[T2] Disc brakes dragging

Chris Dreike cdreike at gmail.com
Mon Aug 17 20:29:39 PDT 2020


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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