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 Can't remove flexplate bolts
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CRM318
Tribal Scout

USA
30 Posts

Posted - 13 May 2014 :  12:17:13 AM  Show Profile  Reply with Quote
I removed the original YS 400 from my 1970 GTO and before I put it on the engine stand, I tried to remove the flexplate bolts. I couldn't remove them, not even with an impact wrench. I coated them in penetrating oil for the night. What should I do before I round the bolts off?

1970 Pontiac GTO, Atoll Blue, 400, TH400, 3.73 Safe T Track

Blued and Painted
Chief PONTIAC

USA
3404 Posts

Posted - 13 May 2014 :  01:01:30 AM  Show Profile  Reply with Quote
They only torque to 90lbs or so. Use the correct good fitting 1/2 in drive socket, and use a bigger impact. Check the air supply.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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bigD
Indian Spirit

USA
643 Posts

Posted - 13 May 2014 :  04:29:28 AM  Show Profile  Reply with Quote
Sometimes, guys overtighten. Like wheel lugs for example. Most tire shop guys just tighten the lugs with the impact and never torque anything. This usually gets the lug nuts so tight that your emergency lug wrench won't budge 'em when you have a flat out on the road. Anybody besides me ever been there ?

For many years now, I've always asked the wheel installer to just run the nuts up snug and let me finish 'em off with my short handle lug wrench. That way I know they are plenty tight, but that I'll be able to take them off with that same lug wrench, should the need ever arise.

Meanwhile, back to the flexplate bolts. I have had some that absolutely would not come loose, neither with impacts nor with long breaker bars and cheater pipes over those bars to make 'em longer. That's when I'd just break out my little 4" side grinder and grind the head off the bolt. if you are REAL careful, you can usually save the flexplate.

It ain't no fun, but it works.
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Bill Boyle
Horse Feathers (Charter Member)

USA
4793 Posts

Posted - 13 May 2014 :  05:54:53 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
quote:
Most tire shop guys just tighten the lugs with the impact and never torque anything. This usually gets the lug nuts so tight that your emergency lug wrench won't budge 'em when you have a flat out on the road. Anybody besides me ever been there ?


Oh yeah..it drives me nuts too. I've had those "wanna be" NASCAR pit men cross thread my lugs causing the studs to break off on my truck. It's happened twice during the past 28 years.
When I've driven across country pulling my trailered car, I'd take a breaker bar and socket to get more leverage. Even then it was a bear to loosen them after getting a flat while going through a construction area on the interstate.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.
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CRM318
Tribal Scout

USA
30 Posts

Posted - 13 May 2014 :  07:48:33 AM  Show Profile  Reply with Quote
I'm not to worried about the flexplate as I am about saving the crank. The flexplate has starter wear and needs to be replaced anyhow.

1970 Pontiac GTO, Atoll Blue, 400, TH400, 3.73 Safe T Track
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bigD
Indian Spirit

USA
643 Posts

Posted - 13 May 2014 :  07:53:18 AM  Show Profile  Reply with Quote
quote:
Originally posted by CRM318

I'm not to worried about the flexplate as I am about saving the crank. The flexplate has starter wear and needs to be replaced anyhow.




In that case, break out the big side grinder, put on some safety goggles or glasses and make sparks fly ! But don't set your shop on fire !

Edited by - bigD on 13 May 2014 07:56:51 AM
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CRM318
Tribal Scout

USA
30 Posts

Posted - 13 May 2014 :  09:04:53 AM  Show Profile  Reply with Quote
So you're thinking I'm going to have to tap and drill the bolts out?

1970 Pontiac GTO, Atoll Blue, 400, TH400, 3.73 Safe T Track
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Phil
The Great White Buffalo

USA
7214 Posts

Posted - 13 May 2014 :  10:12:07 AM  Show Profile  Reply with Quote
First, make sure you're using a 6 sided socket on a 6 sided bolt. Then, take a look at that socket and make sure its not the usual "recessed" flats I see on many socket makes. If so, put the socket on a band sander or bench grinder and dress the end so that the flats go ALL the way to the edge. Install squarely on bolt and make sure its a tight fit before trying to break loose. You could also heat the bolts (just a little) as a last resort before taking drastic measures as mentioned in earlier posts.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.

