Tab 400 screen door string repair

JeffroNC · July 2020

Has this happened to anybody? Does anybody know how to fix it?

Image: https://us.v-cdn.net/5021717/uploads/editor/1x/e8hwl6wdg0me.jpeg

Verna · July 2020

That happened on my T@B S Max. I was told in 2016 it was not repairable. You do have to order the entire door/screen assembly, and the shipping is not cheap.

I imagine a super patient person could put new thread in. I’m patient when comes to wood, but not screening material.

On second look, the screening is torn....I think the new door/screen assembly is in your future.....unless you want to prove me wrong😉

PamandJohnUpNorth2 · July 2020

The black outer cover on the strings on my 2018 T@B 400 have started to unravel. If it gets to the point where the screen door is no longer viable i think i would consider replacing at a much lower cost and more convenient than sliding screen door IMHO. I might opt for a magnetic closure screen door. Check it out here: https://bugoffscreen.com/custom-sizes/

MandoBiker · August 2020

I recently had the same problem in my 2019 T@B400 BDL with the black outer covering unraveling on the string on the screen door. I was able to restring the door with some issues but it's working ok for now. I didn't photograph the process, but if anyone else is interested in trying this, here is what I used:

First, I found instructions from the manufacturer of the screen here: https://a3449449-b500-4315-8e52-2f46b9e780ac.filesusr.com/ugd/14074c_37227aee5fd3463abc4cc71b1d603ef8.pdf

And I purchased the following from from amazon:
Cord

Crimps
These are smaller than what was on it originally, but they worked.

Tape
I didn't have this when I was putting it all together, and it doesn't seem essential, but 3/8" double sided tape (leaving the backing on one side) is close to what was on there.

The restringing was pretty straight forward, but getting the door apart and back together was tricky. Once the door is removed from the trailer, the top piece comes off easily by just removing some screws. The bottom piece was the tricky part. It is secured with plastic L-brackets that are riveted in place. I couldn't figure out any way to remove the rivets and ended up breaking one of the brackets. I also damaged the rivet, which is used to hold the cord in place. I was able to still run the cord around that damaged rivet, but it has rough edges and tensioning the cord could damage it.

Once I secured the door back in the trailer, it functions pretty well, but that lower right corner is not held together and the bottom rail occasionally needs to be pushed back in place.

Jyll · August 2020

I may be oversimplifying but it looks like you could string it back thru then super glue just the end to the screen?

Verna · August 2020

Jyll said:

I may be oversimplifying but it looks like you could string it back thru then super glue just the end to the screen?

The push and pull of the string as the screen folds and unfolds would cause it to quickly pull out of the super glue. It needs to be secured within the screen door frame.

JeffroNC · August 2020

I am going to have the Screen replaced at NuCamp when I take the tab in this December.

Until then, I drilled holes in the frame, stuck a twist tire through them, added some thread my wife had to make up the difference. Ugly but it works.

Sharon_is_SAM · January 2021

I just added screen door repair directions as provided by member @vhollow. They are stored under the Category "User Manuals...". Look for "Windows, awnings, shades and screens".

https://tab-rv.vanillacommunity.com/discussion/6399/windows-awnings-shades-and-screens#latest

ScottG · January 2022

And now it's my turn...

About mid-season the screen door on my 2015 320 started sticking--a precursor to the string breaking shortly thereafter. Not one to dodge a challenge (especially one that could save me $300 for a whole new door) I decided to take this on as an off-season project. I'm still awaiting materials to complete the repair, which I am confident will be successful in no small part thanks to the contributions of @MandoBiker (who was the first to document a successful repair) and @vhollow (whose excellent directions really help to make sense of the obtuse Horrex repair manual). I'll add my experiences only to the extent that they differ from or supplement those already available.

For starters, understanding how the door actually works is helpful. The mechanism is surprisingly simple, but was not at all obvious (at least to me) until the door was apart. For those who are interested, I've whipped up a crude schematic. In this case, the screen is shown in a half-deployed position.

Image: https://us.v-cdn.net/5021717/uploads/editor/6i/2z6qjy4wvxc4.jpg

In reality the string is a single 13-yard length that is woven in and out of the screen stack multiple times. However, from a functional perspective, it's easier to think of it as two separate string "units" which I have shown here in red and blue. One one end, the strings are fixed to the leftmost edge of the screen stack, on the other they are anchored to the top and bottom of their respective tracks. The strings are under tension at all times.

