irvined
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| posted on 15/9/08 at 09:08 AM |
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Car Lifts
Hello,
I've just got myself a new garage, or at least I've got the option of getting myself one, and its rather tall, and quite long. I'm
thinking of getting a car lift, as I'm tall so leaning over to work on the car usually leaves me with a sore back. (Yes, i know this is a thin
excuse.)
I'm contemplating buying a car lift, the way I see it there are two options - a 4 post lift that you can drive onto, and a 2 post lift that
supports the car from the bits which you place under the chassis.
My view is that the two post lifts are better for what I want as they will take up less space when not in use, I don't need to have wheels on
whatever I'm working on to get it off the ground, and they are easier to transport.
I do have a small worry though, 4 post lifts are very solid, in the sense that they are supported from all corners, whereas a 2 post lift is only
supported from the center - what stops them falling over - is it only the bolts from the post into the concrete? How strong are these?
In general how do these work? Are they hydraulic or screw threads? Cables? Etc?
There is a big difference in price between three phase ones, and two phase - how much effort/work is it to convert to a single phase - wiring I think
I can handle - the motor on the other hand - how is that connected up to the drive gear?
The other advantage of a ramp for me is that I can get another car in the garage - its big enough for two at the moment, but it would be great if I
can also occasionally store my ragtop daily driver in there when I’m away on a trip with work rather than leaving it on the street - so this could
easily provide some extra space.
What do you think - any reason why I should run away from a two post ramp and will it be stable enough?
Thanks
David
http://irvined.blogspot.com
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Mr Whippy
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| posted on 15/9/08 at 12:00 PM |
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look up suppliers of them and most will have installation guides. Don't think there is anything too wrong with the 2 post ones unless the cars
are very badly balanced from overloading or the weight is on one end like a truck. Did you put rebar grid into the floor?
Fame is when your old car is plastered all over the internet
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mr henderson
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| posted on 15/9/08 at 12:20 PM |
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4x4 specialists round the corner from me used to have one 4post and one 2post. Now they've got two 2posts.
When I can afford a lift it won't even cross my mind to get a 4 post
John
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theconrodkid
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| posted on 15/9/08 at 01:00 PM |
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2 post all the way,they have to be rawl bolted to the floor,min concrete thickness is 12 inches if i remember right and you have to load them right to
balance them,mine was screw thread dive,check the bronze lifting nuts for wear ,the motor drives via a couple of fan belts to the post,a chain goes
under the base and drives the other post,its a professional job to set them up 
who cares who wins
pass the pork pies
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pewe
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| posted on 15/9/08 at 01:47 PM |
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Local garage totalled the family Volvo estate when one of the lift nuts on their two post stripped as they lowered it from the top. Fortunately it
didn't injure anyone but trashed the whole side incl. A, B & C posts.
Evidently you cannot check the nuts to prevent them stripping so I'd always go four post for pref. - or do what Charlie Broomfield in PPC does
and use an old fork-lift (not!).
Cheers, Pewe 
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mr henderson
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| posted on 15/9/08 at 02:03 PM |
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quote:
Originally posted by pewe
Local garage totalled the family Volvo estate when one of the lift nuts on their two post stripped as they lowered it from the top.
Would we say that was a rare occurence? or very rare? or even extremely rare? Surely sufficiently rare to maybe not factor into a decision as to which
type to get
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Peteff
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| posted on 15/9/08 at 03:24 PM |
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I asked about this at the local MOT station and he said if theirs fails it stops where it is and will not come down. They use two posts because the
access is far easier to all parts of the vehicle. You will most likely need 3 phase to run one though.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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mad-butcher
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| posted on 15/9/08 at 04:52 PM |
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why not a good old fashioned pit
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irvined
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| posted on 15/9/08 at 04:52 PM |
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Thanks for the response guys, from what I can tell the only potentially dodgy thing with a two pole one is that it could tip over if the bolts holding
it to the ground aren't in strong enough concrete - i've not seen how thick the floor is yet, but I can find out easily enough once I get
the keys.
It seems to me that with a screw drive moving it up and down, there should be no real danger of it slowly going down over time, only very quickly
going down if the bronze nut that takes the weight of the car strips its threads. (Why bronze btw?)
Since the motor is connected via drive belts it should be trivial to change it for a single phase one, so it looks like the jobs a good'un.
I suppose if I was worried about the strength of the floor, I could always make a base plate or something to spread the load both going downwards, and
also to give it a wider base for the anchors bolts to secure it down with.
http://irvined.blogspot.com
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irvined
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| posted on 15/9/08 at 04:52 PM |
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Thanks for the response guys, from what I can tell the only potentially dodgy thing with a two pole one is that it could tip over if the bolts holding
it to the ground aren't in strong enough concrete - i've not seen how thick the floor is yet, but I can find out easily enough once I get
the keys.
It seems to me that with a screw drive moving it up and down, there should be no real danger of it slowly going down over time, only very quickly
going down if the bronze nut that takes the weight of the car strips its threads. (Why bronze btw?)
