Subaru Forester Owners Forum banner
1 - 20 of 32 Posts

·
Registered
06 Forester XT 2.5
Joined
·
82 Posts
Discussion Starter · #1 · (Edited)
Well, I followed all the directions I found on here (and scoobymods) about installing subframe bolts on the car. I let PB blaster sit in the threads for hours, cleaned them well, then chased the threads with a tap. When I went to run the bolt through the first time (without the black spacers, according to scoobymods), it got about halfway up, i heard a 'SNAP', and I believe the nut inside the frame must have broken from its welds. Now i have a subframe bolt stuck in there, no spacer, that moves around (luckily I havent herd any 'clanking' noise in the cabin yet). So for anyone who has a high mileage car like mine (90K), and lives in a area with harsh winters (like we get in NE) that get alot of salt and grit up there - be very careful, it doesnt take much to snap that nut up there, I would say I had about 50-60 ft lbs of torque on the wrench when i did it.

Now some questions?:

1.) Is this fixable w/o having to cut through the body?

2.) Lets say I can get the other subframe bolt in without snapping the nut inside, would it even be worth it to run with one fully installed?

3.) Are there any other options that I have now to keep the rear from moving like that? I got the subframe bolts in the first place because the car is really 'floaty' in the back.
 

·
Registered
06 Forester XT 2.5
Joined
·
82 Posts
Discussion Starter · #3 ·
Replace the subframe with an STI subframe?

Do the STI subframes eliminate the need for the subframe bolts?

How involved is removing the rear subframe?
 

·
Registered
Joined
·
4,128 Posts
the sti subframe is a different design. I won't say it eliminates the need for subframe bolts, but it makes them less necessary.

the subframe is not that difficult to remove; getting the lateral links off of the knuckles probably won't be fun. I'd try to drop the entire setup (sans struts) onto a jack with a piece of plywood strewn across it.

and, my feeling on the high number of Forester owners snapping these is this: it's not a thread cleanliness issue...its an issue with the differences in the forester/sti chassis, and the subframes. Just a hunch from having both models apart.

I could post pics of the subframe differences if anybody is curious.
 

·
Administrator
2007 Forester Sports XT 4EAT
Joined
·
41,757 Posts
Curious... you cleaned the threads with PB Blaster & chased the threads with a tap. IMO you should have been able to thread the bolt in with little or no force after that prep! Did the bolt go in easily or did it require some heavy wrenching?

Bobby...

['07 FSXT Member Journal] ['03 X Member Journal]
 

·
Registered
none none
Joined
·
8,844 Posts
The biggest difference is that the forester subframe mounts to the body using soft rubber bushings, while the STI part is basically all metal, much more solid mounting. If you look at the bolts on either side of where the lockdown bolts go, you'll see why the lockdown bolts make such a difference on the forester, its basically stopping movement of the subframe on those rubber bushings, the important suspension links bolt right to the subframe, so while the lateral links might have stiff bushings, the entire subframe isn't particularly well connected to the unibody. The entire subframe is also much beefier ie less flex.

I'd say it would probably be easier to unbolt the LL from the subframe than the knuckles?

Also the bolts welded into the frame rails are a bit prone to rusting as salty water/mud can get in there and just sit on them. I've even had issues where the swaybar brackets mount to the frame. I'm curious what sort of torque the nuts welded to the frame that the lockdown kits utilize are designed to withstand (or why they're there in the first place, although its nice to have a quick bolt on solution for the lockdown kits)
 

·
Registered
06 Forester XT 2.5
Joined
·
82 Posts
Discussion Starter · #7 ·
Curious... you cleaned the threads with PB Blaster & chased the threads with a tap. IMO you should have been able to thread the bolt in with little or no force after that prep! Did the bolt go in easily or did it require some heavy wrenching? :confused:

Bobby...

My MODding Journal

Yes, I PB'd them, then chased them as far as i could. My tap was only about 2" long, so thats about all i could do with the tap. I got the bolt started, and it was easy going until I hit the grimey threads. I went back and forth many times with the bolt until I got to the end. When I was taking it out to put the black spacers back on is when I snapped the bolt in the frame. And it wasnt really 'heavy wrenching', i'd say 50-60 ft lbs.