When the screen is deployed, the strings feed into the top and bottom of the pull bar. After splitting into three, they slide into grommets on the rightmost edge of the screen stack.

When the screen is retracted, the opposite occurs. The strings are drawn back through the grommets and back out the top and bottom of the pull bar. As the pleats of the screen collapse, the tight strings keep the folds in line with one another and prevent buckling.

As you can surmise, the strings are subject to friction in various places, including the grommets on the screen, the points where they exit the pull bar, and the flange/rollers in the upper and lower tracks. There is also potential chafing where the strings and their associated hardware slide past each other inside the pull bar. Breaks will likely occur at one of these locations--the specific location will probably determine whether your screen experiences a little bulging, or suffers a complete meltdown.

My break occurred at the orange dot shown below. As such, only the topmost string was affected and tension was maintained in all the others. The door still worked fine except for a little unruly bunching in the upper left corner when the screen was retracted. I probably could have lived with it indefinitely (or at least until another break occurred) had I known exactly how the door worked.

In contrast, a break in the single string that exists the pull bar would release tension on at least half the door and, I suspect, render it virtually inoperable.

Image: https://us.v-cdn.net/5021717/uploads/editor/a4/bmmxxp60hl91.jpg

The bottom line is that given all the sliding and scuffing I'm impressed that these strings hold up as well as they do. Regardless, I'll bet more than a nickel they will break eventually and owners of older T@Bs with well-used doors will be faced with either making this repair or forking over the dough for a complete replacement!

Bayliss · January 2022

Three cheers for @ScottG, @vhollow and @MandoBiker!!! Real trail blazers.

ScottG · January 2022

Thanks, @Bayless. However, talk is cheap so I will decline nomination to the trail blazers club at least until I have successfully completed the repair! :-)

It's also worth noting that someone recently posted their new T@B arrived without a screen door as a result of supply chain issues. It's conceivable that in some cases repairing a broken door may be the only short-term option. :-/

Tabaz · January 2022

I spent HOURS trying to repair my 2016 screen door without luck. Gladly spent the $250 on a new door and installed it in about 10 minutes. Scott, I suggest you do a video of your repair instead of still photos. That would be very helpful to those attempting this project.

ScottG · January 2022

I wondered when you would surface in this discussion, @Tabaz...

Practically speaking, the repair is half-done. I've got the door apart, I've figured out how it works, and I've rebuilt the flange/roller assembly in the lower track since whatever was in there originally got savaged when I drilled out the rivets.

I'm not much of a cinematographer--nor will I likely welcome the distraction of recording video while I'm concentrating on getting the door restrung--so no promises there. As noted previously, I will pass along any tips above and beyond what others have already provided.

Maybe the next time I do the repair I'll assemble a video if someone else hasn't beat me to it!

And remember, LUCK favors the bold. ;-)

Tabaz · January 2022

Mine did not have a "roller" in either track - just a smooth area of plastic that the cord went around. A photo of your roller would be helpful.

ScottG · January 2022

Mine didn't have "rollers" either, but it seemed like the least confusing term to use for the sake of describing how the door works.

The top rail had a little plastic fin--probably the same thing as what you are describing. The bottom I'm not sure about. vhollow recalls a similar plastic piece that was attached to the bottom rivet, but if I had such a thing I mangled it beyond recognition when I drilled out the rivet. Here is what I have replaced it with--a longer rivet that fills the entire track and provides a smooth surface for the string to wrap around when everything is reassembled

Image: https://us.v-cdn.net/5021717/uploads/editor/h3/3ob73bkwglv3.jpeg

Tabaz · January 2022

Looking forward to your photos and write-up when completed. The more details, the better!

ScottG · January 2022

@Tabaz any chance you have a photo of the plastic piece (or whatever it was) that the cord went around in your lower track?

ScottG · January 2022

[EDIT: The peculiar dohicky I pictured here earlier is part of the door mounting hardware but is not part of the lower rail assembly.]

