904 mike

Can anyone tell me the proper sized hex or XZN wrench to use in removing the camshaft bearing cap bolts on a 1987 S4 engine. Common sense approach is failing on what appear to be 12 point M6 bolts. Thanks in advance for any help!

Jim bailey - 928 International

Mike you have the right tool those bolts often strip . Probably 20 % of those WILL STRIP . If so be very careful how you get them out , the cam caps are matched and numbered and are not supposed to be changed . They are 8 mm bolts 35 mm long part # 999 218 023 02

Tony

Use it in conjunction with an impact air wrench on a failry light setting, it wont take much.. I had ALL of mine out in a matter of minutes, not a mark on the bolts. Bzzzzzzzzzzzzzzzzzshhaaa......next.
My air compressor is the best addition i have made to my garage.

Jim bailey - 928 International

Tony is as usual correct the quick sharp hit of the impact gun is far less likely to strip bolts . That is also one reason why I think so many water pump bolts seem to break for the home mechanic , but just a theory ....

Vilhuer

If or I should say when you strip them, 8mm or 1/2" drill bit works best. Just drill it into center of bolt head and head part will come out leaving tap still in threads but allowing cam caps to lift out. Done with care there will not be single mark in cam caps. Drilling will also heat up remaining part and it'll come out easier. Don't ask how I know. Heating bolts slightly before even trying to open might help to loosen them also.

Erkka

1992 928 GTS 5-speed only 4 bolts needed drilling
Oak Green Metallic 22L
Classic Gray MX

UKKid35

If you're working with the engine in then the bolt head you're most likely to strip is the one closest to the inner wing because you can't get a 1/2" drive on to it. It would also be very difficult indeed to drill out for the same reason. Somehow I managed to avoid this potential nightmare.

Rob Edwards

+1 on hitting these bolts with an impact gun. I had cleaned out the heads of the bolts, tapped the socket into the threads (a fancy schmancy Hazet 990-8 XZN socket, no less...) kroiled the bolts, and still managed to strip 2 when trying to remove by hand with a 1/2" ratchet. I tried my spiral flute extractors, then a cold chisel to try to turn the bolts, no love. What worked finally was to drill out the head with a 1/4" cobalt bit, then cut a big 'X' into the remaining bolt head with a dremel cutoff wheel, then chip out pieces of the head with a chisel until you could see the head move a bit. Then they could be turned out by finger pressure.

After these 2 were out, I removed the remaining 40+ bolts by loosening one at a time with the rattle gun and then snugging them back finger tight. Then I started the process of backing each one out 1/4 turn at a time until the cams were released from any spring pressure from the lifters.


They're only to be torqued to 15 ft lbs? They must have heat cycled a lot in 20 years or done the galvanic corrosion thing, 'cause no freakin' way were they only 15 ft lbs tight:

RyanPerrella

Rob

Use the Irwin brand tools bolt extractor. It is the type unlike your snap-on's which bit onto the exterior of the head, (not the interior hex portion)

This tool set costs less than $20 at Home Depot and does in fact fit the bolt and the cam cap. (In that the tool doesnt interfere with the cam cap at all.

Worked perfect for me, honestly it was all too easy. When i stripped it i was bummed! But this pulled the thing out no problem


Below is an example of what i am talking about (because we know pictures are so much more better-er)

Rob Edwards

Ryan-

Good info- I have the Craftsman external extractors and they're too thick to fit on these bolts. Oh well, should have posted this before I spent an hour banging on these 2 bolts....

RyanPerrella

ha ha, i think i posted this info in another thread 2 years ago when i did it LOL

guess you just got the wrong thread in your search.

Glen McCartney

So, would the opinion be to use an impact wrench on light setting for removal of some of the stubborn/breakage prone bolts, like the water pump, 85/86 cam cover bolts, cam cap bolts rather than hand tools? Getting ready to do TB/WP replacement and cam cover removal on my MY85.

GregBBRD

Buy a Hazet tool to fit these. The Hazet tools are harder and don't round out the 12 point....I've never replaced my Hazet bit and I've used it literally hundreds of times. Not the case with my Snap-on bits. Give the entire top of these bolts a solid hit, or two, with a brass drift to "loosen" the grip that the washer and the head has on the aluminum cap. They come out really easy, if you do this. The threads are never the part that sticks on these bolts. If you drill the heads off, you can always unthread the remaining piece, with your fingers. The washer friction is the culprit.

On the water pump, the actual threads are the part that freezes. We do not use an impact on water pump bolts...this will break off anything that is semi-frozen. Turn the water pump bolts slowly, to salvage as many as possible. Always replace the water pump bolts, use a factory gasket, and factory anti-sieze and you will not have a problem getting them out, next time.

Glen McCartney

Thanks Greg!

fraggle

Wow mine came out nice with no problems. I just gave each one a wack with the bit, then moved them maybe a quarter or half turn at a time until they were loose and out.

Is everyone using some sort of 9226 tool to hold the cams in place against the valve springs while they take out the caps?

brianrheffron

On the topic of dealing with difficult to shift fasteners this link has some interesting and useful hints.
http://www.pumaracing.co.uk/ToolUse.htm