Farm Equipment - strange noise after stopping. fiat 645b

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strange noise after stopping. fiat 645b

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=194214
Printed Date: 13 May 2025 at 7:57am
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Topic: strange noise after stopping. fiat 645b

Posted By: bjorn tore
Subject: strange noise after stopping. fiat 645b
Date Posted: 23 Mar 2023 at 11:18am

I have an Fiat allis 645b wheel loader. I have been refilling some hydraulic oil because it was low on oil and it seemed like i had some air in the system. But after refilling this it seems like the hydraulics works fine now. But after i stop the wheel loader i hear a whistle sound, its sounds like a tire that has a leak. the sound comes from right under the cabin near the hydraulic pump. it disapears again 5 min after stop. Cant see any oil drops either underneath.

Does anybody know what this problem is ?

Replies:

Posted By: darrel in ND
Date Posted: 23 Mar 2023 at 11:20am

Pretty sure it has a compressor/air system for the brakes (both of mine do) so quite likely you're hearing an air leak from that.
Darrel

Posted By: steve(ill)
Date Posted: 23 Mar 2023 at 12:15pm

in addition to what Darrel said... i think the air brakes might bleed off and LOCK when the tractor is OFF... You start the motor and let it build up air pressure to RELEASE the brakes ?

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Like them all, but love the "B"s.

Posted By: SteveM C/IL
Date Posted: 25 Mar 2023 at 9:52am

My 78 545B has air over hyd brakes. No air-no brakes. Has a drum parking brake on driveshaft with the over center lever. Mine has a dual air tank near the hyd pump with petcock drains as well as a large tank in the rt rear corner. Could be similar. I would pursue air leaks first.