[RS Barn]

The Timing belt tensioner pivot shaft should be replaced when changing the timing belt. Especially now after 25 years and who knows how many miles.

I have seen many of these seize and then brake resulting in pistons and valves meeting in a very unhappy manor. The part itself was unavailable from Porsche for awhile and I had bought up all the stock in Germany. They are now available from Germany.

The pivot shaft itself has two O rings and two very thin washers and a retaining circlip. The thin washers stay flush to the timing belt tensioner arm and help retain the lube on the pivot shaft. It is very important to use a high temp and high pressure Copper based anti-seize. Anything else will not hold up for long.

When you remove the pivot, make sure to chase the threads to remove the Loctite residue which has hardened.

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[apex]

Thanks RSBarn!

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[unknown4u]

I will certainly replace it the next time.

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[94SilverCab]

Thanks Pete, do you have a "street legal" 968 at the moment?

 

Jay

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[Rap]

Hmm street legal huh. Is it street legal if it's not plated? He has a totally rad one now.

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[MLB]

Interesting. I was never able to get the two flat steel washers on there the last time I replaced the timing and balance shaft belt. Even my local indie mechanic agreed it wouldnt fit

There was only one of the flat metal washers present when I got the car in 2013. The circlip wouldn't fit when I tried to put the second thin metal washer on...

I think I lubricated it a bit with some wheel bearing grease, not knowing any better.

I will look into replacing this in the spring, thanks

(944 105 170 04, currently $50 from Sonnen)

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[Bulti]

You probably got the old style shaft. Porsche updated it somewhere along the way. The old one didn't have the o-rings, IIRC, just the center groove.

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[Cloud9...68]

I've always had problems with this as well.  I have the new style shaft, which I replaced a few years ago during one of my belt changes.  It is supposed to take two o-rings, but no way, no how was I ever able to fit both o-rings, and a pair or washers, under the circlip.  One of my belt replacements was with the engine out of a car, on a stand, where I had all the room and leverage in the world, and I still couldn't get both o-ring on there.  I just lubed it up really well, and left it with one o-ring.  So far, so good after many years, but it always makes me nervous.

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[unknown4u]

I recognise this kind of story. I didn't had the time the last time I changed the belt but I saw that the arm has a bit of space. With a spacer it was gone. I thought about milling a new one with a nut on top of it so I could ajust the clearance. Otherwise a new pivot is cheaper and will last another 25 years.

Then i will be be 73....
The 968.... 50 years old.

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[MLB]

Hmm, mine has the two grooves for the O-rings and the center depression which looks to me like a space to hold some grease. And getting those oh rings on and placed required a bit of care. I cut one the O rings at first by being too hasty. But it seems to hold lubrication like cloud said.

In any case I'll be sure to check it this spring

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[Cloud9...68]

Hmm, mine has the two grooves for the O-rings and the center depression which looks to me like a space to hold some grease. And getting those oh rings on and placed required a bit of care. I cut one the O rings at first by being too hasty. But it seems to hold lubrication like cloud said.

In any case I'll be sure to check it this spring

Yes, I cut several o-rings in the process. and even when I was able to keep them intact, there was no way I could fit the circlip over the assembly.

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[Waylander]

The current part number for the new version that was fitted to 95> cars

 

944 105 170 05 £46.78 or $60.86

 

O rings

999 707 078 40  $6 each,  you can use any rubber or Nitrile O ring 12x1.5 mm

 

 

Flat washers

900 234 182 02 $1 each

 

Circlip

 

900 041 023 01 $1

 

Prices from Porsche price update 135 7th Dec 2017

 

from the PET diagram

 

two O rings first, then one flat washer, then tensioner arm, then flat washer, then clip

 

PET does not show a different order for new or old pins,

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[apex]

I encountered this problem when refreshing the head and front end a few years ago - I bought the new style pivot to replace the old and there was NO WAY it would accept the existing pivot arm when o-rings were on. So I did as has been mentioned here - just greased it up good and moved on. No worse than the old-style pivot, right?

 

I assumed at the time there was a new-style pivot ARM mated to the new pivot PIN. True? Haven't checked. Next belt change would be a good time to bring the whole assembly up to '95 standards.

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[Bulti]

Interesting idea about the arm. If it was changed too, that would explain a lot.

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[Cloud9...68]

I wonder if the old style arm could safely be milled down a bit to accomodate the stack of o-rings and washers associated with the new pivot shaft.

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[paulzebo]

I believe the o-rings ride inside the arm and have no effect on the stack up. I pulled a spare arm and new pivot for illustration

 

   

 

Without the spacers, there appears to be plenty of clearance.

 

   

 

Until you look at the bushing. This one is riding about .011" above where it should.

 

   

 

Something over the years has caused it to go outward by a small but critical amount. The choice is to press it back in place or carefully file the bushing excess without damaging the arm surface. Yes, there is enough room on the opposite end to press it down, but the risk is that whatever caused it to go forward will repeat the issue. On the other hand, maybe it was this way since new and problems only show up when used with the new pivot.

 

   

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[Cloud9...68]

Thanks for posting these pictures - it's very helpful in understanding what's going on.  I thought I must be going crazy with how much difficulty I was having getting the circlip on with the o-rings in place.  It's interesing to learn how common of a problem this is.  I wonder if it wouldn't be worth taking the arm to a maching shop at the next belt job and having a new bushing pressed in.

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[Waylander]

there are two arms shown in the PET

 

but no year attached

 

944 105 074 06

944 105 074 07

 

there is huge difference in price

06 $253.00

07 $398.00

 

that would suggest if you have the earlier shaft then you use the 06 tensioner, later shaft 07 tensioner

 



 

The "A" in front of the part number means stock to be used up

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[apex]

Waylander I was just looking up the same thing - but your PET is better than mine so I'm glad you posted first.

 

My (poor man's pdf PET - but just downloaded from porsche.com) lists the pin FOUR times but under two part numbers (diagram number 13), but only ONE version of the arm (the 06 but not the 07) (diagram number 21).

 

THAT'S confusing, and a little concerning since I depend on this document a lot.

 

Are you referencing the electronic version of the PET? 

 

 

PS I've read the tutorials on the site but they do not seem to match the current toolbar - could someone throw me a bone? Thanks.

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[Bulti]

So now we just need somebody to buy all the different parts and try them on his or her car. Simple.


Lol.

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