Is It Just The Weather?

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RustyZ4
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Is It Just The Weather?

Post by RustyZ4 » Wed Jul 11, 2018 5:14 pm

I have noticed in the last couple of weeks, when I put my roof down, it seems to have developed quite a loud "thunk" to it, i was wondering if its just the hot weather making the hydraulic fluid thinner, therefore less resistance, or is it something else?
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geordie_zed
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Is It Just The Weather?

Post by geordie_zed » Wed Jul 11, 2018 5:16 pm

Which part of the process is the 'thunk' ?
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buzyg
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Post by buzyg » Wed Jul 11, 2018 5:17 pm

Do you mean it flops shut over the last few inches of the close operation? Mine has always done that a bit. I usually put my left hand up to ease the weight over those last couple off inches of travel.
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Is It Just The Weather?

Post by RustyZ4 » Wed Jul 11, 2018 5:38 pm

geordie_zed wrote:
Wed Jul 11, 2018 5:16 pm
Which part of the process is the 'thunk' ?
Sorry should have given more info, its the last bit when the roof is closing, when the rear window comes down and shuts
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Is It Just The Weather?

Post by buzyg » Wed Jul 11, 2018 5:59 pm

RustyZ4 wrote:
Wed Jul 11, 2018 5:38 pm
geordie_zed wrote:
Wed Jul 11, 2018 5:16 pm
Which part of the process is the 'thunk' ?
Sorry should have given more info, its the last bit when the roof is closing, when the rear window comes down and shuts
Ah just spotted it's an E89 thread :oops:
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Is It Just The Weather?

Post by flybobbie » Wed Jul 11, 2018 10:09 pm

Mine as always done that, for the five years i have owned it. My roof is opened everyday, during summer months.

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Post by jabber » Wed Jul 11, 2018 10:29 pm

Mine also does the same seems to be fairly normal
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Is It Just The Weather?

Post by Busterboo » Wed Jul 11, 2018 10:32 pm

Mine, too.
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Post by Smartbear » Wed Jul 11, 2018 10:41 pm

Higher temps would make the hydraulic fluid less viscous, which could give a less “damped” operation.
Wait till the temperature drops & see if it becomes less slammy :?
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Post by srhutch » Wed Jul 11, 2018 11:02 pm

Busterboo wrote:
Wed Jul 11, 2018 10:32 pm
Mine, too.
It’s that 98ron petrol you’ve put in it doing that :wink:
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Post by Busterboo » Thu Jul 12, 2018 7:20 am

98 RON? Me? Nah. Never have, never will.
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Post by flybobbie » Thu Jul 12, 2018 9:20 am

If the cylinders are designed properly they would have a last moment slow down port built into the piston to cushion the end of travel.
I think at the point of closing there is simply too much weight at that leverage for the cylinder to cushion the blow.
https://www.cylinder.co.uk/technical/hy ... types.html

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Post by JamiesZ4 » Thu Jul 12, 2018 10:27 am

Mine won't open currently (need to get it booked in when I get a chance) so complete lack of thunks and my neighbor thought it was a Coupe until I explained my roof mechanism is stuffed :D
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Is It Just The Weather?

Post by RustyZ4 » Thu Jul 12, 2018 4:51 pm

Thanks all, everything works ok (that will be the kiss of death :D ) maybe I am just noticing it more these days
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Is It Just The Weather?

Post by geordie_zed » Sat Jul 14, 2018 3:09 pm

Mine gives a good thunk! Hadn't really noticed it before but now I'm hearing it a few times a day... :rofl:
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