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Rear Torsion Bar Bushings

 
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goturbo  



Joined: 15 Jun 2004
Posts: 87
Location: Massillon Ohio, USA

PostPosted: Thu Jan 20, 2005 2:12 pm    Post subject: Rear Torsion Bar Bushings Reply with quote

So I have read that the rear torsion bar bushings are molded to the housing, although mine are falling apart. Has anyone repalced these? I would like to replace mine but do I have to buy the whole part? I might consider making some replacements but if they are not rubber how would that affect the dampening of the torsion bar/suspension vibration? Does anyone have a solution or know where to get repalcements?
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My924gtc  



Joined: 14 Aug 2004
Posts: 1362
Location: 248

PostPosted: Thu Jan 20, 2005 2:58 pm    Post subject: Reply with quote

Not sure exactly which bushings you need but here is some food for thought...http://www.racersedge-inc.com/bushparts.html
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MJ
'81 924 2.0L T
'82 924 2.3L SC/EFI <---online fall '06

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jpab924  



Joined: 03 Nov 2002
Posts: 1538
Location: Crown pt. IN. 50 miles southeast of Chicago Ill.

PostPosted: Thu Jan 20, 2005 3:27 pm    Post subject: Reply with quote

If this is what your looking for and depending on your year car, heres one to look at. The Porsche part number is there too.


http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7948242838&category=42609&sspagename=WDVW
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924RACR  



Joined: 29 Jul 2001
Posts: 8320
Location: Royal Oak, MI, USA

PostPosted: Thu Jan 20, 2005 11:54 pm    Post subject: Reply with quote

Yeah, too many bushings back there, you'll need to be more specific.
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Vaughan Scott
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'79 924 #77 ITB racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype
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goturbo  



Joined: 15 Jun 2004
Posts: 87
Location: Massillon Ohio, USA

PostPosted: Fri Jan 21, 2005 2:12 pm    Post subject: Reply with quote

Yea sorry about that. The manual lists that part as the 'spring plate' but basically it is the torsion bar tube end plate; the part where you set the ride height. Anyhow there are two rubber bushings on either side of that part, one that 'seals' the torsion bar tube and one that holds the rear tube support bracket. What is a good replacement? Make new or buy a repalcement (if possible)?
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924RACR  



Joined: 29 Jul 2001
Posts: 8320
Location: Royal Oak, MI, USA

PostPosted: Fri Jan 21, 2005 10:50 pm    Post subject: Reply with quote

OK, essentially the torsion bar bushings, yes. The original ones are molded on the spring plate.

From what I understand stock replacement consists of the part shown above - new spring plate with bushings.

Or if you go aftermarket and want it stiffer, you can get delrin outers and poly-graphite inners. That's what I have on my racecar. Upside is they're relatively cheap. Downside is they're a major PITA to install. In addition to completely tearing apart the suspension (expected, and required even just to replace with the stock part) you'll have to take your old spring plates and grind or burn off all the old rubber - takes quite a bit of time. Easiest way is a couple cans of MAP gas, a blowtorch, and a six-pak of beer... sit and watch 'em burn. Then you probably also want to clean up the housing surfaces, get rid of burrs and weld spatter.

If you want to go that route. Time-consuming, but great for a car that's to be driven hard. Not sure you'd want them on a street car, though. Not sure how much harshness just changing those would create.
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Vaughan Scott
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'79 924 #77 ITB racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype
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goturbo  



Joined: 15 Jun 2004
Posts: 87
Location: Massillon Ohio, USA

PostPosted: Sat Jan 22, 2005 2:18 am    Post subject: Reply with quote

That is what I figured. I already have everything torn apart and ready to be powder coated so replacing them now is not an issue. I am concerned with ride harshness though. Like you say I am not sure what that would really do for the ride, but sometimes I have a hard time determining what Porsche engineers did for a reason and what they did to keep costs low. I read in the shop manual that the rubber bushings were added to dampen the vibrations fom the suspension operation. But does that mean that it will shake the car so bad that stuff will come apart or just make it so it has a more congenial ride-that is the real question.

Here's my thinking. For the bushing on the inside of the spring plate where it seals the torque tube; make that one out of Nylon or other semi-flexable plastic since that 'system' is still isolated from the chassis. Leave the outer bushing rubber or other flexable plastic since that is mounted to the chassis via the aluminum bracket. That way the vibrations that are transferred to the chassis are kept to a minimum while the turque tube operation is made more rigid. What do you think?

I might be splitting hairs with this whole issue, but my inner bushings are in bad shape and need repalcement, but I don't want to be counter productive by making them too stiff. That's the reason for my concern.

On a side note, a knotted wire wheel (available ar any good hardware store) on an angle grinder makes quick work of any molded-on rubber product. Kinda messy but real fast
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