pilot_jb Posted October 29, 2018 Report Share Posted October 29, 2018 My plane is pulling pretty hard to the right when my yoke valve is installed. Been doing this over the entire year that I’ve owned the plane. I understand that this means that there is likely a leak on the right side of the system. However, we just had the plane apart for annual and found not find any breaks in the tubes, or connections. Also, all of the servos look really good, including the tape, and feel like they have a balanced amount of pull when manipulated manually. What does look bad is pretty much all of the surgical tubing that comes off the turn coordinator. Have any of you seen this tubing cause an imbalance in the system? Additionally, does anyone have a source for this tubing? I really don’t care about the functionality of teh autopilot, but I love the idea of being able to use the wing leveler. Quote Link to comment Share on other sites More sharing options...
Yetti Posted October 29, 2018 Report Share Posted October 29, 2018 (edited) Your vacuum tubing is old. It does that when it gets old. Brittian would send you down to the auto parts store for some more. Something about a high ozone environment Surgical tubing would look worse. 2 of these for filters http://www.fram.com/parts-search/G12 Edited October 29, 2018 by Yetti 1 Quote Link to comment Share on other sites More sharing options...
cliffy Posted October 30, 2018 Report Share Posted October 30, 2018 YUP Brittain told me to go to the auto parts store and find the right size vacuum tubing. Quote Link to comment Share on other sites More sharing options...
Yetti Posted October 30, 2018 Report Share Posted October 30, 2018 11 minutes ago, cliffy said: YUP Brittain told me to go to the auto parts store and find the right size vacuum tubing. so you're the one. I remembered someone posting that. Quote Link to comment Share on other sites More sharing options...
Shiny moose Posted October 30, 2018 Report Share Posted October 30, 2018 Brittain (Jerry ) would not have said vacuum tubing!!!! He would have said windshield washer tubing!!! 1 Quote Link to comment Share on other sites More sharing options...
Shadrach Posted October 30, 2018 Report Share Posted October 30, 2018 LASAR sells the correct tubing by the foot ~$5.00/ft). 6ft is plenty to replace everything behind the panel. Your's might look old, but I know from experience that it has a short service life (6-10years max). As bad as they look, I'd be surprised if they were your problem. If your plane is banking in one direction there are several potential causes. 1) servo leak. 2) hose leak. 3) internal leak or problem with source instrument. 4) incorrect hose routing (entirely possible as the MM illustration could be more clear in my opinion. 5) control surfaces out of rig beyond roll trim limits (highly unlikely). The first thing I would do is test the unit on the ground during taxi. The yoke should turn in the opposite direction of a ground turn in either direction. If turns in each direction yield the same results, then the PC is functioning. If it's only working when turning left, then you know why it's banking right in the air and need to begin trouble shooting. The tubes going to the servo mount against the left side panel just below the removable instrument bay access panel on the pilot's side. If one were knocked off, it would cause the issue you are having. The Brittain maintenance manual has a trouble shooting section that you should review. If that fails, feel free to call or text me at: three Oh One - Fife Oh Two - Tree Nien Two Fowah. I've been through this system from top to bottom and sided to side. I may even be able to scrounge up a nice servo if you need one. Quote Link to comment Share on other sites More sharing options...
Hank Posted October 30, 2018 Report Share Posted October 30, 2018 @Shadrach, do you remember the oring size used to hold the rubber boots to the servo can? It's a large, very thin one with a fair amount of stretch to go over the can. I do remember to fold the boot back over the oring and tape securely with 3M #33 tape. Quote Link to comment Share on other sites More sharing options...
Guitarmaster Posted October 30, 2018 Report Share Posted October 30, 2018 Take a really close look at the red and green tubing. The red stuff gets brittle and cracks and you won't even see it.if you don't have one already, go to Harbor Freight Tools and buy a brake bleeder kit. Pull the vacuum line off each side running to your servos. plug the hand vacuum pump into that line and pump to about 5 PSI. The system should hold pressure, or at the very least, bleed off very very slowly. Both the red and green tubing in my airplane were very brittle and broken. Jerry told me a good way to check for leaks is to smoke a cigar and blow the smoke through the system. I don't smoke cigars, so that was out for me but I did do the vacuum check.In addition to my tubing, I had two servos that were leaking. You wouldn't know it by looking at them, you could only tell when there was pressure applied to them with soapy water as an indicator.Sent from my Pixel 2 XL using Tapatalk Quote Link to comment Share on other sites More sharing options...
