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Compartment Door Fasteners

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https://www.barthmobile.com/eve/forums/a/tpc/f/3431087061/m/9573928197

08-12-2018, 05:57 PM
Clint Webb
Compartment Door Fasteners
Over the last two weeks, I have been removing the compartment doors in order to facilitate welding repairs on the compartment floors of my 90 Regency. I decided to use stainless button head 1/4"-20 thread 1" long bolts to replace the rivets. The button heads look like rivets but have an allen head drive. This required drilling out the rivets and taping all the holes for 1/4" course thread. The taping is tricky because of the thickness of the frame tubing which supports the door. The top piece of tubing is 2" and is especially thick. It is very easy to break off a tap when doing this so I used a little trick to ensure no breakage.

The trick is to use a larger drill for use with the tap. The specs for a 1/4" tap is to use a #7 drill bit to give 100 % thread. If you use the #7 (.201") on the top support, breakage of the tap is guaranteed. I used a 7/32"(.218) for the holes. This will still provide plenty of thread for the fastener in this application and will prevent the tap breaking. You must use a starting tap of the highest quality with lots of cutting oil.

To provide a seal and prevent galvanic action, I used 1/4" stainless bonding washers on the bolts. These have stainless on one side and rubber on the other. Make sure you use anti seize on all the bolts.

Regarding sealant for the door frame, I found that Barth used, on my coach, the same butyl rubber strips used for sealing the windows. These strips are readily available and stay flexible. The top sealing flange is only 1" wide so be fussy on the seal fit.

The bolts and washers are available from Fastenal on line. The bolts are sku 1173755 (.31 cents each) and the washers are sku 1133165 ($17.46 per 100)

One last thing, you may run into (as I did) the situation where someone has used steel rivets in the frame. These are very hard to drill out without wandering of the drill. To prevent this, I used a piece of 1" steel flat bar clamped to the lip of the frame. The length covered the rivet hole in question and the holes on either side of it. Using the holes in the frame as a guide, I drilled 1/4" holes for the three locations in the piece of flat bar. The piece of
flat bar was then bolted to the coach in the two side hole locations which allowed the centre to be drilled for the tap. The steel of the flat bar keeps the drill centered.
08-13-2018, 07:52 AM
Kevin
How are the tails of the door frame supports that extend under the coach? I had to replace my vertical frame "j tubing" before making any basement floor repairs. I removed the aluminum skin. You may find the basement door frames do not always hit the center of the vertical frame supports. This may be the reason you are breaking taps. The vertical frame rails are only .0625 thick. My replacement vertical frame rails are .125 or twice as thick.
08-13-2018, 12:05 PM
Clint Webb
Kevin: I did notice that some of the rivet holes were off centre in some spots and touched the edge of the tubing. This was why I used the larger drill on the sides and bottom holes. Using a #7 drill still caused binding of the tap for these close situations.

In the rear passenger side where I am working, my tails are ok however the horizontal piece attached to them is soft in several spots and will need to be replaced. This can be done without removing the skin. The floor in this area requires only minor patching

I am, however , in big trouble on the driver side where the entire floor under the water tanks is very soft. This will require removal of the skin.The large compartment adjacent to it also has a bad floor. To the rear, behind the wheel,the skin is eaten through on the curve at the bottom from galvanic action against the steel frame.

The driver side work I am leaving until next spring when the coach comes out of storage in late April.
08-13-2018, 07:00 PM
Kevin
Clint, you may have seen the slide show, but for other newbies, here is the link.

Clint be prepared for a lengthy process to remove the aluminum skin. Barth used bonding adhesive with the rivets to put the aluminum skin on.
If you are planning to rebuild the floor of the water cabinets, just buy all new flooring. I patched in the floor in several areas. It would have been much easier to use all new metal. Be sure to consider the weight of your water when replacing the water tank floor supports.
Thanks for your post. It is nice to see another member restoring the components of their Barth.