Cobra trailer hydraulic jack refurb?

[Frank]

My Cobra trailer hydraulic jack is starting to fail, to the point
where I now have to put a 2x4 board under the jack assembly to get my
wheel off the ground.

John Dezutti (7K) gave me some hydraulic fluid, but there doesn't seem
to be a good way to add fluid. I tried, and got everything *but* the
jack filled with fluid, and got no discernable improvement in
performance.

I'm also told that the hydraulic piston is exactly the same as some
found in automotive hydraulic floor jacks, and that I might be better
off just replacing the unit rather than trying to repair it.

Can anyone out there help out a fellow pilot with a limp er, jack?

Frank (TA)

[Darryl Ramm]

Post by Frank
My Cobra trailer hydraulic jack is starting to fail, to the point
where I now have to put a 2x4 board under the jack assembly to get my
wheel off the ground.
John Dezutti (7K) gave me some hydraulic fluid, but there doesn't seem
to be a good way to add fluid.  I tried, and got everything *but* the
jack filled with fluid, and got no discernable improvement in
performance.
I'm also told that the hydraulic piston is exactly the same as some
found in automotive hydraulic floor jacks, and that I might be better
off just replacing the unit rather than trying to repair it.
Can anyone out there help out a fellow pilot with a limp er, jack?
Frank (TA)

It is just a hydralic pump/ram assembly from a floor jack, I believe
Spindelberger actually take them out of floor jacks, but I could be
wrong. I sure wish they'd find something better. I believe they have
tried.

I would remove the jack and flush it and refill, Look for previous
r.a.s posts by bumper and others.

And if you need help look at this http://www.hyjacks.com/H7.HTM (Gawd
dang this Internet thing is amazing...)

If that does not work then replace it. It may be easier to pay the $85
or so plus shipping for a real Cobra replacement. Make sure you order
the right model for your trailer. Williams Soaring and probably other
places have them in stock. Some people have posted before about
finding a suitable unit in a floor jack. I'd be interested if somebody
found a high-quality floor jack part that would fit with some work
(and I'd expect that to cost lots more than buy another part from
Cobra). Other people have previously talked about customizing/
repairing up the standard Cobra units. I'm not sure if anybody is
offering to do that as as service.

Ah this reminds me I want to flush my Jack fluid....

I do not trust the hydraulic jacks and have a wood block that slides
into the bottom metal U channel and a block with a triangular shaped
top that slides under the jack scissors, It can't fall out because of
a lips that locate it in place. With a heavy motorglider I never want
to face the lift scissors bottomed out and unable to lift the
fueslage. Even though I have the safety blocks I also am careful never
to put the gear down until the wings are on. That can be a ~$5 lesson
(for a new canopy).


Darryl

Darryl

[Darryl Ramm]

Post by Darryl Ramm

Post by Frank
My Cobra trailer hydraulic jack is starting to fail, to the point
where I now have to put a 2x4 board under the jack assembly to get my
wheel off the ground.
John Dezutti (7K) gave me some hydraulic fluid, but there doesn't seem
to be a good way to add fluid.  I tried, and got everything *but* the
jack filled with fluid, and got no discernable improvement in
performance.
I'm also told that the hydraulic piston is exactly the same as some
found in automotive hydraulic floor jacks, and that I might be better
off just replacing the unit rather than trying to repair it.
Can anyone out there help out a fellow pilot with a limp er, jack?
Frank (TA)