McMooney Posted October 30, 2018 Report Share Posted October 30, 2018 you guys realize the brittain tubing is auto parts vacuum tubing?? omg like tractor lights and truck rubber pucks aren't, rofl Quote Link to comment Share on other sites More sharing options...
cliffy Posted October 30, 2018 Report Share Posted October 30, 2018 3 hours ago, Shiny moose said: Brittain (Jerry ) would not have said vacuum tubing!!!! He would have said windshield washer tubing!!! OK OK maybe he did say "windshield washer tubing". It was a long time ago when he told me. Its like "kleenex" all tissues are the same :-) Tomato Toe mah toe It is 3M #33 tape for sure. I have heard that in a pinch until the tubing can be replaced there is a certain size widely available clear vinyl tubing that will slide over the area of the break in the tubing and seal tight with about 3 inches over lap on the break area. I've also heard from a temporary point of view that there are corbin clamps that also will go over the vinyl tubing to help seal the break area until the tubing can be replaced. As noted, the red tubing is especially susceptible to breaking. Quote Link to comment Share on other sites More sharing options...
Browncbr1 Posted October 30, 2018 Report Share Posted October 30, 2018 Check to make sure your step servo and linkage is in good order. If the step is not fully coming up it will make the plane pull to the right pretty hard. It will also render the AP basically inop because it creates false feedback from the turn coordinator. If the step is out by only an inch or two, it makes a big difference. The tubing you can get from advanced is 3/16 and comes in a clear plastic box in the vacuum and gas line isle. It’s a little more rigid that the original stuff, but it’s the same size and look. Quote Link to comment Share on other sites More sharing options...
pilot_jb Posted October 30, 2018 Author Report Share Posted October 30, 2018 Thanks for all of the feedback, guys. I'm going to go ahead and replace all of the vacuum tubing and filters under the panel and then run the checks per the manual. I'll let everyone know how it went. For reference, the step is retracting fully. 1 Quote Link to comment Share on other sites More sharing options...
pilot_jb Posted October 30, 2018 Author Report Share Posted October 30, 2018 13 hours ago, Freemasm said: The collar/seal at the pitot (static??) 90 deg brass fitting is toast as well. Airspeed. This is an illusion. All is well with that connection. Quote Link to comment Share on other sites More sharing options...
Yetti Posted October 30, 2018 Report Share Posted October 30, 2018 12 hours ago, McMooney said: you guys realize the brittain tubing is auto parts vacuum tubing?? omg like tractor lights and truck rubber pucks aren't, rofl It's like the wheelen 71578 or a 71833 (Parmetheus) Do you really think they build a separate production line with different components to create the two lights? Quote Link to comment Share on other sites More sharing options...
Shadrach Posted October 30, 2018 Report Share Posted October 30, 2018 17 hours ago, Hank said: @Shadrach, do you remember the oring size used to hold the rubber boots to the servo can? It's a large, very thin one with a fair amount of stretch to go over the can. I do remember to fold the boot back over the oring and tape securely with 3M #33 tape. I do not remember the O-ring size off hand, but I am sure it could be sourced locally. Quote Link to comment Share on other sites More sharing options...
Hank Posted October 30, 2018 Report Share Posted October 30, 2018 1 hour ago, Shadrach said: I do not remember the O-ring size off hand, but I am sure it could be sourced locally. I bought some locally, but don't recall the size. Jerry gave it to me on the phone, along with taping instructions. Quote Link to comment Share on other sites More sharing options...
