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to silicon or not to silicon
Posted: Thu Feb 22, 2001 2:07 am
by Charles_Shiplee@batesuk.com
I rebuilt the brake system from scratch with new lines and replacement
wheel and master cylinders.
I still have a problem with a spongy pedal that slowly goes to the floor
stopping about and inch above the firewall and a leak from the breather
hole on the master cylinder.
I have decided that the replacement master cylinder is at fault and have
decided to rebuild my original ( "never throw anything TC away" ) and then
refill the system with silicon fluid.
I assume that the old fluid must be drained well from the system before the
silicon goes in.
Does any one have any experience of replacing DOT 4 with silicon.
Would you recommend it or should I preserver with the DOT 4
Charles
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Re: to silicon or not to silicon
Posted: Thu Feb 22, 2001 7:48 am
by David and Joyce Edgar
Charles,
The silicone fluid will mix with the DOT 4 just fine but you don't
get the full benefits of the silicone if you do. The DOT 4 will
absorb water for one and if any is left in, will continue to do so.
I would empty out as much of the old stuff as possible, but don't
worry about making it 100% pure unless you are a perfectionist. When
I converted over 20 years ago I pulled the cups out of the wheel
cylinders and the master was off already. I then blew the lines
clear and reassembled.
David Edgar, TC 5108
La Mesa, California
>I rebuilt the brake system from scratch with new lines and replacement
>wheel and master cylinders.
>I still have a problem with a spongy pedal that slowly goes to the floor
>stopping about and inch above the firewall and a leak from the breather
>hole on the master cylinder.
>I have decided that the replacement master cylinder is at fault and have
>decided to rebuild my original ( "never throw anything TC away" ) and then
>refill the system with silicon fluid.
>I assume that the old fluid must be drained well from the system before the
>silicon goes in.
>Does any one have any experience of replacing DOT 4 with silicon.
>Would you recommend it or should I preserver with the DOT 4
>
>
>Charles
Re: to silicon or not to silicon
Posted: Thu Feb 22, 2001 8:29 am
by Chip Old
On Thu, 22 Feb 2001, David and Joyce Edgar wrote to T-ABC list:
> The silicone fluid will mix with the DOT 4 just fine but you don't get
> the full benefits of the silicone if you do. The DOT 4 will absorb
> water for one and if any is left in, will continue to do so. I would
> empty out as much of the old stuff as possible, but don't worry about
> making it 100% pure unless you are a perfectionist. When I converted
> over 20 years ago I pulled the cups out of the wheel cylinders and the
> master was off already. I then blew the lines clear and reassembled.
According to the silicone brake fluid manufacturers, it can coexist with
DOT3 and DOT4 fluid, but doesn't actually mix with it. If you drain the
old fluid but don't clean the system thoroughly (or at least blow it out),
you may end up with pockets or layers of old fluid still in the system.
That doesn't impair the hydraulic capability of the system, but that old
fluid will still absorb moisture.
According to the manufacturers, if at all possible the brake cylinders,
hoses, and pipes should be dismantled, cleaned with alcohol, dried
thoroughly, and reassembled. If that's not possible, the system should be
drained completely and blown out with air, then use silicone fluid to
flush the system thoroughly.
--
Chip Old 1948 M.G. TC TC6710 XPAG7430 NEMGTR #2271
Cub Hill, Maryland 1962 Triumph TR4 CT3154LO CT3479E
fold@bcpl.net
Re: to silicon or not to silicon
Posted: Thu Feb 22, 2001 8:53 am
by Ray McCrary
I have always changed to the silicone being very careful to either rebuild
the system first, or use 70% rubbing alcohol to clean the entire system.
Failure to do so MAY leave with a drip......MAY not WILL or SHALL.
The change also affords you an excuse to check the lines!
Best,
Ray McCrary
"Speed is Life;
of course Luck and Altitude
are helpful, too."
----- Original Message -----
From: "Chip Old" fold@bcpl.net>
To: "T-ABC list" mg-tabc@yahoogroups.com>
Sent: Thursday, February 22, 2001 10:29 AM
Subject: Re: [mg-tabc] to silicon or not to silicon
> On Thu, 22 Feb 2001, David and Joyce Edgar wrote to T-ABC list:
>
> > The silicone fluid will mix with the DOT 4 just fine but you don't get
> > the full benefits of the silicone if you do. The DOT 4 will absorb
> > water for one and if any is left in, will continue to do so. I would
> > empty out as much of the old stuff as possible, but don't worry about
> > making it 100% pure unless you are a perfectionist. When I converted
> > over 20 years ago I pulled the cups out of the wheel cylinders and the
> > master was off already. I then blew the lines clear and reassembled.
