I did exactly that a few years ago. All dimensions were the same except the
bushing in the ram was a different size. I didn't have a lathe at the time,
so I took it back and bit the bullet for a new Cobra. Now I could do the job
in about 15 min including set-up. But still crappy quality.

Bumper said he could get the jack apart with a pipe wrench on the large hex
near the top of the reservoir. I tried with an extension on my pipe wrench
handle but nearly tore the vise off the bench, The nut didn't budge!

I'll just drain my new one, and refill.

Hartley Falbaum
"Udo Rumpf" wrote in message
...
Not long ago I finished building a Hydraulic Scissor Jack.
I used a 2 ton mini automotive jack (the one with 2 small casters and 2
fix wheels) worth about $24.00.
I removed the hydraulic unit for use with my set-up. Based on that I
would say the dimension are the same as the one on the Cobra unit. Right
now I have my trailer in storage and I can not
take measurements. I would buy a jack, try it out and if the dimension do
not work out for you take it back.
Udo

At 23:36 01 December 2008, wrote:
I am looking for a source for a replacement bottle jack for a cobra
trailer ramp (yes, I know I should switch to the mechanical jack and
all problems will go away, but I don't want to go down that route
yet). The Torin 2-ton jack that Walmart and Autozone sell is extremely
poorly built, in addition to the dimensions not being quite right.
Somebody must have gone through this before and found a decent source?