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Q&A: PA-34 Leaky Door Seals & Bouncing Fuel Gauges, PA-28R Main Gear Sidebrace Studs

Q&A: PA-34 Leaky Door Seals & Bouncing Fuel Gauges, PA-28R Main Gear Sidebrace Studs

Q: Hi Steve,

Couple of questions for you. I own a 1975 Piper PA-34-200T Seneca II Turbo. I have air leaks through the pilot entrance door. We’ve put in a new seal and adjusted it, but it still leaks. We think if we replaced the windlace with a new, more supple one that it would take care of the problem. Can you tell me where I could purchase this product? 

I also have a fuel gauge problem on the right engine. It does not indicate accurately and will vary between full and empty and anywhere between. What would be the best way to repair this problem? I read in your October 2016 issue on the Seneca II that Michael has had problems with this also. (See Resources for a link to the story. —Ed.)

I live in Glenwood Springs, Colorado, and fly out of Glenwood Springs Municipal Airport (KGWS). The runway is 3,300 feet by 50 feet, at 5,916 feet msl. The Seneca II operates very well here. Love this PA-34; it performs everything
I ask of it.

I appreciate any advice you can give me.



A: Hi Darwin,

Glad you like your Seneca. I wish I had one. 

The two companies that sell a variety of door seals are Brown Aircraft in Jacksonville, Florida, and Aircraft Door Seals in Wisconsin. I don’t have enough experience with these companies to recommend one over the other, but I believe both will send you a sample of the seal they recommend for your airplane so you can take a look at it. (Aircraft Door Seals is a Piper Flyer supporter. —Ed.)

I do know that Dennis Wolter of Air Mod, who is now writing for Piper Flyer, sometimes has to “build up” the surface behind the seal to get the seal he wants. Wolter uses flat rubber sheets in different thicknesses. He and his staff trim and adjust to get the proper build up. That tells me that you can have a very good length of seal, but you may still have to spend time tuning the installation to get the sealing you want. 

As far as your bouncing fuel gauge, it can be a couple of things. 

It can be problems with the gauge itself. Remove the signal wire at the sender and, while watching the gauge, touch the signal wire to the body of the fuel sender assembly. If the gauge is good, the needle should move smoothly from empty to full. If there’s hesitation or nonlinear needle movement, it’s probably a malfunction in the gauge.

If that looks good, you can test the fuel level sender by flying until the fuel level is below half so you can look inside the tank to locate the sender float.

Remove the signal wire from the sender. Then, by reaching in through the filler, use a safe tool to move the float on the sender arm up and down while an ohmmeter is attached to the signal stud on the sender. The varying resistance seen on the meter should be smooth and linear as the float is moved. I’ve used a long, smooth wooden dowel to move the float.

Other than visually inspecting the signal wire for bare spots—which is impossible in some installations—if you can find no other explanation for the bouncy needle, replacing the wire is probably the best solution. 

One option if you determine it’s the sender is to order new senders from CiES. They are much better and more accurate than the original Piper senders, and are FAA approved for installation on your Seneca. The CiES fuel level senders rely on a magnetic connection between the float arm and the signal arm. This type of connection eliminates corrosion and wear problems in the senders and provides a very linear signal. CiES senders are compatible with a wide variety of gauges and engine monitors.

Happy flying,


Aircraft Door Seals, a PFA supporter, will send prospective customers a sample of the seal material best suited for their aircraft.

Q: Hi Steve, 

Every 500 hours, my 1971 PA-28R-200 Arrow requires a removal and inspection of the main sidebrace bracket assembly to comply with an AD. My time has come...and apparently, it’s a bit of a job to remove these brackets. 

My A&P mentioned that if the brackets are replaced by those from a PA-32, then they will not require inspection again. The part numbers he provided me are: Part No. 95643-06/-07/-08/-09. I’ve found some new, but they are over $2,000 each! Any assistance locating some reasonably-priced alternatives would be greatly appreciated.



A: Hi Pete,

Your mechanic is referring to AD 97-01-01 R1. The title is “Main Gear Sidebrace Stud.” It calls for removal and inspection of the sidebrace studs. 

The initial inspection does not require the purchase of anything.

I suggest you remove the sidebrace stud brackets. It’s an easy task in my PA-24 which is also affected by the same sidebrace stud inspection as your PA-28R. 

After you remove the sidebrace stud brackets, remove the stud from the brackets and get your mechanic to find a shop near where you live that can do the fluorescent penetrant inspection or the magnaflux inspections called for in the AD. I believe all aircraft engine shops have the tooling to perform the magnaflux inspections. 

