[Trumpetman]

I've been flying for a long time but I am new to retracts. I have a set of Robart retracts installed in a giant scale TF P-47. The retracts were purchased about 4 years ago and I am at the point were I have done a maiden flight last fall with the plane in primer. I was not able to maintain enough pressure in the system to safely retract and then extend the gear so I just flew it with the gear down. I'm finishing up the paint now and I want to sort out the gear issues. From what I have read there may be a problem with the seals leaking (given how much it has sat around!) and I would like to get some tips from you guys on how to lubricate the seals and any other maintenance work that should be done on a regular basis.

Any info would be appreciated!

[Max]

Originally Posted by Trumpetman

I've been flying for a long time but I am new to retracts. I have a set of Robart retracts installed in a giant scale TF P-47. The retracts were purchased about 4 years ago and I am at the point were I have done a maiden flight last fall with the plane in primer. I was not able to maintain enough pressure in the system to safely retract and then extend the gear so I just flew it with the gear down. I'm finishing up the paint now and I want to sort out the gear issues. From what I have read there may be a problem with the seals leaking (given how much it has sat around!) and I would like to get some tips from you guys on how to lubricate the seals and any other maintenance work that should be done on a regular basis.

Any info would be appreciated!

For my air retracts, every once in a while I would put a drop of 3-in-one oil in the air line between the bottle and the retracts. Once I learned to do this, I never had a problem with seals going bad.

[Pauld]

Usually this problem shows up at the valve itself. Remove the valve, take the c-clip off and pull the spool out. There should be some small o-rings on the spool that you can lube up with some o-ring lube, clean out the bore of the valve and carefully reassemble. Also check for pinholes in the lines.

Another source of leaks can be the air fill valve. One valve that I purchased I found the valve inside was loose and therefore leaking past the threads.

Good luck. Sometimes these leaks can be a real bitch to track down but a methodical approach will usually find them. You should be able to get at least 5-7 retract cycles and still have 50% of your air pressure left.

PaulD

[Trumpetman]

So, 3 in 1 oil to lube the cylinder seals and "o-ring" lube to do the valve. Is "O-ring" lube something I can pick up at Canadian Tire etc? I found a video at Troy Built Models where the guy says to use "compressor oil" to lubricate the cylinder seals and valves. According to him anything else can apparently damage the seals and gum up the cylinders etc. He says it is the stuff that is used to do the seals in air conditioners etc. Anybody else heard of this? Where can a person get a small amount of this very light oil?

Another question: when I put the system back together do I need to cut the tubing back to "fresh" tubing or can I just press it back over the nipple. Do you guys use anything to seal these connections when assembling/re-assembling?

[michel gravelle]

Hi

And Good Morning To All

1 ) never , " PULL " , on an air line , push it off
2 ) Always , " snip " off a small bit , when reinstalling
3 ) Always leave extra line when routing
4 ) Watch out for kinks
5 ) leave youre fish line in the wing , you never know
6 ) lub with a very light oil such as sewing machine oil , or a very light white grease ( used very sparingly )
These are the rules I live by , I learnt them from error , to get the experience

Have a good one

Michel

[MikeCam]

Never use petroleum based oil, it destroys rubber. Petroleum based oil will cause the seals to swell up, become brittle and break over time.

White lithium or silicon grease are the preferred products from the retract manufactures. They want you to open up the retracts and lube the o-ring with the grease.
I use tool oil, much easier to use. Every air tool has rubber o-rings and I have air tools that are 20 years old.

Air conditioning oil is also good, safe for rubber.
Another oil I just heard about is RC shock oil. Shocks have rubber o-rings and are kept under pressure.

I have a small syringe and I add some to my fill line once in a while and then pump up the retracts. The oil lubes the o-rings and also helps to keep any particles in the system from tearing the o-rings. I've read that guys have used tool oil for 30+ years and they still hold air.

One guy I know used wd-40 and a year later he had to pull all o-rings and replace. They were all cracked and looked like they had been left out in the sun for 10 years.

There is a reason they say not to use Vaseline for lubricant because it breaks down rubber. LOL

[michel gravelle]

Hi
And Good Morning on this very rainy day .

+1 on the above post . all excellent advise .

Michel

[Sailor]

Dow Corning 111 valve lubricant and sealant. Silicone based. Used in plumbing industry.

[Jim 15256]

A wealth of information can be found here. Click on this link ...... http://www.robart.com/faqs.

White lithium grease can be purchased from Canadian Tire in a small tube. Look in the automotive section.

FWIW Great Hobbies carries parts for Robart retract systems.

[Trumpetman]

Thanks for the info guys. I have used some lightweight R/C car shock oil. Pure silicone oil and we will see how it goes.