Interesting Fix to weak Hatch Shocks

[Racerbvd]

Like most of our cars, the hatch shocks are very tired and installing new ones tend to help the old hatches separate from the glass. Well, I decided to go old school with a prop.

My cure was to install a carbon fiber hood prop for the rear hatch. So far I am very happy with this fix.




[img]http://uploads.bmxmuseum.com/user-images/23382/20200921_1504445f691011a6.jp


A fellow Pelican makes these, here is the thread.
FS:Carbon Fiber & Titanium Front Hood Prop Rod

[racer]

Slick alternative and works great on 911 trunk lids in the link.

Do you run two prop rods? I would think running only 1 would flex the frame unevenly and perhaps cause more stress than popping in two newer gas struts.

I considered a regular (wood) prop rod that I could center on the rear hatch to even the stress on the frame, but if its centered, its hard to get things in or out of the hatch

[Racerbvd]

Originally Posted by racer

Slick alternative and works great on 911 trunk lids in the link.

Do you run two prop rods? I would think running only 1 would flex the frame unevenly and perhaps cause more stress than popping in two newer gas struts.

I considered a regular (wood) prop rod that I could center on the rear hatch to even the stress on the frame, but if its centered, its hard to get things in or out of the hatch

Good point, so far, no problem.

[944 Ecology]

https://www.amazon.com/gp/product/B0002SRCYM

[wwdwgs]

A single prop on one side would flex the rear glass hatch and may cause damages - the glass is to heavy and its frame many not HOLD it well.

[Monkey Wrench]

https://hoodstay.com/

the idea is ok but the stainless steel clamp bolt will gall up the shaft and tear the seals.

maybe with a brass bolt.

I think the nicest way to accomplish holding the hood up is to create an over center locking arm that can support the glass when open and is easy to unlock with both ends permanently fixed.

to understand how an over center locking mechanism works use your knees as an example. when you are standing you don't exert much energy to stay in the standing position and yet the can fold quite easily. they do not bend backwards.

all it takes is a piece of flat iron with a hinge pin and a flat part to prevent it bending very far past center. that can neatly fold away..



a very simple solution is to place about 8" or so of plastic pipe over the cartridge , then you just lift it up so it is loose and then cock it to one side so the end of the tube is against the end of the strut, between where the rod exits and its' top mount.

when you close the hatch you just guide the strut back inside the tubing.


if the old worn struts are still in place they can still take a lot of the weight, the tubing only supports the difference ( what was lost by it loosing some pressure)

if you put them on both sides it may be a little awkward to work. i like the over center arm idea best..

[924RACR]

I just went with the Jeep struts (new from Amazon and real cheap) as posted in a previous thread here... rather like them, and not so crazy strong like the stock ones, subjectively...

[TheSecondChris]

I'm using the Lisle clamp that George recommended. I was too cheap to buy the one with the magnet inside. I wish I had spent the extra two dollars.

I would probably want to use one on each side if I routinely was keeping the hatch open for long periods of time. But using it on only one side seems fine since I rarely use the hatch at all and only keep it open for a few minutes when loading and unloading.

[Dano944]

When my father-in-law passed and I took ownership of his 944, he was way ahead of the curve. He had both the hood and hatch supported with silly broom handles. Call me wrong, but the first thing I did was order new struts from Pelican. To be able to work on the car without the hood or hatch hitting my head was a thrilling accomplishment.

[Monkey Wrench]

its not really a problem with the hood, the problem is with the gas struts pressing constantly on the glass frame, a lot of owners are finding the frame distorts over time from the constant pressure , then the glass comes loose. Its a weak point in factory engineering .

I wonder if the problem could be eliminated with a rod that attaches to both the front and back of the hatch so the constant pressure could be upon this rod , which could in turn have more than one mounting bolt to secure that to the hatch. that way any pressure applied would be spread to the bolts that secure the rod to the hatch rather than being so localized

on the underside of the hatch maybe there is room for a rod, for the strut to push upon , rather than just one point of the hatch. it would also help stiffen things up a little.

i'm thinking a hunk of 3/8 rod or 1/4" x 1/4" angle iron or 3/8" square bar stock, something like that.
It could that be attached to the underside of the hatch, maybe bent a little to fit nice, then attached to two or three points along bpth edges of the hatch, with a mounting point for the stock strut? the parts might add to the weight a little maybe you'd need a slightly stronger strut if you added much weight. use aluminum to reduce weight of the added parts, maybe..

[wwdwgs]

Originally Posted by Monkey Wrench

I wonder if the problem could be eliminated with a rod that attaches to both the front and back of the hatch so the constant pressure could be upon this rod , which could in turn have more than one mounting bolt to secure that to the hatch.

MW. I tried that without a lasting success. That means, the tension was applied, but I didn't "feel" that the frame was "squished" "back". I didn't increase tension in fear that the glass would shatter. So, I left the glass hatch as is and removed the gas shocks.

Presently, I play with other options to use gas shocks, but eliminate glass hatch stretch and still have opening height, comparable to the original. Fun.

[BobCT]

I can live with “lifting” the hatch up but I really want the remote release and hatch light to be functional. The struts I have now are new from the prior owner and hold the hatch up no problem but there is zero “pop up” so the remote release can work.

I think I’m just going to get the OEM struts and deal with the frame when that day comes.

Bob

[wwdwgs]

BobCT, dealing with the glass/frame separation is harder than with the gas shocks....

[Monkey Wrench]

here's a drawing of what I'm thinking, it can also look like just a flat bar with an edge welded to it near the pivot, that stops movement just past the center point. in the image they used a pin as a stop, same result, different ideas. The flat bar thing is easier to make up in your basement without a milling machine.

I think if something like that could ride along beside the struts it would be just a matter of giving it a little push to lock or unlock, and it would be stable even with weak shocks.

I like that a lot more than a prop rod , but might take a little though to mount it and position it so it isn't interfering too much..

maybe a spring with an inch or so of compression could be added to make the latch pop the first bit,, then you'd compress the spring as you closed the hatch?

I think it's an interesting engineering problem that could be solved with a 12 V l linear actuator.. but that gets a little too complicated.. in theory a linear actuator ( or a pair) worth under a hundred bucks could automatically open the hatch and close it too , it would not put pressure on the hatch when not being actuated, removing the 24/7 pressure entirely on the hatch and replacing the gas shocks.

some new SUVs have a sensor where you wag your foot and it opens the hatch. kind of similar..

it might get stuck and self destruct if blocked mechanically.. and basically that's just a half baked plan..

[originalowner]

Originally Posted by BobCT

I can live with “lifting” the hatch up but I really want the remote release and hatch light to be functional. ... but there is zero “pop up” so the remote release can work.

Remote release:
https://forums.pelicanparts.com/porsche-924-944-968-technical-forum/1104821-remote-rf-control-rear-hatch.html

After taking ours back 7 times to the dealer when new, Porsche AG declared that they were not warranted to pop up when released, and manually lifting the hatch to get it started up was acceptable performance.