If you don’t find any cracks, reinstall the stud in the brackets and reinstall the brackets in the aircraft. Fly for another 500 hours and repeat. When I did the inspection on my PA-24, there were no cracks in either of my studs. 

The AD provides two ways to comply if cracks are found in either of your sidebrace studs. 

First, since the original-sized stud is no longer available, owners have the option of installing a larger stud in the original bracket after installing a new bushing and machining the larger stud to work with the original bracket and new bushing. 

Piper Flyer Association member Jason Williams added this on the PiperFlyer.org forum: “You can buy the new 5/8-inch stud (Piper Part No. 78717-02) and bushing (Piper Part No. 67026-12), along with the washers, roll pin and nut for around $700. A good machine shop should be able to ream and chamfer your bracket to accept the new parts.”

Thanks, Jason, your help is appreciated.

The second option is to buy new brackets, studs and bushings, and install these parts. 

As far as buying less expensive parts, that’s not as easy as it once was. Piper now sells its parts through Aviall, a national parts house. 

You may find the parts you need through an internet search or used from a salvage yard (see Resources for more information on how to locate parts and parts suppliers —Ed.) but they will have to be inspected in accordance with the AD prior to installation.

Let me know what the inspection turned up.

Happy flying,


AD 97-01-01 R1 calls for removal and inspection of the sidebrace studs for Piper PA-24, PA-28R, PA-30, PA-32R, PA-34 and PA-39 series airplanes.

Know your FAR/AIM and check with your mechanic before starting any work.

Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation (EllsAviation.com) and the proud owner of a 1960 Piper Comanche. He lives in Templeton, California, with his wife Audrey. Send questions and comments to .



Aircraft Door Seals – PFA supporter
Brown Aircraft 


CiES Inc. – PFA supporter


Piper Flyer Yellow Pages
Piper Flyer parts locating request form (must be logged in)




“Life with a Seneca II” by Michael Leighton
Piper Flyer, October 2016
AD 97-01-01 R1, “Main Gear Sidebrace Stud”
Piper Flyer forum (must be logged in)
Proper Entry Procedure: Fitting & Adjusting the Piper PA-28 Entry Door

Proper Entry Procedure: Fitting & Adjusting the Piper PA-28 Entry Door

Before you can properly seal the door, you must ensure it is fitting properly. Here is a step-by-step guide for removing, checking and adjusting the door.

The only way to properly adjust a door on a Piper PA-28 series aircraft is with the door seal removed. Only then will you know if the door is fitting properly. The following procedures should be accomplished before installing a new seal, and they can only be done by or under the supervision of an A&P mechanic.

Remove the door

Remove the screw, step bushing and washer attaching the doorstop to the doorsill plate. Remove the cotter pins, clevis pins and washers from door hinges. Set the door aside on a blanket or other protective covering.

Remove the old seal

There is no easy way to remove the old seal and adhesive, but I’ve found that using an electric heat gun (such as those used for paint removal) aids this process considerably. First, locate the seal joint and with the heat gun apply heat to the seal and carefully begin to lift the seal from the edge of the door. Continue applying heat in the apex of the seal as you lift it from the edge of the door until you have it completely separated from the door.

Remove the door seal adhesive

Removing old adhesive can be performed using one of two methods. One way is to use a small (three-inch) brass brush on a drill motor and literally peel the adhesive off the door. This method does require that the door edge be repainted. (An aerosol such as Krylon paint may be used to repaint the edge of the door, and it stands up well over the years.)

The second method is to dissolve the adhesive with a product called Goof Off. Goof Off, touted as “The Miracle Remover,” will not affect paint or Plexiglas.

I’ve found that applying heat to the old adhesive and then wiping the area using a rag saturated with Goof Off will remove the residue. Use caution to prevent combustion. Ensure any Goof Off liquid remaining on the door has fully dried before reapplying heat from the heat gun.

When the door edge is cleaned up, you are ready proceed with the adjustment.

Check for wear in the hinge

Over the years, the eyebolts and clevis pins (door hinge system) can become worn to a point where the door will sag and not close or seal properly. It’s imperative that these parts be checked for wear before proceeding.


A good way to check the parts for wear is to slightly open the door and see if you can raise up on the door. There should be no movement (or very little movement) of the door vertically.

If you can raise up on the door, the eyebolts and clevis pins are worn out and should be replaced. (The tolerance when new is only three thousands of an inch.)

These items are not expensive, yet they are critical to properly closing and sealing the door. Aircraft Door Seals sells eyebolts and clevis pin sets. The new eyebolts and clevis pins come with complete instructions for installation and can be replaced in less than five minutes.


