QUESTION - I need to do some
work under my car. I have never used jack stands. Can someone
give me a primer about what to buy and how to use them?
ANSWER - I claim to be fairly
good at it. As proof I offer the fact that my TR3 was on jack
stands during the '89 Loma Prieta earthquake and it stayed up
on the stands. I live about 1 mile for the surface of the epicenter.
Kinds of Jack stands:
There are two basic kinds of jack stands. One kind has a vertical
rod with a flat 'Y' at the top that adjusts upward from a base.
This is meant to support a frame rail or axle. There are two common
construction types. One is stamped sheet metal with a hollow tubular
raising centre tube. Centre tube adjustment is usually done by
a removable pin through a set of holes. The other common construction
is cast steel. The raising centre rod is solid cast steel with
a row of teeth on one side. Adjustment is via these teeth and
Of the two types, the cast design is usually stronger and rated
for higher loads. A general rule of thumb is to get the stand
with the highest load rating and the widest base that will fit
under your car.
The other kind of jack stand is basically a rectangular box,
with or without a ramp, with or without a raising centre post.
This type is designed to support a wheel when you are doing work
that does not require wheel removal. This type is a LOT more stable
than the narrower adjustable rod jack stand and should be the
type of preference any time you need to work under a car and do
not need to remove a wheel from that corner. Some companies are
now making this kind of stand out of nonmetal materials. I have
never used one that is not metal. Pay close attention to the load
ratings and read the safety part of the user instructions before
Jack stands will break/bend if you overload them. If you are
getting the adjustable rod type get, the biggest one (widest base)
that will fit under your car at your jacked up working height.
The lower the adjustable rod is the more stable the jack stand
is. An adjustable rod type at it's fullest extension can be fairly
Use the right tool for the right job. Do not use bricks, cinder
blocks or any other similar materials in place of a jack stand.
These materials are prone to breaking under load. Be wary of logs
or any other handy material. The top surface of your jack stand
was carefully designed to centre the weight and keep it from sliding
off. Other "sturdy " objects may allow the weight to slide off.
Stacked boards, even under weight, tend to become unstacked when
sideways pressure is applied.
Never go under a car with just a jack holding it up. Jacks were
never meant to substitute for jack stands and are a lot less stable
than jack stands. This includes the hydraulic floor jack. Don't
fool around with your life. Use the right tool the right way.
The best jack stands you can find.
I have both kinds of jack stands and use the wider, stronger,
more stable box type any time I can. Get a set of the adjustable
rod type and at least two of the box type that supports wheels.
Two full sets would be best.
Placing a jack stand:
Your jack stand resting surface is critical. If any corner of
one jack stand base should sink it can quickly destabilize all
the other jack stands and bring the car crashing down.
Flat level cement is best. Asphalt looks stable but is not. A
jack stand will sink into the asphalt, especially on a warm day.
If you are working on any surface other than flat cement you
need to add a stable "floor" between the jack stand and the ground/asphalt/blocks/bricks/whatever.
I suggest wood at least 1/2 inch thick that reaches at least six
inches in any horz direction from the outside base edges of the
If you are on a grade you will need to tie the uphill end of
the car to a stationary tie point. I had my TR3 on a few degree
slope. I sank a 17 inch iron water pipe with a 'T' at the top
into the soil as a tie point. I used a come along to connect the
car frame to the tie point then put a slight tension on the wire.
If you are in an earthquake area, orient the car lengthwise
to the normal direction your nearest fault moves then tie it at
each end to tie points. In my case the car was on a slight slope,
pointed in the direction of movement. Gravity kept it from falling
over uphill and the tie kept it from falling off downhill. I had
box style stands under the rear wheels and the adjustable rod
type on the front with the front wheels removed. The car was on
dirt with plywood under each stand.
The fireplace in my house literally exploded, the kitchen sink
fell through the counter. The refrigerator and stove walked out
into the middle of the kitchen and were almost in contact. I had
to replane the house doors to get them to close into their sills.
We had a great deal of damage from a 7+ force earthquake almost
directly under us.....but the TR3 remained up on the jack stands.
If I were under it at the time of the quake, I would have very
much appreciated it.
If you do not know the normal movement direction of you nearest
active fault look in the phone book for an earth quake preparedness
centre or a geologist. If you are in earthquake country it never
hurts to know how the earth will move. Tall furniture is more
stable if it is oriented lengthwise to the movement of the earth.
I know that an earthquake is very unlikely to happen when you
are under your car, but it does happen. Just like people just
happen to be on or under a bridge or raised roadway when it collapses.
You can not predict it. You just need to decide if you want to
be prepared for it or not.
If you live in an area with strong afternoon wind gusts,
point the car nose or tail into the wind and anchor the upwind
Jacking the car up onto the stands:
Different cars have different constructions. Always check your
car's user manual for jack point recommendations. Usually the
frame is the best lift point. The differential of a solid axle
car is normally another good lift point.
Jacking a car onto jack stands is done one end at a time and
not one side at a time. This provides the least lateral force
when jacking up the second half.
The adjustable rod type of jack stands should be set under a
main frame section or a solid axle as close to the corner as possible.
Stay away from sections that are not normally horizontal to the
ground when the car is on it's wheels.
Any time you jack a corner you should block the opposite corner
wheel. Same when you jack up one end of the car. Jack up one end,
set the stands and any boards. Do the same to the other end. THEN
go back to the first end and jack it back up again, verify stand
placement, then lower the jack. When you jack up the second end
you very frequently put a lateral force on the first set of stands.
This means the first stands may be cocked a little and unstable.
Resetting the first pair eliminates any instability caused by
lifting the second end.
Once the car is on the stands give it a firm shake from a side
and from an end before going under it. If you have the car up
on multiple days, do it every day you crawl under it. If the car
does not feel stable reset the stands. Check the stands for damage
or bending, check the surface under the stands.
When you are under a car and trying to get something off or on,
do not do a lot of hard pulling or pushing in any direction other
than up or down. I read a story once about a guy who was replacing
his exhaust system under jack stands. He was having a hard time
getting pipe sections to separate & pulled so hard he knocked
the car off the stands onto him.
Each year people die when their car falls on top of them. I doubt
that suffocating with the weight of the car on your chest is all
that pleasant of a way to go. You would probably have between
one to two minutes of consciousness to reflect upon that before
you die. So spend the extra money to purchase the best jack stands
that you can get then spend the extra effort to set those stands
up for maximum stability under likely and unlikely conditions.
All this takes a little extra time & expense. But there is
only one you and you have to decide how important seeing the next
morning is to you. If you are not willing to go through the effort
and own a nice condition 1800 or 2000 Triumph Roadster, please,
will it to me before you go under your car?
Best of luck & stay safe
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