Rear sub-frame. Help!
Discussion
When the bolts break off this is what you do:
Weld a 3/8" nut onto the stub of the broken boly. They normally break with at least 0.5" of bolt stub sticking out. Heat up around the bolt/sub-frame area with a butane lamp, making sure it gets really hot. Then undo the nut. This works about 90% of the time. Three of those on my 1990 car snapped of a couple of weeks ago and they all came out like this. It's worth running a 5/16" unf tap down the threads to remove any residual corrosion, then pumping the void behind the nuts full of Waxoyl. Put the new bolts in with lots of copper grease.
If that doesnt work, you grind off the bolt stub flush, drill out the old bolt, then drill oversize and tap 3/8" unf, opening out the sub-frame bracket hole to take a 3/8" bolt.
If all that doesnt work, you cut away the sill locally to get access to the inside and cut out/weld in a new nut. Then weld a closing piece of sheet metal to re-make the sill, gring flush and spray or paint.
You certainly don't scrap the shell!
Peter
Weld a 3/8" nut onto the stub of the broken boly. They normally break with at least 0.5" of bolt stub sticking out. Heat up around the bolt/sub-frame area with a butane lamp, making sure it gets really hot. Then undo the nut. This works about 90% of the time. Three of those on my 1990 car snapped of a couple of weeks ago and they all came out like this. It's worth running a 5/16" unf tap down the threads to remove any residual corrosion, then pumping the void behind the nuts full of Waxoyl. Put the new bolts in with lots of copper grease.
If that doesnt work, you grind off the bolt stub flush, drill out the old bolt, then drill oversize and tap 3/8" unf, opening out the sub-frame bracket hole to take a 3/8" bolt.
If all that doesnt work, you cut away the sill locally to get access to the inside and cut out/weld in a new nut. Then weld a closing piece of sheet metal to re-make the sill, gring flush and spray or paint.
You certainly don't scrap the shell!
Peter
Sorry if it is against the rules but i have a good second hand rear subby for sale in the southampton area. Mail me if you are intrested.
I changed the rear subby on mine and they aren't bad if they have been changed regularly. The best thing to do is tighten the nuts up before undoing them and do 1 turn on 1/2 a turn off and that should free them.
The worst thing with a subframe change is the other stuff that you find that needs replacing. Budget for:
-A rear subby (oviously)
-New bolts
-New bushes
-Knuckle joints (x2)
-Suspension cones (x2)
-Handbrake cable (not essential but for the price you might aswell change it while it is off)
-Rubber brake hoses(you would be stupid not to replace them)
The brakes will need bleeding aswell so have some good quality brake fluid ready.
Ian
I changed the rear subby on mine and they aren't bad if they have been changed regularly. The best thing to do is tighten the nuts up before undoing them and do 1 turn on 1/2 a turn off and that should free them.
The worst thing with a subframe change is the other stuff that you find that needs replacing. Budget for:
-A rear subby (oviously)
-New bolts
-New bushes
-Knuckle joints (x2)
-Suspension cones (x2)
-Handbrake cable (not essential but for the price you might aswell change it while it is off)
-Rubber brake hoses(you would be stupid not to replace them)
The brakes will need bleeding aswell so have some good quality brake fluid ready.
Ian
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