Regardless, it appears that the cord did wrap around the lower rivet (or some appendage thereof) though exactly how that was constructed will remain a mystery until someone else more careful than I disassembles their door. I'm thinking my concoction (pictured above) is probably pretty close to what was there originally.

In contrast, Here is the counterpart from the top rail (the right end of which is visible to the left of the photo. It's just a little plastic flange not much bigger than the cord itself. (@vhollow describes replacing this with a steel "roller" that will exert less stress on the cord.)

Image: https://us.v-cdn.net/5021717/uploads/editor/jy/lqkuw6dbwizg.jpg

Similar plastic bits guide the cord where it exits the top and bottom of the pull bar.

Although the plastic bits are smooth, there is evidence that they get worn down over time. If the cord is chafing the plastic you can almost bet the opposite is happening, too.

Tabaz · January 2022

Scott - Those metal "screws" are what hold the vertical door frames to the T@B body. The rounded area between the base and head slip into a metal bracket attached to the T@B. They have nothing to do with the operation of the door itself. I did have the two plastic pieces shown in the lower two photos, so it looks like our doors are the same.

ScottG · January 2022

Oh duh. You are so right!

When I removed the door some time ago, one of those four screws was broken. I threw the sheared off head in the pile with all the other pieces-parts and promptly forgot where it came from.

It does seem that the lower "roller" was something comparable--maybe a rivet with a washer on it. I have a few of those parts I can't quite account for, either... :-/

I will edit my previous post to avoid introducing unnecessary confusion to those who may be following.

ScottG · January 2022

I finally got my parts and was able to wrap this project up this weekend. I'll reiterate that the information previously provided by @MandoBiker and @vhollow are excellent resources. Maybe I could have figured this out on my own through sheer force of will, but I am pleased that I didn't have to.

I've already posted a schematic and simplified description of how the door operates. I'll limit the remainder of my comments to those things that are different from or in addition to those already published:

1) After spending a bit of time in the internet rabbit hole, I opted to use 0.9mm polyester blind cord rather than nylon. Polyester cord seems to be the industry standard. Nylon cord apparently has more stretch in it and some reviewers (non-T@B) felt this complicated repairs they had made of their RV window shades. That doesn't mean the nylon cord won't work, I just opted to go with the slightly more expensive polyester. The 60lb monofilament used by vhollow is probably an even better choice, but I thought it would be more challenging to work with so opted to stay with the original material for this first attempt.

***EDIT August 2022: DO NOT use this polyester cord. It began fraying almost immediately, and started binding and breaking after only a few more trips. See my more recent comments further down.***

2) My repair was on an older 320. Previous discussions have been for the 400 door, and the official Horrex repair manual appears to be for yet a slightly different model. Regardless, the basic principles are the same. The 320 door is apparently shorter than the 400 door--I only used about 10 yards of string vs 13. Regardless, string is cheap and the excess is easy to remove, so err on the side of more vs. less.

3) If you drill the bottom rivet on the right side, you will destroy the mechanism around which to cord winds--which appears to be an extra long rivet with a washer on top. My solution was to replace this rivet with something similar, but to do this I had to also remove the right side rivet.

You may be able to avoid this by drilling just the side rivet. If you do, be careful not to damage the flimsy plastic bracket or the existing bottom rivet.

3) Threading the cord is easy, but (I feel your pain @Tabaz) getting just the right needle is challenging. Thinner needles are easier to push through the screen mesh pack, but their holes may be too small to thread the cord. Larger needles with larger eyes may be too fat to pass through the metal grommets on the mesh pack. My needle was just a little too large when threaded, but I made it work.

I found positioning a nylon zip tie near the grommets helpful helpful to maintain the alignment and tightness of the mesh pack while threading the cord.

Image: https://us.v-cdn.net/5021717/uploads/editor/ow/93kvg39wy7os.jpg

4) Once the cord is threaded, adjusted, and taped, insert the mesh pack back into the left side frame before tightening and crimping the cord. This is in vhollow's directions, but I emphasize it because having the mesh pack held perfectly straight is important to getting the cords equally tight before crimping.

Image: https://us.v-cdn.net/5021717/uploads/editor/65/aa7ssxo1adik.jpg

5) As mentioned previously, my cord broke because of apparent chafing on the metal crimps inside the pull bar. vhollow addressed this with a dab of silicone, but I opted to try this with a less messy length of 3mm heat shrink tubing. If you do this, use a heat gun set on low (300F)--higher temps or open flames rink burning the cord you just carefully threaded!