Since the motor is connected via drive belts it should be trivial to change it for a single phase one, so it looks like the jobs a good'un.
I suppose if I was worried about the strength of the floor, I could always make a base plate or something to spread the load both going downwards, and
also to give it a wider base for the anchors bolts to secure it down with.
http://irvined.blogspot.com
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davidwag
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| posted on 15/9/08 at 08:26 PM |
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Hi,
Use both at work, two post is good for general service work but a four post is needed for certain jobs like setting up suspension.
If you are going for single phase electrics then the only real option is electro-hydraulic (whether two post or four). The screw type lifts need large
current when you start lifting. I know some people who have converted them to single phase but it can cause problems like if you are working on the
vehicle at half height and want to raise it a little, you first have to take it down onto the floor as the starting current is too high.
Beware if you are buying a second hand 2 post that you need to make sure that the arm locking mechanism is working correctly.
http://www.hse.gov.uk/foi/internalops/sectors/manuf/3_05_05.pdf
hope this helps
David
[Edited on 15/9/08 by davidwag]
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rusty nuts
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| posted on 15/9/08 at 08:57 PM |
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I have been using 2 and 4 post lifts for over 40 years and would say that for general servicing and repairs you can't beat a 2 poster. Lifting
nuts on all of the lifts I have used can be measured for the amount of wear in them . As usual correct maintanence and use will extend the working
life and safety of the lift . Have a word with your local garage equipment sales company , they sometimes get some decent used lifts if garages are
upgrading . Get and read the operating manual as well.
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owelly
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| posted on 16/9/08 at 09:27 PM |
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On all the two post lifts I've worked with and on, there are two lift nuts on each side. The top one takes all the weight as the lift is working
and the bottom one is there in case the top one fails. The idea is, if you notice the gap between the upper and lower nut has shrunk (or gone) then
the working (upper) nut has worn/failed and all the weight has gone onto the lower nut.
A two poster is OK for most jobs but I prefer a four poster so you can be sure that the vehicle won't tumble off when you are swinging on a
breaker bar!
In fact, that's why I have a four post lift!!
http://www.ppcmag.co.uk
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britishtrident
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| posted on 17/9/08 at 07:11 AM |
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Lifts can use -- hydraulics or screw s -- some use wire ropes or chains as part of the mechanism.
With screw lifts lifting screws and nuts are prone to wear -- and can be easily damaged the damage isn't often obvious to the untrained eye. --
so require at least 6 montly inspection.. Those with wire rope types also need regular inspection.
4 post lifts with a single lifting screw to lift the other 3 corners they will often employ either a chain drive (the original lift of this type
was the Laycock "Corination" or wire lifting ropes.
Hydrualic types are generally the most reliable and are safer on the rare occaisions they fail they tend to descend very slowly.
You can buy portable hydraulic or air hydraulic lifts and these are probalbly the best choice for occaisional DIY use.
[Edited on 17/9/08 by britishtrident]
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wilkingj
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| posted on 18/9/08 at 03:57 PM |
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quote:
Originally posted by irvined
Thanks for the response guys, from what I can tell the only potentially dodgy thing with a two pole one is that it could tip over if the bolts holding
it to the ground aren't in strong enough concrete .
Hmm... You want to see the size of my bolts holding up my 15 metre steel mast in my back garden (for my aerials). They are nearly 600mm long, 25mm
dia, and only 2" stick out the top of the concrete.
The concrete slab is 1.5 x 1.2 by 2 metres deep. (3.6 Cubic Metres of concrete  )
So if you do the prep work right, and build it properly, it will not fail.
Doing a bodge job on anything will always put you and others at risk.
The concrete for my slab cost a small fortune. But then the mast will not fall over through shody or poor fixings.
Do it right first time! Then you dont have to worry for ever after.
Its no different to building a kit car is it?
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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C10CoryM
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| posted on 19/9/08 at 02:14 AM |
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I've been a mechanic for several and also spent a year installing hoists/lifts so if I can be of help let me know.
2 post overhead beam require a very good floor. Most home shops will not have good enough floor for these.
These will be mostly dual hydraulic cylinders with cables to balance. Best style of lift IMO.
2 post floor beam can be installed on a lesser floor, but means you have a hump in the middle to drive over. These will be chain,cable or screw
drive.
4 post also can be used with a lesser floor but for most home stuff the hoist is in the way. One good thing is you can raise the lift with a car on
it and fit 2 cars in one spot (make sure to put it on the locks ).
A 2 post is probably best for you. You will also probably want assymetrical arms so you can lift different vehicles.
Good luck.
"Our watchword evermore shall be: The Maple Leaf Forever!"
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DarrenW
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| posted on 22/9/08 at 05:26 PM |
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If car has flat floor a locost option is to get a high lift pallet truck. Chris Mason had some a while back. Might need to be wide enough so you can
actuate the handle unless a cylinder from a body straightener can be rigged up.
Nowt wrong with Charlies solution as long as walls are strong enough etc.
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