Date: Sat, 27 Jun 2015 09:44:41 -0700
Reply-To: Neil N <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Neil N <musomuso@GMAIL.COM>
Subject: Re: Low Brake Pedal, Caliper Piston Movement.
In-Reply-To: <BAY405-EAS3353309E245C79C48C4055A0AC0@phx.gbl>
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Thanks Dennis.
> .... For adjuster to work when the hydraulics push the shoes out the
> arm has to free of pressure on both side for the wheel to turn easily.
That imagery helps me see better how the adjuster works.
Speaking of that part......
The long tang of each e-brake fork end of adjuster appeared to be splayed
slightly more open. I may have "muscled" that part into place
during prior work. (adj. metal is soft) As such, that long tang may have been
contacting less of bottom point of slot in shoe. i.e. there might've
been a tendancy for that fork to slip past the shoe and bind or at
very least, cause an improper initial manual shoe adjustment??? I very
carefully straightened it out.Several images of parts I refer to:
https://picasaweb.google.com/musomuso/RearBrakes#6159350969131974418
I also noticed a slight teet on the e-brake lever at shoe. These being Raybestos
Premium shoes. You can see that bit in images above. Is that teet
there to help keep
the adjuster arm in place?
As per your tips in the archives, I cleaned and lubed the adjusters with
dry lube graphite stuff. Each adjuster wheel spins nicely.
Good to know a small gap (1/16" ?) is acceptable at lever and adjuster bar.
After using brakes, pedal feels high and firm, just like my '88.
I don't feel a hydraulic pressure loss. I know that feeling. BTDT.
The brakes work better since replacing
the worn at a slight angle front pads and checking-adj. rears.
Problem is, the pedal can remain fine overnight, or not;
it can return to it's lower feel.
And, maybe my leg is too strong, but regardless of pedal height,
if I push REALLY hard, I can push the pedal to the stop. But then that
isn't a real
world test. I doubt a panic stop would entail that kind of force.
I'll adjust the shoes again and report back.
Neil.
On 6/27/15, Dennis Haynes <d23haynes57@hotmail.com> wrote:
> Properly adjusted there should be a small gap between the lever and the
> adjuster. For adjuster to work when the hydraulics push the shoes out the
> arm has to free of pressure on both side for the wheel to turn easily. The
> threads should not be lubed with a heavy grease or ant-seize. That wheel has
> to be able to turn freely.
....
> Back the hydraulics, the beauty of the system is the pressure will be evenly
> distributed. Braking effect front to rear is balanced by the cylinder and
> brake friction designs and the Vanagon also has a pressure reducer for the
> rear. This reducer functions on tilt. Yes jack up the back you reduce the
> rear force. Larger tires on the back and you reduce both the force and
> effects of the brakes. The goal here is to reduce the possibility of rear
> wheel lock-up and the resulting spin out.
>
> So when the pedal is a little low due to a bad adjustment or wear or what
> have you, at the point the pedal gets firm the braking effect to all the
> wheels will be normal. The calipers will work as they should. If a circuit
> should fail, the pedal will travel real far and then stops inside the master
> cylinder will cause the reaming circuit to work. To get a feel for this open
> a bleeder and work the pedal. You will feel this. .......
> A soft pedal can be caused by a number of issues. To rule out adjustment set
> the parking brake and try. If the pedal operation remains firm you are good
> hydraulically. If you need to regularly pump you still have air in system or
> a bad check in the master cylinder. If excessive travel and everything is
> ruled out then you most likely have a bad rear brake pressure regulator.
> Find a shop with a brake pressure gauge set to test.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Neil N
> Sent: Friday, June 26, 2015 2:46 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: Low Brake Pedal, Caliper Piston Movement.
>
> the Vanagon brake hydraulic is set up differently.
> 1/2 of MC is for fronts etc.
>
> As noted in Bentley (and previously missed by me), and as you obviously
> know, if shoes are set properly, e-brake cables are ok, then the gap between
> each e-brake lever on shoe is properly eliminated via adjustment at e-brake
> equalizer bar, the e-brake works just fine. That said, since I'd backed off
> the nut at equalizer bar quite far (in a somewhat ignorant effort to take
> those parts out of shoe adjustment situation), I had to "mess around" with
> the e-brake cables to ensure that the noted gap was taken up properly. i.e.
> I found that even after gap was eliminated, if I levered slightly on the
> shoe at lever, thus pulling on the cable, this would cause a small amount of
> gap to reappear.
> Thinking now, doing this on one cable/lever may simply have pulled on the
> other thus causing a gap between lever and adjuster bar??
>
> For others who may have been in this position (not understanding e-brake /
> shoe adjustment relationship), I think of these two systems as separate
> things, even though they are obviously related. i.e.
> properly adjusted and functioning shoes should work fine in spite of slack
> e-brake cables. This is why one sets shoe adjustment, then e-brake. AND, the
> e-brake once adjusted, should not affect brake shoe position, at rest.
> As has been noted already by folks far more knowledgable than me!
>
> Neil.
>
>
>
> On 6/26/15, sailingfc @dslextreme.com <sailingfc@dslextreme.com> wrote:
>
>> If you are not getting a firm pedal, l would say you are not getting
>> effective braking from the calipers. I don't know if our vans have a
>> diagonal hydraulic circuit like the old Rabbits/Sciroccos did, where
>> the you had one front and the diagonal rear brake on the same circuit
>> in case of a failure..
>>
>> My current parking brake shoes are adjusted to the point I get slight
>> drag when I spin the wheels and at one click of the parking lever, it
>> will hold in my slightly inclined driveway.
>
>
>
> --
> Neil n
>
> Blog: Vanagons, Westfalia, general <http://tubaneil.blogspot.ca>
>
> 1988 Westy Images <https://picasaweb.google.com/musomuso/New1988Westy>
>
> 1981 Westfalia "Jaco" Images, technical <http://tubaneil.googlepages.com/>
>
> Vanagon-Bus VAG Gas Engine Swap Group <http://tinyurl.com/khalbay>
>
--
Neil n
Blog: Vanagons, Westfalia, general <http://tubaneil.blogspot.ca>
1988 Westy Images <https://picasaweb.google.com/musomuso/New1988Westy>
1981 Westfalia "Jaco" Images, technical <http://tubaneil.googlepages.com/>
Vanagon-Bus VAG Gas Engine Swap Group <http://tinyurl.com/khalbay>
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