Strange Brake Failure

LSolheim

Member
We went on a great tour with the MG Club Saturday (http://www.mbmgcc.org/gallery/082308-CrabRun/index.html), as described. We had another couple with us, as they discovered an MG fuel pump failure as they prepared to leave Saturday morning. Possibly significant only in that we had a VERY full load.

All went well during the drive, as it had since I reworked the brakes back in April. After the feast I backed out of the place I was parked, backwards down a small slope, and applying the brakes Amphi’s brake pedal went to the floor (although not “slamming” down) and without brakes (or with a tiny bit of limited brakes) I rolled slowly into the fence of the host’s neighbor across the street.

Fortunately, no one was hurt and there was no damage to the Amphicar. All-in-all, pretty scary. To get there we had gone down a very steep road ending in a ‘T’ at the bottom, drop-off across the road. I had just commented that it would be a nasty place to lose brakes!

Fluid in the reservoir looked about normal and after moving Amphi to a flat area I could not duplicate the brake pedal action. She drove (and stopped) normally all of the way home.

After the car has set in the garage for a day the pedal will again go to the floor. Pulling the rear seat and floor, I have found no leaks at any wheel cylinders, on the master cylinder or any of the hard or flex lines or their connections. The reservior shows no drop, so I figure the problem must be in the Master Cylinder, but am at a loss to know what it might be. There is no "brake fade" when holding light pressure on the pedal indicating fluid moving past a seal. Since there is no pressure on the system when just sitting, where and how can the fluid move? It is silicone fluid. After testing a bit the pedal is nice and firm again. We'll see what she feels like in the AM.

Pretty strange how this just occurred after months of driving and swimming. I do recall when restoring MetalBeast, I had flushed and rebuilt the brakes and was in the process of bleeding them. I stepped on the pedal and felt a wetness on the back of my neck. It turned out that a horizontal line to the RR on the bulkhead under the back seat had rusted and there was a pinhole allowing fluid to spray up and out. Couldn’t find it before as the whole system was frozen up.

Long message, but thanks for your inputs/ideas,

--Larry
 

dougklink

Member
Silicone fluid can be very strange. I quit using it due to the inability to get and maintain and good hard pedal. Seems to need Viagra....
----- Original Message -----
From: LSolheim
To: dougklink@gmail.com
Sent: Tuesday, August 26, 2008 2:16 PM
Subject: [General Amphicar Discussion-t-20133] Strange Brake Failure


We went on a great tour with the MG Club Saturday (http://www.mbmgcc.org/gallery/082308-CrabRun/index.html), as described. We had another couple with us, as they discovered an MG fuel pump failure as they prepared to leave Saturday morning. Possibly significant only in that we had a VERY full load.

All went well during the drive, as it had since I reworked the brakes back in April. After the feast I backed out of the place I was parked, backwards down a small slope, and applying the brakes Amphi's brake pedal went to the floor (although not "slamming" down) and without brakes (or with a tiny bit of limited brakes) I rolled slowly into the fence of the host's neighbor across the street.

Fortunately, no one was hurt and there was no damage to the Amphicar. All-in-all, pretty scary. To get there we had gone down a very steep road ending in a 'T' at the bottom, drop-off across the road. I had just commented that it would be a nasty place to lose brakes!

Fluid in the reservoir looked about normal and after moving Amphi to a flat area I could not duplicate the brake pedal action. She drove (and stopped) normally all of the way home.

After the car has set in the garage for a day the pedal will again go to the floor. Pulling the rear seat and floor, I have found no leaks at any wheel cylinders, on the master cylinder or any of the hard or flex lines or their connections. The reservior shows no drop, so I figure the problem must be in the Master Cylinder, but am at a loss to know what it might be. There is no "brake fade" when holding light pressure on the pedal indicating fluid moving past a seal. Since there is no pressure on the system when just sitting, where and how can the fluid move? It is silicone fluid. After testing a bit the pedal is nice and firm again. We'll see what she feels like in the AM.

Pretty strange how this just occurred after months of driving and swimming. I do recall when restoring MetalBeast, I had flushed and rebuilt the brakes and was in the process of bleeding them. I stepped on the pedal and felt a wetness on the back of my neck. It turned out that a horizontal line to the RR on the bulkhead under the back seat had rusted and there was a pinhole allowing fluid to spray up and out. Couldn't find it before as the whole system was frozen up.

