[E-Type] brake balance link s1 3.8

E-Type
1

Would appreciate if someone could explain the function of
the balance link that is connected to the master cylinder
pushrods.

Understand from feedback that the lower pushrod is longer by
design - is the reduced throw Jaguar’s method of reducing
hydraulic pressure to rear brakes? For I see no pressure
reducer.–
'62 otr
Uitgeest, Netherlands
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2

In a message dated 7/12/04 2:52:59 PM Pacific Daylight Time,
ssmaan44@yahoo.com writes:

<<
Would appreciate if someone could explain the function of
the balance link that is connected to the master cylinder
pushrods.

Understand from feedback that the lower pushrod is longer by
design - is the reduced throw Jaguar’s method of reducing
hydraulic pressure to rear brakes? For I see no pressure
reducer.

I can tell you that you need to have some backlash in the system or the
brakes will start to drag as you drive!

I am not at all clear on the theory behind this design. It seems like if you
lose either cylinder, you’ll lose the brakes as the bad cylinder will go to
the bottom and you will not be able to engage the other cylinder. Its like
having a two engine airplane which HAS to have both engines running to fly.
Most two engine airplanes will fly nicely on a single engine, so you have
twice the chance of losing an engine, but half the chance of losing your last
engine. The S1 braking system, (as demonstrated on my car!) has twice the
probability of losing a cylinder which will cause a brake failure.

Best Regards, Mike Moore

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3

In reply to a message from MMoore8425@aol.com sent Tue 13 Jul 2004:

             Hi Mike,in my case the system did work when the

front master cylinder failed ,I was able to stop the car on rear
brakes only.
However if I had been doing some late braking I
would have been in trouble.
As far as the balance link goes I think how far
off center the middle hole is would alter the front brake bias,I
don’t know if the cylinder dia’s are the same?

             Gez 63 ots Ontario Canada 878269

P.S. We need Ray and Jerry on this topic.–
The original message included these comments:

Would appreciate if someone could explain the function of
the balance link that is connected to the master cylinder
pushrods.
Understand from feedback that the lower pushrod is longer by
design - is the reduced throw Jaguar’s method of reducing
hydraulic pressure to rear brakes? For I see no pressure
reducer.
I can tell you that you need to have some backlash in the system or the
brakes will start to drag as you drive!
I am not at all clear on the theory behind this design. It seems like if you
lose either cylinder, you’ll lose the brakes as the bad cylinder will go to

–
gez
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4

In a message dated 7/13/04 12:55:14 AM Pacific Daylight Time, leics49@look.ca
writes:

<< As far as the balance link goes I think how far
off center the middle hole is would alter the front brake bias,I
don’t know if the cylinder dia’s are the same?

My cylinders are the same dia (Dunlop -S1). There is a slight difference
which may or may not be important regarding stroke.

If you were able to stop, then you obviously still had fluid and some
pressure available to stop the car. I noticed on mine that when the fluid was out of
a single cylinder, that one cylinder would bottom first with no travel
available in the pedal for the second cylinder.

Best Regards, Mike Moore

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5

Although they are the same diameter, one has a noticeably longer piston,
therefore less fluid volume. I forget which, but I assume it’s for the
rear.

Gez, it sounds like you lost your fronts, correct? When this happened
to me, it was the rears that were lost and caused my pedal to go to the
floor. Perhaps the failure will occur in one case, and not as badly in
the other. As you hint at, I had VERY modest braking, say, 25-0 in 100
yards. Then again, perhaps it was just gravity and friction doing their
thing. If the floor pan wasn’t there I probably could have Fred
Flintstone’d it more effectively.
Eric

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6

In reply to a message from Eric MaLossi sent Tue 13 Jul 2004:

            Hi Eric,yes it was my front brakes that failed,my

pedal did go to mabye within an inch of the floor,but I did have
some braking I assume from the back end.I was off the gas slowing
down for a red light at the time.
If I had been doing 70 mph it would have taken for
ever to stop.

            Regards Gez 63 ots--

The original message included these comments:

Gez, it sounds like you lost your fronts, correct? When this happened
to me, it was the rears that were lost and caused my pedal to go to the
floor. Perhaps the failure will occur in one case, and not as badly in
the other. As you hint at, I had VERY modest braking, say, 25-0 in 100
yards. Then again, perhaps it was just gravity and friction doing their
thing. If the floor pan wasn’t there I probably could have Fred
Flintstone’d it more effectively.

–
gez
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7

In a message dated 7/13/04 6:58:04 AM Pacific Daylight Time,
emalossi@austin.rr.com writes:

<<
Gez, it sounds like you lost your fronts, correct? When this happened
to me, it was the rears that were lost and caused my pedal to go to the
floor. Perhaps the failure will occur in one case, and not as badly in
the other. As you hint at, I had VERY modest braking, say, 25-0 in 100
yards. Then again, perhaps it was just gravity and friction doing their
thing. If the floor pan wasn’t there I probably could have Fred
Flintstone’d it more effectively.
Eric

I guess I’m pretty excitable about brake failures on the road!
A pedal going waaaaay down and diminished braking to me is a failure.

Best, Mike
ps-it bruises my brain each time I try to figure out which cylinder controls
which end-and I’m not even sure I have the correct cylinder in the correct
location. But, it stops.

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8

In reply to a message from MMoore8425@aol.com sent Tue 13 Jul 2004:

I share Mike’s misgivings, but then, we must be forgiving
for we are talking about the fifties when C types with disc
brakes belonged in the cutting edge. I will make sure there
is enough backlash, though.

Have the whole kaboodle on the bench.

It seems that the lower pushrod, for the rear brakes, is
about a 1/4’’ longer. (My poor Mini can keep it’s pushrod for
now.)

The fork end, (#25 in brake control details) which is
attached to the balance link midway, can move a greater
distance forward, than the pushrods (can move forward before
bottoming).
Thus, the fork end can still push the serviceable system
pushrod further forward, even after the failed system
pushrod has bottomed.

Mike, this is probably why both Eric and Gez could stop.

Still, WHY is the lower pushrod LONGER?

There seems to be a lot of thought put in by the brake
designers. Enough to win Le Mans three times in a row thanks
to braking, if I recall right.

It is an injustice to the designers surely, that there seems
to be nothing in print on this feature?

santokh–
The original message included these comments:

A pedal going waaaaay down and diminished braking to me is a failure.
Best, Mike

–
'62 otr
Uitgeest, Netherlands
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

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