Worrying 'grinding' noise ...

[Flappers]

Hello again, my Daimler has gone from an avarage example to close to concourse in the 16 or so months I have owned her, lots of work done. But for a long time, there has been a rubbing, contact / grinding noise coming from underneath the car. Its noticable on mid to hard acceleration away from a standstill, much more so if I'm turning right and accelerating, more so uphill. Its only a slight rumble on a straight line, but with lock on its very noticeable, a hell of a noise .. With the work thats been done on the car, the engine mountings have been checked, fan cowling checked, exhast rubs looked at and fixed. So I'm at a loss .. without strapping a film camera to the underside of the car I really dont know where to turn. The chap that replaced my front cam seal & rad keeps looking, but cant find the real issue. I just cant justify another X amount of hours of labour to diagnose this.

Anyone have any suggestions please ?

1989 Daimler Double Six.

[mike020150]

Like all noise issues, it's difficult to make suggestions without experiencing the noise first hand. On XJs the exhaust runs close to the shields and bodywork and it has a myriad of possible adjustments so it's always a prime suspect. Another slightly less obvious culprit can be the driveshaft UJ shields. These can rub. The outer shields are more likely to produce a grinding type of noise which can change with the direction of cornering. The cure is to move them along the shafts away from the UJs. A soggy prop centre bearing mounting can allow excessive movement and contact with the shields there. Just a few suggestiions for you. Mike.

[NATONEIL]

Had a problem with mud flaps once that caused a grinding noise. It should have been a no brainer but it took some finding. With the car parked everything was clear but with the car loaded and cornering and also squatting under power a rear mud flap touched the road and it sounded as if the floor was coming off..

[Flappers]

If only I could find Daimler mud flapps, she's flap free at the min



Is it possible to point out on this image where I need to look on the prop please ?

[mike020150]

The prop centre bearing is not in the pic. It's further back. However, the pic reminds me that you might also like to check the 'cotton reel' in the centre of the rear gearbox mount, the spongey material deteriorates in contact with oil and can allow excess movement of the driveline, typically accompanied by knocks. Mike.

[Flappers]

This is the 'Cotton reel' mount yes ... How do I check this, just get under it and try strong arming the box by hand to see if there's movment ? And the same with the prop centre bearing ? How much play should I expect if there within normal working peramiters ? Please forgive my ignorance, may seem a silly question but I dont want to start dismantling that mount without being sure This isn't my car by the way, just an image I found.

[mike020150]

Hi Sam,
The orangey coloured piece in the picture is the 'cotton reel'. If you grab hold of the rear of the gearbox and move it around as much as you can, it should not allow the gearbox/prop to touch the underside of the car. As designed, there is quite a lot of movement but there should not be any clunks as you push and pull. If the prop is making contact anywhere, it will leave 'witness' marks on the underside. A mirror and a good lamp should make it easier to spot problems. Mike.

[Flappers]

It was the 'cotton reel' combined with an engine mounting. Thanks for the pointers

[mike020150]

Isn't the peace and quiet wonderful after fixing a problem like that? Mike.