[T2] Disc brakes dragging

[Chris Dreike]

Chris Dreike
8:29 PM (0 minutes ago)
to VW
oops I missed the last link. Here it is again.

I now have 1/64 thick shims in place and the brakes are working fine. I
don't think I want to go any thinner. I also found Samba links that talk
about adjusting the booster to M/C rod to avoid this problem.

https://www.thesamba.com/vw/forum/viewtopic.php?t=705144
https://www.thesamba.com/vw/forum/viewtopic.php?t=693460
And scroll down about half way on this one to see a diagram that is true
for both non booster and booster systems. Booster systems the rod from the
booster to the M/C needs a 1mm (.04") gap too.
https://www.thesamba.com/vw/forum/viewtopic.php?t=679475
And this one has a nice cut away drawing of the booster. Item 4 pushes into
the M/C and needs to be adjusted for a 1mm gap.
https://www.thesamba.com/vw/forum/viewtopic.php?t=405936&postorder=desc

Cheers,
Chris


On Mon, Aug 17, 2020 at 8:29 PM Chris Dreike <cdreike at gmail.com> wrote:

> I now have 1/64 thick shims in place and the brakes are working fine. I
> don't think I want to go any thinner. I also found Samba links that talk
> about adjusting the booster to M/C rod to avoid this problem.
>
> https://www.thesamba.com/vw/forum/viewtopic.php?t=705144
> https://www.thesamba.com/vw/forum/viewtopic.php?t=693460
> And scroll down about half way on this one to see a diagram that is true
> for both non booster and booster systems. Booster systems the rod from the
> booster to the M/C needs a 1mm (.04") gap too.
> https://www.thesamba.com/vw/forum/viewtopic.php?t=679475
> And this one has a nice cut away drawing of the booster. Item 4 pushes
> into the M/C and needs to be adjusted for a 1mm gap.
>
> Cheers,
> Chris
>
> On Mon, Aug 17, 2020 at 8:40 AM Bob <accessys at smart.net> wrote:
>
>>
>>
>> FWIW I have had bad parts right out of the box so I wouldn't "trust" that
>> a new part, any part, is working until inspected and tested
>>
>> Bob
>>
>>
>> On Sun, 16 Aug 2020, Erik Burtis wrote:
>>
>> > "Thanks for all the input. All the parts are new save the steel brake
>> > lines"- these coil be rusting from the inside out and causing a
>> blockage,
>> > but since the symptoms go away with the booster disconnecting, I don't
>> > think this is your issue.
>> >
>> > " Erik, Where is the check valve you mentioned earlier? Is it in the
>> M/C? or
>> > were you referring to the vacuum check valve in line to the manifold?"
>> > Yes, it's the one by the manifold.  As Bob suggested, make sure it's
>> > installed in the right direction.  Memory is a little fuzzy but I think
>> the
>> > bentley has it backwards.  Search the samba for the bentley mistakes
>> > thread.  The check valve should hold a vacuum for several minutes after
>> you
>> > turn the car off, overnight in some cases.  So if you go back 5 min
>> after
>> > turning the bus off, press the brakes and the pedal should go down
>> easi=y
>> > for the first cycle or two.  Then it'll become more difficult.
>> >
>> > " AND one more thing. In perusing the forums on the Samba I found a post
>> > complaining of exactly the problem I'm having"  Shoot the PO a message
>> and
>> > see if/how he solved it.
>> >
>> > There are some problems that show up with the new boosters verse
>> rebuilt.
>> > Call your vendor, maybe they have some suggestions?
>> >
>> >
>> > On Sun, Aug 16, 2020 at 4:29 PM Chris Dreike <cdreike at gmail.com> wrote:
>> >
>> >> Wow, Thanks for all the input. All the parts are new save the steel
>> brake
>> >> lines. The brakes worked fine before I installed the drop spindles.
>> >> I looked up How works a brake booster. The brake fluid level is not
>> >> dropping. There appears to be a weep hole at the bottom of the M/C
>> mounting
>> >> flange. No fluid dripping out.
>> >> Yes the brakes are working fine with the vacuum line disconnected from
