Rear Hatch Hydraulics

Upgrades and modifications to Trims, Seats, Carpets, Roof Racks, Panels, Dashboard, Bumpers, Rocksliders, Paint, Decals...

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parallel
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Joined: Fri Jun 21, 2013 12:53 pm
Location: New Orleans Area

Hate to Necropost but...

Postby parallel » Wed Jun 26, 2013 9:10 pm

This thread is how I found this forum. Did a search looking for replacement hatch struts and found The Nissan Path.

I ordered my McMaster rear hatch and rear window struts on Friday 6/21 and they were here on Monday evening 6/24. I'm not thrilled with how they were packaged as the rods were literally poking through the too short box and there wasn't anything holding them still so they're a bit beat up.

I'm looking to install these tomorrow, hopefully the rough transit didn't harm them.

Image


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parallel
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Location: New Orleans Area

Postby parallel » Thu Jun 27, 2013 11:06 am

Got them on, they work as advertised. Thanks to all who contributed information on these.

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disallow
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Postby disallow » Thu Jun 27, 2013 11:09 am

cool

mwohlg
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Joined: Sat Jul 06, 2013 2:43 pm
Location: Greenville SC

background info

Postby mwohlg » Sat Jul 06, 2013 3:27 pm

I found this forum looking for roof rack tips, and I think I'll be sticking around a while. But I feel like I've been taken out to the woodshed for a beating. I used to work for the company that made the OEM gas springs that most of you are hating on.

I think we started with the 06 model year, and stopped with the 10 MY. The 2011 I bought used last summer has another company's gas springs. I am somewhat glad to see that a few of you have issues like me even with newer vehicles. (Mine sag in the cold temps also). The problem is mostly with the vehicle geometry, and the car company requirements.

I left the gas spring company in 2008 after 12 years. In the 5 years since, I have forgotten most of the details about these particular OEM parts, but can shed some light on how the gas springs work generally.

High pressue nitrogen gas is captured & sealed inside the tube. How much pressure inside initially, is what determines the output force of the spring. But the pressure of the gas drops dramatically as the temperature drops, remember the ideal gas law from chemistry? I don't remember exactly the ratio, but its something like 20N force loss for every 5 degree drop in temperature.

Plus the nitrogen gas permeates through the seal over time, just like your tires lose pressure. So a gas spring that worked OK when new can be nearly useless after a few years. The common minimum design guideline is to have enough pressure remaining to hold the door open after 5 years (not necessarily to open the door by itself).

The biggest problem in the design of the OEM gas spring is the geometry of the vehicle itself. The center of gravity of the Pathfinder liftgate is much lower than on the Xterra - it's longer, has more sound dampening, more steel, etc. Plus the Pathfinder has a flipper glass as opposed to the Xterra's fixed glass, so there is added weight of latch mechanisms, flipper glass gas springs, etc. The space requirements between the gate and the body D pillar affect how long the gas spring can be, and specifically how long the body can be (more volume in the gas spring body (tube) gives more nitrogen and longer life). Finally, the car manufacturers have to make sure that no 4'9" wives are left dangling by the liftgate because they're not strong enough (or heavy enough) to close it - it has to be designed for a 5th percentile woman to be able to close the liftgate in 100 degree weather.

Long story short, the 200# or 225# springs that many of you have switched to won't meet the OEM design requirements because of the 5th percentile woman thing. Plus the automaker would rather replace a cheap set of gas springs because they lost pressure over time, then repair a damaged liftgate or hood or broken glass because the pressure/temperature combination was too high.

markscalise
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Postby markscalise » Wed Sep 18, 2013 8:42 am

I'm not particularly handy but I was able to swap out my hatch struts on my 2005 Pathfinder SE for the 200lb McMaster struts. One thing I might suggest is putting the clips halfway into their respective slots before you put the strut heads back on their corresponding balls. Then you can just push the clips back into place once the strut is on. Also, the stock strut heads (or whatever they're called) screwed on to the new struts just fine.

Very worthwhile fix for not much money or effort!

Jolly Roger
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Joined: Mon Nov 04, 2013 4:50 pm
Location: Ocean Park, BC, Canada

Postby Jolly Roger » Wed Nov 06, 2013 11:13 am

I recently purchased a 2005 Pathfinder and immediately noticed (after being clunked on the head a few times) that the struts supporting the lift-gate were failing miserably. I did a search online and was delighted to find this thread. I ordered some struts (225 version) from McMaster-Carr and had them shipped overnight to BC, Canada. Even with the overnight shipping they were cheaper than getting Nissan ones from my local dealer, who also quoted me 3-4 days to bring them in. Installed them in about 20 minutes and the lift-gate works great. Opens nice and high and doesn't droop down or clunk me in the head anymore when I'm getting the dogs in and out. The gate also closes much more smoothly and doesn't slam shut like it used to. I'm VERY happy and really pleased that I discovered this forum. Thanks to everyone who posted information on this topic . . . really helped me out a lot. :D

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BigEz
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Location: Houston, Texas

Postby BigEz » Wed Nov 06, 2013 11:49 am

I also did my 08 this week. I'm sure they were the originals, as the rear hatch would bairly stay up. I did both the hatch and rear window support. I ordered the default replacements from http://autopartsbylou.com/index.php

Both sets installed in less than 10mins and work great... easy breezy

mc01ta
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Postby mc01ta » Tue Dec 03, 2013 3:33 pm

I bout replacements from amazon http://www.amazon.com/gp/aw/d/B001DCJ3P ... SY165_QL70

These aren't fitting or I'm installing wrong. These have one end that can screw off and you can use old fitting from OE strut. But on the end which goes closest to top of roof does not come off and won't slip on the ball end. Has anybody used this replacement part orsjoukd I send back and get something else?

