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931 S2 Throttle Body repair kit NOW AVAILABLE

 
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ideola  



Joined: 01 Oct 2004
Posts: 15511
Location: Woodstock IL

PostPosted: Mon Oct 11, 2010 10:00 pm    Post subject: 931 S2 Throttle Body repair kit NOW AVAILABLE Reply with quote

One of the common problems on the 924 throttle bodies is leaking seals. Unfortunately, the S1 / NA throttle bodies are not easily repairable due to the style of bushes used. All the more reason to convert to the S2 intake setup if you have a 931!

I worked with Bruce Arnn (of Arnnworx) to develop this throttle body repair kit for the S2 throttle bodies. It includes the shaft seals, the TPS seal, the idle air valve seal, the main throttle body seal, and all new hardware for mounting and reassembly.

Last night, I rebuilt the TB for the Club Sport project car, and I could not believe how bad the two shaft seals were! The main butterfly shaft pivots on two sets of needle bearings, one at top and one at bottom. The small seals that you see in the photo with the square cross section provide a seal on top of the needle bearings and at the extreme opposite ends of the shaft where it exits the casting. On mine, these seals were completely shot...they were crumbling and falling apart. So for that reason alone, it was well worth the effort to disassemble, clean, and rebuild the TB.



Price: $25 + shipping

Kit includes four page pictorial instructions.

I'll be adding these to the website a little later this month, but for now, just send me a PM to purchase.
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75 Fiat X1/9 | 80 US 931 '941' | 78 Poli-Form


Last edited by ideola on Tue Mar 01, 2011 12:08 pm; edited 1 time in total
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Rich H  



Joined: 10 Jun 2007
Posts: 2665
Location: Preston, Lancs, UK

PostPosted: Mon Oct 11, 2010 10:20 pm    Post subject: Reply with quote

You have PM.

Rich
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1978 Homo-Sapiens - Tired spec
1953 Landrover S1 - Pensioner Spec
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bnoon  



Joined: 12 Oct 2009
Posts: 607
Location: West Des Moines, IA USA

PostPosted: Mon Oct 11, 2010 11:17 pm    Post subject: Reply with quote

Wow, good job Dan! Those TB's gotta be a pretty good boost leak too if the seals are that bad.

Are the new seals rubber, Viton, or ??? Are they any better than stock is what I'm asking.
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924RACR  



Joined: 29 Jul 2001
Posts: 8422
Location: Royal Oak, MI, USA

PostPosted: Mon Oct 11, 2010 11:25 pm    Post subject: Reply with quote

Wow, they're actually seals? I'd thought they were just worn-out brass bushings... guess I never looked close enough at mine - I know they're shot! Will definitely have to pick one of these up from you, looks like...
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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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ideola  



Joined: 01 Oct 2004
Posts: 15511
Location: Woodstock IL

PostPosted: Mon Oct 11, 2010 11:34 pm    Post subject: Reply with quote

The ovoid NA / S1 throttle bodies have brass bushes. I had Bruce take a look at one of my spare S1 TBs, and he thought it would be pretty difficult to find repair parts for. So I haven't pursued that path any further. Since all of my cars are either S2s or will have the S2 setup, that was my primary focus.

The main shaft pivots on two needle bearings that are seated in the TB casting. There appears to be some sort of retainer that holds them in place, so I'm not sure what would need to be done to replace the needle bearings, but the old seals will crumble right out, and then the new ones can be maneuvered into place. Having a decent set of dental picks is critical.

The primary places where the TB can leak are at those two seals on the primary shaft; there is also an o-ring on the idle air valve screw, which you need to remove completely in order to replace; and also one on the TPS switch.

As far as I know, the o-rings are all rubber.
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924RACR  



Joined: 29 Jul 2001
Posts: 8422
Location: Royal Oak, MI, USA

PostPosted: Tue Oct 12, 2010 12:05 am    Post subject: Reply with quote

Maybe mine used to have the seals, but have long since disappeared!!
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Vaughan Scott
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bnoon  



Joined: 12 Oct 2009
Posts: 607
Location: West Des Moines, IA USA

PostPosted: Tue Oct 12, 2010 12:07 am    Post subject: Reply with quote

I'll take a look at the brass bushings in my S1 TB. I have a pretty good contact for purchasing brass bushings and also bushing round stock from my old RC car/plane days. Anything I couldn't buy, I just turned on my lathe. The problem would be if the shaft has any wear and if the old bushes can be pulled out without damaging the housing. If the shaft has damage then it would require a polish and a custom sized bushing... Much more work than the S2 rebuild for sure.

If the S2 needle bearings are damaged, you can usually find those pretty easily online. They're just press fit into the casting on all of them that I have done for many other brands of throttle bodies in the past. (I've ported/polished throttle bodies and done TB rebuilds since the 80's). Usually pretty easy to pul those needle bearings with a slide hammer at worst, usually even easier than that with a drift punch and a couple hammer taps.
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ideola  



Joined: 01 Oct 2004
Posts: 15511
Location: Woodstock IL

PostPosted: Tue Mar 01, 2011 12:09 pm    Post subject: Reply with quote

I have now added these TB rebuild kits to my site:
http://garage.ideola.com/prod-Kits.html#931TBSK
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Wed Mar 10, 2021 4:02 pm    Post subject: Reply with quote

Can anyone post the sizes/Pn#'s of the seals mine just blew
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Thu Mar 11, 2021 4:34 pm    Post subject: Reply with quote

well it looks like the shaft seals are the same as the 944 turbo:

5/16 ID, thickness 1/16, Order the Quad style if you can I believe there are 2 on one side and 1 on the other (as it is on the 951 TB)

and the TB to manifold seal is 69mm OD/4mm thickness.

Im willing to bet ALL Older TB's have shot seals.

I did the one on my 951 earlier, and I just checked the spare 931 TB I have, it's seals too, Just crumbled. So im sure they were Causing a Vac and Boost leak.
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