>> the
>> >> intake manifold. The vacuum check valve is new and working as I
>> checked the
>> >> function.
>> >> The vent line is in good working order. Sadly the boot at the front of
>> the
>> >> booster is shot after an year and a half. Anyone know where to get a
>> new
>> >> one? I'll try Wolfsburg West tomorrow.
>> >>
>> >> Later today I will add a small shim between the M/C and the booster
>> and see
>> >> if that helps. The booster seems to be the problem. Will report back
>> later.
>> >>
>> >> Erik, Where is the check valve you mentioned earlier? Is it in the
>> M/C? or
>> >> were you referring to the vacuum check valve in line to the manifold?
>> >>
>> >> AND one more thing. In perusing the forums on the Samba I found a post
>> >> complaining of exactly the problem I'm having. New booster from
>> Wolfburg (
>> >> I got mine from CIP1 and it looks to be the same manufacturer) and his
>> disc
>> >> brakes were dragging. I did not see a solution on that thread however
>> there
>> >> were a lot of posts saying to have your old OEM booster rebuilt rather
>> than
>> >> buy a new one as the new ones are problematic.
>> >>
>> >> Cheers,
>> >> Chris
>> >>
>> >> On Sun, Aug 16, 2020 at 7:10 AM Jamie <jrivers at globalserve.net> wrote:
>> >>
>> >>> Inside the booster, there is a valve, opens on brake application and
>> >>> allows vac to assist movement Of cylinder in master cylinder
>> >>>
>> >>> If fluid is in that area, it will hold the port open,, and keep brakes
>> >>> applied while vacuum is available
>> >>>
>> >>> and when more fluid gets in there ,,A slight tap of the pedal will
>> cause
>> >>> the vac to depress it and pull it out from under your foot, and apply
>> >>> brakes fairly hard!
>> >>>
>> >>> Sounds to me that there is fluid that has bypassed seal on master ,,,
>> >> over
>> >>> the years,, so you don’t notice a recent drop in fluid in the
>> reservoir,,
>> >>>
>> >>> Pull the master (loosen off far enough) and field fab a dip stick from
>> >> box
>> >>> board to slide into booster below the master .. see if there is fluid
>> in
>> >>> there
>> >>> I don’t worry about a little fluid,,
>> >>>
>> >>> If there is a “lot” <relatively speaking,, I’ve devise a way to
>> siphon/
>> >>> wet vac out the fluid ... a u shaped steel line ,,
>> >>> There isn’t much room ,,
>> >>>
>> >>> Of course , if there has been a recent drop in reservoir level,, then
>> a
>> >>> master cyl repair/ replacement is in order
>> >>>
>> >>> My take on it,,  Jamie
>> >>>
>> >>>> On Aug 16, 2020, at 9:51 AM, Erik Burtis <ewdb92 at gmail.com> wrote:
>> >>>>
>> >>>> I was thinking about this problem early this morning.  Let's see:
>> You
>> >>> said
>> >>>> you replaced all the brake lines, so unless dirt got into the system
>> at
>> >>>> that time or there is a defect, they shouldn't be the issue..  The
>> >>> problem
>> >>>> went away when you disconnected the brake booster.  I think this
>> rules
>> >>> out
>> >>>> blockage in the lines or brake fluid issues.  This sounds like a
>> >> buildup
>> >>> of
>> >>>> vacuum to me and when you stop driving and press the brakes, you
>> >> release
>> >>>> the vacuum.  It can happen if the check valve is in backwards; can
>> also
>> >>>> happen if the booster vent line is blocked (did it get pinched during
>> >>> your
>> >>>> spindle work?).  Do both front brakes drag?  If so, also an
>> indication
>> >>> this
>> >>>> is not line related.  Maybe a failed booster would hold extra vacuum,
>> >> but
>> >>>> it seems to me that they do the opposite.  One of the tests for a
>> >> failed
>> >>>> booster is a change in rpms when you press the brake pedal.
>> >>>> Erik
>> >>>>
>> >>>>
>> >>>>>
>> >>>> _______________________________________________
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>> >>>
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