GRAND PRIX 231 v6 to 305 v8 mounts

justacruzr2

Greasemonkey
Jun 16, 2017
106
43
Midlothian, Illinois
Couldn't find any info here on the metal part of the mount that's attached to the engine crossmember. So I'm asking if anyone has an easy way to remove the 231 metal mounts from the crossmember? Have heard from a few people that the only way is to remove the lower control arms so you can get access to the bolts/nuts that hold it on. Is this true? Or is there a special tool?
 

stew86MCSS396

Apprentice
Aug 1, 2022
81
18
(808)
Circa 1991 is when I've done this. Seem to recall using a longer than usual boxed end wrench through the hole on the front of the frame to hold the bottom and wrenched it loose from the top. Pita with the fuel line coming out of one side. Putting the mounts back on had no choice to go through the bottom with a extension and universal. I was putting in frame pads for a Buick 455 that the bolts thread in from the bottom. Should be able to do the same removing.
 

buick7332

Master Mechanic
Oct 21, 2014
311
93
N.E. Philadelphia area
Couldn't find any info here on the metal part of the mount that's attached to the engine crossmember. So I'm asking if anyone has an easy way to remove the 231 metal mounts from the crossmember? Have heard from a few people that the only way is to remove the lower control arms so you can get access to the bolts/nuts that hold it on. Is this true? Or is there a special tool?
On my Grand Prix I cut the bolt heads off with a grinder. I pulled the lower control arms because I was also going with new springs. However someone told me that they had success installing the nuts with a piece of wire and duct tape. Good luck.
 

justacruzr2

Greasemonkey
Thread starter
Jun 16, 2017
106
43
Midlothian, Illinois
A friend who has done this a few times at his job said he used a long handle box end wrench with a piece of tape under the box end to hold the nut during removal and replacement. Any way you do it it's not one of the easier jobs to do. Prefer not to cut the nuts/bolts since this is a 2 way swap. 305 coming out of the one car and going into the other and the 231 coming out of that one and going into the previously 305 car. Thanks for the info.
 

CopperNick

Royal Smart Person
Supporting Member
Feb 20, 2018
2,238
113
Canada
Cut them. Why?? From the factory they came as metric fasteners. The closest fractional analogue is a 7/16ths capscrew and you have to resize the matching frame holes ever so slightly. A rotary file on a drill motor or even just a 7/16ths drill bit does the trick. Even try just fitting a bolt into the hole by itself first. It might surprise you and drop in.

Totally agree that cutting them is a PITA and that you have to be careful not to ding the mount. Thing here is that, from the factory, the bolts came in from below because the factory installed the frame portion of the mounts before they plugged in the lower control arms. Replicating this method to re-install the bolts is possible, been there, done that, but it is a monumental wrestling match and the meanest, most miserable part of it is to keep the bolt installed in the box end of the wrench. The tape trick will work, and I think that I used liquid pipe thread sealer at one point as well. You can even use locktite to temporarily attach the bolt to the wrench and if possible use a 6 point combination wrench instead of a 12 pt. Makes it easier to secure the bolt.




Nick
 
  • Like
Reactions: 1 user

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot Mike's Montes UMI Performance

Contact Admin@GBodyForum.com for info on becoming a sponsor