>
> According to the silicone brake fluid manufacturers, it can coexist with
> DOT3 and DOT4 fluid, but doesn't actually mix with it. If you drain the
> old fluid but don't clean the system thoroughly (or at least blow it out),
> you may end up with pockets or layers of old fluid still in the system.
> That doesn't impair the hydraulic capability of the system, but that old
> fluid will still absorb moisture.
>
> According to the manufacturers, if at all possible the brake cylinders,
> hoses, and pipes should be dismantled, cleaned with alcohol, dried
> thoroughly, and reassembled. If that's not possible, the system should be
> drained completely and blown out with air, then use silicone fluid to
> flush the system thoroughly.
>
> --
> Chip Old 1948 M.G. TC TC6710 XPAG7430 NEMGTR #2271
> Cub Hill, Maryland 1962 Triumph TR4 CT3154LO CT3479E
>
fold@bcpl.net
>
>
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
>
>
>
Re: to silicon or not to silicon
Posted: Thu Feb 22, 2001 9:24 am
by avanparys@viperlink.net
I had a rather unusual situation in that I started out with new
lines, rebuilt wheel and master cylinders and began with silicon
fluid because of all of the benefits it presents (no water
absorbtion, doesn't eat paint, etc). Unfortunately, for some reason
I was never able to keep the silicon fluid from seeping out over
time. I would bleed the system, check for leaks and all would be
fine. Then, in about two or three days of sitting, there would be
small traces that would weep out of areas around both the wheel
cylinders and master cylinder connections. After taking the system
apart, replacing new lines with other new lines, using permatex on
connections, etc., I gave up and on the eighth attempt, I went to the
Castrol GTX. No leaks. While I've talked with others who have had
similar experiences, most who use silicon fluid have no trouble at
all.
Anyway, where all this rambling is leading is that even after I
flushed the silicon out, you can still see traces of it in the GTX
when the system is bled. So, while DOT 4 and silicon fluid may
be "compatible," they do not blend.
BTW, don't forget that you might want to take .050" off the master
cylinder piston if you go with the silicon.
VR
- Terry V.P.
Charleston S.C.
--- In mg-tabc@y..., Charles_Shiplee@b... wrote:
>
> I rebuilt the brake system from scratch with new lines and
replacement
> wheel and master cylinders.
> I still have a problem with a spongy pedal that slowly goes to the
floor
> stopping about and inch above the firewall and a leak from the
breather
> hole on the master cylinder.
> I have decided that the replacement master cylinder is at fault and
have
> decided to rebuild my original ( "never throw anything TC away" )
and then
> refill the system with silicon fluid.
> I assume that the old fluid must be drained well from the system
before the
> silicon goes in.
> Does any one have any experience of replacing DOT 4 with silicon.
> Would you recommend it or should I preserver with the DOT 4
>
>
> Charles
>
> IMPORTANT NOTICE:
> This message is intended for the use of the person(s) or
organisation (the
> Intended Recipient) to whom it is addressed. It may contain
information
> which is privileged and confidential within the meaning of
applicable law.
> Accordingly dissemination, distribution, copying or other use of
this
> message or any of its contents by any person other than the Intended
> Recipient may constitute a breach of civil or criminal law and is
strictly
> prohibited. If you are not the Intended Recipient please contact
the sender
> as soon as possible. All information or opinions expressed in this
message
> and/or any attachments are those of the author and are not
necessarily
> those of The Group. All reasonable precautions have been taken to
ensure no
> viruses are present in this E-mail. As The Group accepts no
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> for loss or damage arising from the use of this E-mail or
attachments we
> recommend that you subject these to your virus checking procedures
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> use.
Re: to silicon or not to silicon
Posted: Thu Feb 22, 2001 12:17 pm
by Chip Old
On Thu, 22 Feb 2001, Ray McCrary wrote to T-ABC list and Chip Old:
> I have always changed to the silicone being very careful to either
> rebuild the system first, or use 70% rubbing alcohol to clean the
> entire system. Failure to do so MAY leave with a drip......MAY not
> WILL or SHALL. The change also affords you an excuse to check the
> lines!
Rubbing alcohol isn't the best type to use because it has additives that
leave residue after the alcohol evaporates. I don't remember what the
additives are, but they enhance the mixture's effectiveness as a rubdown.
Use 90% or better alcohol.
Having said that, I'll admit to using rubbing alcohol in a pinch, but I
don't like to.