Long message, but thanks for your inputs/ideas,

--Larry
 

LSolheim

Member
I have heard that also, Doug, but have not experienced it. There have also
been reports (not Amphicar) that some brake system components have not been
compatible w/ silicone fluid. I've been running it in Amphi since 1994
though, (actually that was when I last rebuilt the master cylinder) and this
is the first problem I've seen.



Thanks,

--Larry



From: dougklink [mailto:]
Sent: Tuesday, August 26, 2008 4:58 PM
To: lrsnpark@gmail.com
Subject: RE: [General Amphicar Discussion-t-20133] Strange Brake Failure



Silicone fluid can be very strange. I quit using it due to the inability to
get and maintain and good hard pedal. Seems to need Viagra....
----- Original Message -----
From: LSolheim
To: dougklink@gmail.com
Sent: Tuesday, August 26, 2008 2:16 PM
Subject: [General Amphicar Discussion-t-20133] Strange Brake Failure


We went on a great tour with the MG Club Saturday
(http://www.mbmgcc.org/gallery/082308...n/index.html),
<http://www.mbmgcc.org/gallery/082308-CrabRun/index.html),> as described.
We had another couple with us, as they discovered an MG fuel pump failure as
they prepared to leave Saturday morning. Possibly significant only in that
we had a VERY full load.

All went well during the drive, as it had since I reworked the brakes back
in April. After the feast I backed out of the place I was parked, backwards
down a small slope, and applying the brakes Amphi's brake pedal went to the
floor (although not "slamming" down) and without brakes (or with a tiny bit
of limited brakes) I rolled slowly into the fence of the host's neighbor
across the street.

Fortunately, no one was hurt and there was no damage to the Amphicar.
All-in-all, pretty scary. To get there we had gone down a very steep road
ending in a 'T' at the bottom, drop-off across the road. I had just
commented that it would be a nasty place to lose brakes!

Fluid in the reservoir looked about normal and after moving Amphi to a flat
area I could not duplicate the brake pedal action. She drove (and stopped)
normally all of the way home.

After the car has set in the garage for a day the pedal will again go to the
floor. Pulling the rear seat and floor, I have found no leaks at any wheel
cylinders, on the master cylinder or any of the hard or flex lines or their
connections. The reservior shows no drop, so I figure the problem must be in
the Master Cylinder, but am at a loss to know what it might be. There is no
"brake fade" when holding light pressure on the pedal indicating fluid
moving past a seal. Since there is no pressure on the system when just
sitting, where and how can the fluid move? It is silicone fluid. After
testing a bit the pedal is nice and firm again. We'll see what she feels
like in the AM.

Pretty strange how this just occurred after months of driving and swimming.
I do recall when restoring MetalBeast, I had flushed and rebuilt the brakes
and was in the process of bleeding them. I stepped on the pedal and felt a
wetness on the back of my neck. It turned out that a horizontal line to the
RR on the bulkhead under the back seat had rusted and there was a pinhole
allowing fluid to spray up and out. Couldn't find it before as the whole
system was frozen up.

Long message, but thanks for your inputs/ideas,

--Larry
 

DavidC

Amphicar Expert
If no fluid loss and with other symptoms you describe that can only be the master cylinder. I'd change it right now. Ideally make sure it's original Amphicar as some of the VW replacements don't work right. It could also be something didn't go together right. What can happen is a seal sticks and works like a valve stopping the fluid entering .

Will be nothing to do with Silicon fluid which is a fabulous product for Amphicar. I've used nothing else in my Amphicar brakes for more than 20 years. Original NOS Amphicar brake rubbers work fine with silicon as do the new manufactured seals that Hugh is selling.

One very easy mod is to fit a fluid level sensor from a later VW to the fluid reservior conencted to a buzzer, there is a picture and a bit more info in the tech section of amphicars.com

David C
 
R

Ron Green

Guest
Larry, I too suspect the master cylinder however I would flush the system with the silicone brake fluid and bleed the brakes as it could be dirt. I flush my system every year and I am amazed at how much dirt and gunk accumulate in the brake system.
 

