The International Cessna^® 170 Association

I've noticed for quite awhile my middle rudder hinge bolt was upside down so decided this annual was time to investigate. Removed rudder and found both the middle and upper bolts were too long, not tightening the hinge to the bearing. This caused the bolt and hinge bracket to wear. Both hinge brackets are slightly egg shaped, bearings were fine. Bottom bushing had lots of wear, new one on the way Also have all new bolts. Any ideas for reaming and bushing the hinge brackets? I would guess there is .010 free play.
Scott, now with a 170A.

Another question, spring color in the oil pressure relief valve, mine is blue with no washers. Oil pressure indicates 55 psi hot. 200 hours on the overhaul. Front main seal weeping and other minor weeps. I will verify gauge accuracy but i am wondering if we should try to lower the pressure?
Scott

Scott, I can't help you on the rudder hinge, but I had the same issue as you on the oil pressure relief valve spring when I overhauled my O-300A in 2006. I ordered a new spring and it came painted blue. No washers are called for in the parts or overhaul manual for this engine so I didn't use any. My cruise oil pressure has been 55 psi since day one. I asked about it here, and was told it is normal. No problems in 350 hours.

Can't help on the hinges either. Probably have to be there to see it to figure the best approach.

But I can tell you lots about that pressure relief.

First this engine is not a Lycoming where you will find washers in the relief valve and spring. There are never any washers called for in association with the high pressure relief in this Continental.

Your pressure is fine and well within tolerance. Oil pressure is not causing the front seal to leak nor I'll bet any other areas you have seeping. Many of the areas prone to leakage such as the valve covers and pushrod tubes have no oil pressure behind them. Yes there is a very very low crank case pressure unless your breather is clogged.

Breather tube has been reamed out and cleaned, last year. Used an old throtel cable shieth on a cordless, worked great, lots of gunk. If 55 is OK I'll just leave it. Thanks.
I'm inclined to not wory about the hinge bracket wear as it's not too bad and properly reinstall making sure there is clamping force on the bearing to make it work properly.
Scott

Scott,
I found my rudder hinge bearings frozen. I imagine you've checked for seized bearings already but if not here is a link to the subject.
Edit: Missed that you said, "bearings were fine".

McFarlane Has new old stock of the upper and center hinges in stock. check them out.

I believe you're referring to the hinge bearings. In case anyone else is looking for these, the IPC they are shown as SIK-5 with the second character a letter rather than the number one. McFarlane has these bearings listed as S1K-5, with that second character the number one rather than the letter I.

The bearings were not the problem, the bolts through the bearings were. They were too long and bottomed out before creating clamping force on the bearing. This caused the hinge to wear and egg shape out the holes. Also the bottom bushing was completely worn out on the back side especially, due to no slack in the tail wheel steering springs.
Replacement bearings are $ 1100.00 plus each from Cessna, start shopping.
Scott

Check for those rudder bearings at a local bearing supply house and be sure NOT to tell them what they go on. Many times those suppliers will not sell bearings if they know they are going on aircraft. Probably a liability issue for them. My wheel bearings came from a major supply source and are Timken like the ones they replaced.

170C wrote:Check for those rudder bearings at a local bearing supply house and be sure NOT to tell them what they go on. Many times those suppliers will not sell bearings if they know they are going on aircraft. Probably a liability issue for them. My wheel bearings came from a major supply source and are Timken like the ones they replaced.

I've bought an awful lot of parts for my John Deere tractor....might even own one some day....

Joe

cmsusllc wrote:..., due to no slack in the tail wheel steering springs....

No slack is correct, and unlikely the cause.

Bushing worn on the back side, rudder control cables tention to the front side, must be flying too fast