I just think the bolt up in the frame was rusty to begin with, and the welds holding it on were crap.
 

·
Registered
06 Forester XT 2.5
Joined
·
82 Posts
Discussion Starter · #8 ·
The biggest difference is that the forester subframe mounts to the body using soft rubber bushings, while the STI part is basically all metal, much more solid mounting. If you look at the bolts on either side of where the lockdown bolts go, you'll see why the lockdown bolts make such a difference on the forester, its basically stopping movement of the subframe on those rubber bushings, the important suspension links bolt right to the subframe, so while the lateral links might have stiff bushings, the entire subframe isn't particularly well connected to the unibody. The entire subframe is also much beefier ie less flex.
Do you know if anyone makes any solid bushings? Its probably far fetched, but it might be better than replacing the entire subframe since all we need to is 'firm it up'.



Also the bolts welded into the frame rails are a bit prone to rusting as salty water/mud can get in there and just sit on them. I've even had issues where the swaybar brackets mount to the frame. I'm curious what sort of torque the nuts welded to the frame that the lockdown kits utilize are designed to withstand (or why they're there in the first place, although its nice to have a quick bolt on solution for the lockdown kits)
My thoughts exactly. So much crap gets in there, and especially my car with 90k, yearly driven in these harsh, salty, New England winters it was going to take more than PB blaster to remove that stuff. But I'm with you, why are these bolts there in the first place?


I guess I need to buy an STi Rear Subframe now, anyone seen one for sale lately? :)
 

·
Registered
06 Forester XT 2.5
Joined
·
82 Posts
Discussion Starter · #9 ·
The biggest difference is that the forester subframe mounts to the body using soft rubber bushings, while the STI part is basically all metal, much more solid mounting. If you look at the bolts on either side of where the lockdown bolts go, you'll see why the lockdown bolts make such a difference on the forester, its basically stopping movement of the subframe on those rubber bushings, the important suspension links bolt right to the subframe, so while the lateral links might have stiff bushings, the entire subframe isn't particularly well connected to the unibody. The entire subframe is also much beefier ie less flex.

I'd say it would probably be easier to unbolt the LL from the subframe than the knuckles?

Also the bolts welded into the frame rails are a bit prone to rusting as salty water/mud can get in there and just sit on them. I've even had issues where the swaybar brackets mount to the frame. I'm curious what sort of torque the nuts welded to the frame that the lockdown kits utilize are designed to withstand (or why they're there in the first place, although its nice to have a quick bolt on solution for the lockdown kits)
the sti subframe is a different design. I won't say it eliminates the need for subframe bolts, but it makes them less necessary.

the subframe is not that difficult to remove; getting the lateral links off of the knuckles probably won't be fun. I'd try to drop the entire setup (sans struts) onto a jack with a piece of plywood strewn across it.

and, my feeling on the high number of Forester owners snapping these is this: it's not a thread cleanliness issue...its an issue with the differences in the forester/sti chassis, and the subframes. Just a hunch from having both models apart.

I could post pics of the subframe differences if anybody is curious.
Thanks, so it doesn't sound that bad pulling it down. Something that could probably be done in your garage?


If you could post pics of the difference that would be great. It might help someone in the future.
 

·
Registered
Joined
·
4,128 Posts
why are these bolts there in the first place?
This is what the factory used to align the subframe up before bolting it down; that should give a good indication on why the locking bolts make such a nice difference.

I guess I need to buy an STi Rear Subframe now, anyone seen one for sale lately? :)
pretty sure I have one. PM me if you are interested. Shipping shouldnt be *terrible*
 

·
Administrator
2007 Forester Sports XT 4EAT
Joined
·
41,757 Posts
Yes, I PB'd them, then chased them as far as i could. My tap was only about 2" long, so thats about all i could do with the tap. I got the bolt started, and it was easy going until I hit the grimey threads. I went back and forth many times with the bolt until I got to the end. When I was taking it out to put the black spacers back on is when I snapped the bolt in the frame. And it wasnt really 'heavy wrenching', i'd say 50-60 ft lbs.