6) If you have gotten this far, reassembly is relatively straightforward. Or not. The lower tensioner (the doohickey that anchors the cord in the aluminum bottom rail) needs to be pretty tight to prevent slipping. It's also made of cheap plastic. Mine broke in two upon tightening (left photo), prompting the fabrication of an emergency replacement (middle and right photos)--this one made of 1/8" aluminum. While this is far superior to the original, it did require some additional tools and skills. (The upper tensioner--which is narrower and is tightened to the plastic upper rail--snugged up without issue.)

Image: https://us.v-cdn.net/5021717/uploads/editor/pr/l123ux264857.jpg

7) The door may need some final adjustment after being reassembled. Cords that are too loose may bunch when the screen is retracted. Those that are too tight may prevent the door from deploying fully. You can adjust this by moving the tensioners a bit one way or the other in the rails. Keep in mind that the upper tensioner controls the lower three strings in the screen panel, while the lower tensioner controls the upper three.

Ideally the tension on the strings within group should be equal. This will be a function of how well you tightened the cords before crimping (see #4 above). Mine were not 100% perfect--the uppermost and lowermost strings seem a little tighter than the others--but it is close enough and everything works as it should.

ScottG · January 2022

I'll also add that should a critical part break and you are unable to fabricate a replacement, this place may be able to provide what you need.

(Thank you @mjwaldner. Original comment here.)

dragonsdofly · January 2022

@ScottG I AM disappointed! I was looking for the special t@b yoga lesson to be included, but alas... However, I do make note, and allowance that some mental and physical t@b gymnastics (also special) were employed in the making of this repair. In that regard, I AM impressed. Congratulations on your preserverance and fortitude. Perhaps, a t@b university badge is in order in the advanced adversarial accomplishment category. Just sayin'! -Denise

ScottG · January 2022

Thanks, @dragonsdofly Fortunately there was not much T@B yoga required for this task, but the mental gymnastics were more than enough! Really not all that big of a task if you study up beforehand, take your time, and follow the leads those who have gone before have generously provided.

ange · April 2022

The set of cords that go to the bottom of the door and as a single cord to the tensioner has frayed and broken. This is going to happenagain and again as dust/grit enters through the brushes on the bottom rail. Has anyone figured out whether it would work to redirect them to the opposing side of the top rail?

ScottG · April 2022

ange said:

The set of cords that go to the bottom of the door and as a single cord to the tensioner has frayed and broken. This is going to happenagain and again as dust/grit enters through the brushes on the bottom rail. Has anyone figured out whether it would work to redirect them to the opposing side of the top rail?

Unfortunately this would not be possible for a couple reasons.

The operation of the screen requires that the cord rollers are placed on the side of the frame opposite the screen pack. Study this schematic carefully and you will see why.

Also, note that the bottom cord actually feeds into the top half of the screen pack. This allows sufficient length for the cord(s) to run up and down within the pull bar as the door is expanded and retracted.

Cheryl13 · May 2022

We took our screen assembly out of our T@B400 2021. We still have it if someone needs one. I can post it in the 'for sale' area in case. Will get hubby to take a pic or 2.

PamandJohnUpNorth2 · May 2022

I could be interested. depending on your location. Shipping can get pricy for door sized items. Please post on "for sale" with your contact info.

KAR · May 2022

Damn! This looks complicated. I may have to do the Jeffro NC tie trick! Or just leave it as is!

Thanks for all the info though in case my husband decides to tackle this!

ScottG · July 2022

Ugh.

Three trips in and I noticed the new upper and lower cords are fraying, apparently from the abrasion of normal door operation. While they have yet to break, the fraying sometimes causes a bit of binding. Otherwise, the door continues to operate normally--for now...

My speculation is that the replacement cord I used--even though I researched carefully and purchased the more expensive polyester cord designed specifically for blinds--lacked the abrasion resistance of the original product. If (when) I end up repeating this repair, I will strongly consider @vhollow's approach of using heavy duty fishing line!

vhollow · July 2022

The heavy, clear monofilament has worked very well for me. No sign of abrasion after many, many trips.

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