My active Q makes a rattling sound like a piece of 2 by 4 hitting something under the trunk. It only makes this noise when I am riding over a continuous patch of rough road. Could this be the "water hammer noise" that an active is supposed to make if only 4 out of the 9 accumulators are recharged. One accumulator is claimed to be specifically to deal with water hammer noise.
Apart from this I am struggling to find the source of this annoying noise
Active water hammer noise
I've experienced the "water hammer" noise you are referring to, and it's much more of a low groan than a rattle. Mine usually happens for a few seconds after a cold start. A little tap of the accellerator usually clears it right up though. In your case, I would suspect worn subframe bushings or LSD mounts. My Q thumps when engine braking as the subframe shifts position slightly. We seem to have similar issues with our active Q's.
AZSKYGOD
AZSKYGOD
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texasoil
- Posts: 875
- Joined: Mon Sep 02, 2002 3:18 pm
- Car: '92 Infiniti Q45A
'94 Infiniti Q45A
'94 Mercedes-Benz SL600
'active' rattle cause
ckeck the rear subframe front mounts/bushings --if they go, it will allow the subframe to hit on the car body and cause a clunk. This will happen on the first bump that is right to trigger the clunk. If it happens ONLY after several bumps and never on the first, it is probably a very low rear accumulator--either one of the strut units or the main unit, or the valve unit. Also check to ensure the plumbing is still tightly mounted. It will vibrate and hit the body and make a lot more noise than you think possible from the size of it.
Active cars that were driven a while with flat accumulators will have more failures of these rubber mounts as they were severely stressed during the 'flat' operation period.
I always advise people driving with flat accumulators is a very expensive operation. Far lower cost to fix them right away--either recharge or convert.
Active cars that were driven a while with flat accumulators will have more failures of these rubber mounts as they were severely stressed during the 'flat' operation period.
I always advise people driving with flat accumulators is a very expensive operation. Far lower cost to fix them right away--either recharge or convert.
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rover3l
- Posts: 514
- Joined: Sat Oct 11, 2003 3:22 am
- Car: 1998 Q45, 2000Q45 Anniversary, 1965 Rover 3L,
The 4 strut accumulators were replaced with your recharged ones last fall, but I recall that the noise was present before I changed them. The noise is never evident after a single bump no matter how large the road defect is. It only occurs after multiple medium size bumps and sounds like a something banging lightly on the underside of the body shell in the vicinity of the center trunk area.
As discussed in another thread I would like to continue to upgrade my suspension with new bushings and probably the remaining 5 accumulators. However, the thought of a problem with the subframe mountings and other not easily replaceable bushings at the rear is holding me back. If I can determine that the subframe etc is ok then I will go ahead. Is there a way to test the integrity of the bushings?
As discussed in another thread I would like to continue to upgrade my suspension with new bushings and probably the remaining 5 accumulators. However, the thought of a problem with the subframe mountings and other not easily replaceable bushings at the rear is holding me back. If I can determine that the subframe etc is ok then I will go ahead. Is there a way to test the integrity of the bushings?
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rover3l
- Posts: 514
- Joined: Sat Oct 11, 2003 3:22 am
- Car: 1998 Q45, 2000Q45 Anniversary, 1965 Rover 3L,
Re: (texasoil)
thoroughly inspected rear subframe and suspension bushings. All seems solid and no evidence of leaking fluid. Assume it would appear like a leaking front tension rod bushing???
After fitting new sway bar bsuhings, front tension rods and upper links the Q does not take bumps well. With only the 4 strut actuators recharged how should it take a moderate hole in the road or a bump.? It currently crashes into holes and thumps when going over a sudden bump.
On a continuously bumpy road such as a cheap repair job following sewer line installation the Q just seems bouncy and not as well planted as I am sure it should be.
I am probably going to spring for recharged other 5 accumulators but I hope I don't have something else going on like the struts themselves??
Keith (Texaxoil) would appreciate your input and anyone else with an active Q
After fitting new sway bar bsuhings, front tension rods and upper links the Q does not take bumps well. With only the 4 strut actuators recharged how should it take a moderate hole in the road or a bump.? It currently crashes into holes and thumps when going over a sudden bump.
On a continuously bumpy road such as a cheap repair job following sewer line installation the Q just seems bouncy and not as well planted as I am sure it should be.
I am probably going to spring for recharged other 5 accumulators but I hope I don't have something else going on like the struts themselves??
Keith (Texaxoil) would appreciate your input and anyone else with an active Q