Hey guys, I finally got my engine put back togehter again... For those that dont know, I was leaking boost real bad, and found 2 stripped exhaust manifold studs, actually the head was stripped not the studs... So I heli-coiled them and reinstalled the manifold, turbo, and downpipe finally now that the mitsu and hahn gaskets arrived.. Well, I finally got around to making a good boost leak tester with pvc and a compression fitting for an air tool... I put 10psi in the lines, and the tb is leaking like a mug. It is leaking between the spring that holds the arm(the one with the buttery fly valve attached. I have taken it off yet, will in a few min, but any ideas what this is? a blown seal or something? I also hear a leak at my boost gauge, so one i fix these two, i can check for others... damn, you really gotta get all the lines real fuggin tight not to leak. Any help is much appreciated.

edit: ok, i got the tb off, and took it apart. The shaft seems not to have a seal on that side? just a roller bearing the shaft slides through? Am i missing a seal ARD might have forgot to put on it when they bored it? if so, can i pick it up locally quick, cause i'd like to drive my car this century, the mail order parts take forever, and the local dealer parts are outrageous...

Ok, so I look in the FSM and talk to Dino... That bearing IS the seal... ha, what a seal it is.... if you saw it you'd know what I am talking about, that bearing doesnt seal at all if you ask me... How are you guys fixing that? Cause I looked at a few other tb's and they are the same way. I'd hate to jb weld that mug into place incase i want to take it back apart, lol... and ultra black rtv, i dont know if that will hold for too many psi before sucking it in the engine.... I put a thin bead around the shaft towards the end about where the shaft will sit on the bearing, and inserted the shaft, pressing a little black inbetween the bearing and the shaft, but i really doubt thats a decent fix... I don't know what to do though to make that totally sealed... Any ideas? Cause boost leaks arent efficient, hehe.

No help here brad, but i got a question for you. How do you know that all your exaust valves are closed to know you arent bleeding off pressure out those? I didnt think you could get all the valves closed at the same time, at least all you really need to have closed is the exaust valves. Did you line up timing marks or something? I really need to do this also, becuse i am fading boost when my rpms get up high, like 5000 and up, i hit a good 10 psi, then it fades to about 8.5. Its either my boost controller, or a boost leak. You pressureized the whole entire engine right?

Yeah, i clamped onto the turbo inlet, so i was pressurizing the intake system, and no, it wasnt leaking through the exhaust so either its always like that or i got lucky when i shut the engine off.... you'd be amazed at the leaks you find, expecially as you crack up the pressure, get it too high and shit will pop off right and left...

but, anyone that has solved this tb problem is more than welcome to post :-) don't be afraid guys, hehe.

*bump* I still havent had any insiteful ideas pop into my head... Other than a thin rubber o ring maby shoved in there? I doubt that will work, but just trying to stir up some ideas. maby a different bearing altogehter, like on with a notch in the middle with an o ring inserted, or one with a rubber skirt like a axle seal for the tranny? Atleast can greg or armond or someone confirm that when you pressurized the intake manifold, that you also encountered this leak?

I have never had that leak, but I am on a stock tb. I know Armond is not leaking either, but his was hand ported and still has the stock throttle plate if I am correct.

Mine leaks. I tried putting some rtv around it, but it didn't seem to help any (other than making a mess). I would like to find a cure as well.

Dino is leaking too... I think he used RTV. But theres gotta be a better solution than that... If it effects most TB's, then I'd think the turbo guys could really use this leak fixed, cause no telling how much faster the car will spool... I emailed Bill to see what he did, but havent got a reply yet.

are you leaking between the bearing and the shaft or past the rubber bearing seal?

between the bearing and the shaft... its just not a tight fit, and even if it was decently tight, i believe it would still leak due to metal to metal is always gonna leak unless its exactly perfect... what do you mean rubber seal?

edit: ok, so i know what you mean now, didnt sink in... I really doubt its the rubber part of that bearing, or if it is that too i dont know, but I know leaking inbetween the shaft and bearing is definate, I can see light through it...

okay if that is it, this is what i did
get a very thin washer, like .002 or .003 inches thick that will fit around the shaft nicely. now go buy some o-rings that will fit over the shaft nicely. then remove the c-clip that holds the shaft in place. and remove the throttle plate and slide out the shaft. slide on however many o rings you need. i put 3 on the spring side and 1 on the tps side and push it back together and put the washer on the tps side and put the clip back on. make sure the o-rings are the right size, they should not be so fat that they touch the bearing's rubber seal, just the metal inner part of it that rotates. remember that when you are pushing the shaft back into place there should be some pressure from the o-rings. this will ensure that you have a good seal. this has worked good for me. I have been able to pressurize the system to 20 psi and not get a leak.
lates
james

I am gonna try and see if the rtv holds tonight when i get home, if it doesnt, i'll pull it back apart and take some pictures so people know what I am talking about. and then i'll try the washers and o rings.