Shadrach Posted October 30, 2018 Report Share Posted October 30, 2018 2 minutes ago, Hank said: I bought some locally, but don't recall the size. Jerry gave it to me on the phone, along with taping instructions. I don’t know what type of rubber they used to make those boots but it is amazingly resistant to aging. Mine are all original and 51 years the only thing that seems to have deteriorated is the tape. Our step servo is also still functioning beautifully after 51yrs. Quote Link to comment Share on other sites More sharing options...
pilot_jb Posted November 1, 2018 Author Report Share Posted November 1, 2018 Yesterday, I went to every auto parts store in town. None carry 3/16 tubing. It’s all either 5/32 or 7/32. The 7/32 seemed to fit snug enough. Ground test in the next day or two. The weather is supposed to be garbage today. Quote Link to comment Share on other sites More sharing options...
carusoam Posted November 1, 2018 Report Share Posted November 1, 2018 Try looking for the tubing under the names it goes by in industry... Surgical tubing and rubber hose go together... not what you want... Britain (?) used flexible PVC tubing that had a softener/flexibility component compounded into it... Search on the brand name Tygon Tubing... The company that owned the product was called Norton performance plastics... they made it in a whole variety of dimensions... PVC is stable and lasts forever... but the additives have a tendency to leach out over the decades causing stiffness and shrinkage... mold can eat the additives as well... https://smile.amazon.com/gp/aw/s/ref=is_s?k=tygon+tubing some sizes are really popular, it may take some effort to find the size you need. Check with Britain as they are still alive... and hanging in there... PP thoughts only, not a mechanic, but I do have experience running an extruder at Norton Performance Plastics... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
pilot_jb Posted November 1, 2018 Author Report Share Posted November 1, 2018 12 minutes ago, carusoam said: Try looking for the tubing under the names it goes by in industry... Surgical tubing and rubber hose go together... not what you want... Britain (?) used flexible PVC tubing that had a softener/flexibility component compounded into it... Search on the brand name Tygon Tubing... The company that owned the product was called Norton performance plastics... they made it in a whole variety of dimensions... PVC is stable and lasts forever... but the additives have a tendency to leach out over the decades causing stiffness and shrinkage... mold can eat the additives as well... PP thoughts only, not a mechanic, but I do have experience running an extruder at Norton Performance Plastics... Best regards, -a- This is helpful. I'll start searching. The "washer/vacuum" line sold at the auto parts store is stiffer and has a thicker wall than the original tubing, which has a neoprene feel to it. Several of the selections from the auto parts stores were marked that it was good to 1 bar. Seems to me that's as strong as it's going to get without stepping up to hose that is reinforced with fiber braiding. Quote Link to comment Share on other sites More sharing options...
carusoam Posted November 1, 2018 Report Share Posted November 1, 2018 The Tygon description mentions lab use and vacuum pump specs... The inner dimension is set, by spec... the wall thickness is important to its strength to avoid collapsing... The dimensions during production actually controls the OD... physically, and adjusts the ID by changing the Take-off speed of the tube puller/winding equipment downstream. So get out your mic, and measure both ID and OD to avoid any surprises... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Hank Posted November 1, 2018 Report Share Posted November 1, 2018 1 hour ago, pilot_jb said: This is helpful. I'll start searching. The "washer/vacuum" line sold at the auto parts store is stiffer and has a thicker wall than the original tubing, which has a neoprene feel to it. Several of the selections from the auto parts stores were marked that it was good to 1 bar. Seems to me that's as strong as it's going to get without stepping up to hose that is reinforced with fiber braiding. That should be fine. 1bar = 14.5 psi; I only run 5" of vacuum. Atmospheric pressure is 14.7 psi on a standard day at sea level, and falls to about half that at 18,000 feet. Quote Link to comment Share on other sites More sharing options...
larryb Posted November 1, 2018 Report Share Posted November 1, 2018 I would find something at McMaster Carr. Here you can pick exact sizes and materials and know what you are getting. Perhaps you can find a product which will last a bit longer. https://www.mcmaster.com/9776t6 or https://www.mcmaster.com/9776t5 Quote Link to comment Share on other sites More sharing options...
Gary0747 Posted November 1, 2018 Report Share Posted November 1, 2018 Might also check the orings in the wing leveler button on the yoke while you are at it. That could cause the leveler to not engage. I think that button just pulls out. I never bothered since my leveler has always worked fine. Quote Link to comment Share on other sites More sharing options...
carusoam Posted November 1, 2018 Report Share Posted November 1, 2018 Great idea, Larry! Here is a chart that has all the sizes, from McMaster... oddly enough, the specs didn’t mention vacuum... https://www.mcmaster.com/tygon-tubing Also look at other pics... the OP pics show what looks like actual rubber hoses... The OEM tubing was colored red and green flexible PVC tubing... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
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