Calling All Brake Gurus

[drellis]

hi martin, please could you tell me exactly which parts you used as your solution sounds great.

many thanks

David

oh meant to also ask how do you get it through an MOT with no ABS, or just wire the abs bulb to one of the others so it comes on with ignition then goes out.

[MartinL]

Hi David, I am sitting eating lunch, then back to work, so no time for full step by step, I will get round to it as so many are askingI

you will need

MR2 master and servo, any model as long as it has the low resevoir (easier to fit than the Subaru item) Vacuum resevoir tank (Audi A4/A6)

8mm copper heating pipe

8mm vacuum hose, samco or similar about 2meter and clips.

2x non return valves

basic engineering skills and tools to make mounting brackets and new brake pipes , recut servo rod thread to metric etc

"T" for vacuum takeoff at manifold

Brake fluid etc.

Several spare hours, patience and a understanding wife!!

all parts available from ebay!!

I think start to finish in less than a day DIY once all parts to hand

Mike and I are still experimenting with vacuum pumps and various methods of switching but the system fitted without as I am currently running is 10 times better than the original S4 system with LOTS of feel and the ability to lock wheels at speed if req.

MOT ??? dont see any problems, my last tester didnt ask, as I understand the regs. (someone out there will know better and correct me!) If its not fitted/removed/disabled then its not part of the test.

PM. or phone if you need more info. Martin

[drellis]

thank you very much. My s4 switch has gone but brakes have been garbage fro 6 years before that.

david

[MartinL]

Mike can get you a new switch, but that will only get the abs working and wont improve the braking efficiency or pedal feel,

good luck!!

Sorry, didnt make clear in above list of parts, the master and servo you need is the one from NON ABS models with the dumpy servo, the big flat pancake type wont fit in !!

or if you pm. Mike he has the part nos. and source for the SE master and servo if you want to buy new items.

[G_Reaper]

Hi

With ref to the MOT, the DVLA told me that if the car has no functioning ABS light (pull the fuse) and there is no evidence of ABS under the bonnet i.e no form of ABS pump then they mot as non ABS. Depending on your MOT station that may require removing wheel sensors etc however I checked with my local MOT station and they were happy if there is no ABS pump and no ABS warning light upon switching the ignition on.

Remember on some cars in the 90's ABS was an optional extra.

I agree with Martin the S4 system was probably at best OK in the early 90's but it really is quite a poorly designed over complicated very early form of ABS that blunts feel and is not even very good when it is fully functioning. It certainly should never have been fitted to a sports car. TVR did not fit ABS till much much later when ABS systems had advanced considerably.

I think you cannot beat non ABS brake feel.

Just my opinion.

Regards Mike

[drellis]

Thanks all clarifying the mot situation. Can i ask why did you go for the subaru servo? does it give increased pressure to the calipers?

I intend to rip out the rubbish as soon as i source the parts

many thanks

again

David

[MartinL]

David.

When I started looking for a suitable master and servo I knew the approx max diamater for the space available and knew I had limited height to play with so I searched ebay for something that looked a likely fit!!............£15 for a Mr2 unit looked good value as a starting point, with very few problems and a home made bracket it was in place very quickly,initial tests proved to give much improved braking and pedal feel but with a lot of travel and a "spongey" feel. in an attempt to overcome the travel, I felt a larger bore master might do the trick so back to ebay for a similar size servo but with a larger bore master, Subaru impretza give 1" bore (mr2 is 15/16) and a nightmare to fit in place needing new brackets and alteration to bulkhead etc. The result was no improvement in pedal travel but a very light pedal with high initial braking but still a spongey feel, I felt this to be very overservoed and prefer the feel of the mr2 and the ease of fitting,

I used the car like this with no problems for some time and realised after much reading and talk to "brake people" that the pedal travel is all down to the pivot and pedal length ratios and after checking pedal travel against piston movement found that to improve would mean redrilling the pivot point on the pedal but as it is impossible to get a drill in there and I dont feel like stripping out the pedal box this aint going to happen to my car at this point!!

At this stage Mike got involved and his investigations into GT3 systems with electric vacuum pumps set us off in that direction, something we are still playing with............

However along the way after trials with pumps and vacuum tanks I found that a combination of engine vacuum with a tank almost eliminates the spongey feel and gives VERY strong braking at all speeds and more important is the confidence you gain!

The pedal travel is not a problem when you know that you are not going to run out of piston travel and the advantage is greater control and feel, I am happy to "mix it" with Elises on all types of road and all speeds with no worries, I can stop as quick as them,

We may gain something with pumps and switches, I am open minded and prepared to try to improve.

