In over my head — stripped valve cover threads

sa1126

sa1126

TJ Enthusiast
Joined
Sep 4, 2019
Messages
123
Location
SA, TX
Hey guys — I think I am in over my head here.

My valve cover gasket job has been going okay until now. The second to back passenger side valve cover threads appear to be stripped. I tried hand tightening the bolts and it was not budging past a turn. It seemed to go a bit with the wrench but then slowed down so I stopped. I tried another bolt and same thing and I tried the same bolt in another hole and it worked fine so it appears the threads are stripped. There is a little play in the bolt.

Any ideas how to proceed?
 
This is a COB JOB... I've gotten away with using a metric in a similar situation. Find one just a RCH larger if possible. The different thread pitch has allowed the new bolt to grab into the stripped threads. Be slow and be careful. I have also used a screw in stud with a bit of either locktite or weld putty to hold it together. Not really proud of either, but sometimes field expediency overtakes pride.
 
  • Like
Reactions: Willys LJ, sa1126 and Flivver250
For future reference, always use a small ratchet for these jobs. 1/4 drive is adequate. Goatman is correct, you can often get another fastener with different threads or slightly larger (exactly a RCH larger) to fit in these cases. It does not require much force. Worse case, break out the taps or helicoil, but this is a surmountable case. Maybe the bolt is what stripped?
 
  • Like
Reactions: AndyG and sa1126
sa1126 said:
Hey guys — I think I am in over my head here.

My valve cover gasket job has been going okay until now. The second to back passenger side valve cover threads appear to be stripped. I tried hand tightening the bolts and it was not budging past a turn. It seemed to go a bit with the wrench but then slowed down so I stopped. I tried another bolt and same thing and I tried the same bolt in another hole and it worked fine so it appears the threads are stripped. There is a little play in the bolt.

Any ideas how to proceed?
Click to expand...

You're saying the bolt will not go in more than 1 turn...is that correct? Or is it going in all the way but just keeps spinning and won't get tight? The later is stripped, the first one is just dirty or buggered threads. I would start by attempting to clean out the hole...small pick, shot of brake cleaner, etc...If you can't get a clean bolt in there after that, get a tap and clean up the threaded hole, then you're done.

Edit: I'm not sure if the threads are M6 or 1/4-20, but in a pinch (and since it's a holiday) you can make a thread chaser out of another bolt...or even maybe the long end of that stud in the back that the wiring harness clips over...take a dremel with a thin cut-off wheel and grind a slot across the threads (inline with the length of the bolt) to make it look sort of like a tap...I usually do 2 slots. Any debris stuck in the threaded hole will end up in your slots...just be careful.
 
Last edited:
  • Like
Reactions: sa1126 and MountaineerTom
So random thoughts about this job after watching some videos on helicoil. The bolts are long, say an inch but only the the first two threads are marred. Could I theoretically drill out those threads lightly, leave existing okay threads and just use a new screw there?
 
PatMc said:
You're saying the bolt will not go in more than 1 turn...is that correct? Or is it going in all the way but just keeps spinning and won't get tight? The later is stripped, the first one is just dirty or buggered threads. I would start by attempting to clean out the hole...small pick, shot of brake cleaner, etc...If you can't get a clean bolt in there after that, get a tap and clean up the threaded hole, then you're done.
Click to expand...

Bolt won't go in. I shot it with brake cleaner but I think it might be dirty. I will try some q-tips tomorrow night.
 
It sounds like junk fell down the hole and is junking up the threads or causing the bolt to bottom out early. Before repairing the threads I'd make sure everything is clean. If the threads on the engine are messed up slightly (but not majorly) you can probably get away with chasing the threads with a tap instead of a coil.
 
  • Like
Reactions: reddvltj and MountaineerTom
sa1126 said:
So random thoughts about this job after watching some videos on helicoil. The bolts are long, say an inch but only the the first two threads are marred. Could I theoretically drill out those threads lightly, leave existing okay threads and just use a new screw there?
Click to expand...

if only the first two threads are damaged then you’re not looking at much work at all. Remove the valve cover so you can see the hole and gently run a tap down in it. I say gently because the starting threads are ruined and you could cross-thread the tap and re-cut the threads.
 
