Master vac

[syrius]

Hello

I have a very bad sensation with my brakes
Is not very clear , and i would like to suppres the master vac
the car in not so heavy ( light is right ) and i think its may be much better without this device
Do you have some experiences on this way
Thanks in advance for your help

Serge

[lotustus]

I would also like to know ..to suppres the master vac

[peterako]

Hi Serge...

My personal experience of when I was getting no Servo Boost (similar to having no vac) was scary.

So much pedal pressure was needed to get any sort of stopping action that the pedal box and fibreglass around it was distorting.

I was afraid that eventually I'd break the pedal mechanism.

Having said this....

Some other members will point out that if you change your pads for grippier ones then everything will be alright in the end.

I very quickly fixed my Servo problem and am extremely happy now

I think with the 2 seater Elan things are different and it is preferable to have no Servo Assistance.

But with the +2....well the jury may be out....but I certainly would prefer to have the Servo boost!

Oh....to stop the servo vac....simply disconnect the vac cable/tube from the servo...remembering to block the tube coming from the engine! (The Tube comes from the inlet manifold closest to the windscreen).

It has been commented before on this forum that this is NOT the same az removing your Servo as the Servo...when disconnected this way....makes the braking less efficient.

Best of luck,
Peter

[bengalcharlie]

I removed the servo becuase I was not happy with the softish overassisted pedal feel in my plus two.
I changed to softer pads and the result is perfect. Nice firm pedal and good braking ( I can lock the front wheels under hard braking)
As previous stated the opinions on this subject are divided so in the end it comes down to personal choice.
cheers
Robin

[Melvinelan]

I had twin servos (Federal Car), and removed them "to save weight" and reduce overall restoration costs. I'm seriously thinking of getting a new single servo for the front brakes, as they pedal pressure is extreme, and I've had concerns about the pedal box bending. Yes, I can lock the front brakes, but only with "the power of fear". I guess I should try to get a softer pad material first. Some have written that they have had the master cylinder "re-bored" to get a better pressure to the calipers. This is almost as pricey as a new servo kit.

[worzel]

Hi

Having recent personal experience of "braking issues" on a 2 seater with plus 2 brakes I've found that Triumph GT6 Mk1 (non-servo spec) pads do the trick but I believe some Halfords outlets have the same pads for various older Fords for less cost.

Regards

John

[syrius]

HI

thanks Peter for your help
I understand each way have some advantages
I try to drive an Elan +2 without servo to get more sensations , and after I decide if I need to remove the master vac .
if yes i belive its better to exchange the main brake cylinder to get more pressure ?

Regards

serge

[CBUEB1771]

This one has been beaten to death but I will continue to flog. The servos used in the +2 produce as much as 3:1 increase in braking force at the wheels. No mucking about with higher coefficient pads will recover that multiplier. I tried removing the servos from my +2 and went to the trouble of going to smaller diameter master cylinders. The results were very unsuccessful, nothing I did made the car safe to drive without the servo. You won't damage the pedal, you won't bend the pedal box, you will tear the pedal box out of the fiberglass in a panic stop. Just one opinion.

[mikealdren]

Russ,
You make an important point, without a servo you need a different master cylinder. The system was designed around the increase in fluid pressure from the servo and uses a larger diameter master cylinder than you would use for an unassisted system. The larger system gives a shorter pedal travel for the same fluid displacement but some of that is lost by inefficiency within the servo.

Without a servo, a smaller diameter cylinder gives you a greater mechanical advantage (higher fluid pressure for the same pedal pressure). You will get more pedal travel and you need to ensure that the cylinder has enough travel before bottoming out in all conditions - not usually a problem but you don't want to be pumping the pedal in an emergency.

You may be strong enough (Macho enough) to do an emergency stop in an unassisted car but the loads on the pedal box will not lead to a long life.

I'm not a great advocate of originality (I'm building a Zetec!) but do bear in mind that Lotus will had experts working on the system and they will have considered:
? Ultimate braking performance
? Brake balance
? Performance under light braking (typical use)
? Pedal travel and loads
? Fade
? Snatch etc
? Pad and disk wear
? Noise
? Cost (Chapman!)
? Etc.
Brake materials have changed over the years but there was a good variety of materials available when the cars were in production and the system is always a balance of requirements. I would only change things on a standard car if:
? You are racing.
? You are changing the whole system (e.g. Spyder Zetec)
? You know enough to do all the calculations and have the skill/equipment to test the results ? you don?t want to run out of brakes in an emergency!


Mike