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Usher UD-3 Fuel Caps

Aggie78

Well Known Member
I have an Usher fuel cap that's got some worn parts...specifically, the latch and post.

ACS and Van's don't carry this part and a forum search revealed an Usher order sheet with the parts/part numbers, etc. Great, I'll just reach out to the manufacturer.

So, I made a call last week to Usher, spoke with a rep there and described the problem and the part I needed to avoid having to throw the entire, still usable (if repaired) assembly away.

Just got the following email back from him this morning:

"It does sound like it is worn out. I will have to direct you to Aircraft Spruce where you may have to purchase a new gas cap. Since June 2020 we no longer sell directly to public."

So, they won't sell you the part and our usual supply sources don't/won't carry it either...

Like I emailed back to the company rep...disappointing.

Just passing along the news...
 
I too just contacted them. They told me to contact ACS. ACS said they don't sell the parts, just the o-rings or entire cap. I contacted usher again and they agreed to sell me the posts but I ordered 4 of them. The posts seem to be a wear item. Perhaps we should use a grease on the corner of the post where it goes overcenter rubbing away the corner?
 
I too just contacted them. They told me to contact ACS. ACS said they don't sell the parts, just the o-rings or entire cap. I contacted usher again and they agreed to sell me the posts but I ordered 4 of them. The posts seem to be a wear item. Perhaps we should use a grease on the corner of the post where it goes overcenter rubbing away the corner?

Yep, same thing I did in the same order, only they are saying they won't sell me the parts.

Looks like you got lucky and found a sympathetic ear.

They appear to be pushing the sale of caps at the cost of irritated customers...
 
McMaster-Carr has the replacement hinge pin, P/N 98381A422.
.062” dia x .750” long, 4140 Alloy Steel Pin

I tried .062 dia SS welding rod but it is not as tough as a 4140 dowel pin.
 
The problem I've encountered with multiple of these caps is the bottom corner of the latch gets rounded off resulting in gradual incremental failure of the overcenter mechanism. The latch then fails to stay closed. Perhaps some grease on that contact point would slow this process.
The manufacturer recommends lubrication as needed and annual replacement of the o-rings. I have not been replacing the o-rings, just lubricating it. I have not been lubricating the contract point for the latch overcenter, but believe I will start doing that.
 
McMaster-Carr has the replacement hinge pin, P/N 98381A422.
.062” dia x .750” long, 4140 Alloy Steel Pin

I tried .062 dia SS welding rod but it is not as tough as a 4140 dowel pin.

1/16" drill bit (6 for 2 bucks) sourced from Harbor Freight and cut down to fit is working good so far too...
 
The problem I've encountered with multiple of these caps is the bottom corner of the latch gets rounded off resulting in gradual incremental failure of the overcenter mechanism. The latch then fails to stay closed. Perhaps some grease on that contact point would slow this process.
The manufacturer recommends lubrication as needed and annual replacement of the o-rings. I have not been replacing the o-rings, just lubricating it. I have not been lubricating the contract point for the latch overcenter, but believe I will start doing that.

That's the problem, exactly same as mine.

In fact at the stage mine is at, adding grease now reduces what friction fit the part has now to practically nil and the tension on the part when closed...pops the tab back up again. I definitely think a light coating of lube/grease would be appropriate on new or undamaged caps. After the damage? No dice...

I've tried dressing the ears of the tab lightly with a file to bring back more of a right angle but either my technique is bad or removing material with the file just made the situation worse.

A cheap, simple fix to repair (with the right parts that the manufacturer used to allow us to obtain) that some manager/cube-dweller has now vetoed, rendering the problem cap good only as a spare parts source.

Frustrating.
 
Sounds like requests to Van's or https://www.flyboyaccessories.com/Default.asp to purchase the latch and post in quantity and make them available would be in order.

In the meantime, here's some preventative maintenance for those who's caps are not worn out yet.
1. Lubricate the o-rings with Krytox GPL 205 grease (not fuel lube)
2. Flip the stainless washer under the latch if it shows wear.
3. Lubricate the latch and underling stainless washer with a dry lube such as
https://www.triflowlubricants.com/product/tri-flow-superior-dry-lubricant/
4. Adjust the latch so that it just snaps over-center. Do not over-tighten! The rest of the instructions can be found here https://www.aircraftspruce.com/catalog/appages/Usher_flushCaps.php
I can open my caps with my little finger, and they don't leak fuel or water (from rain or washing the RV).
 
Why not fuel lube? Been working fine for me for the last decade.

Erich


I have found it to be a little sticky/tacky when I put it on the o-rings... Don't know but I suspect that that would carry over to the tab mechanism.

I am going to give the Krytox a go... Thanks for the tip.
 
Why not fuel lube? Been working fine for me for the last decade.

Erich

Yes; fuel lube gets sticky/tacky, and as it gets cooler, the resistance of the o-rings to sliding between the two cap halves goes up. This increases wear on the latch.

Krytox is a very light grease and only a thin film is required. It is chemically insoluble in nearly all solvents.
 
I've used chapstick. Is fuel lube the manufacturers recommend lubricant?
 
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Yep, same thing I did in the same order, only they are saying they won't sell me the parts.

Looks like you got lucky and found a sympathetic ear.

They appear to be pushing the sale of caps at the cost of irritated customers...

Or you could get this item. Unfortunately I saw this only after I already bought new Usher UD-3 caps from Aircraft Spruce. This is also posted in Facebook's Vans RV-4 Group but he makes it also for RV-6/7.
https://www.ebay.com/itm/VANS-RV-4-...qjg8qClRbk-2zI1fDQrQwJrDy2EyV6N-DwmtMooRigWrM
 
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