Reinstall the door

Place the door into position over the eyebolts and install the washers and clevis pins in the door hinges. (Do not reconnect doorstop to the doorsill on the fuselage at this time.) Close the door and secure the upper latch.

With the door closed and latched, verify the front edge of the door is flush with the fuselage. Many times the door will not be flush; instead, it will actually be fitting inside of the fuselage anywhere from 1/8 inch to 3/16 inch. It must be flush with the fuselage before you proceed.

If you find the door is not fitting flush, this may be corrected by the installation of spacers (washers) under each eyebolt (or as required) which will move the upper or lower portion of the door and enhance the door’s fit. The washers you’ll need are AN960-516 (thick) and AN960-516L (thin)—typically, just one or two under each eyebolt will correct the fit.

To remove the eyebolt, you must remove the door. Just inside the cabin in front of the door opening (behind the interior trim), you will find a 5/16-24 nut for the upper and lower eyebolt. Slide a half-inch box wrench behind the upholstery, placing it over the nut.

Using a crescent wrench on the eyebolt, unscrew the eyebolt (counterclockwise) and remove it. It is helpful to have an assistant place the washers on the eyebolts so you do not have to move the wrench and nut. Install one or more washers as required on the eyebolt(s) and reinstall. Do not over-tighten—just snug is sufficient.

Reinstall the door and verify the front edge of the door fits flush with the fuselage. If not, repeat this procedure using thick and/or thin spacers until it does fit flush.

Note: Many times the factory installation leaves a little to be desired. With the door fully closed, inspect the clearance between the edge of the door and outer periphery of the fuselage door opening. Many times I have found the edge of the door skin actually hitting the fuselage, especially at the front edge. You should have a minimum of 1/16 inch clearance. If not, file the edge of the door until it has the proper clearance.

Adjust the door

If the door does not fit flush with the fuselage around the entire opening, start with the adjustment of the main latch by loosening the two flat head screws and move the striker plate (in or out) as required. Re-tighten the two screws. Repeat this as necessary until the door fits flush. The door should have a 1/16 inch to 1/8 inch clearance around the entire edge of the door and fuselage.


On early Piper models (pre-1968) I’ve found the latch clevis pin to be bent, which will prevent the door from latching properly. If it is bent, it must be replaced. Aircraft Door Seals stocks this clevis pin.

To provide the proper vertical adjustment of the door, insert the necessary washer combinations between the cabin door hinge(s), clevis pins and the fuselage eyebolts. Also verify that the fittings riveted to the door have not been bent. The fittings forming the portion that fits over the eyebolts should be straight.

Adjust the upper door safety latch

To adjust the door upper (hook) latch, remove the two screws from the latch plate on the top of the fuselage door opening. Remove the plate and rotate the loop clockwise or counterclockwise (a small amount of WD-40 on the threads will help) to make necessary adjustments.


Replace the latch plate and secure with the two attachment screws. Check the fit of the door.

Many times the upper latch hook can become bent and actually hit the upper portion of the door opening (fuselage). The upper hook should be centered in the upper opening. If not, using vise grips, clamp the hook at the point where there is a slight bend in the hook and slightly bend the hook until it is centered in the opening. Caution: When bending the hook, support the hook with your thumb in the area where you are bending. This will prevent the latch from being damaged.


Check the fit and make final adjustments

When the door is properly adjusted, there should be approximately a 1/16 to 1/8 inch gap around the outer periphery of the door between the door edge and the fuselage.

Insert the cotter key(s) in the clevis pins and bend the cotter key ends around the clevis pins and trim off the excess cotter key length as required.

It is not uncommon for the forward top edge of the door to not fit totally flush with the top edge of the fuselage. This condition is due to the variables in the assembly process of the door. Many times I have found it necessary to adjust the fit of this portion of the door by slightly bending the door upper edge.

This procedure will not damage the door and has been done by the factory for years, but it must not be done with the door installed. It is best done with the door lying flat on a blanket and manually massaging the upper portion of the door with your knee until you are satisfied with the fit.

The entry door has been cleaned up, fitted and adjusted, but you’re not done yet. Follow the manufacturer’s instructions to the letter for successful installation of the new door seal.

Dick Russ is a multi-thousand-hour commercial, multi-engine and instrument-rated pilot. He’s also a flight test engineer and an A&P/IA who has restored many Pipers. In addition to his career as a freelance writer and aviation business owner, he was senior engineer on the Shuttle Enterprise Approach and Landing Test Program at Edwards AFB. Russ holds three patents on aviation components. Send questions or comments to . 


Aircraft Door Seals
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