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Wrasslin' with the road arms.


Mechanics, the road arm bearings, NSN 3120-01-102-4700 (outer) and NSN 3120-01-102-4701 (inner), on some Bradleys have been failing. Soft bearings are part of the problem, but lack of lubrication is also a culprit. The added weight of belly armor and reactive armor tiles just compounds the problem.


1. Perform a visual inspection. Are any of the road arm seals leaking or protruding? Are any of the road arms out of alignment relative to the hull and in comparison with other road arms? Are any of the road arms canted at an angle?


2. Use a tanker's bar to pry the roadwheel up from the track. This is a quick check for a broken torsion bar, but you can also use it to watch and feel for movement in the road arm that signals free play in the bearings.


3. Put the tanker's bar between the double roadwheels and try to move the roadwheels on the spindle. Movement indicates bearing problems.

If any of these three tests lead you to believe there's a problem, lift the suspect roadwheels with the dogbone tool, NSN 4910-01-118-7711. With the roadwheels in the air and no longer supporting the vehicle's weight, use the tanker's bar to test for movement again. If the roadwheels move, you need to disassemble and repair the bearings.

If the bearings show a lack of lube when disassembled, you should assume that all of the road arms on that vehicle lack proper lubrication. It's strongly advised that you go ahead and inspect and lubricate all of that vehicle's road arms.

Lubrication Update

Proper lubrication and service info is not in the -10 or -20 level TMs. Until those TMs can be updated, make sure the road arms and housing assemblies are lubed with GAA semiannually or every 1,500 miles, whichever comes first.

To lube a road arm that's mounted on the vehicle, remove the two plugs, NSN 4730-00-278-2965, at the top of the road arm housing.

Install a grease fitting, NSN 4730-00-050-4208, into the top hole and a pressure relief valve, NSN 4820-00-542-5683, into the side, angled hole.


Add GAA to the grease fitting until you see clean grease coming out of the relief valve. Wipe away the excess grease, then replace the fittings with the plugs.

You'll find the complete scoop on the road arm bearings in TACOM MAM 08-030:

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No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2008 Gale, Cengage Learning. All rights reserved.

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Title Annotation:M2/M3-Series Bradley ...; Bradley Fighting Vehicles
Publication:PS, the Preventive Maintenance Monthly
Geographic Code:1USA
Date:Dec 1, 2008
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Next Article:Hinges need lube, too.

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