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MT prop spitting grease after overhaul

tkatc

Well Known Member
My MT metal c/s prop (MTV-15) was spitting grease at around 250 hours ttsn. Calendar months suggested an overhaul vs a re-seal so I bit the bullet and had it overhauled by an MT authorized prop shop. It wasn't cheap! Here we are 18 months later and the prop is spitting grease again, 135 hours smoh.

I LOVE this prop and it always works flawlessly but black grease on a bright yellow cowl is certainly disturbing. I dropped off the plane to the same prop shop...I wrote MT an email expressing my concerns and told them I expect them to cover the repair even though I am past the 12 month warranty after the overhaul. This thing only has 135 hours on it! And I noticed the leak about 10 hours ago, so that 125! Obviously I am bummed out. We'll see if MT steps up to the plate or not..... Stay tuned!

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How often do you grease your prop?

Hartzel will tell you, "We never overhaul a prop because of too little grease, but we overhaul plenty because of too much grease."
 
MT props, at least this one, has no zerk fittings. Therefore, re-greasing is normally never required.
 
Be glad a little grease spitting is your only issue. After I got my MTV prop back from fresh overhaul the paint just started peeling off. I took it to a local auto body shop where they advised it was very easy for them to strip all remaining paint due to poor adhesion.
I don't want to berate the MT USA guys as they provided great support when I was chasing a P-120-U failure to adjust prop issue, but they definitely had some paint quality control issues when they overhauled mine.
 
Be glad a little grease spitting is your only issue. After I got my MTV prop back from fresh overhaul the paint just started peeling off. I took it to a local auto body shop where they advised it was very easy for them to strip all remaining paint due to poor adhesion.
I don't want to berate the MT USA guys as they provided great support when I was chasing a P-120-U failure to adjust prop issue, but they definitely had some paint quality control issues when they overhauled mine.

At least peeling paint doesn't stick to your windscreen!
 
It is sad to see the declining quality of products not only in Aviation, but HVAC too. Of course another price increase is just around the corner.
 
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I have an MT two bladed aluminum prop on my RV-8 and it started spitting grease at about 430 hours and 72 months since it was rebuilt by MT. It was their test prop when they developed the prop for the RV-8. I have an MT Governor also and I experienced an overspeed of about 3000RPM and shortly thereafter I started noticing the grease. Had the Prop and governor overhauled to the tune of a little over $3000 and I now watch the RPMs a little closer. We were doing formation when I experienced the overspeed. Have put 50 hours on since the overhaul and all is good so far.:) There is no lubrication required of the prop between overhauls. Just inspection for grease leaking from the hub.
 
Update: MT says there are no internal issues witht he prop. The grease is broken down a bit and getting past the seals. They plan to replace the seals with an updated oversized seal that they hope will fix the issue. I've heard about these oversized seals before and wonder why they weren't installed during the overhaul. Heck, maybe they were. Hmmm...
 
Tony, sounds like MT is taking care of the resealing? I hope so. My experience with the MTV-15 was not all that great and it needed to be resealed twice in 300 hrs, the second time because MT neglected to tell the shop that there were updated sized seals when they did it the first time. I also had to fight with MT and it wasn't until I got the CEO of MT in Germany involved that they decided to cover the expense.

My advice to anyone looking for a prop is to steer clear of MT. While MT props have nice performance, it just isn't worth the hassle dealing with them because they do not stand behind their product without you having to fight them.
 
I picked up my plane from the prop shop today. MT stood behind the product and warrantied the overhaul even though it was passed the 12 month warranty. I can't say I am ecstatic over the situation because it cost me time and a little money to have them do the work but I am really glad they stood behind their work.

They installed the oversized seals and we are all hoping this fixes the issue. I suppose that's all we can ask of any vendor, stand behind your product.
 
Same situation on my whirlwind 200rv. Going back to factory this time instead of service shop in Redding CA. Prop is off, waiting for an empty box to be sent to me from Whorlwind so I have something to send them the prop in. Dreading the wait and the reinstallation process. Safety wiring the prop bolts is a drag.
Misery loves company, so here ya go.

Erich
 
Erich,
It seems we are living parallel lives. P-MAG issues together and now this...

I hope neither one of us ever encounters any SERIOUS problems!!:)
 
Czech it out!

I'd like to know if everything is made in house at MT Germany.

All MT aluminum propellers and hubs are made under license by Avia propellers in the Czech Republic. FYI...

www.aviapropeller.cz

V/R
Smokey

PS: I have about 250 hours in an Extra 300 with an MT 3 blade composite. "Slung propeller grease was a normal post flight item and the prop was overhauled twice in 3 years, of course with hard aerobatics every day it's understandable" However comma, after 3 RV's and a Rocket how do I spell propeller? C.A.T.T.O. :)
 
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MT Prop saga continues. The quick summary. Prop started spitting grease a year after I bought the plane. It was due for overhaul due to calendar months so I spent the big money and had it overhauled. 13 mos later it was spitting grease again. MT covered the re-seal AND dynamic balancing. Pretty cool huh? Except the thing starting spitting grease 12 hours after the re-seal. I wrote numerous emails and MT said they would make me a new hub and fit overhauled blades on it and exchange it for mine. Ok, it would be a zero time prop....it took them 5 months or so to compete this task so I flew my original prop and had to clean the windscreen often. But today, they came through. I am not happy to have issues but I am very happy that they are standing behind their product. I haven't paid them a dime since the overhaul. From talking to the prop technician who removed, replaced, and balanced the new prop I feel lucky. He himself was surprised to see them take such good care of me...I am not even the original purchaser. He said other manufacturers rarely go to this length to keep customers happy.

Anyway, here's some pics.

Here's "Tweety" decowled and depropped.
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Old prop and new prop!
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New prop installed and balanced. The tech was able to record a ZERO IPS! ZERO! As in NO VIBRATION! He had to enter .001 to make it a legal entry in the logbook. According to the FAA there is no such thing as ZERO IPS.

This issue robs me of precious build time but I do learn something...I feel confident I could remove and install my prop if I had to, something I wouldn't have dreamed of before today. The learning never stops. I just hope I can remember everything I learn. :D
 
Almost forgot the finished product!
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BTW, my NEW prop log indicates a NEW hub and overhauled blades from an RV-7A out in Independence, Oregon. The same field where my Tweety was built.
 
I've flown behind MT propellers on DA-40s, Pitts S-2Bs, Extra 300 and 300LPs, Super Decathlons, and various RVs. Every single one of them has leaked grease. Every. Single. One. I've got friends with Edge 540s, experimentals, etc. that have the same issue.

From a performance perspective, MT makes a good product. From a reliability standpoint, they're the absolute worst. I hate to say that. My S-2B has an MTV-9 series prop on it.

These problems go back decades. Read Dick Rutan's book about flying Voyager around the world. They had an MT prop on the rear engine and it failed. Lost a blade, almost destroyed the aircraft. That was a custom build, of course, but if I had a dime for every story of a delamination, paint issue, accelerated wear, premature overhaul, or serious grease leak from an MT prop, I'd be a very rich guy...
 
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