Bolt removal
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
That'll be tough to remove with an easy out, but give it a shot. Also known as "screw extractors".
If you damage the aluminum you can helicoil it.
If you damage the aluminum you can helicoil it.
Burning Brakes
Joined: Jul 2003
Posts: 873
Likes: 2
From: Whittier ca
First question is - did it break flush, inside or a little outside the TB.
Assuming the TB is back on a bench, if the bolt is flush or slightly inside the hole on the TB, you will need to center punch ACCURATELY the screw. If the bolt is extended outside the TB, I would very carefully file it flat without scaring the TB, then center punch. Use screw extractor #1 (use 5/64" drill bit) or #2 (use 7/64" drill bit), drill very carefully the center of the screw and only to the depth you need to insert the extractor. Tap the extractor gently into the drilled hole and unscrew.
I would also get a tap and chase the hole in the TB. I just pulled one the screws from my 91 and checked the size and threads. 4.5MX0.75, however, I did not find a tap that size in my arsenal of metric taps or dies.
If you are careful, don't angle the drill when drilling for the extractor, you should come out unscathed.
Good Luck
Subman
Assuming the TB is back on a bench, if the bolt is flush or slightly inside the hole on the TB, you will need to center punch ACCURATELY the screw. If the bolt is extended outside the TB, I would very carefully file it flat without scaring the TB, then center punch. Use screw extractor #1 (use 5/64" drill bit) or #2 (use 7/64" drill bit), drill very carefully the center of the screw and only to the depth you need to insert the extractor. Tap the extractor gently into the drilled hole and unscrew.
I would also get a tap and chase the hole in the TB. I just pulled one the screws from my 91 and checked the size and threads. 4.5MX0.75, however, I did not find a tap that size in my arsenal of metric taps or dies.
If you are careful, don't angle the drill when drilling for the extractor, you should come out unscathed.
Good Luck
Subman
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
A couple of friends I know solved this by drilling out the old, tapping it for a screw. Then the bought one that was too long and cut the head off, making them studs. They now loosen the nuts on the end to adjust tps.
Team Owner
Joined: Jan 2003
Posts: 20,322
Likes: 248
From: Summerland B.C. Canada
There is good advice here. 
I broke one, extracted it, then retapped to 5mm as i couldn't find that damn 4.5 mm screw. I mailed off my good 4.5 screw to someone who could use it. My memory said the screw was aluminum, which seems retarded 
No wonder they break. 
I broke one, extracted it, then retapped to 5mm as i couldn't find that damn 4.5 mm screw. I mailed off my good 4.5 screw to someone who could use it. My memory said the screw was aluminum, which seems retarded No wonder they break.
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Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
Originally Posted by Pete K
A couple of friends I know solved this by drilling out the old, tapping it for a screw. Then the bought one that was too long and cut the head off, making them studs. They now loosen the nuts on the end to adjust tps.
Thread Starter
Drifting
Joined: Dec 2005
Posts: 1,309
Likes: 20
From: Woodstock Georgia
I have had so many of these @$&*ing screws break. Almost all of the IAC housing bolts broke; bought a new housing and new bolts (it was cheaper than having a machine shop get them out for me). Then I had one of the new bolts strip the TB base under the IAC housing. Now, the TPS bolt issue. Forget it! I just ordered a new BBK 52mm from Summit! Anyone need a ported 52mm TB? A few half bolts included!!!
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
I was able to find replacement bolts of the same size for the TPS and for the IAC housing at my local hardware store. although the heads where not torx. I prefer a regular phillips head on the TPS screws anyway. Cost just a few bucks for all of them.
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
aircraft guys have LEFT hand drill bits especially for this problem (my brother has taken care of several of these for me--gotta catch him early in the morning while he's still in a patient mood and bring big gulp coffee and big fresh donutS).. the screw usually backs out on the drill bit as he approaches biggest bit size before hitting the threads.
j-y supply for tps screws (i think thry're s.s.) in all kinds of gm cars
j-y supply for tps screws (i think thry're s.s.) in all kinds of gm cars