Edited by - Phil on 13 May 2014 10:17:52 AM
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bigD
Indian Spirit

USA
643 Posts

Posted - 13 May 2014 :  10:32:42 AM  Show Profile  Reply with Quote
No, unless they are really rusted, you can probably just let a little penetrating oil soak in for a while, then grab the bolt stub with vise grips and screw it out. If there is not enuff to grab with the grips, you can probably cut a slot in the bolt with a hack saw or dremmel tool, and screw the bolt out with a BIG screwdriver. I've always had one with a square shaft. So you could apply downward pressure on the top of the handle, to keep it in the slot and turn it with vise grips or a large crescent (adjustable end) wrench.

http://www.walmart.com/ip/Dremel-100-N-6-120V-Single-Speed-Rotary-Tool-with-Bonus-Attachment-and-11-Accessories-30-Bonus-Retail-Value/15173789?action=product_interest&action_type=title&placement_id=irs_top&strategy=PWVUB&visitor_id=62687509723&category=0%3A1072864%3A1031899%3A1066925%3A1067607%3A1067722&client_guid=4fef63c7-ed9c-4a95-a09a-69b3a2b2f890&config_id=2&parent_item_id=15173789&guid=b4a71070-0e01-4f27-8c24-de94cb55cb84&bucket_id=irsbucket013&findingMethod=p13n

http://www.zoro.com/g/00054179/k-G0634401?utm_source=google_shopping&utm_medium=cpc&utm_campaign=Google_Shopping_Feed&kpid=G0634401&gclid=CPDRzJeVqb4CFaQF7Aod5g4AcA

Usually, for me, the reason I couldn't get 'em out, was because they were too tight against the flexplate. So, once the bolt head was gone, the threaded part of the bolt was not that tight in the crank. Now if the threads are solid rust, it may be difficult. If this is the case, some machine shops can get 'em out. But their services may be more than a stock 400 crank is worth. Since there have been so many 400 stroker builds around the country, there should be LOTS of cheap 400 cranks out there.

Always use 12 point flex plate bolts, and don't over torque !

http://www.jegs.com/i/ARP/070/200-2904/10002/-1?CAWELAID=1710527874&CAGPSPN=pla&catargetid=1784156372&cadevice=c&gclid=COTXrpGRqb4CFQET7AodAjMA6w

Edited by - bigD on 13 May 2014 11:01:44 AM
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Jack_77GP
Tribal Scout

USA
28 Posts

Posted - 13 May 2014 :  2:22:12 PM  Show Profile  Reply with Quote
One of the cranks that came with the blocks I recently picked up had a partially rounded off bolt still holding the flexplate on. In that case I was able to pound the next size smaller 6-point metric socket on and break it free with some penetrating oil and a long breaker bar.

Sometimes it works to put a socket over the bolt head and give it a smart smack with a hammer to help loosen any rust or corrosion on the threads, just dont beat too hard on your crank. If a quick rap doesn't help, beating the crap out of it probably won't either. Basically its the same principle as how an impact works.

77 Grand Prix LJ, 400, T-tops.
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Merrik66
Cochise

USA
370 Posts

Posted - 13 May 2014 :  8:32:41 PM  Show Profile  Reply with Quote
X2 on Phil's remark on heating it up. A mapp gas torch or even the less hot propane may work. Try about 30 seconds if your using propane and 1/2 that if it's mapp. You could go a few rounds with that approach. X2 on the air pressure for your ratchet. I went through this one time on a 65 389. All info suggested is good.
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bnorris_74
Crazy Horse

USA
1442 Posts

Posted - 06 Jul 2014 :  07:11:17 AM  Show Profile  Reply with Quote
TTT
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