Best way to jack the rear to rotate tires?

Norm Peterson

corner barstool sitter
Joined
Jul 22, 2013
Messages
8,176
Reaction score
3,872
Location
On a corner barstool not too far from I-95
First Name
Norm
Vehicle(s)
'08 GT #85, '19 WRX
almost every car sold comes with a SCREW type jack which aside from the very small base, can not (well, short of metal fatigue) physically collapse.
If they 'bend' laterally, they aren't all that stable. I won't use those things except as a last resort. Never in the driveway, when I've got something like four floor jacks in excellent condition and an older light-duty one that's in maybe "fair" condition that I'd still put more trust in for changing a tire than some of the screw jacks I've seen.


just get one of those car-flipper devices - put the car on it's roof and you can change wheels at a comfortable height and zero risk of it falling on you. Might leave a mark on the roof, but i'll buff out.
One jack, one corner at a time works just fine. No different from changing a flat . . .


Norm





Advertisement

 

jimmerheck

Well-Known Member
Joined
Jan 10, 2018
Messages
522
Reaction score
173
Location
Vancouver, Wa.
First Name
Jim
Vehicle(s)
2016 Mustang GT Cal Special
if you had the jacking rails, you could do all four at once. I love my jacking rails.
 
  • Like
Reactions: Ebm

Rapid Red

Well-Known Member
Joined
Nov 4, 2019
Messages
2,022
Reaction score
1,260
Location
Woodstock GA
First Name
Greg
Vehicle(s)
RaceRed>GT PP2 >RXCAIL2
Vehicle Showcase
2
Do you have a spare? You could jack up one side, use the spare and then go at the other. That's what I would do rather than getting both off the ground.
That actually would work just fine .
 

M.A.N.

Well-Known Member
Joined
Mar 15, 2020
Messages
138
Reaction score
54
Location
TN.
First Name
Mike
Vehicle(s)
2010 Ranger 2018 F-150 2019 GT350
Taken from HoosierDaddy

For a live axle car (like my 2014) the pumpkin and axle tubes and mounts are designed to support the weight of the car. For an S550, the pumpkin does not support any load and the bolts that hold it to the car, are to support the weight of the pumpkin and hold it in place. Those bolts are not designed to support the weight of the car. Sure, anyone can get away with it....until they don't.
Are you saying that jacking up the rear of the car by the pumpkin it may shear the
four bolts that hold the pumpkin in?
 

CJJon

Well-Known Member
Joined
Nov 18, 2020
Messages
893
Reaction score
1,136
Location
Port Orchard
Vehicle(s)
2020 Mustang GT/CS Convertible - Race Red
Are you saying that jacking up the rear of the car by the pumpkin it may shear the
four bolts that hold the pumpkin in?
Or more likely bend.
 

M.A.N.

Well-Known Member
Joined
Mar 15, 2020
Messages
138
Reaction score
54
Location
TN.
First Name
Mike
Vehicle(s)
2010 Ranger 2018 F-150 2019 GT350
Or more likely bend.
NO way! You could say it's not a good idea for many reasons, it may damage
the cover, it may bend a bracket, it may damage bushing or whatever [ not that
I think it would ], but I could go with it. But to say jacking up rear of car would
bend or shear them 4 bolts, sorry I have to call foul on that, not happening.
 

shogun32

Well-Known Member
Joined
Feb 8, 2019
Messages
7,218
Reaction score
4,103
Location
Northern VA
First Name
Matt
Vehicle(s)
2019 GT+PP, SS+1LE, 2020 F150
Vehicle Showcase
2
cracking the threaded bosses is not that far fetched. In classic "you miserably failed mechanical engineering 101" the sheer load is carried by the threaded portion of the fastener, not the shank.
 

CJJon

Well-Known Member
Joined
Nov 18, 2020
Messages
893
Reaction score
1,136
Location
Port Orchard
Vehicle(s)
2020 Mustang GT/CS Convertible - Race Red
NO way! You could say it's not a good idea for many reasons, it may damage
the cover, it may bend a bracket, it may damage bushing or whatever [ not that
I think it would ], but I could go with it. But to say jacking up rear of car would
bend or shear them 4 bolts, sorry I have to call foul on that, not happening.
So Ford is wrong then?