It is just a hydralic pump/ram assembly from a floor jack, I believe
Spindelberger actually take them out of floor jacks, but I could be
wrong. I sure wish they'd find something better. I believe they have
tried.
I would remove the jack and flush it and refill, Look for previous
r.a.s  posts by bumper and others.
And if you need help look at thishttp://www.hyjacks.com/H7.HTM(Gawd
dang this Internet thing is amazing...)
If that does not work then replace it. It may be easier to pay the $85
or so plus shipping for a real Cobra replacement. Make sure you order
the right model for your trailer. Williams Soaring and probably other
places have them in stock. Some people have posted before about
finding a suitable unit in a floor jack. I'd be interested if somebody
found a high-quality floor jack part that would fit with some work
(and I'd expect that to cost lots more than buy another part from
Cobra). Other people have previously talked about customizing/
repairing up the standard Cobra units. I'm not sure if anybody is
offering to do that as as service.
Ah this reminds me I want to flush my Jack fluid....
I do not trust the hydraulic jacks and have a wood block that slides
into the bottom metal U channel and a block with a triangular shaped
top that slides under the jack scissors, It can't fall out because of
a lips that locate it in place. With a heavy motorglider I never want
to face the lift scissors bottomed out and unable to lift the
fueslage. Even though I have the safety blocks I also am careful never
to put the gear down until the wings are on. That can be a ~$5 lesson
(for a new canopy).
Darryl
Darryl

Ah that was supposed to be ~$5k lesson. Nothing in aviation costs $5,
except for the beers you buy the towpilot afterwards.

Darryl

[Darryl Ramm]

Post by Darryl Ramm

Post by Frank
My Cobra trailer hydraulic jack is starting to fail, to the point
where I now have to put a 2x4 board under the jack assembly to get my
wheel off the ground.
John Dezutti (7K) gave me some hydraulic fluid, but there doesn't seem
to be a good way to add fluid.  I tried, and got everything *but* the
jack filled with fluid, and got no discernable improvement in
performance.
I'm also told that the hydraulic piston is exactly the same as some
found in automotive hydraulic floor jacks, and that I might be better
off just replacing the unit rather than trying to repair it.
Can anyone out there help out a fellow pilot with a limp er, jack?
Frank (TA)

It is just a hydralic pump/ram assembly from a floor jack, I believe
Spindelberger actually take them out of floor jacks, but I could be
wrong. I sure wish they'd find something better. I believe they have
tried.
I would remove the jack and flush it and refill, Look for previous
r.a.s  posts by bumper and others.
And if you need help look at thishttp://www.hyjacks.com/H7.HTM(Gawd
dang this Internet thing is amazing...)
If that does not work then replace it. It may be easier to pay the $85
or so plus shipping for a real Cobra replacement. Make sure you order
the right model for your trailer. Williams Soaring and probably other
places have them in stock. Some people have posted before about
finding a suitable unit in a floor jack. I'd be interested if somebody
found a high-quality floor jack part that would fit with some work
(and I'd expect that to cost lots more than buy another part from
Cobra). Other people have previously talked about customizing/
repairing up the standard Cobra units. I'm not sure if anybody is
offering to do that as as service.
Ah this reminds me I want to flush my Jack fluid....
I do not trust the hydraulic jacks and have a wood block that slides
into the bottom metal U channel and a block with a triangular shaped
top that slides under the jack scissors, It can't fall out because of
a lips that locate it in place. With a heavy motorglider I never want
to face the lift scissors bottomed out and unable to lift the
fueslage. Even though I have the safety blocks I also am careful never
to put the gear down until the wings are on. That can be a ~$5 lesson
(for a new canopy).
Darryl
Darryl

And I had meant to say originally if you are not seeing hydraulic
fluid leaking out of the jack, adding more is likely a waste of time.
The leak may be internal from shot seals. Flushing it out and
replacing the fluid might help but is likely a waste of time.

Big things are if you do, add the fluid with the piston is fully
compressed or you are going to make a big mess with fluid everywhere
when the piston compresses later. A small hose with a nipple on it
attached to a plastic bottle makes this easy. And be careful popping
off the rubber fill hole plug. I lost one once. Ouch.

Also while checking out your hydraulic ramp check the vale arm (the
thing you let the ramp up down with) does not ever touch the wall of
the ramp base. If so that can lead to failure. If they do touch you
should file out a notch in the wall to provide clearance. I believe
that is one reason Cobra would replace some jacks free of charge.
Cobra had a very clear PDF on this but I can't find it on-line.

