Thottle Body O-ring repair/replace with PICS

[3Sfever]

Sounds like we use #7 if stuffing inside the metal holder, and #8 if using the o-ring only. Correct?

I bought some o-rings at a local autoparts store that are 3/8" I.D., but after getting them home, and measured myself, I found that they are .100 dia, which results in O.D. of approx .57

Any chance that is the measurement of a #8 ?

Thanks,

[Synchro]

Originally Posted by 3Sfever

Sounds like we use #7 if stuffing inside the metal holder, and #8 if using the o-ring only. Correct?

I bought some o-rings at a local autoparts store that are 3/8" I.D., but after getting them home, and measured myself, I found that they are .100 dia, which results in O.D. of approx .57

Any chance that is the measurement of a #8 ?

Thanks,

Sounds about right. I tried a #7, but it was loose. #8 required a bit of coaxing, but once it was in there it made a great seal, and didn't hang up at all (used silicone grease).

Getting the metal seals out without damaging them is one hell of a neat trick. It's possible, but a huge PITA.

Greased #8s will give a solid seal. They might pop out of the channel once or twice while assembling the TB, but once you get things together, they're in there for good.

Poled 'em down into the groove with a small screwdriver. Just gotta remember to be gentle, so you don't tear the 'ring. Piece of cake.

[3Sfever]

Assembly of the ones I have sound very similar to what you describe. They are tight. I greased them up with dielectric, It took some coaxing but finally got both sides to stay in.

This assembly was just a trial run however. Unfortunately for me, I was one of the lucky ones with really tight throttle plate screws. I stripped the phillips cross trying to get them out, and had to drill out the heads. It was frustraing because I was as careful as I could be, I followed instructions --> ground off the "peened" ends, and used a #1 Phillips, etc. but just could not get those suckers to turn.

I will be assembling it "for real" after I get some new screws. The screw thread is M4x.70 if anyone is interested.

I took a few pictures along the way, might be able to use them in the Wikipedia. (pics that might help . . . not of my stripped screws )

[Detox]

Tryed taking it apart tonight as well and striped the damn heads with a P1. That's even after grinding the back down. Will stop by sears tomorrow and see what they have for a reverse bit to get them out.

[Synchro]

Future consideration for those who are doing this for the first time: Before trying to remove the screws, treat them with a bit of penetrating oil. Grind off the backs first, then give both sides a rub-down using a soaked q-tip. Maybe even give a few light taps with the metal tip of the screwdriver.

These screws are very soft metal, so be careful.

[3Sfever]

Good tip! Wish I had done that.

I added it to the wiki.

Mine is back together, works great, no leaks.



To Detox: not sure if this would work for everyone, but I drilled out the screws from the head side (the wallowed out cross made a great center ) . . . I used a drill bit same O.D. as the screw thread, after drilling half way thru, the head popped off (look like a donut at that point). . . . The nice thing was that then the tension was released from the rest of the screw, the drill bit actually started driving the rest of the screw out the other side. I then just grabbed the end with pliers, twisted and removed it. . . . No special tools needed. . . . Just be careful not to drill too deep and wipe out the threads.

[skunkworks]

exactly - the backs of these screws are peened(sp) so they will not back out accidentally.

sam

Originally Posted by Synchro

Future consideration for those who are doing this for the first time: Before trying to remove the screws, treat them with a bit of penetrating oil. Grind off the backs first, then give both sides a rub-down using a soaked q-tip. Maybe even give a few light taps with the metal tip of the screwdriver.

These screws are very soft metal, so be careful.

[Detox]

Thanks for the info, but I got them out last night with a reverse bit. I just drilled with multiple bits - small -> bigger -> even bigger -> biggest to keep from popping of the head. Tapped in, or should say banged in the reverse bit. Turned and came out like butter. Pick up some new screws last night. Will be putting it back together sometime this weekend in the middle of the upgrade to 15gs, motor mounts, drive axles, gauges, etc.

By the way did you replace the biss o-ring with a 5, and if so how did you adjust the idle, read something about grounding the something with iac to hold the current steady. Gotta go back and read some more.

[VR4neophyte]

Adding my 2 cents...

THE FIRST TIME I did this several months ago, it was with the Home Depot #8 o-rings. The #8 rings seemed to fit snug, but okay, and this was with the removal of the worn stock metal-and-rubber o-rings. The car seemed okay, but after starting it weeks later, I found that the throttle plate didn't easily return to closed. In fact, it got to the point where it just stayed open. Not good. I'd also read about the problem with using o-rings from Home Depot meant for plumbing, not oil and gas.

THIS TIME I did it the right way. I ordered Viton o-rings, and ordered them with 1/2" O.D. x 3/8" I.D. They fit perfectly, and so far, they work perfectly too. The car idles very well, and the throttle plate moves on and off smoothly with no binding whatsoever.

I might have been able to make #8's work if I'd kept them lubed, but otherwise, no. Plus, the Viton rings will far outlast the HD rubber at virtually the same cost.

I took the opportunity to make my throttle-body coolant lines perfect as well, and all seems good now. Idle is just about perfect at 1000 rpm, and I'm not sure I can go lower than that with street cams anyway.

[Drweldin]

Originally Posted by VR4neophyte

Adding my 2 cents...

THE FIRST TIME I did this several months ago, it was with the Home Depot #8 o-rings. The #8 rings seemed to fit snug, but okay, and this was with the removal of the worn stock metal-and-rubber o-rings. The car seemed okay, but after starting it weeks later, I found that the throttle plate didn't easily return to closed. In fact, it got to the point where it just stayed open. Not good. I'd also read about the problem with using o-rings from Home Depot meant for plumbing, not oil and gas.

THIS TIME I did it the right way. I ordered Viton o-rings, and ordered them with 1/2" O.D. x 3/8" I.D. They fit perfectly, and so far, they work perfectly too. The car idles very well, and the throttle plate moves on and off smoothly with no binding whatsoever.

I might have been able to make #8's work if I'd kept them lubed, but otherwise, no. Plus, the Viton rings will far outlast the HD rubber at virtually the same cost.

I took the opportunity to make my throttle-body coolant lines perfect as well, and all seems good now. Idle is just about perfect at 1000 rpm, and I'm not sure I can go lower than that with street cams anyway.

Good tips....where did you order the o-rings from? McMaster or?
I used AC system o-rings, hopfully of better material than the Home Depot...