Canadian four amphs

Amphicar Expert
Mater cly. do strange things over the years,, I have one right now that is at the very top when pressed but has very poor stopping effect.. all wheel cyl, have just been done and has my new linnings on it. will put new mater on it and report back.
MASTERS. VW types... there is only 1 that may work it is of a VW bus,, all othere have a smaller diamiter piston and should not be used,
the Bus one has a smaller dia rod lenght and Amphis must be ground down.. not a good thing..
I do have a replacement master that has the original type piston so no grinding is needed.. but sell exchange only..
I also have a few NOS original Amphicar master cylinders.(more expensive)

GORD SOUTER>
 

DavidC

Amphicar Expert
> all othere have a smaller diamiter piston

Gord makes a good point, a lot of VW stuff has smaller bore wheel cylinders than Amphicar and therefore a smaller bore master cylinder. Check this carefully. If you fit a smaller bore master cylinder to Amphicar it won't move enough fluid so although it will appear to work if you need to make a full emergency stop - or the brakes aren't adjusted regularly - then the pedal could hit the floor when you most need it.

David C
 

gzink

Member
Very good point. Have to weigh that versus risk of no brakes due to 1 wheel cylinder or line with single chamber. Do you know the bore of the original Amphicar master David?


--- On Sun, 8/31/08, DavidC <> wrote:


> From: DavidC <>
> Subject: RE: [General Amphicar Discussion-t-20133] Re: Strange Brake Failure
> To: g_zink_us@yahoo.com
> Date: Sunday, August 31, 2008, 4:52 PM
> Quote:
>
>
>
>
> > all othere have a smaller diamiter piston
>
>
>
>
> Gord makes a good point, a lot of VW stuff has smaller bore
> wheel cylinders than Amphicar and therefore a smaller bore
> master cylinder. Check this carefully. If you fit a smaller
> bore master cylinder to Amphicar it won't move enough
> fluid so although it will appear to work if you need to make
> a full emergency stop - or the brakes aren't adjusted
> regularly - then the pedal could hit the floor when you most
> need it.
>
> David C
>
>
>
 

DavidC

Amphicar Expert
> Do you know the bore of the original Amphicar master David?

Pretty sure it's 22mm but best if you measure it - especially if you want a
measurement in those fractional inch thingys !

David C
 
S

SplitPersonality

Guest
Regarding silicone fluid, I have used it in 3 different vehicles. The first
two ( one was a VW) worked like a dream or at least never gave me any problem.
However, in a 64 Corvette, I do not know why, but it was an endless problem.
I had put in all new cylinders ( all 5 ) but the fluid would leak from one
or both front wheel cylinders ( all drum brakes on the 64 ) and get on the
shoes. I finally just replaced all the wheel cylinders and went back to regular
fluid. Maybe it was just a defective cylinder on one side, I don't know.
Vic Nelson Otherwise, I strongly believe in the value
of Silicone fluid



**************It's only a deal if it's where you want to go. Find your travel
deal here.
(http://information.travel.aol.com/deals?ncid=aoltrv00050000000047)
 

azpaul50

Member
Seeing as how EVERYONE will be having a grand time this weekend... and I don't even have my Amphi to look at, and it is 107 outside... and did I mention (we) Arizonans regularly bury ourselves in sand to our necks and withstand ant attacks for hours (an old west tradition), I thought I'd comment about SOMETHING!! The ant thing impresses the Californians! :002: My Nash Metropolitan has Gerling brakes and the buzz in that community is to not use any petroleum or silicon based brake fluid. Believe it or not they say to use some veggie based stuff that prevents the rubber hose part of a brake system from internally swelling. The whole dealie there is that this stuff is "LMA" meaning Low Moisture Activity. Now... being a car guy and biker for many years in several communities, I've come to realize that some communities have urban legends and some advice is plain voodoo. Sometimes it comes from suppliers trying to create a market for certain products or just some guy throwing in their 2-cents in every forum. This is a persistent bit of advice for Mets so I do it just to be "sure." In the U.S. it sells as Castrol GT-LMA brake fluid. I can't say thay I've seen any improvement since I began using it but brake performance isn't any worse. As for my Amphi, the brakes are AFU beyond fluid problems right now. But as it stands, I'll be putting this stuff in it on the premise that if I don't, the two cars will get together and conspire against me! :012: Arizona Paul of the Western Amphi Fleet (currently in dry dock)!
 
R

Ron Green

Guest
Having had a discussion this past week with a car guy regarding brake fluid: I was told that your standard DOT 3 and 4's are now synthetic, won't absorb moisture and will last much longer. I still flush and bleed my brakes every season and there is a lot of odd looking colors and on occasion debris in 1 year old fluid.
 
