Date: Mon, 21 Jul 2008 16:48:21 -0400
Reply-To: Mike <mbucchino@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike <mbucchino@CHARTER.NET>
Subject: Re: Master Cylinder - Help!
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
Vacuum bleeders DO suck in air. The first place they leak by is thw bleeder
screw threads. You need to repve them, coat the threads with grease and
then reinstall and proceed with attempting to bleed the system. If you
decide to give it a try with no grease, you'll be re-doing it later. The
next place that vacuum bleeders leak air into the system is when they create
a negative pressure (suction), past the lips of the slave (or wheel)
cylinder internal seal(s). They designed to expand against the cylinder
walls under pressure, so they will contract under suction. This will allow
air to leak in past the seal lips, taking any dirt or brake dust deposits
sitting outside the lips into the system along with it.
There are some people who swear by these vacuum bleeders, but I will never
use one in this application. I only use my 'Motive' pressure bleeder for
this job; it's slicker than anything else you could use. It forces brake
fluid, air, water and dirt out of the system, and won't allow it back in.
Fast, easy, one man operation.
IMHO, vacuum bleeders suck, literally!
Mike B.
----- Original Message -----
From: "Scott Daniel - Turbovans" <scottdaniel@TURBOVANS.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, July 21, 2008 1:35 PM
Subject: Re: Master Cylinder - Help!
> hi,
> not following you exactly Jim,
> I will always say that if both units are old, and you replace one, it's
> fairly likely the new strong one will blow out the older weaker one before
> too long.
> On using vaccuum to bleed - I'm sure that works. I've never liked that
> idea much as seems to me it could suck in air.
> Bleeding that way would eleminate the difficulty of getting a new clutch
> master cylinder to start moving fluid through that line back to the slave.
> The displacement of the clutch M/C is so small each stroke, that in a dry
> system it has trouble bleeding at first with either the two person method,
> or the one person 'bottle of brake fluid with clear hose' method. Once
> going though......
> I personally like using the master cylinder, either clutch or brake, to
> push
> fluid and air through the system - you can just feel when it's working
> right.
>
> well are we talking about brakes or clutch system here ?
> one guy talks about brake bleed valve on the back of a wheel,
> another person about 'the slave' ............and while rear wheel
> cylinders
> 'can' be called slaves..........usually they are not.
> they're called 'rear wheel cylinders' and 'the slave' refers to the clutch
> slave cylinder.
>
>
> ----- Original Message -----
> From: "Jim Felder" <jim.felder@GMAIL.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Monday, July 21, 2008 10:02 AM
> Subject: Re: Master Cylinder - Help!
>
>
>> I'm not so sure about this. It may be true, and a lot of people think it,
>> but it also may be--and I know that this is true--that the slave will
>> need
>> bleeding a few hundred to a thousand miles after the master is replaced,
>> leading one to believe that the slave has failed also.
>> Jim
>>
>>
>> On Mon, Jul 21, 2008 at 8:48 AM, Jonathan A. Sinclair <
>> jonathan@jasinclair.com> wrote:
>>
>>> Always replace the slave and the master together - if one is worn out,
>>> likely the new one will wear out the other quickly.
>>>
>>> There is a bleed screw on top of the slave in the engine compartment you
>>> can open that and use a vacuum bleeder to do the job. Will also serve
>>> to clean out your line.
>>>
>>> Good luck.
>>> Jonathan
>>>
>>>
>>> John Rodgers wrote:
>>>
>>>> Sounds like you need to open the bleeder valves on the back of the
>>>> wheel
>>>> and have someone pump the brake pedal while you bleed each brake. If
>>>> that doesn't do it, then you may have a bad MC. It can happen, has
>>>> happened, will happen.
>>>>
>>>> John Rodgers
>>>> 88 GL Driver
>>>>
>>>> pete wrote:
>>>>
>>>>> 80 Westy - installed a rebuilt brake MC from a list vendor - the male
>>>>> from the servo and the female on the MC are mated. I fill the
>>>>> reservoir and pump the pedal - the reservoir stays at the same level
>>>>> and there is no brake resistance. Any ideas? Please?
>>>>>
>>>>> TIA
>>>>>
>>>>> Pete
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
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