GMC Engine Door Gas Struts

[gus]

I just today added gas struts to my 4107 fiberglas engine door.

I attached a used stock '88 Dodge Caravan rear hatch strut to the original mounts after welding a one inch wide 3.25" bolt hole to bolt hole extension to the original 4107 door bracket. I used the original bottom bracket with some spacer washers to keep the strut from rubbing the bracket. 

Extending the top bracket makes the door raise a bit higher than the original sliding support, but the real benefit of the extension is that it holds the door closed with no latches or hooks necessary. The resulting geometry makes the strut push the door toward the closed position when down. This makes some moderate force necessary to get the door started up but the strut quickly takes over and raises the door with no more effort required.

I did this same thing on my 4104 which was easier because it had brackets on both sides. For some reason the 4107 only has brackets on the right side so I had to improvise on the left side. The left side works but is not to my satisfaction so I will probably change it. One strut alone holds the door up but I decided to add another one on the right side to even the strain on the door.

I have no idea of the pounds of force of these old struts but they must be at least 200 lbs when new because those minivan hatches are really heavy and I have to replace at least one a year on my two minivans. This gives me a steady supply of used struts so I probably won't ever need to replace them. These used struts have been on my 4104 door five years which is a lot heavier than the 4107 door, and show no sign of ever wearing out.

Believe me these things are worth their weight in gold, I can't even imagine doing without them!

The Dodge struts measure 23.75" open and 14.25" closed and cost around $20 new. These strut ends have holes so bolts will work in the original 4104 mounting brackets. If you use new struts the top bracket extension probably needs to be a bit shorter but it would be easy to shorten it by drilling another hole closer in.

I'll take some photos and email them to anyone interested.

[pabusnut]

Gus,

I'd appreciate some of the pictures.  I put struts on all six of my bay doors, and needed the 250lb ones attached to the original points at the top.

I can't picture in my mind how the strut would help keep it closed?!

Thanks!

Steve Toomey
PAbusnut

[happycamperbrat]

Can you post the pics here or send them to me and I will post them for you?

[gus]

I just now went out and took some photos.

Posting photos here to me is a real pain so send me an email to

egusDOTcATcenturytelDOTnet  and I'll send them to you.

You will see from the photos how the strut keeps the door closed and tightly. It is because the extension on the original door bracket sticks back into the engine compartment and becomes a short lever when the door is closed.

One thing I forgot to mention is that, because the struts keep the door tightly closed, it is necessary to mount rubber bumpers at the bottom of the door either on the door or the engine compartment. On my 4107 some brackets were already there so it was not much of a job. I used wood blocks and thick closed cell weather stripping on one and an old rubber bumper I had in my grab bag on the other.  Now I need a nice looking handle for the bottom of the door so I can keep it from slamming shut. My 4104 already had a nice SS handle but the 4107 has nothing and there is nothing to hold on to on the fiberglas door.

[buswarrior]

Big Transit here retrofitted gas struts onto the engine doors of the 5307's.

Great improvement, wish it was done sooner.

Yes, these early 1980's fishbowls are still hauling folks up and down.

happy coaching!
buswarrior

[gus]

I had to do it on my 4104, that door was too heavy for me to lift. It has a steel frame and is just about more than I can lift. Even as heavy as it is one of my old used struts could almost lift it.

The 4107 door has an Al frame and is fiberglas so it is much lighter but still too heavy to keep lifting when it is not at all necessary and so cheap and easy to fix.