I just think the bolt up in the frame was rusty to begin with, and the welds holding it on were crap.
Did you use a bottoming tap, plug tap or a taper tap? I have a set of bolts in my future project box, but haven't purchased a tap yet.

Bobby...

['07 FSXT Member Journal] ['03 X Member Journal]
 

·
Administrator
2007 Forester Sports XT 4EAT
Joined
·
41,757 Posts
@NickFury That would be a "plug tap". That tap should have cleaned the threads nearly all the way. The only one that would do better is the "bottoming tap", which I might have to invest in. I'm saving this MOD for Spring when the weather warms up.

Bobby...

['07 FSXT Member Journal] ['03 X Member Journal]
 

·
Registered
05 Forester XT
Joined
·
541 Posts
This is timely info!
I just got a set of bolts too. The holes look perfectly aligned, but there is crude build up on the threads so the bolt won't even start. I just got a tap but it has been so cold that I haven't felt a need to spend any time in the garage :)
I was thinking about mounting some sort of brush on a drill and trying to clean some of that crude out before using the tap...
 

·
Registered
2008 XT Limited 4EAT
Joined
·
414 Posts
^ brush on a wheel sounds like a great idea. I'm sure that will get the thick crud, if not all of the crud, out of the threads. I just installed a set this weekend. I'm lucky our 08 is young with a relatively clean bottom. Didn't need to tap or even clean out the holes. Although, I did have to loosen the subframe bolts as the holes on the passenger side weren't straight enough to accept the sleeve.
 

·
Registered
none none
Joined
·
8,844 Posts
^ brush on a wheel sounds like a great idea. I'm sure that will get the thick crud, if not all of the crud, out of the threads. I just installed a set this weekend. I'm lucky our 08 is young with a relatively clean bottom. Didn't need to tap or even clean out the holes. Although, I did have to loosen the subframe bolts as the holes on the passenger side weren't straight enough to accept the sleeve.
You didn't happen to check the alignment before and after? I bet the camber is much better side to side now. The subframe's poor mounting is part of the reason most have a decent amount of cross camber from the factory. I really wish I had money to get the sti part!
 

·
Registered
08 Audi RS4 6 speed man
Joined
·
156 Posts
i remember when i did the subaframe bolts in the sti. the instructions said you would hear a loud audiable pop.. dont know if thats what you heard or not.
 

·
Registered
2008 XT Limited 4EAT
Joined
·
414 Posts
You didn't happen to check the alignment before and after? I bet the camber is much better side to side now. The subframe's poor mounting is part of the reason most have a decent amount of cross camber from the factory. I really wish I had money to get the sti part!
I didn't check alignment before and haven't gone in for the after alignment yet. Will soon though.
 

·
Registered
06 Forester XT 2.5
Joined
·
82 Posts
Discussion Starter · #19 · (Edited)
Yes, cleaning out the threads in there as best as you can is a great idea. Peaty's suggestion of just using a cotton swab just wont cut it for most of us with the higher mileage/winterized cars.

A great suggestion on putting a wire brush on a drill, that could work very well - wish I had though of that! :chair:

A buddy and I were thinking of dropping the subframe and cutting a hole to get to the nut, taking the bolt off, then re-welding the nut back on and welding the hole shut.

Anyways, I still have one 'good' side. Do you think putting in the other subframe bolt would make much of a difference? Or is two really needed for the full effect?
 

·
Registered
02 Foz 4eat
Joined
·
5,536 Posts
I have the rear subframe from my '04 sitting in the garage. I can meet you someplace if you want it for what the scrap yard was going to give me for it.

If you want the STi one, and Garage has one available, I'm hoping to meet with him in the next couple of weeks and can get it from him and transport it back to NY anyway for some gas money.

Let me know if I can help.
 
1 - 20 of 32 Posts
Top