Another TW Shimmy question

redneck · Post by **redneck** » Mon Jul 11, 2016 6:45 am

Hi, guys. I'm back in a Maule after too many years away. Sold my MXT7-180 to Ray Maule in '09 supposedly for a diesel retrofit. (Jeremy, do you remember being involved and participating in this transaction? Thanks again.) Drove a C170B and then a PA15 Vagabond for a few years, and now back in the family with '84 M5-180C. Glad to be back, really appreciate the forum and looking forward to connecting with some of you in the Southeast.
A well-intentioned mechanic shot my Maule tailwheel full of grease the other day, and I'm pretty sure I need to disassemble and clean the excess out to reduce the significant shimmy that occurred immediately following the "grease it 'til some comes out" episode.
I've got a parts DVD coming from Brian, but wanted to ask for guidance on a. type of grease and b. quantity. I've read a number of forum posts but didn't pick up on recommended grease type as well as initial and recurring lube quantities. Any tips on disassembly and reassembly would be appreciated. I'm budgeting for larger mains and a new t/w assembly later in the year, but need to get this one functional for the present. Thanks, R.

maules.com · Post by **maules.com** » Mon Jul 11, 2016 12:04 pm

Hello Roger, welcome back to Maules.
First off, which tailwheel do you have. Maule P8A, P8B tundra, Scott 3200, or ABW 3200 ?
Scott and ABW have double fork and Maule is single arm.
P8A has aprox 1.5" diametre cap, P8B 2.5" cap on housing.
The grease you want is a non migrating type like boat trailer axle grease.
There is no fixed amount. Once you disassemble, you will find there is lube needed for the swivel/bearing assembly area, and a separated anti shimmy clutch area which requires a very tiny bit of grease.
Every spring many owners complain of shimmy. It is because the wx is warmer and wrong grease is migrating to the anti shimmy area.

redneck · Post by **redneck** » Wed Jul 13, 2016 6:59 am

The tailwheel I have is the P8B. Still waiting on the parts DVD from Maule, but I have the drawing needed. Anything extra difficult about disassembling, cleaning and reassembling? Local shop is a Mooney service center and unaccustomed to tailwheel work. Pretty sure the over-application of the wrong grease has the friction washer and ring assembly gunked up and causing the shimmy. Also, I have compression springs on the steering chains. They are currently tight with slight compression both sides. Is this correct? Thanks.R.

maules.com · Post by **maules.com** » Wed Jul 13, 2016 8:20 am

The P8B is pretty straight forward to a mechanical mind.
The three little pressure springs may be tired and not putting enough force on the friction plate.
The steering springs and chain should be slack, not hanging down but no tension. You may need to add a chain link.
As the leaf spring gets tired the wheel moves back and chain/springs get tightened which causes spring loaded oscillation side to side.
When reassembling, the nut on top is not for bearing preload.
Bearing preload is adjusted by the shims on bottom, usually 1 or 2.
Spare shims are stored under the cap when tailwheel assy is new.
Check that the sliding lock and spring are in good shape with no burrs or nicks to prevent smooth movement.

redneck · Post by **redneck** » Wed Jul 13, 2016 1:05 pm

Thanks, Jeremy. I'll check on parts availability and then dig in to it (slowly) next week.

captnkirk · Post by **captnkirk** » Wed Jul 13, 2016 3:54 pm

Here is a good video on rigging the compression tailsprings.
https://www.youtube.com/watch?v=QtokU8mIDQk
I hope that helps.

redneck · Post by **redneck** » Sat Jul 16, 2016 6:08 pm

Disassembled and cleaned everything. Both felt washers were shot. New ones plus a couple shims on the way from Maule. My question is how to know whether shims are needed under the friction washer? And if so, how many. Bryan is sending 2, but there were no shims installed now. The 3 springs TW76B appear good. The lock ring, pin and its spring all look good. Just not sure about the shims.
Also, the swivel bracket has slight movement on the tailspring. Jeremy, one of your posts says tighten the nut to the last castellation. With only one point of attachment, is a slight amount of play on the tailspring acceptable? Thanks.

maules.com · Post by **maules.com** » Sat Jul 16, 2016 6:55 pm

If you tighten the bolt well, the middle leaf will still be able to slide.
Assemble the complete unit with no shim and bring top nut all way down but do not torque too tight.
Check the movement in the taper bearings.
Add one shim at a time until taper bearings turn freely and do not drag. The shims sit on a shoulder clear of the anti shimmy system.
Jeremy

redneck · Post by **redneck** » Mon Jul 18, 2016 6:59 pm

Got it, and thanks. Re: tail springs. MM says "Install the connector springs, using the heavier spring on the right side. Install the springs so that the light spring is compressed approximately 1/2 to 3/4 inch." Is this unique to the Maule tailwheel? Everything else I've read, plus the video, seems to indicate that these springs should be barely loose on both sides. I had no shimmy prior to the overgreasing event, and the chains were slightly compressed on both sides. I can obviously try slightly loose to begin with, but this is a bit confusing. ???

maules.com · Post by **maules.com** » Mon Jul 18, 2016 7:10 pm

It has a lot to do with how tired the leaf spring is. As it depresses with load, it moves backwards.

redneck · Post by **redneck** » Sat Jul 23, 2016 1:56 pm

Everything back together and works perfect. Got the grease out from the anti-shimmy section and new chains properly adjusted, and no shimmy. Only problem now is new 8.50's make that P8B tailwheel look mighty small.

Akafrank · Post by **Akafrank** » Sat Dec 10, 2016 4:35 am

All,

I've got the SFS-P8B pneumatic tail wheel. One bearing completely feel apart, other very worn. Will call Maule on Monday but checked aircraft spruce and saw parts available. Bearings are 111.95 each. This appears to be a standard 1/2 x 1 3/8 bearing, so why so much?

Do I need to be sitting down when I talk to Maule and order them?

Ralph
akafrank

maules.com · Post by **maules.com** » Sat Dec 10, 2016 7:14 am

It's just a bearing, and will have a number so you can match it.

redneck · Post by **redneck** » Sat Dec 10, 2016 7:33 am

Bought all parts from Maule. Washers, felt seals, bearings, new safety-wire chain clips. Don't remember exact price, but bearings weren't near that high. Check with Bryan. Could probably have bought bearings locally for less. They should be a common skf bearing. Check spindle for wear. It's replaceable as well. Felt seals are important. Mine were shot and allowing grit into bearing.

Akafrank · Post by **Akafrank** » Sat Dec 10, 2016 12:45 pm

Can't find any part numbers on the bearings. Right is different than left, looks like somebody may have changed a bearing in the past. Anyway, I will call Maule and make everything right.

The law of unintended consequences, all this started with just checking the air pressure.

Ralph
akafrank

Another TW Shimmy question

Another TW Shimmy question

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