two more jobs for superman.......
Tyke ......South Africa
my recommendation is swap the brake rotors (disks). They are not expensive and if they are 8 years old they may have some run out, which may cause the vibs.
A clacking thermostat is not possible. What you might hear is a clicking valve (or more) normally it goes away when the engine warms up. It may be caused by a worn out hydraulic valve. It does not cause any problem rather than an anoying noise.
Another option are burnt gaskets betwenn the muffler manifold and the engine block. This can also cause irregular clicking noises. If you see burns around the muffler flanges it could be the case. You need a small mirrow to also see the bottom side.
As for the CLACKING, I now have a clue as to what to look for....thank you.
My inspection this morning was little more than a perfunctory one, if anything differant arises I will come back to you if I may.
Thanks again..........have a pleasant evening
John Clarke
Luckyly it seems to be a lot simpler than envisaged and I feel a little foolish for not spotting it at the first inspection.
The thermostat housing is acting as a sound box for a vibration from the worn bushing of the belt tensioner pulley damper unit. The top end bushing of the damper unit is bolted to the underside of the thermostat housing casting. Putting firm pressure on the bushing completely eliminates the noise. Which when magnified in this manner sounds quite expensive.
The cure seems to be either replacing the tensioner damper complete, or re-bushing same. I would suspect the lower bushing might well be worn as well. Either way a welcome relief.
Thanks again.......
John (Tyke) Clarke



