elmshoot

My Feedback: (6)

I picked up a Royal Bearcat already built with Rom-Air retracts and control valve already installed. I have been chasing leaks and have now found a leak in the selector block. It is a flat aluminum block with 3 air barbs on one side and 2 on the other side. The 2 side has been capped off and sealed.
I presurised the block and stuck it it in some water and it is leaking from the spool. The easiest thing to do is replace the O rings. Does anyone have any spare Orings or do they know what size they are or who supports the rom-air stuff.

Also the retracts them selves have no markings on them. I suspect they are Rom-Air. They are air up and air down but when in the retracted position they do not lock in the up position. They can be pulled down and I suspect that under G loads with low system pressure they will droop. I have not dunked the gear to look for leaks from them but due to the age of the units I think the O rings are dry. Can I lube them with some oil and if so what type. The guys at B&D retracts says to use STP oil treatment on their brand. What about the engine after run oil that is safe for OS/YS or how about pure Castor or MMO Air tool oil. I have all kinds of oil but I'm not sure what is the best to use.
Sparky

The Ghost

The O rings you should be able to pick up at auto stores. As fro oil I would only use a good quality air tool oil.

Cheers.

Chad Veich

My Feedback: (60)

I took the old o-rings out of mine and easily matched them up to some at a local hardware store. To lube them I used the grease that they make for lubing the o-rings in faucets, forget the name. I've had good luck with Rhoms in the past as they have been more dependable than many newer brands. However, the lack of an up-lock is definitely their drawback. Good luck with your Bearcat.

paladin

My Feedback: (9)

Sparky, I have 5 pairs of Rohm-airs, all purchased at flea markets. I usually do this when I have some time to spare before the plane is ready to go. I go to my local Low’s, while they usually do not have the sizes I’m looking for they will order them with not extra fee’s. Which is important because to order all the o-rings in the retracts will probably cost you all of $2.00.

Your O rings need replacing if you push a finger nail into them and the nail imprint stays. You should feel good pressure from the o-ring as you are pushing on it and it should return to shape immediately upon your relaxing the nail pressure on it. If the o-ring reacts well to the nail teat it needs some TLC.

Go to your local auto parts store and ask for AC lube. It comes in a aerosol can you want it without Freon, just the lube. I then empty the lube can into a bowl and transfer that to a medicine jar with an eye dropper or an old Visen bottle with a cap. You want to do this quickly as the stuff that will expand the o-rings will evaporate quickly.

Once that is done pull the spool valve out and put enough of this stuff on each o-ring that it has had one drop fall off each o-ring, then reinstall it in the spool valve. Pressurize the system to full pressure and walk away. Check it periodically to make sure it still has pressure over the next three days. Eventually it will start to hold pressure again and you are done.

The recon. Oil component that causes o-rings to swell vaporizes quickly. So once in the system and under pressure the leak will get a constant exposure to this stuff as the air escapes past it causing that area to swell faster than the others on the o-ring and sealing the leak.

You can use this on the cylinders, and fill valve as well, the cylinder walls unscrew. Do not use tools to unscrew them!!!!! They will come loose with hand pressure. Once the leak is sealed I would wipe the o-rings clean with a towl/diaper (that wont leave a lot of fuzzes behind) and use marvel mystery machine tool oil to lube up the retracts.

Doing this stops the expanding of the o-rings, well slows it down. Then every year before I use the plane I suck oil into the filler hose for about three inches then fill the air system. The chemical that causes the o-rings to soften and expand will recondition the system. If you are loosing some air I would want to leave the oil in the system for a long time. If I have no leaks then I will put the recon. oil in right at the field so that As I use them the conditioning gasses will be expelled.

Good Luck
Joe

Tsutomu Mabuchi

My Feedback: (1)

I think you can use Robart or CJM control valve that has
two air lines, up and down.

Tsutomu Mabuchi

elmshoot

My Feedback: (6)

Guys,
Thanks so much for your help I used the Oil that is sold for lubeing the Ys engines (silicon safe). It fixed the leak in one of the retract units and I went to a Robart selector valve. It will hold 120 lbs of air for several days both in the up or down position. Now I just have to wait on the cowl so I can start on the muffler installation.
Sparky

8178

My Feedback: (17)

The silicon lube used for automotive brake calipers is a very good lube for the Rom-Air retracts and others with “O” rings.

Ch0pp3r

My Feedback: (3)

Vasoline is also inert and a good lube.