| Author | Message | ||
     Udo Hoffmüller Experienced User Username: udo Post Number: 19 Registered: 2-2008 |
We have a Bentley TurboRL MCX35566 with ARC. One question I have concerning the rear dampers/struts: The car has done about 240.000 km. How does one know if the dampers are worn out or if they are close to the end of their lifetime? They are not leaking, but do they give any other signs of giving up their job? Best regards - Udo | ||
| Jan Forrest Frequent User Username: got_one Post Number: 60 Registered: 1-2008 |
The usual method of testing a damper is to 'bounce' each corner of the car a couple of times and watch for what happens when you let go at the bottom of the bounce. The car should rise and fall once then settle at the normal ride height. If it continues to bounce on its own more than that then the damper is on its way out and should be replaced as soon as practical. | ||
| Richard Treacy Grand Master Username: richard_treacy Post Number: 1655 Registered: 4-2003 |
No Way. They are struts, not dampers. Unless they leak they are fine. The damping and ride control are all done exclusively by the valves and solenoids in the valve body, and the spheres are all that need attention normally if the ride deteriorates. The struts have nothing to do with damping or ride at all. Leave the struts well alone unless they leak badly. A little weepage will do no harm. Fluid weepage normally cures itself within a few kilometres anyhow. R. | ||
| Udo Hoffmüller Experienced User Username: udo Post Number: 20 Registered: 2-2008 |
Thank you for your comments. I asked because there is a clacking noise from where the left rear damper is fixed (on the right side there is no such clacking). Moving the car up and down at the rear bumper a little bit, one can reproduce this clacking noise. If one puts his hand on the bottom end of the damper or the screw, one can feel that there is play somewhere for the damper to move up and down. It seems that the rubber dampers are weak and the strut has play when being moved so that it can clack in its fixation. We will try to shorten the distance tube by 2 mm and see if the fixation of the strut will be stiffer so that the fixation with the rubber dampers has no play any more - or if there is at least any change in the noise we hear/heard. Maybe we have to try the same with the upper fixation. Do you think these measures can cure the clacking noise? We hope so because the weakened rubber dampers will be more pressed together to prevent unallowed movement of the dampers fixation. If you have comments, please post them. I will inform you about the results of the described measures. Regards - Udo | ||
| Bill Coburn Moderator Username: bill_coburn Post Number: 1105 Registered: 4-2003 |
Udo/ The whole problem is addressed in Issue 82 of Tee One Topics now on the Technical Library. Assuming the gas springs have plenty of gas in them I would get eight new mounting rubbers and 4 'O' rings and pull both dampers for refitting. The most likely problem is that the nut at the top of the damper has come loose! | ||
| Jan Forrest Frequent User Username: got_one Post Number: 61 Registered: 1-2008 |
"The most likely problem is that the nut at the top of the damper has come loose!" Almost as common a fault as the nut behind the steering wheel being too tight  I'll get me coat  | ||
| Bill Coburn Moderator Username: bill_coburn Post Number: 1106 Registered: 4-2003 |
Sure an' all Jan I'm familiar with the latter but reckon you will sympathise with me when I tell you that a noise in my latest Shadow challenge is a piston broke which just neatly summarises the situation.! | ||
| Jan Forrest Frequent User Username: got_one Post Number: 62 Registered: 1-2008 |
Very similar to the situation with the Toyota Estima. Me Big End's gone! Not bragging, mind  | ||
| Udo Hoffmüller Experienced User Username: udo Post Number: 21 Registered: 2-2008 |
As described in my last post I shortened the distance tubes (top and bottom) so that the weakened rubber damper could be me more compressed. Result: Less knocking or clacking with the suspension blocked in "soft" and no knocking/clacking at "normal" or "sport". But this cannot be the final solution because the chip of the ARC-ECU is modificated so that the suspension stays in "soft" up 115 km/h (if not influenced by rough surface e.a.) - and therefor it is clacking and knocking a lot up to 115 km/h. With the ARC test unit connected I can block the suspension in "soft" or "normal" or "sport" and if I block it in "sport" there is no noise from the strut. But whoe likes to use a Bentley/RR a 50 or 80 km/h with the suspension blocked at "sport"? This is unsoportably uncomfortable! Bill, I read the article about the struts in Tee One Topics issue 82. But there is nothing mentioned about noisy struts!? Do you believe that changing the rubber dampers will cure the noise? I hope it does because the fact that the suspension blocked in "sport" suppresses the noise indicates that the weakened rubber dampers are the reason. Can you explain why the knocking/clacking noise appears? I am not sure about the reason. Is it really the distance tube knocking against the strut? The rubber dampers are not worn out, they are simply very weak/soft, no contact of the strut to the body. Best regards - Udo (Message edited by udo on 20 April 2009) (Message edited by udo on 20 April 2009) | ||
| Udo Hoffmüller Experienced User Username: udo Post Number: 22 Registered: 2-2008 |
This is just to inform you what I did to sort out the problem: First I changed all the rubber mounts of the struts (four on each side). Great part of the knocking noise is gone. But there was still more knocking, less intensiv, irregular, but always audible. It seemed to come from somewhere beneath the rear seats. I had a look at the crossmember dampers, one was wet. I took them off and drove the car gently for some kilometers, and again a great part of the noise disappeared. When I checked the removed dampers I found that I could press them togother with some effort, I expected they would come back to there extended status just like the usual dampers of a car, but nothing like that, they always stay in the position where I press or pull them, fully in or pulled fully out, they stay just as I leave them. Is that correct? Or do they have to react like the usual dampers of a car? If you press a damper, it usually comes out again! But these old crossmember dampers do not! Because one of them is leaking, I will fit a pair of new ones. But there is still - even with the crossmember dampers removed - another light knocking from somewhere beneath the rear seats, not like pinging, more a tapping noise, not very intensive, with the air condition fully running it is hardly to hear. I checked - as far as I could - the bushes of trailing arms - nothing, they look fine. I checked the crossmember rubber mounts - nothing, they are dry and the bolt is in the center of the rubber mount. But who knows? I did not found anything loose there around and do not see where this noise comes from. Any ideas? Best regards from TF - Udo | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 332 Registered: 6-2006 |
Udo, Have you made sure that every point where the parking brake touches the chassis is well greased? Also that they are clipped and will not 'slap' around. Also make sure that the exhaust hangers are solidly mounted to the floor under the rear seats. Some were prone to metal fatigue on the floor and can make a cracking, rattling sort of noise.It's hard to spot, but the floor metal will have a jagged crack along the edge. Also check loose brake pads or linkages ( although these can usually be heard more with the window open and driving next to a wall.) The dampers are not pressurised, just dampers. |
