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Ok- first up. My replacement vacuum check valve arrived...
And on it went. Literally takes a few seconds....
Drive report - yes, much of what has caused me to head down the road I'm on with this thread, is now taken care of. Resonance flap functions and the car is significantly zippier at wide open throttle. Duh. 19 dollar part.
I think i said up above- it's made by pierburg and you can buy one on amazon for 19 and free shipping through prime- that's the cheapest i found, but did not yet check with sunset. On amazon it's listed as a Volvo part. I'm wondering if these fail so easily due to the gasoline fumes that are in the throttle body. But that's just a wonder. It doesn't seem to be engineered to handle chemicals.
Now- i have been sitting here at night fretting over the removal of things i shouldn't remove. But I'm curious. And I've been shoved into going down the rabbit hole -and to take this thing to the end.
So I've been fully expecting that - since it seems relatively normal to do this- that there would be a seal, some kind of an o-ring in the bushings for the resonance flap (and for the plenums as well). Because, as we know, vacuum in these cars is important , and vacuum leaks cause all kinds of strangeness. So it stands to reason there would be some way this bushing was designed to hold vacuum.
In fact- i was told by the experts- when my motor had a vacuum leak in that bushing , that my throttlebody needed to be replaced, because it's not serviceable and the only way to fix that vac leak was to buy new.
And - I've heard this from others and even read this on rennlist.
So down the hole we go...
Peened ends, do they need to be filed or ground down? No. Just back them out...
And then take out this e-clip...
And slide it out from this end...
And here you go. These are all the parts.
Now what's left in the holes? There is no o-ring. No seal. It's a needle bearing on both sides.
So that begs the question. How does it seal?
Well there are two little flat washers on the outside that rest on either side of the shaft. So I'm going to surmise that between the fact that there should be grease in the bearing, and then you have these flat flush washers, that under vacuum, they seal up well enough.
Now. How is this not serviceable? If the bearing is good, you pack it with grease. Service done. Of the bearing is bad. Removing this bearing will be an absolute bear. The hole it sits in doesn't go all the way through. So it's pressed into a stop. And there is no way to grip it to pull it out. So good luck if you ever want to attempt that. Maybe a lot of heat around the outside and it'll loosen up enough. But holy hell.
Thankfully, i have no intention of bothering and no need to, since my bearings are fine. So I'll support them while i take apart the rest of the throttle body and prep for paint, and then repack them on reassembly. And it should be good as new.
Now - all that said, I've only just looked at it. it is possible there is some kind of a sealing ring back there behind the bearing that I'm not seeing yet. But i think we are good to go. Cuz I'm still not taking apart this bearing.
Sorry says not eligible for prime. But it was free shipping..so all good.
Black side goes to the hose coming from the throttle body. White side is in the loop for the vac canister and the resonance flap controller.
But- you can check yours easily. Take it out and blow through the white side. It should flow freely. Flip it and blow through the black side. Should not flow. That's all it does. So if yours functions, no need to replace. If not...replace.
Good read- interesting that he found a seal in his. That's what i had expected. But i see nothing in mine. Maybe they are just so deteriorated they are gone?
There is no lip left in the bore to cover the seal on the 964. But- from the pics I kinda wonder if there isn’t an o-ring sitting on the inside of the bearing.
Also thought the pressurizing idea was cool and that you might want to give that a try ... but maybe with vacuum.? Maybe your initial thoughts about the washer and grease holding vacuum are spot on.
”The original seal in the bearings is a small lip seal, not an o-ring.
On my S4 I just pulled the bearing out and replaced it with new, they're reasonably cheap and come out easily enough with a blind bearing puller and slide hammer.
Just heat the throttle body up in an oven first to expand the surrounding material - makes getting the bearing out much easier.”
Boy I’m just making this worse for ya! First the throttle plate screws and now this.....
Interesting. And when you look at the cross section. You'll see the seals. I actually have a source for those seals. I'm curious if the design of the needle bearings in the one on my bench matches this.
So if anyone else wants one - pm me. It's 35 dollars each. Happy to make them available. I can be super disorganized via pm, and email, so stay on me if i don't respond. But so long as it's not 1000 people pm'ing we should be good...
07-09-2018, 11:06 PM
