Broke thermostat housing bolts - ZR-1 Net Registry Forums

IowaZR-1 · 05-06-2009

Yep!

I done did it!! Was looking everything over getting ready for the trip to BG next week and spotted a little leak coming from around the thermostat...started draining it and I twisted off 2 of the 3 bolts. I haven't touched the 3rd one yet as I'm leaving it in(one of the mounting bracket bolts) so I can drill out and retap the broken ones first (surprisingly there is a clear shot to drill them) and with any luck #3 will come out. My question is.....what is the size of bolt....all I have to go by is the twisted off heads. I need to know diameter and pitch of the threads. Anyone ever don't this before, any helpful tips? Thanks!

05-06-2009

M8 x 1.25 x 35mm

A26B · 05-06-2009

Center punch the bolt first & start drilling with a smaller bit first. It will stay centered better & drill easier...... 1/8 ~3/16 bit. Keep lubed with WD40 or similar stuff. Work up in bit size until you can get good engagement on the EZ out. If you dont get enough, can break the extractor off.

rkreigh · 05-07-2009

I was thinking about the thermostat housing problem and looking the part over. seems like a little cnc billet part would be worthwhile here.

carter, you out there buddy???

secondchance · 05-07-2009

Quote:

Originally Posted by rkreigh

I was thinking about the thermostat housing problem and looking the part over. seems like a little cnc billet part would be worthwhile here.

carter, you out there buddy???

If anyone has a pic could you post? I can look into what it would cost to have it CNCed if I see interest.

Old buddy of mine has a CNC machine and I can AutoCad it.

05-06-2009	#1
IowaZR-1 Join Date: Feb 2006 Location: Iowa aka "one big cornfield" Posts: 341	Broke thermostat housing bolts Yep! I done did it!! Was looking everything over getting ready for the trip to BG next week and spotted a little leak coming from around the thermostat...started draining it and I twisted off 2 of the 3 bolts. I haven't touched the 3rd one yet as I'm leaving it in(one of the mounting bracket bolts) so I can drill out and retap the broken ones first (surprisingly there is a clear shot to drill them) and with any luck #3 will come out. My question is.....what is the size of bolt....all I have to go by is the twisted off heads. I need to know diameter and pitch of the threads. Anyone ever don't this before, any helpful tips? Thanks!

05-06-2009	#2
Jeffvette Guest Posts: n/a	Re: Broke thermostat housing bolts M8 x 1.25 x 35mm

05-07-2009	#4
rkreigh Join Date: Jan 2004 Location: Alex VA Posts: 1,087	Re: Broke thermostat housing bolts I was thinking about the thermostat housing problem and looking the part over. seems like a little cnc billet part would be worthwhile here. carter, you out there buddy??? __________________ 95 390 LPE ZR1 (505 rwhp) LSV = Lingenfelter Super Vette Twin Turbo 2003 Z06 (800 RWHP)

05-06-2009	#3
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,394	Re: Broke thermostat housing bolts Center punch the bolt first & start drilling with a smaller bit first. It will stay centered better & drill easier...... 1/8 ~3/16 bit. Keep lubed with WD40 or similar stuff. Work up in bit size until you can get good engagement on the EZ out. If you dont get enough, can break the extractor off. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.