MR2 v Subaru parts ??

imho the ease of fitting and the better feel gives the MR2 my vote, the Subaru is a pig to fit and is overservoed for me

Anyone want a already modified Subaru servo and brackets ??

[drellis]

again thank you very much. If there is anyway I can help please let me know.

david

[drellis]

Hi all just a possible note of caution. My daily 1989 bmw 635 just failed MOT on no ABS. The ABS bulb was taken out by a previous owner. It came up on the MOT testers sheet that ABS should light then go out after engine started.

Now researching this it appears most MOT testers let this past but letter of the law seems to be if iy shows up on the computer as having been fitted with ABS then it must have a ABS light that comes on and goes out.

Hopefully lotus did not put this information on the ?VSI? database the MOT uses. You may need a friendly MOT tester or be creative with the light coming on and off (?you could wire in series to the oil pressure light).

I still think it worth going ahead as I sick of the brakes.

dave

[G_Reaper]

Your MOT station needs to read the rules and talk to the local and national DVLA office.

I spoke with the DVLA direct locally; then nationally and then with my local MOT station. However your car obviously apart from the lack of an ABS light will show every sign of having ABS fitted. The key item is the ABS pump and wheel sensors (maybe). A car is never going to pass an MOT by just removing the bulb or fuse.

I hope this clarifies the situation, I have spoken with DVLA not just a local MOT station who may not have come across people actually modifying their car away from ABS. The DVLA were quite clear about the removal of the ABS pump in particular.

Note also my insurance company are OK with the change but needed to be aware of the change, bottom line is if it passes an MOT they are OK as long as they are kept informed.

Cheers Mike

Edited April 28, 2011 by G_Reaper2

[drellis]

Thanks for clarifying that, I did not look into complete removal of abs.

David

[MartinL]

MOT test today....................................NO PROBLEMS !!

Brakes performed beyond all expectations and almost jumped out of rollers , the examiner did ask if the car had originally had ABS fitted as wheel sensors were in place but no dash lights showed, I pointed out the lack of abs pump and the replaced master and servo running from engine and vaccum pump, he examined the new mountings for security etc. and pronounced the system to be more than adequate for the job!!

I think the soft Volvo pads I have fitted did the intended job and gave instant bite at the slightest touch of the pedal, great for roller testing but not too clever on wet roads as too easy to lock wheels up and not as good as the "Hawks" for enthusiastic driving.

[greekmix]

Martin

Your solution I am sure will have a positive result with many owners around the world.

I am very interested to see a full service guide with photos and parts used.

Your work in been noted and thank you for sharing your solution.

[MartinL]

Tony, I hope to have the final set up installed and road tested soon, Mike (G-Reaper) and I are currently testing various vacuum switches in an attempt to get a constant predictable vacuum to the servo, some recent tests have proved unreliable. as soon as we are happy with the parts we are using then we will post our findings.

I am still using the Subaru servo after damaging the MR2 unit with high vacuum, I hope the new switches will overcome this problem as the Subaru setup is a little overservoed for me with a very light pedal,..............................watch this space!

Mike is using a master cyl. and servo similar to the Esprit SE models on his S4s, road testing results available soon !!

[PaulEspritGT3]

This long and then a little bit more.

They're just testing the production ready version.

Hello Bibs,

(Ref: ABS Pressure switch / B082J6137S).

Do you have an update on this please?

I've just found that my Pressure switch is broken and unrepairable!, and so my GT3 is effectively unusable!

[fflyingdog]

Lotus Verhiest

Joseph Plateaustraat 5

8400 Oostende, Belgium

T +32 (0)59 51 81 55

F +32 (0)59 51 30 86

E info@lotus-verhiest.com

Try this guy,i bought mine off him last year.

[PaulEspritGT3]

Availability of ABS Pressure Switch (B082J6137S).

My GT3 recently developed a fault which appeared to be the ABS pressure switch, this caused me to thoroughly investigate all the replacement options.

As it turned out my local independent Lotus garage, Paul Matty Sportscars, did an excellent job fixing it without needing a new switch.

Thank you to all the people that helped with suggestions, this is a summary of the current situation with the supply of a new switch.

The response from Lotus themselves was ....

"The Engineering work on the replacement pressure switch is complete.

We are just going to do the checks on the sample production parts.

As soon as that is complete our Aftersales Group will get the production parts in stock."

New switches are available from http://www.lotusesprit.com.au/parts.htm (Tony Papas) for 890 Australian dollars plus shipping.

Also thanks to fflyingdog - I emailed Lotus Verhiest but so far no reply.