Honestly, if most of these do that, all the turbo guys should check it out, and your engine will probably run smoother and hold boost better i am sure.

Right on. I just make my pvc pressurizer(hehe cool), and i am too leaking from the throttle body throttle shaft. Its a pretty good leak, but not terrible. My plate shaft has just a tad bit of play in it, but its def not excessive. Doesnt the stock TB already come with a rubber o ring to seal this? I'm also leaking boost out my PCV valve...i can get some air coming into my catchcan..so i took off the vac line after the pcv valve, and its leaking some air. Its a fairly new one too. Can i just block off the opening at the intake mani for the pcv, and then just take out the thing, and then run a line from the barb on top of the valve cover to my catch can? I would think that would be ok, right? I tested at 10 PSI, and it took about 3 to 4 seconds for the pressure to be leaked off back to 0. Thats not good :(

I havent ran the engine yet for results, but I got rid of the pcv valve and just ran the nipple on the talve cover to the other arm of my catchcan,and mine was leaking some too, even with a pretty new pcv valve...

I am still on campus, so i havent got a chance to get home and fiddle with the throttle body today, but anyone got any better ideas than the o-ring one? I bet that will work either a) for awhile, or b) under lower boost applications.. I'll probably do that for now, but i'd like to find a good permanent fix for all around boost levels, and also still being able to disassemble the tb if need be.

Ok, so I finally got my lazy ass out of bed and working on the car. I put the TB back on, and pressurized again... still leaks but not quite as bad.. So I took it back off, cause if it still leaks, my job is not done...and it will probably worsten over time too... so that ideas didnt work for me. So here are a few pics of the shaft and the bearing to let people see what I am talking about. In the pic of just the shaft, on the tip of it, you can see a ring cut into it, I suppose a o ring is supposed to sit there on the TPS side... Is that o ring in the TPS already, I havent removed that part cause that side doesnt leak and I dont wanna kill any bad karma I already have going, hehe. So, jamesman's idea with o rings between the shaft and bearing is the next try.. Anyone give me any good info here? I am thinking of using my dremel tool with a really thin wheel to cut an indentation on the shaft where i want the o ring to seat, think that is a good idea or am I just gonna f#%K the shaft up? I have a million diff sized o rings, so I am ready to go :-)

put that o-ring in there like you are talking about, and slap some RTV in there.

well, the machine shop cant do it for a month, i guess they are REAL behind... and I dont wanna mess it up doing it with a dremel tool, so I am gona try teflon tape around the shaft, and if that doesnt work, locktite, the servicible kind...

Update: Ultra Black RTV for a 2nd try didnt work, well... it did hold at 6psi, I jacked it up to 15psi and it held and I was like... fxck yeah! and whoooosh.... it blew out 1 sec later....

Tried Locktite too since its thinner, it locked the shaft up tight as a tick so I thought it was gonna work, but it didnt hold even as well as RTV, but I had to remove the TPS and beat the shaft with a hammer to break it loose... bad idea :-)

Soooo, I didn't try the teflon shit, cause nothing is gonna fix it like that... only way to do it is to have it machined. So I went down today to a machine shop my buddy took some classes at, and the teacher was so eager to help me out. The shaft reads .372 and the bearing reads .375, so .003 is what the air is leaking though, he had to leave for a funeral, and another one next monday, so tuesday or wednesday i will go back, he's not charging me or anything , he's a real cool guy. I bought some real thin o rings with an outer diameter of .375 that will hold up to contact with gas, so we will put the shaft on the lathe next week and get the work done. He said he will guarantee it will help, but can't tell me if it will hold 30psi without a leak. I am sure it will be fine though, and if it still doesn't satisfy me, he said he'd just turn me a new shaft.

Have him make 2, I'll take one. :D

"every" car leaks from there. you may think it is a bad leak, but in reality, it is quite a small leak. you just don't have any major leaks. both mine and chris's and my buddy brandon's and my stealth's throttle bodies leak air right there. nothing to worry about.

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

Well, I did the o-ring trick over the weekend and now I can't get the thing to hold any boost - it's all going out the tail pipe. :( I'm getting so frustrated with this thing lately. I guess I need to rip apart the front of the engine AGAIN and check the timing. Runs fine though, other than the revs hanging when I'm coasting to a stop (hmmm, sounds like a vacuum leak, no?). Stupid POS.

At least I don't hear a leak at the TB....