Darryl

[Bela]

Post by Darryl Ramm

Post by Darryl Ramm

Post by Frank
My Cobra trailer hydraulic jack is starting to fail, to the point
where I now have to put a 2x4 board under the jack assembly to get my
wheel off the ground.
John Dezutti (7K) gave me some hydraulic fluid, but there doesn't seem
to be a good way to add fluid.  I tried, and got everything *but* the
jack filled with fluid, and got no discernable improvement in
performance.
I'm also told that the hydraulic piston is exactly the same as some
found in automotive hydraulic floor jacks, and that I might be better
off just replacing the unit rather than trying to repair it.
Can anyone out there help out a fellow pilot with a limp er, jack?
Frank (TA)

It is just a hydralic pump/ram assembly from a floor jack, I believe
Spindelberger actually take them out of floor jacks, but I could be
wrong. I sure wish they'd find something better. I believe they have
tried.
I would remove the jack and flush it and refill, Look for previous
r.a.s  posts by bumper and others.
And if you need help look at thishttp://www.hyjacks.com/H7.HTM(Gawd
dang this Internet thing is amazing...)
If that does not work then replace it. It may be easier to pay the $85
or so plus shipping for a real Cobra replacement. Make sure you order
the right model for your trailer. Williams Soaring and probably other
places have them in stock. Some people have posted before about
finding a suitable unit in a floor jack. I'd be interested if somebody
found a high-quality floor jack part that would fit with some work
(and I'd expect that to cost lots more than buy another part from
Cobra). Other people have previously talked about customizing/
repairing up the standard Cobra units. I'm not sure if anybody is
offering to do that as as service.
Ah this reminds me I want to flush my Jack fluid....
I do not trust the hydraulic jacks and have a wood block that slides
into the bottom metal U channel and a block with a triangular shaped
top that slides under the jack scissors, It can't fall out because of
a lips that locate it in place. With a heavy motorglider I never want
to face the lift scissors bottomed out and unable to lift the
fueslage. Even though I have the safety blocks I also am careful never
to put the gear down until the wings are on. That can be a ~$5 lesson
(for a new canopy).
Darryl
Darryl

And I had meant to say originally if you are not seeing hydraulic
fluid leaking out of the jack, adding more is likely a waste of time.
The leak may be internal from shot seals. Flushing it out and
replacing the fluid might help but is likely a waste of time.
Big things are if you do, add the fluid with the piston is fully
compressed or you are going to make a big mess with fluid everywhere
when the piston compresses later. A small hose with a nipple on it
attached to a plastic bottle makes this easy. And be careful popping
off the rubber fill hole plug. I lost one once. Ouch.
Also while checking out your hydraulic ramp check the vale arm (the
thing you let the ramp up down with) does not ever touch the wall of
the ramp base. If so that can lead to failure. If they do touch you
should file out a notch in the wall to provide clearance. I believe
that is one reason Cobra would replace some jacks free of charge.
Cobra had a very clear PDF on this but I can't find it on-line.
Darryl

I have this wonderful, Made in China gadget for 6 years.
After speaking in person with Mr. & Mrs. Spindelberger at the last
SSA convention, I am resigned to carry a large bottle of hydraulic
fluid and a small bottle with long needle like spout. The
Spindelbergers were looking for replacement but were unable to find
one as of a year ago.
Bela

[Andrew Wood]

my 4-year-old hydraulic jack also failed. Could not find a local
replacement or an economical overhaul. Cobra sent me a new one, for the
cost of postage.

Post by Frank
My Cobra trailer hydraulic jack is starting to fail, to the point
where I now have to put a 2x4 board under the jack assembly to get my
wheel off the ground.
John Dezutti (7K) gave me some hydraulic fluid, but there doesn't seem
to be a good way to add fluid. I tried, and got everything *but* the
jack filled with fluid, and got no discernable improvement in
performance.
I'm also told that the hydraulic piston is exactly the same as some
found in automotive hydraulic floor jacks, and that I might be better
off just replacing the unit rather than trying to repair it.
Can anyone out there help out a fellow pilot with a limp er, jack?
Frank (TA)