  • Like
Reactions: sa1126, AndyG, LJGreg and 3 others
↑ What he said. Chase the treads with the correct tap. I had wrongly assumed you had stripped out the entire guts. For the future, always start fasteners by hand and turn them by hand a good number of revolutions. Practice and experience will give you a good feel for fasteners. Stripping and breaking a few in difficult to reach places will teach you the wisdom of patience. Nothing tempers a hasty personality quite like an experience in an area that a right angle drill won't quite reach. People from the rust belt have 6 degree black belts in fastener wrangling.
 
  • Like
Reactions: taylormade73, HarleyMick, reddvltj and 4 others
And if you feel a bolt hang up when you’re starting it, spin it backwards by hand until you feel the start of the threads. WD40 and the correct tap will have you going in no time though 👍🏼
 
They also make a tap that isn't a tap that is made especially to clean up buggered threads. A tap is technically for creating threads. It is sharper and more aggressive.
Full disclosure: I have never personally used the non-tap tap. But my buddy swears they are a lot better for this type of job.
Just go slow and easy.
 
  • Like
Reactions: Blondie70
sa1126 said:
So random thoughts about this job after watching some videos on helicoil. The bolts are long, say an inch but only the the first two threads are marred. Could I theoretically drill out those threads lightly, leave existing okay threads and just use a new screw there?
Click to expand...

You could, but it is very likely the drill will raise a burr on the first good thread at the bottom of your new counterbore and leave you with the same situation. Get a tap, get a thread chaser, or make a thread chaser out of a good grade 8 bolt and simply repair the damaged threads.
 
Goatman said:
They also make a tap that isn't a tap that is made especially to clean up buggered threads. A tap is technically for creating threads. It is sharper and more aggressive.
Full disclosure: I have never personally used the non-tap tap. But my buddy swears they are a lot better for this type of job.
Just go slow and easy.
Click to expand...

Those are thread restorers. They are pricey but a lifesaver if you live in rust prone areas. A tap still works but you do have to be careful you do not create a second set of threads when using them as a chase.
 
Thanks all for the tips. I'm attaching pics to make sure a tap is still the way to go. Does anyone have a link to said tap?

Good:
IMG_20191128_211833.jpg


Bad (excuse mess from cotton swab):
IMG_20191128_211842.jpg


IMG_20191128_211833.jpg
 
Also does anyone know the exact specs for the bolt? I'm no machinist but I know length, width and thread sizing are important. I would like to try to chase the threads first if possible.
 
Just pulled a bolt out of my '97 and it's 1/4-20 threads. Any hardware store/home depot/lowes has this tap in stock for less than $5.

Those threads were not damaged taking the old bolt out, but by starting to put the new bolt back in on a bit of an angle. This should be a flanged head bolt, but if yours doesn't have a flange on it...find some shit to pack into your socket so that only the head is able to go into the hex...this lets you apply down pressure to the bolt while starting it. If you can get a longer bolt and a couple nuts...to effectively make a longer hex head...try that. A good bolt will go right into that hole if you can apply some down pressure and keep it straight.

If it's a flanged head bolt, it won't sink into a socket so you should be able to apply down pressure but make sure you keep it straight while turning it...it will go in.

If you use the "add nuts" method, you can either leave that bolt in once it gets a purchase on some good threads and use a 7/16 open end to snug the valve cover down using the lowermost nut, or pull that bolt out once it's restored the threads enough and install a new bolt (with washer) of the appropriate length
 
  • Like
Reactions: Jerry Bransford and ranger101
sa1126 said:
Bad (excuse mess from cotton swab):
View attachment 127057
Click to expand...

Yah, in that 2nd pic the issue is visible, between 3rd and 4th thread.
Only thing i cant tell is if im looking at two threads where one is stripped and next is pushed in, or is it just a 3rd thread slightly deformed.
The more i stare at it, the more it looks like 3rd thread is slightly deformed, but not stripped.

From my experience, take a matching tap and slowly go in there, twist in - twist out - twist in until it can freely go all the way.
Luckily its in the middle, so first two threads should provide some tap support while working it in, and it should still handle torque spec once you done.
 
Last edited:
Top Bottom
Back