[ramjet]

Not trying to take anything away from Tony Papas, but where did he get his switches? This thread has been around for a long time and Tony has never mentioned them before.

Anyway, this is the post I put up here before about the solution from Steve Taylor here in Victoria.

http://www.thelotusf...post__p__305864

I don't know if the prices are still relevant. I will contact Steve tomorrow and let you all know. I will also ask him details of a group buy. On your own, Steve's setup is only $400 AUD.

[MartinL]

And my solution was less than £50 !!!!!!!!!!!!!!!!

[ramjet]

I am not sure in Australia as to what the legal issues are, if any, to removing a manufacturers system in a car and replacing it with something else?

Are there any Aussies on here that know if you are able to replace an ABS system with another braking system?

[G_Reaper]

Are Lotus going to also supply a kit to overhaul the now very old Master cylinder seals solenoids etc? Because you can bet you will replace the pressure switch and something else on the system will go.

They have already made the GT3/ V8 master cylinder and servo obsolete along with the GT3 electric vacuum pump.

Just more info to be aware of.

Cheers Mike

[G_Reaper]

OK I am now extremely happy with my brake set up.

My car passed an MOT test no problem last Thursday.

I am running an Esprit SE master cylinder (VW T2 Transporter)+ Standard Stevens Esprit Servo ( the same as a Renault Extra Van Servo I was informed)

The brake servo is provided vacuum by a Hella LP28 /LP29 Electric Vacuum pump as fitted to certain models of Audi TT and Ford Mondeo. I have mounted this pump hidden in the compartment in the rear lugauge area along side the other vacuum pump which operates the heater controls, engine idle & EBP valve. It is necessary to fit the Hella pump in the rear compartment as fitting the pump in the front luggage compartment near the servo makes the pump noise too intrusive in the cabin. The pump is switched by an adjustable electric vacuum switch. There is also an auxilluary supply of vacuum from the engine. Both vacuum supplies are fed through Vauxhall Vectra non return Valves to the servo. An extra reserve is also supplied by an Audi A6 vacuum tank mounted near the servo.

The Brake feel is now superb, no wooden feel anymore and the brakes are consistent, which intern gives the driver confidence in the cars braking capabilities. If you prefer more servo feel to the brakes simply adjust the electric switch to achieve the fell you prefer.

This set up is the result much trial and testing by Martin and myself. Although Martin is currently running a different master cylinder and servo his testing has also provided an alternative set up which I am sure he will post here when he is happy with the results.

No more Delco worries !!!!!!!!!!

Cheers Mike

For more info PM Me.

NOTE: My car was test driven by another S4s owner last weekend and he was absolutely blown away by my cars brake performance and feel!!

Edited October 8, 2011 by G_Reaper2

[nicknick68]

Reaper,

how much did you spend for this job?

Would be nice to have all part numbers and pictures showing the job.... can you do that for us?

Nicola

[dodge1979]

Yes, can you sort out maybe a zip file with pics and info in detail? Would be gd to see the setup. Where abouts are you based? Darren

[MartinL]

EUREKA !! as some old guy once said...............I also feel that i have now resolved the few remaining gremlins in my system, i f you read the previous posts my myself and Mike you will see the problems we have encountered as we have experimented with various sevo/master combinations, vacuum switches and lotus electrics, Mikes system is a work of art and looks like the car came out of the factory like this, i have gone for a "working alternative" and although the results are spectacular alongside original S4 brakes my car may not be as neat as Mikes, however it WORKS.

I am still using the Subaru Impretza (non ABS) master/servo that needs new brackets and re machining to mount, but have always had long pedal travel and a slightly soft feel...........not any more!!! A chance conversation at Donnington with a former Lotus engineer pointed out the obvious, too much vacuum, Subaru run the servo of one bank ie. 2 cylinders, the servo is set to work at a lower vacuum than the 2.2 4 cylinder produces, I have installed an adjustable bleed valve between 2 non return valves in line and hey presto a hard pedal with little travel and wheel locking ability if required!!! and lots of feel as a bonus.

Parts used.....

Subaru Impretza master/servo

home made mountings

copper and silicone vacuum pipe

non return valves

Audi vacuum resevoir

"forge" turbo bleed valve used to controll vacuum

jubilee clips etc.

Workshop time !

Mike and I have spent LOTS of time working on this and have resulted in 2 braking systems that may be used as alternatives to the aging S4 Delco set up, we have not used ABS as we both felt it was crap to start with, but no doubt someone will be along to tellus how to improve that as well. In the UK this is not a problem but may be in other parts of the world so please check before ripping it all out !!

Now if only I could find a way to stop the new pads squeeeeeeeeling at slow speed ?????