Lotus Elan

Plus 2 Braking No Servo

PostPost by: Galwaylotus » Tue Feb 09, 2010 7:18 pm

I'm doing the same conversion on my S3 SE FHC. I did a lot of investigation and found a suitable tandem m/c in a AP Racing CP5615-2CD. I was able to purchase one through a racing distributor but found that AP produces these specially for Caterham and shouldn't have sold it through my supplier. In any event they are available and mine is now installed with remote reservoir. I'm also installing Aeroquip ss braided brake hoses all around and Greenstuff pads in the front calipers. I haven't been able to try it out yet as I had a ring gear problem and the engine is out for replacement. The servo was locking up on me and that prompted me to make the change, eliminating the faulty servo and improving the safety with a front-rear split system. 8)
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PostPost by: kstrutt11 » Tue Feb 09, 2010 10:20 pm

I did tell my insurance company about deleting the servo and they raised no Issue (I am a chartered engineer though)

In all honsety I think it's safer without the servo, with it it used to someimes lock up rear wheels and the random loss of fluid was also a worry.
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PostPost by: gerrym » Tue Feb 09, 2010 10:56 pm

Kevin, thanks for additional feedback: from the comments you don't miss the Servo. I guess secondary benefits are extra space under the bonnet.

On the question of rear lockup, the calc sheet can be used to provide a little insight on this. Just play around with the curve for nthe rear proportioning valve (or multiply by unity if not using one)

Did you ever give consideration to fitting a tandem master and split circuit brakes.

An option I've unearthed for this is the Fiat 128 master. It has the outlets on top and is plumbed for remote reservoirs. They are extremely cost effective due to all the Yugos that also used them. I might just buy a cheap one and check it for fit etc??

Regards

Gerry
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PostPost by: fjbm » Wed Feb 10, 2010 11:18 am

brian wilson wrote:Elan Factory master cylinder is a slightly modified Mitsubishi E300 van one.

I supplied them with the original as it was my idea to use one.

The reservoirs are simply lathe turned alloy tubing with original Girling caps.

It is my car on the web site (used without my permission) and also has 2 Lockheed servos.

The dual system works really well with no braking problems.

Brian Wilson


Hi Brian

I was really surprised when you said a Mitsubishi E300 van master cylinder was used.

What do you mean by "slightly modified"?

Cheers
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PostPost by: ppnelan » Wed Feb 10, 2010 11:33 am

kstrutt11 wrote:I did tell my insurance company about deleting the servo and they raised no Issue (I am a chartered engineer though)
Interesting. I expected the opposite reaction... They must take the MoT test as sufficient proof of effective brakes.
I was thinking of the scenario, +2 crashes into something, brake system checked & found to be missing the servo, should be fitted as standard, so insurance company doesn't pay. I will PM the LDC insurer & see what he has to say...

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PostPost by: mikealdren » Wed Feb 10, 2010 11:56 am

My days of brake testing were long ago in the 1970s but I was very familiar with the regs at the time the Elan was produced.

The UK, EEC and Swedish regulations were all concerned with stopping performance (stopping distance without lockup) and fade. Pedal pressures were measured as well but servos for cars tend to take the pressures way below the legal maximum for driving comfort rather than meeting regs. I think the Elan would easily pass the regs without a Servo, especially since the Elan would far exceed the legal minimum performance in standard form.

Secondary braking performance was measured with one system failure and a significantly lower level of performance was required. This would have to be met with a Servo failure (easy) but also for a single circuit system like the Elan, the secondary level would also have to be met by the handbrake, I wonder how they managed that!

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PostPost by: atthelimit » Wed Feb 10, 2010 4:33 pm

Someone asked me to comment on the insurance issues relating to removing the servo.

Here goes.

Firstly, you MUST tell the insurers about it, it is a modification , not performance enhancing granted, but still a modification.

As most of the Elans will be insured on "Classic" insurance most companies will take a relaxed view. Each company will look at it differently but they all have access to expert motor engineers should they need to think about it.

