What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Safety Wire Gascolator

newamiga

Well Known Member
Guys installing the gascolator the directions say to safety wire the four screws on it. What I am wondering is exactly how to safety wire them? Not how to use the tool and wire but rather where do you run the wire? Maybe a dumb question and I searched the forums but no luck finding an answer.

Thanks Carl
 
The 4 screws that connect the bottom bowl from below have holes in their heads for the wire to pass through. Many online resources exist for the techniques. Basically run the wire from screw to screw in a way that it resists the screws unscrewing.

NOTE! You will have to drop the gascolator bowl after you do some fuel flow testing in the engine commissioning process. Thats to check for debris. So wait until after that to safety wire the gascolator or you will just have to cut the wire anyway. Hang some tape or something on it as a reminder.

As I built the plane I checked and initialed every step and signed each page when all steps were done. If for some reason I skipped a step on a page to do it later, I did not sign the page and I put a sticky note on it that stuck out visibly.
 
Last edited:
If its hard to run wire amongst all four screws, you can effectively run two separate safety wires between two screws times two.
 
safety wire

it can be a bit hard to get the wire through but I loosened the back screw a1/4 of a turn to get access to the hole and after threading the wire tightend the screw again pointy nosed pliers helped and I did as mentioned before don't try and do all four screws together just do the two left ones and the two right ones separately
 
Not Wired

Mine is not safety wired. Is there a big problem with these screws backing out?
It seems that the bowl is in pretty tight with the O ring. So when the screws are out, It still is a little struggle to get the bowl out.
 
Mine is not safety wired. Is there a big problem with these screws backing out?
It seems that the bowl is in pretty tight with the O ring. So when the screws are out, It still is a little struggle to get the bowl out.

I suspect the fuel pump may supply the required pressure to remove the bowl when the screws go missing in flight. :eek:
 
They say risk is made up of two parts: probability and consequences. Low probability of coming loose maybe, but very serious consequences. Mine are safeties.
 
Carl... I safety wired pairs of screws on the gascolator. From what I read, the safety wire is there to break if the screws start to back out. So if the wire is broken the screws need to be retightened. This info was counter-intuitive to me. I thought the wire was there to keep the screw from backing out. Silly me.

Jeff
 
Does anyone have a source/part number for those screws? I have buggered them up pretty good and want to replace them next time I remove them.
 
Carl... I safety wired pairs of screws on the gascolator. From what I read, the safety wire is there to break if the screws start to back out. So if the wire is broken the screws need to be retightened. This info was counter-intuitive to me. I thought the wire was there to keep the screw from backing out. Silly me.

Jeff

In aircraft (and all other applications I am familiar with) safety wire is used to prevent an important fastener from rotating, not to show you later (maybe after it is too late), that it has rotated.

Wire used to indicate wither something has been tampered with is not safety wire.
 
Thanks for all the great replies. I will wait until the end to wire them up then.

Carl

That's cheating!! Just think of all the `safety-wiring in impossible places', `bandaid application' and `vocabulary improvement' practice you're going to be missing out on. :D
 
Thanks for all the great replies. I will wait until the end to wire them up then.

Carl

I went just through this, the proper time to do it is after you have finished the ground run of the engine which is PAP Section G6 last step.
I asked a local A&P for the safety wiring as I was afraid the proper procedure would be to twist 2 wires from screw to screw but he told me to just thread the wire through all screw holes and do the twisting between beginning and end of the wire. No particular problem to thread the wire, use a plier with a bent nose and if needed unscrew a little the screws that have the hole in a position hard to access. You still can tighten the screw once it's wired.
 
Loose screw indicator?

Carl... I safety wired pairs of screws on the gascolator. From what I read, the safety wire is there to break if the screws start to back out. So if the wire is broken the screws need to be retightened. This info was counter-intuitive to me. I thought the wire was there to keep the screw from backing out. Silly me.

Jeff

I've also been told (dark humored cynic) that the real purpose of Seat Belts is to make it easier to find the bodies.
 
Does anyone have a source/part number for those screws? I have buggered them up pretty good and want to replace them next time I remove them.

MS35265-63, SCREW, MACHINE, FILLISTER HEAD, 10-24 UNC-2A per email from Usher.
 
Page 28-05 Step 2

The 4 screws that connect the bottom bowl from below have holes in their heads for the wire to pass through. Many online resources exist for the techniques. Basically run the wire from screw to screw in a way that it resists the screws unscrewing.

NOTE! You will have to drop the gascolator bowl after you do some fuel flow testing in the engine commissioning process. Thats to check for debris. So wait until after that to safety wire the gascolator or you will just have to cut the wire anyway. Hang some tape or something on it as a reminder.

