[AJD] What are failed Master Brake Cylinder Symptoms?

[Bruce Mahr]

Dean: That is why I suggested plugging off the master cylinder as a way to 
check it before doing anything. If that shows the master cylinder to be 
good, you can hook it back up and unhook the line going out of the vacuum 
booster and plug it off and see whether the cylinder on the booster is the 
culprit or not. I have seen several vacuum booster cylinders that were bad 
but didn't give an indication in the exhaust of burning brake fluid, some do 
and some don't.
Sometimes you have to systematically isolate components to find the cause, 
starting at the front and working you way to the end of the system.

Bruce Mahr

----- Original Message ----- 
From: "Dean VP" <deanvp at att.net>
To: "'Antique John Deere mailing list'" 
<antique-johndeere at lists.antique-tractor.com>
Sent: Thursday, July 14, 2005 6:02 PM
Subject: RE: [AJD] What are failed Master Brake Cylinder Symptoms?


> Thanks for all the suggestions, but.........Well folks, I replaced the
> Master Brake Cylinder and I still have the same problem. Bench bled the 
> MC,
> installed it, bled all the lines and at each wheel twice. Get initial
> pressure on the pedal and then the pedal slowly fades away to the
> floorboard. Bleeding the lines offered no additional help although air was
> pushed out of the lines.
>
> I haven't verified that I'm loosing fluid during the fade down because I
> lost so much fluid bleeding the lines. Need to next check with a full
> reservoir to see if there is fluid being pumped somewhere.
>
> Either I got another MC that is as bad as the one before or I have a bad
> Vacuum assist mechanism or a leaking wheel cylinder somewhere. No visible
> leaks but harder to tell because now I made a mess bleeding the wheel 
> lines.
>
>
> I was hoping to get lucky and have the problem solved with a replacement 
> MC.
> No such luck. Going to plug the line just before it goes into the Vacuum
> assist the next chance I get and see what happens.
>
> Something isn't kosher here. Not making logical sense.
>
> Dean A. Van Peursem
> Snohomish, WA 98290
>
> I'm a walking storeroom of facts..... I've just lost the key to the
> storeroom door
>
>
> www.deerelegacy.com
>
> http://members.cox.net/classicweb/email.htm
>
>
>
> -----Original Message-----
> From: antique-johndeere-bounces at lists.antique-tractor.com
> [mailto:antique-johndeere-bounces at lists.antique-tractor.com] On Behalf Of
> Dave Ernst
> Sent: Thursday, July 14, 2005 6:33 AM
> To: Antique John Deere mailing list
> Subject: Re: [AJD] What are failed Master Brake Cylinder Symptoms?
>
> Hey Dean, Ed is correct. I have a dump truck and just went through the
> identical problem. I stalled a couple of days before I bought a rebuilt
> hydro-vac because I was trying to determine if burning brake fluid was
> cheaper than gasoline....:)
> Dave
>
>> Dean-
>> Sounds to me like you have 2 problems. 1. Being the master cylinder 2.
>> Being
>> the vacuum booster or hydro-vac. The Pedal fad sounds like fluid passing
>> by
>> the rings and cups on the master cylinder piston and should be rebuilt.
>> The
>> unexplained fluid loose tells me the booster is bad and the brake fluid 
>> is
>> being sucked back into the engine intake by engine vacuum. Some boosters
>> my
>> be rebuilt but I would recommend buying a remanufactured unit. The master
>> cylinder you should have no problem rebuilding yourself. Good luck
>>
>> Ed Allandar
>> Rohrer Bus Service
>> P.O. Box 100 - 1515 State Road
>> Duncannon, PA 17020-0100
>> 717.957.5114 Direct
>> 717.418.4401 Cell
>> 1-800-735-6700 x223 Toll free
>> 717.957.4884 (fax)
>> eallandar at rohrerbus.com
>>
>
>
> _______________________________________________
> Antique-johndeere mailing list
> http://www.antique-tractor.com/mailman/listinfo/antique-johndeere
>
>
>
> _______________________________________________
> Antique-johndeere mailing list
> http://www.antique-tractor.com/mailman/listinfo/antique-johndeere
>