[Bruckner]

I recently noticed on acceleration from a stop I hear a fairly loud knock from rear suspension: a single "bang" that will occur again when I reverse the car, and so on again when accelerating forwards, just one knock. Any idea before I bring it to specialist? Thanks.

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[unknown4u]

The cv-joints I should check first.
The cv-joints I should check first.

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[tejon007]

Could be a CV joint, but those usually are a "knock, knock, knock" sound when they fail. And is normally noticed during hard turns. Wild guess is a failed transmission mount.

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[Inkedupfatboy]

Jehovah's witness or do they knock more than once?

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[Rap]

Inner joint rear axle

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[Waylander]

Broken beam mount

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[Bruckner]

Broken beam mount

 

Can you be more specific please? Thanks.

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[Waylander]

Hi

 

 

there are four rubber mounts that hold the rear subframe / beam to the body, they come apart with age, this could give you a knock as the axle tries to rotate,

 

these 4 mounts are over $1000 now

 

951 333 088 032 x2

944 331 076 01 RH

944 331 075 01 LH

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[Bruckner]

Hi

 

 

there are four rubber mounts that hold the rear subframe / beam to the body, they come apart with age, this could give you a knock as the axle tries to rotate,

 

these 4 mounts are over $1000 now

 

951 333 088 032 x2

944 331 076 01 RH

944 331 075 01 LH

 

Thanks, will look more closely. I also imagine these aren't straightfoward to replace, whole rear axle needs to be dropped?

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[tejon007]

Pelican Parts has the two bottom ones for $200 each and wants $300 for the "Porsche" part.

 

https://www.pelicanparts.com/search/?q=+944-331-075-01

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[Waylander]

No you can replace them all without removing the besm

Pelican Parts has the two bottom ones for $200 each and wants $300 for the "Porsche" part.

 



They are the top ones, made for the 924 by URO





https://www.pelicanparts.com/search/?q=+944-331-075-01

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[tejon007]

Hi

 

 

there are four rubber mounts that hold the rear subframe / beam to the body, they come apart with age, this could give you a knock as the axle tries to rotate,

 

these 4 mounts are over $1000 now

 

951 333 088 032 x2

944 331 076 01 RH

944 331 075 01 LH

I meant the two at the bottom of your list. 

 

944 331 076 01 RH and 

 

944 331 075 01 LH

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[Waylander]

I would not fit anything by URO to my car, the few parts I have bought have been total rubbish

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[tejon007]

I agree with you about Uro parts, especially the earlier versions. 

 

However,  I've had to use more and more of their parts as other options may not exist.  Although, I think the quality has improved from Uro.

 

For cars in the "widows & orphans" category (like 968s), I suspect it'll be  increasingly difficult to source parts from Bosch and others. So, we hold our nose and buy Uro...

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[Bruckner]

The mystery of my rear end knock persists. I had 2 mechanics inspect the car and they couldn't find anything wrong with it, including the beam supports which have been deemed to be in good shape. I'll try to make a video hoping the mic will pick up the noise. More later.

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[Petethepug]

Wheel center cap(s) loose or have a broken part in the center of the rim?

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[Bruckner]

Wheel center cap(s) loose or have a broken part in the center of the rim?

 

Interesting, I will have a look at the wheel.

 

The car spent another hour on a lift yesterday with a 944 specialist and nothing obvious came out of the examination. He had the brake caliper and disc taken out to inspect the drum, all checked out. We took out the exhaust hangers and rubber mounts, everything is nice and tidy. Despite the high mileage, all mechanics point out that it is in great shape, not that it helps my enquiry. There is no visible sign of movement anywhere.

 

I have an appointment at an alignment shop to inspect the rear suspension loaded up with the car sitting on its wheels, next step in the sequence, but I'm slowly coming around to the view that I'll have to wait for the problem to get worse and something to decisively show up or break.

 

This could be a problem never seen before, in which case I think the car deserves a badge of honor!

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[Inkedupfatboy]

I assume you have taken everything out of the trunk and there is nothing banging around in there? Just a random thought.

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[Petethepug]

Sway bar bushings, strut bushings & bearings. Theyll kill ya when youre trying to isolate the problem. My favorite was a clunk like yours that occurred only when turning into a driveway or hill from a stop.



The diagnosis was made by Dana @ Autotech Sport Tuning. He took a ride along and determined it was a hydraulic motor mount collapsing only when the chassis flexed enough to let the mount deflect and sound off.

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