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Zen_master
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Postby Zen_master » Sun Dec 08, 2013 7:37 pm

I had new OEM rear hatch struts put on my '11 LE two months ago and with the temp here dipping into the 20s the rear lift gate will not go all the way up. I still need to give it a little assistance to raise the last three inches or so at the maximum point of extension.

Anyone else experiencing the same even with new struts?

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shaggyT
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Postby shaggyT » Sun Dec 08, 2013 7:44 pm

Am I the only one that hits their head on the glass every time?

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Zen_master
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Postby Zen_master » Sun Dec 08, 2013 8:10 pm

shaggyT wrote:Am I the only one that hits their head on the glass every time?
The glass? I don't have issues with the glass hatch opening fully. It's the full liftgate that is failing to extend to the top by about three inches.

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smj999smj
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Postby smj999smj » Sun Dec 08, 2013 9:05 pm

My glass tags me in the head every now and then but they are the original lift struts and I don't use the glass hatch that often. The liftgate, however, has been great since I went to the 200 psi McMaster lift struts. Even in the coldest weather, the extra pressure lifts and holds up the lift gate with ease and it lifts a s little bit higher than the stock struts, as well. No more concussions!

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shaggyT
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Joined: Thu Nov 28, 2013 10:19 pm
Location: NYC

Postby shaggyT » Sun Dec 08, 2013 10:15 pm

both the liftgate and the glass hatch struggle in the winter but not too bad in the winter

linarema
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Joined: Thu Jul 04, 2013 8:57 am
Location: Atlanta, GA

Squeaky/squealing Glass Lift Arms

Postby linarema » Sat Jan 25, 2014 6:11 am

I replaced both the tailgate and the glassdoor lift arms last weekend. Piece of cake. But now the glass lifts are squealing. Can they be lubricated? If so with what? I've got Silicone spray and the ubiquitous WD-40 spray.
How can I stop the annoying squeak :?

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Touchdown
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Location: Dallas Area

Re: background info

Postby Touchdown » Sat Jan 25, 2014 4:42 pm

mwohlg wrote:I think we started with the 06 model year, and stopped with the 10 MY. The 2011 I bought used last summer has another company's gas springs. I am somewhat glad to see that a few of you have issues like me even with newer vehicles. (Mine sag in the cold temps also). The problem is mostly with the vehicle geometry, and the car company requirements.

I left the gas spring company in 2008 after 12 years. In the 5 years since, I have forgotten most of the details about these particular OEM parts, but can shed some light on how the gas springs work generally.

High pressue nitrogen gas is captured & sealed inside the tube. How much pressure inside initially, is what determines the output force of the spring. But the pressure of the gas drops dramatically as the temperature drops, remember the ideal gas law from chemistry? I don't remember exactly the ratio, but its something like 20N force loss for every 5 degree drop in temperature.

Plus the nitrogen gas permeates through the seal over time, just like your tires lose pressure. So a gas spring that worked OK when new can be nearly useless after a few years. The common minimum design guideline is to have enough pressure remaining to hold the door open after 5 years (not necessarily to open the door by itself).

The biggest problem in the design of the OEM gas spring is the geometry of the vehicle itself. The center of gravity of the Pathfinder liftgate is much lower than on the Xterra - it's longer, has more sound dampening, more steel, etc. Plus the Pathfinder has a flipper glass as opposed to the Xterra's fixed glass, so there is added weight of latch mechanisms, flipper glass gas springs, etc. The space requirements between the gate and the body D pillar affect how long the gas spring can be, and specifically how long the body can be (more volume in the gas spring body (tube) gives more nitrogen and longer life). Finally, the car manufacturers have to make sure that no 4'9" wives are left dangling by the liftgate because they're not strong enough (or heavy enough) to close it - it has to be designed for a 5th percentile woman to be able to close the liftgate in 100 degree weather.
At some point you just need to throw science and accounting out the window, admit that something doesn't work and find a viable real-world solution! Shame on Nissan for not doing that! :oops:
shaggyT wrote:Am I the only one that hits their head on the glass every time?
I have a 2011 and I only needed to replace my lift gate struts. Maybe if anyone is having a problem with the window struts on an older model or aftermarket ones, the OEM's from an 11 might do the trick.
mc01ta wrote:These aren't fitting or I'm installing wrong. These have one end that can screw off and you can use old fitting from OE strut. But on the end which goes closest to top of roof does not come off and won't slip on the ball end. Has anybody used this replacement part orsjoukd I send back and get something else?
I had to drill the ends out on one side of the plastic connector and use JB Weld to hold them in because the threads were different. It works great and the strut would break before it ever would! :)


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