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54C Power Flow Rebuild Need Info on DTAC 79102

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I went to see if there was a belt tension adjustment on my power flow today (there is not, just the spring) and found that the outboard bearing had locked up and destroyed the shaft on my fan. So, I have been looking up all the parts I need and noticed there is a DTAC listed for the blower with two different spacers on the shaft, may explain incorrect bearing preload that caused the problem. Anyway, does someone have a copy of DTAC 79102 and could they give me a summary so I can put this back together again. I already know I need a shaft, two bearings and the pulley. Not sure if I should order the original 9/16" spacer or the 1/2" spacer?


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I will notify Kevin for you...He can help.
Here is the text from DTAC #79102, Sorry for the delay. Sounds like the longer bushing is the way to go. Be careful not to over-torque the bolt on the impellar shaft.

Complaint or Symptom :

Power flow impeller shaft bearings seized.

Problem or Situation :

Bearing failure or seizure may cause the belt to lock up & burn, impeller shaft to wear/score from turning inside the bearings, pulley that is bolted to impeller shaft to mushroom up on impeller side, or even allow the impeller to distort & damage the power flow housing.

Tolerance stack-up on the high end of the hub welded to the metal plate (AM130969BLE) where the bearings are seated, plus if the bushing (28H1885) that sits between the bearings (JD7142) is on the low side of its spec, will allow the bushing to be too short & not support the center of the bearings. Tightening the impeller & pulley (AM121832) creates a side load on the bearings & may cause them to bind and fail.

Solution :

Replace both bearings (JD7142) & install a longer bushing (28H1659) between them.

Replace any other parts that may have failed.

Check alignment of fan to make sure it is turning freely.


JD7142 Ball Bearing (2 needed)

28H1659 Bushing

Additional Information :

Bushing 28H1659 has an overall length of 0.562-in.

Bearings may also fail prematurely if water gets inside the bearing.

During re-assembly, there should be a gap between the end of the M144683 impeller shaft and the pulley. It is designed that way. Torque cap screw to proper torque and use loctite.

A print/drawing change was made in November, 2007 to tighten up the possible tolerances on the hub (welded to the metal plate). The tolerance inside the hub where the bushing sits was +/- 0.5-in, it is now only 0.13-in. It will be effective with the parts being made in December, 2007. It will go into weldments shortly after as the current inventory of hubs is depleted.

The 48HP, 54HP, & 62HP power flows were used on the LX, GT, GX, 400's, 500's Lawn & Garden Tractors, the X3/X5/X7 Select Series Tractors, & the Z425/Z445 EZtraks.

This bushing change was also made to the 48QT & 54QT power flows.
thanks Kevin, this is what happened to my unit, the bearings failed from improper preload when it was originally built, and wiped out the pulley and shaft. I wish these things would happen under warranty, considering that it was a potential design issue. I will use the longer spacer when I rebuild.


Well I installed the longer shaft, new bearings, keys, and pulley. All working well now. Thanks everyone for your help
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