924Board.org

HarryOK · Joined: 29 Jun 2006 Posts: 21 Location: Gibraltar

My 924 has recently developed an extremely annoying (and worrying?) knocking from the rear. I've replaced the rear hatch seal, but this hasn't cured it. I doubt that it's the hatch pins as it seems to shut quite securely. Don't think it's anything to do with the exhaust either, as it only happens when I'm driving. Anybody experienced anything similar?

Paul · Posted: Thu Sep 28, 2006 12:30 pm Post subject:

Probably one of more of your CV joints screaming for grease! If not them then maybe your rear wheel bearings need some attention....
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

5150 · Posted: Thu Sep 28, 2006 4:58 pm Post subject:

Straight lines or corners?
Apat from the usual suspects already mentioned, check the fuel pump is still correctly secured, if it's loose then it'll rattle and knock.
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Mars Red '78 Euro 924 n/a
http://www.cardomain.com/id/5150_uk

Graphite? Grey Metallic '85 (late model) 944 2.5

There are two kinds of pedestrians: the quick and the dead.

skemcin · Joined: 02 Sep 2003 Posts: 1284 Location: Plainfield, IL

when I bought my first 924, I had that a noise in the front like that. SO I got out of the car and pushed down on each front fender pretty aggressively - both struts were bad (bottoming out) - maybe check that.
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924.org (no time to complete)
9249206346 - 89k – new shifter bushings, belts, running well.
9249206347 - 8k – waiting its resurrection, no power at the fuel pump and fuse #7 blows w/power

HarryOK · Joined: 29 Jun 2006 Posts: 21 Location: Gibraltar

Hey 5150; straight lines, corners, up hill, down hill, on my head, all the time except at standstill!!! AAARRGH! Thanks for all the suggestions. I'll check them out over the weekend. Somebody suggested wear and tear on the prop-shaft "doughnut" - sound sensible to anybody?

Paul · Posted: Fri Sep 29, 2006 12:14 pm Post subject:

Does the knocking noise increase in frequency with the speed of the car, or the RPMs of the engine?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

HarryOK · Joined: 29 Jun 2006 Posts: 21 Location: Gibraltar

Nope. It's just a constant, erratic knocking /rattling; not an even TAKATAKATAKA type noise, if you know what I mean!!!

Paul · Posted: Sat Sep 30, 2006 9:04 am Post subject:

If it's not changing with engine or wheel speed, it is not the CV joints, wheel bearings, torque tube bearings or the tranny internals.

Let's look elsewhere:

Check your rear hatch to make sure it's really closed.

Check your fuel pump mounts.

Check your exhaust system hangers and mounts.

Check your spare tire compartment for anything that's loose.

Check your shifter rod to make sure it is not banging against anything.

Check your lug bolts.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

HarryOK · Joined: 29 Jun 2006 Posts: 21 Location: Gibraltar

Hiya,Paul. Thanks for you persistence. Because it's not a continuous and even TAKATAKA etc. (sorry, but there's no better way to explain that sound!), which I believe would have been consistant with wheel bearings and related problems etc., I had already mostly ruled those out ...don't mean to seem ungrateful for all the suggestions, which I was going to double check anyway. As far as your six point plan goes:
1):Rear hatch as I explained earlier has a new seal and if I shake it from outside, seems reasonably secure to me.
2):Fuel pump mounts I shall check tomorrow, as I replaced both fuel pumps recently (and two fuel relays and as many combined dodgy mechanics charging exhorbitant ammounts of money for not solving a problem...car dying at random and restarting whenever it wnted to. I sourced the problem myself...crap earth to secondary fuel pump in the loom. SOLUTION: hard wire fuelpump directly to chassis and bypass loom! Sweet as a nut since then!!! That's 3 workshops and about £900 down the drain!)
3): Exhaust...possible, but I doubt, as surely, it would at least do some sort of rattling on standstill but revved up to 3, 4 or 5K revs., don't you think?
4): I cleaned out the spare tyre well, and even opened up the two rear storage flaps (which I was originally convinced was the source of the problem).
5): SHIFTER ROD??? please translate!!! Do you mean gear shift? Surely not, as that's right next to me in the car...sorry, don' know what you mean!
6): Lug bolts checked (although I had a similar problem some time ago on the front left wheel and yet ANOTHER dodgy mechanic nearly charged me another £25 to tighten those lugs which he had left loose in the first place! I waited round the corner and caught him in the act!)
Bloody hell! I'd best stop now...Taking up everybody elses space! BTW, what the hell have you done to your rear arches? Any full pix? Thanks!

Paul · Posted: Sat Sep 30, 2006 1:05 pm Post subject:

Shifter rod: rod that attaches the shift lever to the tranny.

The arches are not on my car....

http://im1.shutterfly.com/procserv/47b6d708b3127cce8d1e79ab4b1e00000016108AZuGrlozZtE

http://im1.shutterfly.com/procserv/47b6d708b3127cce8d1e7e6a0b4400000016108AZuGrlozZtE

http://im1.shutterfly.com/procserv/47b6d708b3127cce8d1fdc0eaa0d00000016108AZuGrlozZtE
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

HarryOK · Joined: 29 Jun 2006 Posts: 21 Location: Gibraltar

Oh, now I get it (the rear arches). Looks like a "loose" version of one of the Le Mans GTR? (Not the 375BHP version, as I 'm quite sure that one didn't have the 'open' ends on the rear, but instead those beautiful and outrageous front and rears). Couldn't quite make out the contents of the CONCOURS certificate, so I might well be totally wrong!
Thanks also for the quick translation! Now I now what you mean there too, and that sounds like a very possible candidate! Yup, I didn't thinkof that one.