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Old 16th November 2014, 14:38   #1
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Default Suspension "bounce back" after braking?

In the process of braking, a car normally bounces back a little immediately after coming to a complete halt, unless the driver releases the brake a bit at the final moment to prevent it. I have observed lately that the "bounce back" is a bit more than it used to be in my car. What does it tell about the suspension/shock absorbers?

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Old 17th November 2014, 10:29   #2
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Default re: Suspension "bounce back" after braking?

It tells you that the shock absorbers are nearing its life, and not absorbing the shock, and hence the bounce back.
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Old 17th November 2014, 10:41   #3
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Default re: Suspension "bounce back" after braking?

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Originally Posted by dhanushs View Post
It tells you that the shock absorbers are nearing its life, and not absorbing the shock, and hence the bounce back.
Yes, I would agree, could be bit worse; if this behaviour appeared more or less overnight, I would say one, possibly both shocks are completely gone. It happens, you might find some evidence of the hydraulic fluid leaking out. If so, replace immediately.

Testing shocks by hand is a bit unscientific but have a go:

Push really hard down on each corner of your car and let go, corner by corner. Notice any difference between how the bounce gets dampened? The corner where you see most of the bouncing is likely to be the one with the worst shock absorber.

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Old 17th November 2014, 10:57   #4
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Default re: Suspension "bounce back" after braking?

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Originally Posted by dhanushs View Post
It tells you that the shock absorbers are nearing its life, and not absorbing the shock, and hence the bounce back.
How exactly is that? When the car brakes - the weight shift due to momentum causes the car to press on the front suspension (opposite of the wheels shocking upwards when going through bumps / coming out of potholes). And the bounch back is the suspension pushing the car back into its normal position. If the bounce back doesn't happen - obviously its the coil springs not doing their job properly. But how would an INCREASED bounce back indicate a dead / dying spring?

It may be that the brake is actually biting more than earlier and resulting in car stopping earlier than before - thus putting the suspension in more compression and eventually giving more bounce back.

Just my hypothesis. The suspension going kaput may still be the reason here.
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Old 17th November 2014, 11:10   #5
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Default re: Suspension "bounce back" after braking?

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Originally Posted by Reinhard View Post
... When the car brakes - the weight shift due to momentum causes the car to press on the front suspension (opposite of the wheels shocking upwards when going through bumps / coming out of potholes). And the bounch back is the suspension pushing the car back into its normal position. If the bounce back doesn't happen - obviously its the coil springs not doing their job properly. But how would an INCREASED bounce back indicate a dead / dying spring?...
The spring and the shock absorber are different components.

Like you said, the spring will try to push the car back into its normal position, but the duty of the shock absorber is to absorb that shock/bounciness of the spring.

So, when the shock absorber fails, the effects of the spring are more prominent.
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Old 18th November 2014, 07:43   #6
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Default Re: Suspension "bounce back" after braking?

Not only bounce back will be more noticeable the car will actually start rocking more and more as the "absorb" becomes weaker. Usually results of internal seals and valve failure or oil leakage.
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Old 18th November 2014, 10:59   #7
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Default Re: Suspension "bounce back" after braking?

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Originally Posted by sudev View Post
Not only bounce back will be more noticeable the car will actually start rocking more and more as the "absorb" becomes weaker. Usually results of internal seals and valve failure or oil leakage.
what is the normal life of stock shock absorbers of a car that is predominantly driven in the city and concrete roads.
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Old 18th November 2014, 13:07   #8
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Default Re: Suspension "bounce back" after braking?

Normal? City roads - 50~100000kms. Potholes, speed of vehicle and style of driving matter. Concrete roads? With constant khat khat khat...? Cannot say
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Old 19th November 2014, 03:27   #9
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Default

Quote:
Originally Posted by Jeroen View Post
Yes, I would agree, could be bit worse; if this behaviour appeared more or less overnight, I would say one, possibly both shocks are completely gone. It happens, you might find some evidence of the hydraulic fluid leaking out. If so, replace immediately.

Testing shocks by hand is a bit unscientific but have a go:

Push really hard down on each corner of your car and let go, corner by corner. Notice any difference between how the bounce gets dampened? The corner where you see most of the bouncing is likely to be the one with the worst shock absorber.

Jeroen
Thanks Jeroen! It did not happen overnight, my suspicion has been growing for a while now.

I checked it the 'unscientific' way, and the bounce seemed getting dampened almost uniformly at all corners. I am requesting the dealer/service centre for an appointment for checkup, will update you guys once I know more.

Quote:
Originally Posted by sudev View Post
Normal? City roads - 50~100000kms. Potholes, speed of vehicle and style of driving matter. Concrete roads? With constant khat khat khat...? Cannot say
Mine is a Mercedes Benz C 200 CDI (W204) which has covered only 21000 kms. Have been using it on decent roads, except during a couple of trips to Czech republic (D1 motorway between Prague and Brno is really bad). Too early to have a dead shock absorber.

Last edited by benbsb29 : 19th November 2014 at 05:10. Reason: Merged back-to-back posts. Pease use the Multi-Quote button to reply to more than one post at a time. Thanks.
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Old 26th November 2014, 21:23   #10
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Default Re: Suspension "bounce back" after braking?

I got it checked in a Mercedes Benz service centre. After a short test drive, the guy said the bounce back is not more than normal. He did not find any issue with the suspension I was nitpicking, probably.

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Joju
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