--
Chip Old 1948 M.G. TC TC6710 XPAG7430 NEMGTR #2271
Cub Hill, Maryland 1962 Triumph TR4 CT3154LO CT3479E
fold@bcpl.net
Re: to silicon or not to silicon
Posted: Thu Feb 22, 2001 5:02 pm
by Emgeeguy@aol.com
I would use the Silicon with a new brake system, but I'm not sure about how
you would be sure to have all of the dot 4 stuff out of the system before
refilling with silicon, and i don't think you want the two to mix.
Larry
Re: to silicon or not to silicon
Posted: Thu Feb 22, 2001 5:08 pm
by Dwyer
Charles
I put silicon fluid into our J2 about 15 years ago and I remain very happy.
The conversion that had been done when the hydraulic brakes were fitted used
Morris Minor type Lockheed brakes and I found that the rear cylinders in
particular were very prone to sieze up due to moisture type corrosion with
the old type fluid.
Since fitting silicon fluid the system has functioned perfectly.
Note that you are recomended to totally clean the system and preferably fit
all new rubbers and flex hoses, as traces of old fluid may remain.
I certainly won't change back and the TC will use silicon when I get to that
stage.
Regards
Dave Dwyer
Re: to silicon or not to silicon
Posted: Fri Feb 23, 2001 12:23 pm
by C. Knight
Charles_Shiplee@batesuk.com wrote:
>
> Does any one have any experience of replacing DOT 4 with silicon.
> Would you recommend it or should I preserver with the DOT 4
I rebuilt the TA with new lines, honed pistons and cylinders, new seals,
and an overhauled master cylinder. (The replacement TA units supplied
would have necessitated modifying the chassis mounting - but that is
another story). I used Silicon fluid and found that I had to shorten the
piston in the master cylinder and fit a slightly stiffer return spring
to get the cylinder to replenish and the pedal to return. Bleeding the
system was VERY difficult. It took many attempts using a pressurized
brake bleeder. Foot pumping does not work with Silicon. That was nearly
3 years ago. We have done about 4000 miles since, mostly in the Welsh
mountains where brakes get more use than the go pedal, and have had no
trouble.
When I came to rebuild one of my YAs last year I used DOT 4 and had no
problems at all once I had tightened up a leaky connection. I felt that
the only real advantage of silicon on a regularly used car is that it
doesn't strip paint, and that isn't very important given the under floor
location of the master cylinder on T-ABC and Y.
If your car is to be little used then Silicon may be worth all the extra
hassle to ensure that you do not get any corrosion problems in the
pistons.
Regards
Cliff
Re: to silicon or not to silicon
Posted: Fri Feb 23, 2001 4:14 pm
by Roger Furneaux
Hi Charles - the best way (in my experience) is to put silicone into a clean
& dry brake system, and NOT to try pushing old mineral oil out with the new
silicone. I used all new geniune Lockheed rubbers too - it seems that all
rubbers are not equal, and that goes for many replacement bushes these days.
even some synthetic rubbers can be degraded by oil.
ocTagonally Roger
>I rebuilt the brake system from scratch with new lines and replacement
>wheel and master cylinders.
>I still have a problem with a spongy pedal that slowly goes to the floor
>stopping about and inch above the firewall and a leak from the breather
>hole on the master cylinder.
>I have decided that the replacement master cylinder is at fault and have
>decided to rebuild my original ( "never throw anything TC away" ) and then
>refill the system with silicon fluid.
>I assume that the old fluid must be drained well from the system before the
>silicon goes in.
>Does any one have any experience of replacing DOT 4 with silicon.
>Would you recommend it or should I preserver with the DOT 4
>
>
>Charles
>
>IMPORTANT NOTICE:
>This message is intended for the use of the person(s) or organisation (the
>Intended Recipient) to whom it is addressed. It may contain information
>which is privileged and confidential within the meaning of applicable law.
>Accordingly dissemination, distribution, copying or other use of this
>message or any of its contents by any person other than the Intended
>Recipient may constitute a breach of civil or criminal law and is strictly
>prohibited. If you are not the Intended Recipient please contact the sender
>as soon as possible. All information or opinions expressed in this message
>and/or any attachments are those of the author and are not necessarily
>those of The Group. All reasonable precautions have been taken to ensure no
>viruses are present in this E-mail. As The Group accepts no responsibility
>for loss or damage arising from the use of this E-mail or attachments we
>recommend that you subject these to your virus checking procedures prior to
>use.
>
>
>
>
>
>Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
>
>