Construction and other equipment - 645B Brake Question

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645B Brake Question

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Construction and other equipment
Forum Description: everything else with orange (or yellow) paint
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=100117
Printed Date: 08 Jul 2025 at 4:29pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: 645B Brake Question

Posted By: Amos
Subject: 645B Brake Question
Date Posted: 08 Jan 2015 at 1:08pm

I am wondering, as I have to overhaul the entire brake system on my 645, if I can eliminate the valve on the transmission from the hydraulic portion of the brake system and use an air cylinder to disengage the transmission rather than the hydraulic brakes. Doing so would prevent the cross contamination of the brake fluid and transmission oil. Is the spool in this valve easily adaptable to attaching and air cylinder? I don't have my loader in the shop, but I do have to replace all the wheel cylinders as they are leaking and the master cylinders are weeping a bit as well. Just wanting to have the parts here to go at it as opposed to having to find them when it is in the shop and possibly holding up the shop space for a few days is all.

Replies:

Posted By: DiyDave
Date Posted: 08 Jan 2015 at 5:51pm

Look for an air over hydraulic valve. Surpluscenter.com might have 'em...

Posted By: Amos
Date Posted: 09 Jan 2015 at 6:03pm

Good idea Dave, thanks

Posted By: DiyDave
Date Posted: 09 Jan 2015 at 6:19pm

Might also work, with a solenoid, and a brake light switch...