Where to support subframe with jack?

[DarkestHour]

I was working on my car the other day and discovered this. Both the 13mm bolts were backed out with one about to fall out/completely loose and the other one nearest the blue subframe bolt to be supporting the bracket and also stripped.

It looks like all I should have to do is remove the two 13mm and the 21mm bolt, but I'm unsure the best place to jack the car to support the subframe as so many instructions recommend but don't show imagery for

If anyone also happens to know the 13mm bolt specifications I will also need to go buy a new one to replace the stripped one.

Thanks in advance!

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[jasonstang]

The best bet is by the diff.

 

[HoosierDaddy]

I would put the rear of the car up on stands and then use a jack to just position the diff/cradle.

I think lifting the car by the diff is a bad practice since the diff just bolts to the car with 4 horizontal bolts that don't need to be any stronger than enough to keep the diff from falling off or twisting in use. Not like a live axle where the diff is welded to tubes that have to support the weight of the car.

 

[mikes2017gt]

Good point about the jacking under the diff and it's 4 bolts, etc. I am guilty of doing this several times and didn't think about it.

I've dropped the subframe twice already and I have used the diff (bad move, now I know), the bottoms of the spring perches, where the bottom of the springs seats into and under the knuckle itself. If your jack has a rubber pad on the lifting plate, great. If not, be sure to use a piece of wood or thick rag b/t the jack plate and the aluminum IRS components to avoid scratching/gouging.

I can't remember the torque spec on those smaller bolts, but I think is 40ftlbs. The big, blue bolts are 129 ft lbs for sure. I set the torque wrench at 130 even and don't worry about it.

 

[gjpundsack]

Here's a jack rail adapter from Amazon: https://www.amazon.com/dp/B01MG9CNUX?psc=1

 

[DarkestHour]

I would put the rear of the car up on stands and then use a jack to just position the diff/cradle.

I think lifting the car by the diff is a bad practice since the diff just bolts to the car with 4 horizontal bolts that don't need to be any stronger than enough to keep the diff from falling off or twisting in use. Not like a live axle where the diff is welded to tubes that have to support the weight of the car.

Good point about the jacking under the diff and it's 4 bolts, etc. I am guilty of doing this several times and didn't think about it.

I've dropped the subframe twice already and I have used the diff (bad move, now I know), the bottoms of the spring perches, where the bottom of the springs seats into and under the knuckle itself. If your jack has a rubber pad on the lifting plate, great. If not, be sure to use a piece of wood or thick rag b/t the jack plate and the aluminum IRS components to avoid scratching/gouging.

I can't remember the torque spec on those smaller bolts, but I think is 40ftlbs. The big, blue bolts are 129 ft lbs for sure. I set the torque wrench at 130 even and don't worry about it.

Hmm...I've looked at Steeda's videos more and they are supporting the subframe by jacking up the differential :shrug:

 

[mikes2017gt]

The Steeda jacking rails are awesome. For something so simple they work really well. You can jack one whole side of the car at a time and slide the stands under the pinch welds. Without rushing I can have my car up on 4 jackstands in about 3 minutes flat. Then it's a simple matter to use your floor jack to hold up/lower whatever piece of the subframe you happen to be working on.

You can jack up the car by the diff, it's just not really the best way to do it. There are times when you have to lift the IRS by the diff, like if you've dropped the entire rear subrame to install spacers or align it or something. But for something like that the weight of the car is being supported by your jackstands, not the diff. At that point you're only lifting the IRS by the diff, not the whole car.

 

[DarkestHour]

I ended up doing what LMR does in this spring install video -

https://lmr.com/products/2015-Mustang-Lowering-Spring-Installation

Worked great and my bracket is now aligned. Now I just need to try to find a replacement bolt.

 

[tj@steeda]

Here is where the jacking rails are:

Here they are in action!

 

[DarkestHour]

I have no idea why anybody is talking about jacking rails in this thread :lol:

BTW [MENTION=7748]tj@steeda[/MENTION], thanks to you guys including extra M10x1.50 bolts in your subframe brace kit I was able to easily replace my busted bolt in the subframe bracket.

 

[mikes2017gt]

I brought up the Steeda jacking rails to bring to your attention that there are helpful products/methods to safely get the car up in the air vs. jacking up by the diff. Glad you were able to get your stripped screw problem sorted out.

 

[Brian V]

Hey guys ya think that is his mugshot ?

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