How to repair scissors jack?

[lagonda 42]

My CTi has b*ggered up my trusty scissors jack!

 

I wanted the NSF wheel as high as possible to aid replacing the inner tie rod, Ordinarily I'd have driven it up ramps, but not viable as I wanted the steering on full lock. I had to wind the jack as high as it would go, just enough to slip a ramp under the wheel, thus ensuring safety ready for the inevitable struggle undoing the tie rod.

 

The jack was unusually stiff lowering it, and with the jack out, the operating arms were no longer symmetrical.

 

This is a generic jack, not the Peugeot one; probably originated from Halfords 30 odd years ago. The operating arms are pressed steel, and have teeth at the inner ends of each arm. These teeth engage those on their opposite arm, and serve to ensure the jack saddle raises precisely vertical, and preventing the jack tipping forwards or back. It seems some of these teeth have somehow jumped, meaning the saddle now tries to rise at something approaching 45 degrees. I don't understand how this has happened, as the jack remained totally vertical until lowering, neither did the car move at all, other than vertically (wheels chocked and handbrake on).

 

Anyone encountered similar, and discovered a ready fix? Any thoughts?!

 

Laurence

[martixsan 0]

Check the base pins for wear, and also the holes they get thru.

Also there could be wear over the die cutted teeth, and at the screw-nut assembly itself.

Check also the axial bearing at the rotation hub, and if there is a pin that holds the screw hub.

Becareful, because if the hub pin snatches under load, there could be serious injuries, by the flying hub!

[Ozymandis 97]

                                                                                      Chuck it in one of these and buy another, they are crappy unstable things at the best of times, You dont want a ton or so falling on top of You, do You?

[welshpug 1,657]

get a trolley jack!!

[Tom Fenton 1,542]

6 hours ago, Ozymandis said:

                                                                                      Chuck it in one of these and buy another, they are crappy unstable things at the best of times, You dont want a ton or so falling on top of You, do You?

Another vote for this

[jackherer 543]

8 hours ago, Ozymandis said:

Chuck it in one of these and buy another, they are crappy unstable things at the best of times, You dont want a ton or so falling on top of You, do You?

I agree a new jack is in order but even if it failed it shouldn't result in a ton of car falling on you. If you are getting under a car with just a jack supporting it you are doing it wrong.

[lagonda 42]

Hi,

  Although the jack is 30 years old, it hasn't seen much use. It's the in-car jack for my 1939 LG6, being light, easy to stow, and lifts the car fine when needed (the car has only been in use for 5 or 6 years). Hence my preference to restore the jack. There is no noticeable wear, so it's not that that's the problem. I think, at this extreme of extension, it ran out of teeth on one pair of arms, so to speak, running up against a plain section, and when lowered, the "wrong" teeth engaged.

 

  Yes a trolley jack would have been ideal for this job. I have one, my second one, this latest blew its seals jacking my V12, and the other also blew its seals. If anyone can recommend from experience a budget trolley jack that doesn't blow seals or twist under load, I'm interested.

[welshpug 1,657]

not had any issues with any of the usual 3 ton type jacks found with many different names on them, Clarke, SGS, Snapon etc.

 

seals can be replaced though, if the piston and bore aren't scored to hell that will be much more cost effective.

 

 

A stamped sheet metal scissor jack really isn't intended for regular use, once bent it will have a weakness that I would not trust.

[jackherer 543]

My SGS jack has failed now like every other one I've bought over the years. The only trolley jack I have that still works is about 40 years old which I inherited from my uncle Jack appropriately enough.

[309SRiguy 15]

If it "skipped" a tooth when fully extended is it possible to fully extend and then line up the the correct teeth before winding it down? 

 

[lagonda 42]

Hi Bryan,

 You'd think that would be the answer, but having had a careful look in daylight today with it fully extended, I think what happened is that, the saddle being somewhat asymmetrical, that the teeth on one side hit and jammed under the saddle, wedging there and causing teeth to jump as I wound it down. I think trying to force the teeth to jump back into sync could cause damage, so I think the safetest option will be to grind off the riveted ends of the 2 pins in the saddle. That will let the upper arms free to be correctly engaged, and will also allow me to check for damage compromising safety. If all OK, I can then more easily properly grease everything, replacing the pins with bolts and nuts.

Laurence

[martixsan 0]

Pins are ok for shearing forces and bolts are ok for normal (axial pulling) forces, hence the different materials they are usualy made from. Do your research carefully, before changing pins with bolts .

[Ozymandis 97]

Looks like Darwin`s natural selection playing out  for our entertainment, I will get another brandy, please give Your nearest relative your sign in details and instructions "upon the event of my death" etc I`m dying to know what eventually happens.

 

Just buy another ,Your not by any chance  from Yorkshire are You?

[lagonda 42]

Seems you are! Funnily enough, ancestry research shows some Yorkshire input, but more Lincolnshire. Rest assured I won't be taking any chances with this, I experienced my brother's old car sliding off its jack whilst I was under the sump. Life saved as a steering arm caught on an axle stand before it got too close "for comfort". That was as frightening as it gets, believe me. Never get under a jacked car without axle stands. In this case, I've jacked the 205 up so that the wheel is supported by the top of a ramp (couldn't drive up as the steering needs to be on full lock). Before you ask, my 6 axle stands are under the Riley and V12.

 

Thanks, yes, had considered different material, although I doubt any special selection was made by the manufacturers of this jack.

[martixsan 0]

Don't know about Darwin, he is not my relative :D.

Anyway, under different materials I ment different types of steels, maybe hardening - such stuff you know.

 

BR

Martin

[welshpug 1,657]

7 hours ago, lagonda said:

 

 

 I doubt any special selection was made by the manufacturers of this jack.

erm, thats pretty much half their job!!

[Leslie green 110]

If you got 30 years out of it you did very well , I bought a halfords 1.5 ton scissor jack and the level of effort needed to lift the lightest of cars (800kg) was immense , what a piece of s*ite it was threads must be far too course , I bought a older bmw  x5 scissor jack and it can lift an x5 with minimal effort (2.2 t worth) it has a 2 piece winding handle  , its of an e53 bmw and looks like a proper scissor jack as there are 2 types and the other is like a dogleg and rubbish .

[lagonda 42]

Interesting! I had a look at mine and the SWL is 750kg, around 0.82 of a ton. My heaviest car is two tons and I've used it for jacking corners of that regularly. That has taken a degree of effort in winding, but not much more than that involved using the CTi's own jack on that. I can't say for certain my jack was Halfords, a tenant left it at a property back in the 90s, it was still new in the box then, however the box disappeared long ago!

 

I take the point about the pins being a different material to bolts, and I think I'd best rule that option out. I suspect bolts would be fine, but I wouldn't wish to risk finding out they weren't!