broken valve cover bolts (1 Viewer)

[sean2202]

Well I was in the midst of changing my leaking valve cover gasket when two of the bottom bots twisted off very easily. I have started soaking in p-b blaster. What are peoples thoughts are there any stud extractors that might work or should I try vice grips? Heat or not to heat? The last thing I want to have to do is drill these out.

 

[Julian Stead]

How tight are they? You could use two nuts on the longer stud. You could weld a nut on the shorter one if the vise grips fail to get it out.

 

[camino70]

Wow, I thought these were notorious walking themselves out. Maybe previous owner broke them and that was the cause of your leak?

 

[sean2202]

Julian, good tip on the nuts thanks. Not sure how tight they are because I had to walk away. Camino previous owner was a hack however I'm pretty sure I broke them, there is some rust on them from the northeast here. Dont know if they have ever been off. Ordered 8 new bolts.

 

[camino70]

I like the stud idea, but one looks too short.

And just for 2001LC, can you measure the valve gap? If you're near Atlanta, I'd love to help.

Valve clearance (Cold):


Intake

0.15 - 0.25 mm (0.006 - 0.010 in.)

Exhaust

0.25 - 0.35 mm (0.010 - 0.014 in.)

 

[DirtDawg]

A pair of vice grips and plenty of pb blaster should make a quick job of those. Lucky you broke them off with studs still showing.

 

[jemsec]

Give PB Blaster 2-3 days with twice daily applications. Double nuts would be the best approach rather than vice grips. Be slow and don't get in a hurry and work them back and forth with as little pressure as possible. If you get them to move use more PB Blaster for a day or two and they will come out. Clean the threads well and use anti seize when reinstalling.
I do hate steel and aluminum contact. PITA!

If that doesn't work get out the drill, tap and heli coils. You'll get it done.

 

[DirtDawg]

Not to contradict but mainly inform, vice grips will give you just as much leverage as double nuts will, I doubt he's trying to protect the threads. Plus the double nut method would only work on the longer stud. And only use drill and tap as last resort. I've never had a steel/aluminum connection that I couldn't undo with a little pb blaster/heat/torque. Also be sure to grab at the base of the stud if using vice grips.

 

[sean2202]

Thanks for all the advice after soaking in pb blaster a couple days then I added heat and sprayed it to let the soak in the threads. I got the longer one out with vice grips. Unfortunately the short one would not budge. I ended up grinding it flat and making a template so I didn't drill into the aluminum head. Ran a tap through all holes.
Camino70 valve clearance cyl 1357 cold
Intake .0060
Exhaust .010
Amazed these were actually all the same on the tight side.

 

[sean2202]

Well I have been putting off the changing of the leaking valve cover on the passenger side for some time now because of the broken valve cover bolts last time. I have been spraying the bolts with Kano Kroil a couple times this week, I even sprayed in the bottom of the hole thinking it might help. Even with taking my time and resoaking, two bolts broke off very easily on the bottom once again in the rear of the head. One broke flush with the head and the other with stud showing. I resoaked the stud and tried extracting it with vice grips but it just snapped off flush with the head. So this time I took pictures to help anyone else that runs into this problem.

First I made sure the bolt was flat with the head with a file, then i stuffed paper towel around the head so no drill fragments could get in.
Pic 2 center punch and tried to get as close to the middle as possible of broken stud
Pic 3 5/32 drill to start then used a 13/64 to finish. for a drill I used an air IR 7807R right angle drill
Pic 4 6mmx1.00 tap to rethread holes. Chased all holes on the bottom of head with tap.
Pic 5 Bolt threaded back in

Also used a magnet on bottom of head to get any metal fragments left behind before paper towels were removed.

 

[2001LC]

Nice mechanic skills @sean2202 What a PITA to have just one bad, but four on one rig WOW.

I helped ben tighten down his (rust belt rig) cover bolts yesterday. I noticed as we re torqued some bolts felt tight. Once I broke pass that tight point, they needed as much halve a turn to get 53in.lbf. We went by the book tightening in sequence starting at ~30in.lbf. Then went over twice at 53in.lbf, finding they would move more on second pass. We hope to save him a re gasket job.

 

[sean2202]

I was hoping that the leaking oil from the gasket would have loosened it up but I was wrong. I was very careful just trying to get them to budge and adding more Kroil (i used a half can spraying on these this week). Once I got the other ones on the bottom to budge I was set. These two just snapped off easily just like last time. I was glad they broke off clean with the head as it is much easier than a nub like on the drivers side. The ones on the top were just "finger tight". I think the problem is that the holes on the bottom go straight through without a plug of some sort that can be removed. This is just an area for salt to sit and corrode it away. Steel and aluminum corrosion probably as well. The gaskets seem to get brittle with age. Antiseize is a must for rust belt trucks on these bolts. I used new bolts for this job.

@2001LC I attached a picture of an "old" bolt with a "new" one to show you the difference in the rubber crush washer. The rubber crush washer on the old bolts are very brittle and I had one break in half when I was messing with it.

 

[benjawi4]

BNice mechanic skills @sean2202 What a PITA to have just one bad, but four on one rig WOW.

I helped ben tighten down his (rust belt rig) cover bolts yesterday.

Rust Belt Beauty*

 

[abuck99]

Anti-seize this time

 

[2001LC]

Worth repeating; @sean2202 really good work, I mean that.

More than one guy has mess up a head drilling these out. The brittle condition of your bolt & bolt seal, making me think that at some point maybe 180K or 260K miles the bolts should be replace as a PM. No doubt age, heat, climate will all play roll in determining when.

I may start incorporating inspecting two bolt on each of any high mileage I work on. Can I ask you a bunch of questions:
What condition was the cover gasket in?
Which two bolts & bolt seals on each side would you suggest I check as a sampling?
Do you have salt damage pitting on covers?
I forgot how many miles, what year and was yours always the Northwest?
Would you mind posting a picture of your head covers, please?

 

[sean2202]

Thanks @2001LC really appreciate that coming from you as I have learned a lot from reading your posts this past year.

I think as we talked about prior that the valves were a PM check @90k and at that time the bolts and washers were probably checked as well. Especially critical on rust belt trucks as one rust spot on a bolt will grow quickly into a seizure.

As for the washers when they are hardened they won't seal properly potentially letting salt inside as well. The 4 on the bottom of both of my heads were the worst ones so I would probably check two on the opposite side of the top for washer hardening. I believe you can just buy the washers but for the cost just replace bolts and washers.

My valve cover gaskets along with the spark plug tube seals were as hard as a rock. I only replaced one tube seal.

My truck spent most of its life on Long Island and I don't believe my truck has a lot of rust (others may think its alot) but the covers have definetly never been off.

There is no pitting on the covers but they are filthy dirty. My aluminum rims are pitted terrible though. I'll post a pic later of the valve covers for you. 155k when I did drivers side 170k now 2000LC

Here is a pic of the old washer I was messing with.

 

[sean2202]

@2001LC here is the ugly picture you are looking for. Now embarrassed I didn't clean it at least you have a good reference. Drivers side in the same ugly condition.

 

[2001LC]

Thanks.

 

[spressomon]

My turn. Thanks @sean2202 for your info! I now have a few more choice four letter words for the team of Toyota engineers that epically failed on this ... lest I digress. Why they thought having a bunch of threads hanging out on the backside of the head doing nothing but inviting corrosion to the party is beyond me.

 

[sean2202]

@spressomon sorry to hear of your troubles and good luck. Glad I could be of assistance.

If you have not already completed your work now would be a good time to check out those valve clearances as well. Would be interesting to see some more numbers on these.