Ron,
What is your "flush" procedure? Does it involve compressed air? Do you open up all bleeders and run fresh fluid through the lines via the master? I recently obtained a '65 that sat for five years and I have replaced all the brake components (not the lines) and am about to fire up the system. Now would be a perfect time to flush.

Thanks,

Brian Crombie




To: bad.dogg@hotmail.comSubject: RE: [General Amphicar Discussion-t-20133] Re: Strange Brake FailureDate: Wed, 3 Sep 2008 12:48:44 -0400From:



Having had a discussion this past week with a car guy regarding brake fluid: I was told that your standard DOT 3 and 4's are now synthetic, won't absorb moisture and will last much longer. I still flush and bleed my brakes every season and there is a lot of odd looking colors and on occasion debris in 1 year old fluid.

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Stay up to date on your PC, the Web, and your mobile phone with Windows Live.
http://clk.atdmt.com/MRT/go/msnnkwxp1020093185mrt/direct/01/
 

DavidC

Amphicar Expert
> What is your "flush" procedure? Does it involve compressed air?

I don't think you are supposed to use air to flush the brake system ? Over here everyone uses a device called a Gunson Easibleed, it pressurises the system using air from the spare tyre and you then just open each bleeder (which has a different name in the UK) in turn until the fresh fluid comes through. Works a treat and is gentle so doesn't result in a system full of air bubbles.

David C
 
R

Ron Green

Guest
There are several ways of bleeding the system and some use a brake vacuum container designed just for bleeding. I never had luck with using these. Through the years my wife has become an expert at the old method of pump pump pump, holding, down, tight, let up, plus this allows for the occasional argument of whom screwed up the sequence so you can start over.


Regarding flushing I believe some use alcohol or possibly a product designed for flushing. Check with your local auto parts store as new products seem to be available all the time. My vehicles through the years have either had decent semi clean brake lines or I replaced them with new, so I just ran brake fluid through them. I wouldn't use compressed air especially if using DOT 3 or 4 as it might possibly end up on a painted area.
 

carnut1113

New Member
OK...just from experience. I've used the vacuum system (air compressor powered creating a venturi) cost around 180-200 bucks, The old pressurized systems (connecting to the brake master reservoir with a seal and applying fluid undr air pressure), and the third and least desirable and efficient (finding someone to help pump the brakes).
The pressurized system increases the potential to spray blake fluid on the body parts, but does work.
The human powered system can give one the false impression that the system has really been flushed, but will get the brakes operational in most cases.
But the vacuum systems will bleed effectively and efficiently. (I've got a couple of older Lamborghini's and the vacuum systems are the ONLY thing that get's*the brake and clutch systems*flushed adequatly. The vacuum system works well on the Amphi too!
Jim
*
*
*
*
*
*


--- On Wed, 9/3/08, Ron Green <> wrote:

From: Ron Green <>
Subject: RE: [General Amphicar Discussion-t-20133] Re: Strange Brake Failure
To: carnut1113@yahoo.com
Date: Wednesday, September 3, 2008, 3:44 PM







There are several ways of bleeding the system and some use a brake vacuum container designed just for bleeding. I never had luck with using these. Through the years my wife has become an expert at the old method of pump pump pump, holding, down, tight, let up, plus this allows for the occasional argument of whom screwed up the sequence so you can start over.


Regarding flushing I believe some use alcohol or possibly a product designed for flushing. Check with your local auto parts store as new products seem to be available all the time. My vehicles through the years have either had decent semi clean brake lines or I replaced them with new, so I just ran brake fluid through them. I wouldn't use compressed air especially if using DOT 3 or 4 as it might possibly end up on a painted area.
 
R

Ron Green

Guest
I too have some cars that can be a pain in the a$$ to get all the air out. Sometimes I will leave the bleeder(s) semi-open overnight and that seems to work on occasion. I have also tried the vacuum canister method that works off a hand held tool that creates a vacuum (can also be used with vacuum gages, etc) but they don't seem to be very effective, for me anyhow. I also have a brake bleeder that works off compressed air as it is part of a fluid evacuator however I have never given it a try.

Whatever works for you is great however you are missing a great opportunity to argue with the wife, pump pump pump, holding, down, tight, let up. :)
 
Questions, How do you start a new thread here? I cannot find the "Start new thread" button. My next question is, is there an off the shelf muffler that fits the Amphicar or does everyone buy what Gordon Imports sells? Thanks
 
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