thal

Hi All.

I have a stock 1984 928S and am starting to replace the leaking cam housing gaskets. While loosening the M8 bolts on the bottom of the cam housings I have one frozen bolt on each bank which I have started to turn but can tell the bolts are yielding and likely to fail if I continue trying to loosen them. I've sprayed rust blaster on them to see if that would help free them, but to no avail. Any suggestions on how to free a frozen bolt in the aluminum casting?

Thanks,

Keith
1984 928S stock

Mrmerlin

if the heads strip then you may have to drill the heads off , this will leave the rest of the bolt shank to grip on once the tower is removed

SharkSkin

Try tapping straight down on the bolts(along the axis of the bolt) with a drift that fits in the socket. I know it's tough to get in there, good luck.

checkmate1996

You may try some heat and then tightening them to help loosen.

But to be honest, a stuck bolt here is not good. To minimize damage your best bet is to yank the engine. Yes it's some extra work, but actually it makes replacing the cam gaskets a hell of a lot easier. Plus, you have maximum leverage to get at all of your hex bolts. If you do strip one now, you will have no choice to pull the engine anyway...

Best of luck...BTDT!

Fogey1

Acetone and Power Steering Fluid works better than Kroil.

Found, posted and testified to by Wally Plumley.
https://rennlist.com/forums/928-foru...ating-oil.html

SharkSkin

Will, this comes up frequently, and I frequently ask(OK, not in that thread, but usually I do) "What PSF are they referring to?" I have yet to hear an answer. I've tried Chrysler PSF but it separates from the acetone, like salad dressing. Have you heard anything more specific?

Fogey1

Nope. Good question. I re-read Wally's thread and didn't find an answer, though there was a mention of water in some brands of nail-polish remover at CVS.

I have to admit I haven't tried it, I'm just a WP acolyte. And I try to reference useful threads when they seem on point, to keep them alive.

WallyP

Actually, the recommendation is for ATF and acetone. I use Dexron, since that is one of the two that I have in stock. I also use straight acetone, not nail polish remover, since there is no way to know what is in the remover.

I seriously doubt this will help with the cam bolts, though.

SteveG

Wally, Fogey's link to your post says: "2) The original article states ATF was used in the DIY mix. It was actually PSF. I corrected the table to reflect this." I read that to recommend PSF, and later in that thread Andrew Olsen is using PSF.

BUT now you are recommending ATF (Dextron). Maybe you could edit that post.

Fogey1

"Wally, your post, to which Fogey linked,
< https://rennlist.com/forums/928-foru...ating-oil.html >
says: '2) The original article states ATF was used in the DIY mix. It was actually PSF. I corrected the table to reflect this.'..."


There you go, Steve - fixed it for you.

And for me, too. It would have been good practice for me to have included the link in my response to Dave.

Will

P.S. An exegesis of Wally's post leads me to believe that it the original author, not him, who changed "ATF" to "PSF." In the second post in that thread he says he used ATF/acetone.

Fogey1

Googling around last night I came across these two threads, in which a bunch of penetrants are mentioned. I've never heard of many of them but thought I might mention them here for entertainment and education. (Then I can find my list again, too.)


http://www.practicalmachinist.com/vb...ht=penetrating
Stuck Diesel Engine... which penetrating oil?

http://www.practicalmachinist.com/vb...ht=penetrating
What is your preferred penetrating oil?

The penetrants below are mentioned in these two threads, in no particular order:

Kroil http://www.kanolabs.com/google/
GM Heat Valve Lubricant 1#1052627
MoPar heat riser solvent
PB Blaster
Sea Foam Deep Creep "Sea Foam is amazing stuff" http://www.seafoamsales.com/deepCreep.htm
Marvel Mystery Oil
"Knock 'er Loose" by CRC http://www.crcindustries.com/ei/cont...nockloose.aspx
"Mouse Milk is my penetrating oil of choice." http://www.mousemilk.com/
Yield http://www.chemsearch.com
Gibbs http://www.usalubrications.com/gibbs.html
Wurth product called "Rost Off" http://www.wurthredlabel.com/product...=18709&cat=249
Free - "it is made by lubemaster" http://www.certifiedlabs.com/certified/splash.asp


Will

thal

thanks Will, I'll track them down!

Keith

86'928S MeteorGrey

I know this is a little late on this subject, but I just had the same issue with two cam bolts. I had let 3in1 penatrant sit on the bolts overnight. Tried knocking the bolt with a punch that fit the hex. Tried tightening slightly then loosen...the bolts ended up starting to round out.

I then applied more 3in1...then drove a 7/32" hex driver (3/8"drive) into the offending bolt. Made a nice tight fitting interface. Both bolts came out immediately.... Good trick I believe, because it worked...TWICE IN A ROW....

My next step would have been to try a heat gun on low setting around the bolt, but I never got there...