Cessna 175 nose gear strut

Cessna 175 nose gear strut

I'm looking for information to service the nose gear strut in my 175.  Amount of hydraulic fluid?  Regularity of service? etc?

Thanks for any help you can provide.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

This is really a 2 person job, easy way is to have a hose hook up to the struct valve, let out the pressure, the hose is hooked into a bottle of fluid, extend the strut ( Your helper ) which sucks in the new fluid, then  put the valve back on and add the air pressure. It should be the same fluid that you use in your brake system.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

Regularity of service - that depends on your system and a lot of factors..
Servicing the nose strut should be accomplished IAW the applicable service manual. that is the safest way and highly recommended.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

You have to have the right amount of fluid and air, and might need new seals. The maintenance manual and an A&P are a good reference.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

Richard, your 175 is just the same to service the nose strut as all other single engine Cessna's
put the tail on the ground, either a helper or sand bag it,
remove the valve core on the strut inflation valve, push a tight hose over the valve body and run the other end into a jar of  hydraulic fluid [MIL H5606, or whatever the equivalent now is, but its red a/c brake fluid] then push the strut up and down until there are no air bubbles in the tube, finish with the strut compressed.
Refit the valve core and inflate.
Put the wheel on the ground and adjust the pressure to the strut extension you like.
Of course you are going to set it to the dimensions given in your 175 owners manual/maintenance manual, arn't you?

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

In adding air to the strut, my 172 service manual prescribes an air pressure of 45 psig when fully extended.  This could be different when just setting the extension by just filling it with air from fully compressed position to some arbitrary height. 

I see two problems with doing the latter and would like to get some of you A&Ps to respond to how it is "normally" done. 

1) Due to frictional forces, setting it from fully compressed to a nominal height results in a higher pressure than it would be if you do it per the service manual.

2) If the air pressure is too great to get it to move, can you blowout a seal or do some other damage?

Another thought, if it is partially extended and you need to add air, it is easy to collapse the strut if the little bit of air is released too quickly.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

I second Barry's request on more input oh "how to do it"
I'm believe that nitrogen should be used, but under the impression
that the majority of those struts out there only have compressed air in them.  I've heard that using compressed air can introduce a bit of moisture that could be detrimental to the strut, over time.
Personally, I use a SCUBA tank for my compressed air for a couple of reasons..  #1 The SCUBA tank is very convenient to use. Enough air to completely fill all three tires, dink around with the strut and do a cood compression check. #2 SCUBA air is supposed to be DRY air to avoid corrosion in the tank.

Getting the strut just where you want it to be can be a real pain in the butt...for me anyway...
More input would be appreciated.
Thanks
Michael

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

Do exactly what howard has said. The only things i would change and this is what we do:

1. push the tail down with sandbags or anything (cases of oil) to hold the tail on the ground. make sure to position them on the spars and equally on each side.

2. Instead of fully compressing strut after servicing leave approx 1/2 inch of piston showing. This helps if the strut blows out, so that it is sitting on fluid and not metal to metal.

3. Inflate strut with air, we just push it on until no more air will enter. 25 gal compressor, 125 psi. allow small amount of air out, push strut up and down and check extension. repeat until right extension is correct.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

Forgot to mention that nitrogen is prefered because it contains no moisture. The moisture will eventually lead to corrosion.  You can get away with compressed air if the strut is serviced regulary.

This is how we do it and the most common way that i have seen.
The 45 lbs usually does not raise the strut high enough. A good rule of thumb is about four fingers of piston showing.

To see where the strut actually sits put your foot on the tire to keep it from rolling and rock the airplane by the prop to allow it to settle

Remember that the air does not absorb the shock of landing it just supports the airplane on the ground. The hydraulic fluid absorbs the shock by restricting flow from one side of the cylinder to the next.

Richard- by following howards' directions the correct amount of fluid will be added and the right air psi. This can be done by yourself, i would have it done at every annual or more frequently. Annuals are when this gets done most frequently.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

I prefer to set aircraft back down on nose then inflate with nitrogen to correct height.  If I have to inflate with strut off ground I fully extend strut prior to inflation to prevent strut from suddenly slaming to full extended position.  I use the four finger method also, works well for the cessna singles.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

richard
howard and allen have the prosess down to the nats patoot but what everyone seems to be missing is do you have a inordmount amount of fluid running down your strut and your fork? if you do just go to your a&p because you need the strut resealed and this takes an a&p endorsment  the kit to reseal a strut is the cheapest thing cessna sells (between 10 and 15 dollars) it should take between 1.5 and 2 hrs. to compleate depending the condition of your strut (if it is a real mess it could take longer) i dissesamble and clean everything my self so it has tken me as much as 3.5 hours to fix a strut and reinstall it
brad

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

Thanks for the input.

Here are Some thoughts on the input all have provided, from a different perspective.

The nitrogen purge prevents corrosion in the air space (Corrosion requires oxygen). Corrosion from any moisture that might be in the strut would be limited to the content of the dissolved oxygen in the moisture (negligible).  Condensed moisture in the hydraulic fluid should not be allowed to accumulate but unless you get a lot it won't make much of a difference. Where's a good place to get bottled nitrogen?

As I see it, the air in the shock is an "air spring."  It works in conjunction with the hydraulic damper to reduce shock to the superstructure on a hard landing and affects the response of the strut to "bumps" in the road.  The quantity of air makes a difference in the damping coeficient.  Too much will tend to be overdamped and too little could be underdamped. Overdamped transmits the largest forces (shock) to the superstructure (Not good). Underdamped would make the nose bounce up and down excessively (Not good).  One hopes that the specified quantify of air in the service manual optimizes this for us.

My question, really goes to the latter point. However, you all have provided me with a wealth of practical experience for accomplishing this.  Thank You!

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

So I went out to my airplane yesterday and found the strut was collapsed.  This is the second time this happened within a 1-1/2 years.  I am attributing it to cold weather - Temperatures about 10 F (-12 C).  Anyone experience this or do I need to some maintenance done?

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

Barry,

One thing to check is service the strut with air then use a soapy solution of water and spray it on the strut around the schrader valve and air seal. If there is a leak it will bubble. Check anywhere you feel the strut could leak. It most likely is the schrader valve, you could try tightening it or taking it out and inspecting it for a bad seal.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

If it's a leak it's got to be real small because it took so long to loose air and there just ain't that much air in these struts.

It was refilled and I adjusted it to show about 3 or 4 inches of the SS cylinder.  I was thinking that the seals lose there resilience in the cold.  I'm guessing it would be worse with age.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: Cessna 175 nose gear strut

My strut went flat last week (about -5 F) and once two winters ago, again well below O.  Twice in seven years.  Maybe the seals shrink just that much more, but other times it has been as cold with no change. go figure.  I am planning to replace seals soon only because they are 1968 original.  I find that 45 psi is too low..just fill to the right extension height and seems to work well.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Board Info

Board Stats:
 
Total Topics:
6046
Total Polls:
1
Total Posts:
16357
Dormant:
User Info:
 
Total Users:
2552
Newest User:
mark.j.boland@att.net
Members Online:
0
Guests Online:
2496

Online: 
There are no members online

Forum Legend:

 Topic
 New
 Locked
 Sticky
 Active
 New/Active
 New/Locked
 New Sticky
 Locked/Active
 Active/Sticky
 Sticky/Locked
 Sticky/Active/Locked

ankara escort ankara rus escort ankara escort bayan ankara bayan partner ankara escort kizlar escort ankara ankara escort ankara eskort ankara escort bayan ankara bayan partner ankara escort kizlar escort ankara