Brake Servo Issues

[summerinmaine]

Further to Robert's follow-up to my mention of brake servo issues, I
have seen at least two mentions of folks who removed the servos from
their cars, plus the article on the website, with the implication
being that the servos somehow interfered with proper brake "feel" or
at least represented a potential site for brake failure.

I have always remembered that the servo brakes on my 65 S2 worked
great; good feel and modulation, and great stopping power (though the
memory is a bit hazy, since it has been so long since the car has
been on the road).

When I got my 66, the servo had been removed, but a new-in-box
Lockheed servo was supplied. The non-servo brake feel is a bit hard,
with less (perceived) stopping power, though I haven't tried locking
up the brakes. I had planned to re-fit the servo during the next
phase of re-assembly, but I thought I'd inquire as to whether
this "anti-servo" undercurrent of thought I perceived had any basis
in real world experience.

Anyone out there who has removed their servo and can articulate the
reasons?

Thanks,

Jim

[elansprint71]

Jim,
I'm in the dithering phase of whether to add more lightness by removing theservo from my Sprint. A friend, who also has a Sprint, has tried more combinations of brakes than you can shake a stick at: standard (with servo), ditto but servo removed, +2 callipers with servo and now, +2 callipers without servo. He swears that the current set-up is absolutely perfect, so this is probably what I will try (when time allows).
John Clegg has a further variation on his +2 with the addition of ABS from a Renault 25.

Pete
----- Original Message -----
From: summerinmaine <***@***.***>
To: ***@***.***
Sent: Friday, January 03, 2003 7:00 PM
Subject: [LotusElan.net] Brake Servo Issues


Further to Robert's follow-up to my mention of brake servo issues, I
have seen at least two mentions of folks who removed the servos from
their cars, plus the article on the website, with the implication
being that the servos somehow interfered with proper brake "feel" or
at least represented a potential site for brake failure.

I have always remembered that the servo brakes on my 65 S2 worked
great; good feel and modulation, and great stopping power (though the
memory is a bit hazy, since it has been so long since the car has
been on the road).

When I got my 66, the servo had been removed, but a new-in-box
Lockheed servo was supplied. The non-servo brake feel is a bit hard,
with less (perceived) stopping power, though I haven't tried locking
up the brakes. I had planned to re-fit the servo during the next
phase of re-assembly, but I thought I'd inquire as to whether
this "anti-servo" undercurrent of thought I perceived had any basis
in real world experience.

Anyone out there who has removed their servo and can articulate the
reasons?

Thanks,

Jim

[TimMullen]

Elan Sprint 71 wrote:


For what it's worth, my US spec Sprint has never had servos (they're not "removed", it never had them). It has the normal Elan brakes, dual circuit master cylinder, and no servos. The best brakes of any car I've ever driven. The pedal effort is "just right" and it stops "right now"...

Tim Mullen

Chantilly, VA
72 Elan Sprint

[Martin_StuartUK]

Jim,

I fitted a Lockheed servo in place of the original Girling unit on my Elan last year.


Installation was very straightforward. I had some initial problems with the brakes binding on during the first test run, but these cured themselves before I could determine the cause. Since then the servo has been very satisfactory, with excellent, progressive braking and good pedal feel.

No anti-servo sentiments from me!

Martin Stuart
----- Original Message -----
From: summerinmaine <***@***.***>
To: ***@***.***
Sent: Friday, January 03, 2003 7:00 PM
Subject: [LotusElan.net] Brake Servo Issues


Further to Robert's follow-up to my mention of brake servo issues, I
have seen at least two mentions of folks who removed the servos from
their cars, plus the article on the website, with the implication
being that the servos somehow interfered with proper brake "feel" or
at least represented a potential site for brake failure.

I have always remembered that the servo brakes on my 65 S2 worked
great; good feel and modulation, and great stopping power (though the
memory is a bit hazy, since it has been so long since the car has
been on the road).

When I got my 66, the servo had been removed, but a new-in-box
Lockheed servo was supplied. The non-servo brake feel is a bit hard,
with less (perceived) stopping power, though I haven't tried locking
up the brakes. I had planned to re-fit the servo during the next
phase of re-assembly, but I thought I'd inquire as to whether
this "anti-servo" undercurrent of thought I perceived had any basis
in real world experience.

Anyone out there who has removed their servo and can articulate the
reasons?

Thanks,

Jim

[summerinmaine]

Thanks all for your thoughts. Based on the various comments, I've
decided that the brakes need a bit of fettling, so I'm going to try
to make them the best that they can be, and then fit the Lockheed
servo (assuming the pedal effort remains too high). Makes sense to
have the brakes dialed in while minor improvements should be
noticeable, before adding a new variable to the system.

Jim

[rgh0]

I have run my plus 2 both with and without the brake servo as I have
struggled to get the servo rebuilt properly and did not want to have a large
non original component in a new style booster in the engine bay.

Without the brake servo the pedal is harder and firmer and brake modulation
easier and less likely to lock up. The higher brake force required can be
reduced to similar levels to standard pads with the booster by using a set
of high friction kevlar pads such as EBC Greenstuff or Ferodo DS2000. I run
these pads in my unboosted Elan and they are excellent under race conditions
but also work very well from cold for road use.

I have had total a rebuild of the plus 2 servo done for a second time and
reconnected it and have finally got it working right. I have currently gone
back to using it with standard pads but it is not as nice to use as the high
friction pads and no booster so I will prbably change back at some stage
again.

I think the main issue with the orginal boosters is that they are hard to
rebuild to work properly so they dont snatch on when applied or drag once
released or feel spongy with a low pedal. These are all affected by the
condition of the booster and the assembly of the vacuum vent valving
components which seems to be a "black art" to get it so it works "just
right". Even when working right the feel is not as good as a good unboosted
system and with modern pad material there is really no need for a booster on
a light car such as the Elan or Plus 2 unless you like a very light brake
pedal as has become the style in a lot of modern cars with ABS.

Rohan
68 S4 Elan
73 +2S 130/5