Lotus Elan

No Servo decision but then what!

PostPost by: terryp » Sun Dec 11, 2011 7:11 pm

Hello
With my S4 arriving soon I have begun to think about brakes. The car has no servo but a dual braking master cylinder. My plan is not to fit a servo as I am use to that on the Seven and I am concerned about all the related problems.
Anyway I have read loads in the archives and are now none the wiser.
I have surmised that there are 3 ways to improve the brake efficiently:-
1. Fit a smaller bore master cylinder
2. Fit +2 larger bore / pad area callipers
3. Fit "no servo" softer pads all round
My problem is that I suspect by doing both items 1 & 2 the brake pedal travel is increased substantially.
Is it possible to do one of item 1 & 2 with No 3 , in which case which of 1 and 2 is the best?

Thanks
Terry
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PostPost by: miked » Sun Dec 11, 2011 7:54 pm

Terry,

I ran an S4 with no servo (sick of problems) and fitted the smaller bore master cylinder with green stuff pads. No problem with travel. The extra travel actually gives you some pedal feel. When bedded in I forgot all about servo's etc. The new owner still runs the car this way. No complaints.

Mike :)
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PostPost by: terryp » Sun Dec 11, 2011 8:16 pm

Mike
And that's with standard callipers?

Cheers
Terry
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PostPost by: cal44 » Sun Dec 11, 2011 10:49 pm

Terry,
is the Elan from the States?

Also, if this helps, under my current ownership the Plus 2 and the Sunbeam Tiger both have had their servos removed and smaller diameter brake masters installed. I suffer no pedal distance problems or problem stopping. Been cut off a few times and all went well.

I'm going to install a surface too air missile launch system in the Tiger. They sell them under the "Get Smart" logo. I will then proceed to launch a preemptive strike at the next bastard that cuts me off..................

Therefore necessitating a launch and brake procedure.

Go ARMY!
Mike
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PostPost by: elansprint71 » Sun Dec 11, 2011 10:59 pm

S4 (not SE) spec. Check the manual, Manuel. :roll:
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PostPost by: AHM » Mon Dec 12, 2011 12:50 am

What are you trying to achieve? Better feel? Better braking?
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PostPost by: billwill » Mon Dec 12, 2011 12:59 am

terryp wrote:Hello
With my S4 arriving soon I have begun to think about brakes. The car has no servo but a dual braking master cylinder. My plan is not to fit a servo as I am use to that on the Seven and I am concerned about all the related problems.
Anyway I have read loads in the archives and are now none the wiser.
I have surmised that there are 3 ways to improve the brake efficiently:-
1. Fit a smaller bore master cylinder
2. Fit +2 larger bore / pad area callipers
3. Fit "no servo" softer pads all round
My problem is that I suspect by doing both items 1 & 2 the brake pedal travel is increased substantially.
Is it possible to do one of item 1 & 2 with No 3 , in which case which of 1 and 2 is the best?

Thanks
Terry



Just drive it!

Only if you later feel that you want softer brake pedal pressure then start thinking about servos. I think you need TWO servos if you have dual braking and that is going to be pretty expensive.

I took the servo OUT of my S3 many many years ago and I've never missed it.
Bill Williams

36/6725 S3 Coupe OGU108E Yellow over Black.
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PostPost by: terryp » Mon Dec 12, 2011 7:30 am

Yes the car is from the US and no I can't drive it as it needs a full rebuild.
The problem is that I can choose what to rebuild, so I need to make the choice

It looks as if the standard Callipers + smaller bore master cylinder will be OK

Thanks
Terry
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PostPost by: UAB807F » Mon Dec 12, 2011 7:47 am

Hi Terry,

I'd suggest you drive the car first and see how it feels before planning upgrades, you might be happy as it is. Having said that, this summer I modified the system on my S3 to remove the servo and took the steps you're contemplating. If you search the forum there's lots of info on exactly what you'll need and folks' views on master cyl. bore, etc.

I did mine in stages to see the individual effect, firstly the calipers with 16P ones & new larger discs/pads. Sourcing new calipers & discs was easy, the brackets to mount them took a little longer and was my biggest problem. That made a noticeable improvement and if I'm honest the increased pedal travel due to larger piston diameter wasn't really significant, like Mike said it gives a better feel to the brakes. I ran the car like that for a few weeks before deciding what bore m/cyl to get. In the end I just bought a later Spitfire one (0.7" bore) and mounted it with a remote reservoir & fluid warning light as the triumph reservoir is angled and would just look wrong. The only thing I overlooked was that the bare m/cyl I bought had metric fittings instead of imperial but easily overcome.

Pedal effort is fine, the only plans for next year are to get some greenstuff pads as it's on standard GT6 ones bought as a package with the discs and I think the greenstuff pads have a better initial bite.
Brian
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PostPost by: terryp » Mon Dec 12, 2011 8:03 am

Thanks Brian but as I said I cannot drive the car as it needs a complete rebuild and I do not want to rebuild something that ultimately will be wrong.
I want to know the right answer first :wink:

I think I will keep the existing callipers, change the master cylinder and buy soft pads initially and then see what happens after I drive it ......in 2 or 3 years time!

Thanks to all
Terry
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PostPost by: miked » Mon Dec 12, 2011 11:00 am

Yes Terry, I was on standard calipers, not plus 2. Mike
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PostPost by: terryp » Mon Dec 12, 2011 11:25 am

Thanks Mike. I'm going to go for your set up.
I have a feeling that the change to softer pads is bigger than the change to +2 callipers and is probably where most difference comes from.

Terry
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PostPost by: mark030358 » Mon Dec 12, 2011 11:55 am

Terry, which softer pads do you intend to use? I found Greenstuff terrible. All new bits throughout and could not under any circumstances lock up the wheels.

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PostPost by: terryp » Mon Dec 12, 2011 12:02 pm

mark030358 wrote:Terry, which softer pads do you intend to use? I found Greenstuff terrible. All new bits throughout and could not under any circumstances lock up the wheels.

Mark


I was hoping you lot would be able to tell me that!

Terry
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PostPost by: worzel » Mon Dec 12, 2011 2:09 pm

Hi

Re pad type. I run a plus 2 front system (no servo, on a sprint) and have tried various pad materials- Greenstuff, Triumph GT6 and std plus 2 ones. Only my opinion but here goes-

Greenstuff- work but not brilliant. Little bite from cold. Warmed up- better- but not confidence inspiring!

Triumph GT6- similar to above. NOTE-I bought these from a main Triumph agent who informed me that there was no difference between servoed and unservoed GT6's- he appears to be incorrect on this point.

Std Plus 2- hopeless- no stopping power to speak of.

Had a (rare) brainwave- scouted e-bay and found a supplier of original type Mk1 Gt6 pads (probably asbestos type).

Result- a world of difference- immediate bite from cold and very progressive in action. MoT tester was particularly impressed with performance on the rollers.

You definitely need genuine old stock Mk1 GT6 pads if you switch to the plus 2 front system. I paid about ?25 inc postage. Look around- these pads are still out there.

Regards

John
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