Do What Thou Wilt
 

M.A.N.

Well-Known Member
Joined
Mar 15, 2020
Messages
138
Reaction score
54
Location
TN.
First Name
Mike
Vehicle(s)
2010 Ranger 2018 F-150 2019 GT350
I know where the sheer load is, I've had several of these out.
Worked with trucks, loaders, dozers and on N&S railroad cars
for around 40 yrs. I know a little about pins and bolts breaking.

Yes it is far fetched, an airplane could crash on top of you when
jacking it up, but it's not happening.

You could stack 5 of these cars on top of each other and it wouldn't
damage the bolts by jacking it up, not happening.
 

Norm Peterson

corner barstool sitter
Joined
Jul 22, 2013
Messages
8,176
Reaction score
3,872
Location
On a corner barstool not too far from I-95
First Name
Norm
Vehicle(s)
'08 GT #85, '19 WRX
Just the basic concept of using a casting as a jack point for a whole end of a car never felt quite right to me.


Norm
 

Ebm

Well-Known Member
Joined
Nov 21, 2016
Messages
2,881
Reaction score
1,115
Location
North Carolina
First Name
Guy
Vehicle(s)
'14 GT
Are you saying that jacking up the rear of the car by the pumpkin it may shear the
four bolts that hold the pumpkin in?
If a car manufacturer wanted to have a jack point at the differential, it would be in the manual. That's why my response said the differential wasn't designed to be a jack point. I believe the Subaru WRX (2018 model year for example) has the rear differential as a jacking point in the owners manual. The WRX rear differential also has a flat spot between the front and rear sections of the differential. So you aren't actually jacking the section up between the differential cover and the differential itself.

Refer to picture (B)

WR4TWIU.png


With that said, the shear strength of the bolts holding the differential in are probably much higher than needed for a floor jack on the differential as a jacking point. Bolt fatigue may eventually change this though.

A very real concern is making the differential leak or causing a differential cover bolt to strip. This is even more of a concern on an aluminum differential cover.
 

shogun32

Well-Known Member
Joined
Feb 8, 2019
Messages
7,218
Reaction score
4,103
Location
Northern VA
First Name
Matt
Vehicle(s)
2019 GT+PP, SS+1LE, 2020 F150
Vehicle Showcase
2
A very real concern is making the differential leak or causing a differential cover bolt to strip. This is even more of a concern on an aluminum differential cover.
or the bending/twists of the diff against the drive shaft and axles. Sure the voided rubber allow much freedom of movement but I'm not familiar with the 'normal' limits of those and whether certain combinations are "impossible" under operating conditions but totally possible (and problematic) when subjected to 1800lbs of weight.

Just fashion a 'U' bracket that picks up off the IRS frame if you can't be bothered to do the sensible thing and use a friggin' stand.
 
  • Like
Reactions: Ebm

tcman54

Stanghead
Joined
Apr 11, 2016
Messages
1,493
Reaction score
708
Location
Palm Coast, FL
First Name
Terry
Vehicle(s)
2016 Ecoboost
Vehicle Showcase
1
My jacking rails help a lot, also know your tires, my Firestone Firehawks can only be rotated front to back.

TC
 

Norm Peterson

corner barstool sitter
Joined
Jul 22, 2013
Messages
8,176
Reaction score
3,872
Location
On a corner barstool not too far from I-95
First Name
Norm
Vehicle(s)
'08 GT #85, '19 WRX
I know where the sheer load is, I've had several of these out.
Worked with trucks, loaders, dozers and on N&S railroad cars
for around 40 yrs. I know a little about pins and bolts breaking.
Maybe the real concern here is the bushings. I can't tell what they look like from the pictures I've found, but if they're voided (which I suspect) there's probably a force direction that would tend to over-strain them locally at the voids and result in some tearing.


Norm
 

Advertisement





 
114 - J&M Products / Hotpart.com - 1


Advertisement
Top