They may decide to ask that you have the car re-MOTd at the time of conversion or to get an engineers report saying the brakes are up to scatch and that there is not a problem with the set up. I suspect most will not require any of this and just note their records.

Removing the servo will not effect the brakes efficiency as such, just the effort to get there. As can been seen from the thread most people are talking about something more than just simply removing the servo and whether it be harder pads, dual circuits, remote reservoirs, different master cylinders or uprated calipers tell them what else you intend to do.

I doubt very much that any insurer will refuse cover or indeed impose terms or loadings.
If possible run it past them before you do it.

The other thing to remember is that in line with the modification there may come an adjustment in the value of the car. For instance if you fit a TT alloy rad, fans, swirl pot, hoses and stat you have spent what ,?700? If the car gets a front end bump and you had not told them you might get a puny small S4 type rad replacment as original equipment. So tell them, get proper insurance and a proper repair or agreed value ioffer if it comes to that. Ditto Willwood calipers, magnesium diff casings and so on.

Its when you don't tell them things they will get upset or at worst through out a claim so the real answer in a nutshell is tell them what you are doing and you should be fine. The other tip I would strongly suggest is to get their acceptance in writing so that if there is at any time a claim and there was a query raised you will be able to prove that they have agreed it.
When ever you insure things that are "out of the ordinary" get it in writing, we insure lots of modified cars and get long lists of everything that has been done, from stainless brake hoses, to alloy fuel tanks and right up to a genuine 200bhp twin cam!

Most cosmetic mods like alloy tanks and radiators just get a nod of approval, a 200bhp twink gets a bit more than a nod but we can still do it.

P.S. Just picked up my new Toyota Prius, would love to talk more but CAN'T stop!


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PostPost by: Galwaylotus » Wed Feb 10, 2010 7:11 pm

atthelimit wrote:P.S. Just picked up my new Toyota Prius, would love to talk more but CAN'T stop!
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Kim, make sure you get the brakes checked on that Prius!!! :roll: :roll: :)
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PostPost by: gerrym » Wed Feb 10, 2010 9:29 pm

One of the many factors to keep in mind - insurance. On the safety side of things, these remote Servos have a silent and potentially deadly failure mode in the form of the internal air valve seal allowing brake fluid (all of it for a single master cylinder setup) to be drained from the hydraulic system and sucked into the engine. There are normally no warning symptoms but then again you might be lucky and spot the smoke or low fluid level before all your hydraulic brakes are lost.
There are also safety related problems with the brakes not releasing, eg at intersections and roundabouts.


Luckily, we still have a free choice system in the UK when it comes to insurance company. If the company doesn't like the mods you declare, or uses this as a basis for unreasonably hikes in premium, then this calls for shopping around and possibly changing the insurance company.

I think the key thing is to think things through, take responsibility for your car and your mods and your driving. Make sure the changes are properly executed and tested if necessary off the public road (end of soapbox).

Note, one of the interesting side issues with the Toyota accelerator pedal recall is that it is the total system which has been implicated, with a long chain of escalating problems. EG, accelerator stuck= no vacuum on petrol engined models therefore no servo assiatance, many are fitted with a push button engine kill button which requires a 3 SECOND push to activate, auto gearshift gates with non-intruative neutral position. Puts the no-servo discussion for the Elan into context.
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PostPost by: kstrutt11 » Wed Feb 10, 2010 11:19 pm

Gerry,

The single circuit system does not have a proportioing valve it just relies on brake sizing, by using the greenstuff pads I have obviously moved the balance to the front which has prevented the lock up. The original brake sizing should have made this impossible but I don't think the regulations came in until after the Plus 2.

I did look at dual circuit master cylinders, mostly Ford ones at the time but all the ones I found were larger bore which would have required revisions to the pedal box geometry etc, if the Fiat one is a 0.7" bore or there abouts then it would be ideal.

Kevin
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PostPost by: gerrym » Wed Feb 10, 2010 11:33 pm

Kevin, thanks for reply.

