Stripped the threading (female end) on EGR mounting bolt hole

[jk3006]

So now I get to hopefully tap it out to the next bigger size. I think the standard bolt is 8x1.25, right? So, should I look for a 9x1.25? I figured I'd bounce this off of others before going ahead with it myself.

Oops, forgot to mention that it's a '96 SL.

[MikeNW]

9 mm sounds like an odd size, but if it exists, and you can get a tap, go for it.

I stripped out the threaded insert for the driver's seat, the front of the seat. Was ready to tap the next size but used a stud and some loc tite.

Could you install a stud with JB Weld if there's no such thing as a 9mm bolt?
Is the threaded hole a blind socket (can't drill through and use a nut)?

Just looking at options....

[jk3006]

Yep, that's why I asked. I like the idea of drilling through and using a nut. I think that's possible, but I'll have to double check.

As to the size of the OEM bolt, it screws really nicely into my 9x1.25 female tap, but when I measure it with the caliper it measures 8mm. So, that confuses me a bit. I have a tap set with 8x1.25, 9x1.25, 10x1, and 10x1.5.

[kt97sl2]

We had one strip for the valve cover and put in a heli-coil. Worked great!

[moresaturn]

If you can find a tap to go the next size, then by all means go ahead and tap it out and put the bigger nut on there. Also, you could as mentioned JB weld it to the underside, there will most likely be room to do it. Or you could just use a bolt and a nut, not bothering mount the nut on the underside of the flange. If you use this method, (or JB weld it to the flange for that matter) make sure that you have a significant amount of area to mount the nut to the flange. I am refering to the doughnut that is the flat part of the nut between the circular section in the middle and the hex end.

Hope this helps.

[OldNuc]

Go to Autozone and buy a helicoil kit for the original size bolt. That is the easy way.

[jk3006]

Great ideas. Thanks guys. What I ended up doing was just running a longer 8x1.25 bolt through the hole with a nut. I kept the nut on top, and I had to use several smaller diameter washers on the bottom side to keep the bolt head away from the side of the casting that juts out (underneath). A bit of a pain, but I had the bolt and nut handy, and it's all back together now.

I had the EGR off about a year ago, and the stripped threads happened then. But it held together well enough at the time. The car sat for about 10 months, and I just started driving it again. It was running like crap, and it was because of the vacuum leak where the EGR is because of that loose bolt.

While I was at it I cleaned the EGR the best I could with carb cleaner, and I followed OldNuc's directions the best I could about spinning the pintle (under air pressure) and cleaning the walls as best I could. Then I pressure tested it with 50 lbs of pressure (couldn't go any higher with the system I had rigged up, otherwise the hoses were being blown off the fittings) and sprayed the pintle with carb cleaner. It still leaks. It's not a perfect seal. Anyhow, I put it back together and went for a drive. It runs as well as it has in a long time. I don't know if that pintle is trouble, and I suppose I could block off the valve for awhile to see if there is any difference at all. But like I said, the car ran great!

[jk3006]

Okay, "running great" is a relative phrase. It's running better without the vacuum leak that the loose bolt was causing me, but there's still something missing. I belive it's at approx. 80-90% full strenth. I need to find a fully functioning EGR. I just picked up three of them at the junk yard. One of them BETTER work!

[OldNuc]

Go buy that helicoil kit and fix that threaded hole. You will have a tough time getting the proper seal with a jury-rig. Do use a new gasket and do not over torque bolt.

[jk3006]

I no longer have a vacuum leak from that mating surface. It's the EGR itself.

[OldNuc]

How are you checking for a vacuum leak?

[jk3006]

1. I had a vacuum gauge hooked up inline at the pcv valve. It read a stable 22 Hg at idle.

2. I like to use propane to test for vacuum leaks instead of carb cleaner. Lots of propane dispensed all around the EGR mounting plate did absolutely nothing to the idle. Before I fixed that bolt the gas would kill the engine (choking it).

[OldNuc]

As long as it does not leak when the engine is hot you should be OK. Hesitation when you stomp the gas is usually a TPS issue or sparkplug/wire/firing order issue. Either pair of wires reversed will run fine but provide a lovely hesitation on acceleration. Platinum plugs will cause a hesitation also.

[jk3006]

I feel that it's entirely the fault of the EGR itself.

See my last posting:

http://www.saturnfans.com/forums/sho...t=87543&page=2

[fdryer]

You can eliminate/isolate the egr valve causing erratic engine running issues by blocking it off temporarily. As far as tapping or rethreading goes, try rethreading the entire hole if the threads goes through an open hole and using a longer bolt. With a closed thread hole you may be able to use a bottom tap instead of a starting tap to tap below the ruined part. Unless you're familiar with drilling and tapping into hard and soft metals, this can be a disaster in itself; snapping the tap, threading incorrectly, drilling with the wrong size drill, etc..

Oh, and here's a bolt chart to go by.

[RobertGary1]

Originally Posted by jk3006

2. I like to use propane to test for vacuum leaks instead of carb cleaner. Lots of propane dispensed all around the EGR mounting plate did absolutely nothing to the idle. Before I fixed that bolt the gas would kill the engine (choking it).

Scarry. I"m not sure where the idea of using combustables to check for vac leaks came from but its not very safe. Just use a bottle of soapy water. The soap creates a momentary seal and you will hear the change in RPM (or see it if you have a vac gauge hooked up). There is less water coming out of the squirt bottle than you have sublimated in the air on a moist day.

-Robert

[OldNuc]

Safe depends on how much gas you blow around. It is one of those experience things. The only people I have ever seen hurt looking for vacuum leaks were using carb cleaner, instant sunburn and shave.

Propane has replaced the freon as a propellant for most of the spray cans.

[fdryer]

Propane gas when used sparingly to evaluate vacuum leaks is relatively safe when used correctly. Its the uninformed amongst us that plunge into opening a new tank of propane and feeding a full pressure release of propane, they're the ones to educate and give stern warnings to.

There was a time long ago when I read up on R12 leak detection. One method was to use a halide leak detector that uses a propane torch to heat a copper plate and a vacuum hose to draw in whatever gases were sampled around a/c lines/fittings/etc.. The byproduct of burning R12...........is phosgene gas................... Do your own analyses. Its considered a safe practice when done properly in skilled hands. I never bought the equipment for personal use as all the alternate methods of leak detection were easier to work with. The eyes are a lot better at observing the obvious when trained to look for tell tale signs than using a torch to sniff for R12. Electronic leak detectors are for the business' needing quick turnovers.

[RobertGary1]

Originally Posted by fdryer

There was a time long ago when I read up on R12 leak detection. One method was to use a halide leak detector that uses a propane torch to heat a copper plate and a vacuum hose to draw in whatever gases were sampled around a/c lines/fittings/etc..

Modern tools help with that. I bought a refrig sniffer a couple of years ago and it works great. You set the sensitivity and it beeps as you near the leak. You can keep turning down the sensitivity as you narrow into the issue.

-Robert

[jk3006]

I fixed the stripped threading well enough that I can leave it the way it is indefinitely, and it is stronger than the OEM threading into the aluminum casting. So, I'm past that stage now. Thanks for the suggestions, though.

I have the EGR blocked off, which I explained in the other thread which link I posted above. The problem is the EGR. No question in my mind about it.

The propane thing works, although it's not the safest method, as has been explained. What I like about it is I can use a long enough length of vacuum tubing attached to the canister to get to any little crevice that I need to.