As I built the plane I checked and initialed every step and signed each page when all steps were done. If for some reason I skipped a step on a page to do it later, I did not sign the page and I put a sticky note on it that stuck out visibly.

Anyone care to opine why page 28-05 (Revision 2), Step 2 says "Safety wire the four screws holding the gascolator bowl to the top of the gascolator." if you're just going to drop the bowl later anyway? Mistake in the instructions maybe? Also, is there safety wire include with the fuse kit? I don't recall seeing any. Thanks for your replies.
 
You will need to supply your own safety wire, and twisting pliers. The wire is available from vans webstore, and won't cost much. It's handy stuff to have in your miscellaneous bits and pieces collection. Also useful for unexpected blood sampling. Trust me, I know
DaveH
 
Last edited:
Anyone care to opine why page 28-05 (Revision 2), Step 2 says "Safety wire the four screws holding the gascolator bowl to the top of the gascolator." if you're just going to drop the bowl later anyway? Mistake in the instructions maybe? Also, is there safety wire include with the fuse kit? I don't recall seeing any. Thanks for your replies.

Safety wire is the only thing that will assure retention of the gascolator bowl.

Safetying them at that point is to save builders from them selves, in case they do not follow the PAP step by step (a lot of the posts here in the forum over the years indicates that a lot of people don't).
If someone chooses to wait until after leak check and flushing the fuel system, then the burden of responsibility is on them.
BTW, this is what we do in our shop, but we put a warning tag on the gascolator so that we don't accidentally bypass safetying them later.
 
Scott is there a reason why Vans didn't use the gascolator type that has a hinged retaining strap with a threaded knob to pull it tight to the bottom of the bowl? They seem easier to service.
 
Safety wire is positive locking, star washers are positive thinking.
Cheers, DaveH
 
Last edited:
Worldwide Shortage of Safety Wire in June 2017

Just finished the engine portion of my condition inspection, and tried to safety the 4 screws holding the gascolator in place. Spent nearly an hour trying to get it right, but it wasn't. Cut the wire and did it again, with success. There has GOT to be a better way to secure those fasteners, otherwise, I will likely use up all the safety wire in the world trying to do it again next year.
 
Scott is there a reason why Vans didn't use the gascolator type that has a hinged retaining strap with a threaded knob to pull it tight to the bottom of the bowl? They seem easier to service.

No where near as secure as the screw type and not acceptable for pressurized systems.
 
Just finished the engine portion of my condition inspection, and tried to safety the 4 screws holding the gascolator in place. Spent nearly an hour trying to get it right, but it wasn't. Cut the wire and did it again, with success. There has GOT to be a better way to secure those fasteners, otherwise, I will likely use up all the safety wire in the world trying to do it again next year.

I hear ya. I wasted far too much time trying to get one run of wire around all four screws. Of course it was something like the fourth time I'd ever used safety wire. The guy who was helping suggested a different way, but I had already decided to do it my way. Should have done it his way, which was to use one piece of wire for the left screws and one for the right screws. Even backing up and starting from scratch would have worked better.
 
Last edited:
Ron,

I don't agree. My Cherokee uses the gascolator type with the wire bracket and screw. I have also used that type on several homebuilts with no issue. Seems like a better choice for maintenance.

Rich
 
Rich, do you think they changed the design over the years just to make maintenance more difficult?
 
Someone once suggested putting the safety wire through the back screws before tightening them the final last 1/4 turn. The gascolator does not depend on the tightness of the screws to prevent leaking. The seal is between the "O" ring and cylinder wall. All the screws do is to prevent the gascolator from coming apart.
 
I purchased stainless steel wire-lockable socket head cap screws (p/n90152A232) from McMaster-Carr. Using these made the re-installation a bit easier.

Mitch Garner
 
I purchased stainless steel wire-lockable socket head cap screws (p/n 90152A232) from McMaster-Carr. Using these made the re-installation a bit easier.
Mitch Garner

Did the same. Well worth the cost. I can put a short length of safety wire thru the socket head capscrew before installing. Can insert it and tighten using a long T-handle allen wrench thru the new hole in the plate immediately under that problematic gascolator screw. The safety wire hole in the capscrew is deep enough to allow an allen wrench even with the safety wire inserted.

Yes, the safety wire will wrap itself around the shank of the allen as you tighten, but, every couple of turns you can unravel.
 
Ron,

The design has not universally changed. There are still plenty of the wire bracket type being made. The only issue I've had in 30 years with the gascolator on my Cherokee was caused by the mechanic who didn't tighten the bracket so the gasket leaked.

The new design may be a belt and suspenders approach, but the wire bracket is adequate.

Rich
 
Back
Top