Fiat M/C is 0.75" which is probably acceptable. It's cheap enough to buy and throw away if it doesnt fit. Outlets are on top, designed for a remote reservoir. Not sure whether it has an integral pressure retaining valve for rear circuit as the 128 had rear drums. By the way, front calipers were 48mm diameter if my source is correct which is not a million miles away from the Girling 16Ps. The other thing to watch of course is the stroke and total fluid displacement. The Girling M/C is approx 37mm mechanical stroke (useful hydraulic stroke less than this)

Re proportioning valve: calcs can be used for what-ifs. On a dry road with good tyres, the rear brakes can prematurely lockup

Regards

Gerry
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PostPost by: stugilmour » Thu Feb 11, 2010 1:08 am

Gerry thanks for the great thread and all the info. Sure several of us are interested in this option, and just don't know the easiest & most effective way to go about it.

If anyone gets additional info on the Elan Factory product I would be very interested. I had email contact (with Steve I think) a while ago, but it kind of tailed off and got lost. I understand from previous posts he has had difficulty with his email in the past. Perhaps someone Down Under will be able to find out if it is still available?

The other option I saw in previous threads is to send the stock dual MC to White Post in the 'States and have them re-build it to the desired ID. IIRC this costs ~$250 or $300, so not cheap but an option if your car has one in reasonable shape.

thx
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PostPost by: Expat+2 » Thu Feb 11, 2010 7:12 am

I installed the Elan Factory tandem master cylinder. It fits well, although it's not easy to get the fittings tightened up.

mc2.JPG and


On the one they sent me I had to grind out the piston to make it fit the pushrod - Not a big deal but I wasn't expecting to have to do that. There's more free travel than I would like, which a longer pushrod might improve. It worked great without servos and with Greenstuff pads - pedal was heavy, but acceptable, I wouldn't personally go with a bigger diameter cylinder.

After about a year I got worried about flexing around the pedal box mounting, and fitted two servos, which work OK, but I liked the brakes better without. On the safety side, I believe the workshop manual requires that servos are swapped after 2 or 3 years, how many people do that?

Much better off without them. But the pedal box mounting needs strengthening. How do Spyder do this?
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PostPost by: gerrym » Thu Feb 11, 2010 12:42 pm

Thanks for your posting. It seems success factors include Gereenstuff front pads and reinforcement of the scuttle/bulkhead/pedal box mounting.

The Elan factory installation certainly seems neat: I guess you may be able to reduce free play by better matching of the pedal, pushrod and master cylinder piston (the hollow ball element). You should be able to shim the master cylinder away from the pedal box if the push rod was very slightly too long. The other thing to watch is the wear on the clevis drilling within pushrod. Are the pushrods available new? If you have the time and parts or know what you want, it may be possible to rebuild the internals with better matched parts and reduce the hydraulic free travel.

The point about scheduled maintenance or replacement of the Servo is indeed a good point. On the MGBGTV8 website there has been much the same discussion over the manufacturer's recommendation that the remote Servo be overhauled or replaced every two years. I wonder if the insurance companies would throw out a claim if there was a brake failure and it there was no proof of correct maintenance.

Regards

Gerry
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PostPost by: stugilmour » Sat Feb 13, 2010 2:06 am

Martin et al:

A while ago Sean at Spyder sent me a dimmensional drawing of their pedal box re-enforcement mod, but I am having difficulty locating it right now. When I find it I will scan and post to this thread.

IIRC the basic deal was a couple of lateral angle irons attaching the pedal box to additional fibreglass and braced to (I believe) the hand brake bracket, if this make sense. I think the basic strategy was to run the angle iron all the way over to the vertical fibreglass panels to remove the flex in the flat portion of fibreglass around the pedal box hole. In the original design the pedal box is essentially floating in the horizontal fibreglass, which is the source of the flex. Nothing elaborate, but I figured the dimmensions he provided would be handy. I think it was half inch angle and a few nyloc nuts & bolts and washers, no welding.

Just ready to install the pedal box, so really must find the drawing!
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