Anyone got Tricks on how to remove front FC Subframe Bolts?
 

Seems like Mazda welded the nuts..maybe the washers too,to the top of the subframe,so if anyone has suggestions on how to get them pesky things out it would be appreciated.
By the way you can't cut the top off and expect the bolt and nut to drop out of the frame as the bolts are tapered.They are thicker at the top compare to near the thread so they won't fall out.
YEP..already found that out.

Thanks Gents.
STYX.

STYX, glad you asked. It was the most physical part of my engine swap.

To start out, the bolts in particular, are both welded on top as you can see, and splined
in the middle.

The only way I got mine out was to grind off the top including the welds being careful not to
take too much of the frame material. then with a long punch, drive the bolts UP and out from the bottom.
They will NOT punch through to the floor. They must come UP and out. There is a tube inside
of the frame and is is tapered somehow.
I really wish I knew this info beforehand. But, "knowing is half the battle" (G.I.Joe)
If you have any further questions feel free to ask.

Cheers,

Mach!..buddy!
I just had the "luxury" of rounding a nut on the passenger rear subframe bolt.The nut is recessed in the engine cradle frame...YAY.
YEP,I had cut the top to try to bang it from the top then went "FRAK!"..

INFO: the heads are CAPPED..they look like a bolt with washer BUT they are NOT..That "washer" is actually part of the bolt,so do not try to cut the head off to do anything...it won't help!

Cut the weld at the outside and if you like use a bigger than bolt socket to separate frame edge from bolt head edge.( I used that along with a flat chisel to see "separation" of bolt from frame).

The Shaft is TAPERED..50 thousandths at the top and 45 thousands at the threads...So you can only get the bolt out ONE WAY..and that is UPWARDS.Once you have cut the welds on the head and loosened the nut at the bottom of the vehicle,put the nut back ON a couple turns as it has a collar that will hold the deep socket with the nut.You can bang the socket/small extension with a 2 pound sledge or a BFH(you figure out what a BFH Is..)The bolt should start to move and eventually come out.

Anyways,I got the darn spacers in today and I tell ya after that damn bolt fiasco?....I'd rather get poked with a cattle prod in my gonads.


*That tube you mentioned?...also has a flat collar on the bottom that allows it to sit into the frame on the inside..so IF you break all the welds holding that tube AND the cut bolt assembly...Say HI to JC and his other buddies as you will now be tossing money into the curse Jar.

..Reminder ..go to bank..cash in 450 dollars in change..!

PICS are of the bolts and you can see what they are not an ordinary bolt.
The nut's collar is also threaded as part of the nut assembly so if you have to cut the nut you also have to cut that collar off..and GOOOOOOD LUCK doin that.

Oh, how misery loves company. I see you faired better then I. Aside from that rounded nut.
By the way which subframe kit did you go with? I made my own and the jury is still out regarding
my approval.
I was thinking these:
Xcessive Front Frame Spacers for Mazda RX7 FC3S - Enjuku Racing Parts, LLC

Ya,I used that kit.
I gotta give credit to Rich at Excessive for good communication and calling me back.I got a funky International Courier (UPS) shipping estimate by the website but he called and gave me a Mailing estimate.it Saved me 50 bucks.
Thanks RICH!

The only thing I ran into was it seemed that the dowels were tight to install on the pieces(good in a way) but the dowel nubs on the car were a bit off to install in the holes of the piece.They didn't seems to line up.
SO,I just zipped the old dowel nubs off the car flush and held the piece to the car while jacking it up and it sat the piece with the dowel into the hole in the frame and the bolt slid in.Done.

*try to do this with a Buddy..or Borrow Grandma.,.you'll need 2 extra hands to position,jack and hold bolt heads.

**..my head is sore.I got whacked with a 1/2"x36" Flat steel bar..it let go and PRANG..right in the Frakkin Noggin!...say OOOOWWWWW!
10 bucks in the swear jar!

Your a funny guy!
Here is an example of what I have in there as of now.
It's the silver collar that's 7/8" thick and I used a perfectly fitting washer inside to locate
the bolt and keep everything centered. I still wish to make a brace to tie the
chassis to the subframe for security, strength, and rigidity.
I may go back and either buy or make a better solution. But, I need the bracing to stiffen the chassis anyway,
so I'll give that a shot first.

.

honestly,I feel that if it was only ONE that got fudged and it was "adequately fixed,then I wouldn't lose sleep over it.
Myself..hmm..I may let the beast make some noise to impress myself but in reality the car most likely won't see too much severe driving..
I like the speed and everything but it won't be smoking tires in town.,.I'll be doing 'slightly above" the limit.
.ahem..cough..sorry officer,..I thought it said 100MPH!
..wut?..100KPH??..woops!
Hey!..these are my Reading Glasses..not my DRIVING Glasses..No wonder things looked fuzzy!