Calling All Brake Gurus

[MartinL]

I think my master is finally dead, after Sundays run to the Gaydon show I was feeling less than happy with my soft brakes and thought I would have "one last try" at bleeding.................

Started by depressurising system, about 40 pedal pushes, remove top to find the rear resevoir looking like milk it was so full of minute air bubbles!! after a few minutes bubbles dispersed and fluid looking normal although level was slightly down...............time to experiment as something very odd going on, push pedal down slowly and a million small bubbles emerge from bottom of rear resevoir, more on release and continue for several pushes, allow fluid to clear and try again, this time no bubbles, at this point I am thinking I had found and released some trapped air, great..........replace top and turn on power to run pump, try pedal..........feeling much better, best have a run down road to try............. Oh shit, just the same soft pedal. Started whole procedure again, more bubbles in fluid, then noticed the puddle of fluid under the master!!

My conclusion is the master seals on the rear section have failed allowing air into cylinder and allowing fluid to weep out.

Anyone got a spare master cylinder???

Are new masters still available ???

Do I rip it all out and fit an alternative system??

Any bright ideas ????

My original complaint was the lack of assistance, but it looks like I have only had any real effort from the front brakes for some time although the rears were good enough to pass an MOT ???

[CarlC]

Sounds sadly familiar Martin...

I'll have to check mine for leakage, but I didn't notice this last time I was in there. However, everything else, sounds exactly the same.

I'm In the process of trying to source a replacement master cyclinder assembly.

[MartinL]

Carl, please let me know if you find a source for new masters as my initial phone calls were a failure!!

PS.

Pete at PNM reckons he can overhaul/recondition the master unit !!

[CarlC]

Glad to keep you posted on any sources or progress. Yea, I heard that (PNM), but the cost isnt much different to what a second hand unit should be and I've yet to hear anyone having it done and reporting on the results. So the jury is still out on that course of action but it may be that we are left with no other choice (other than total system replacement). I'm going to see if i can dig anything up this week.

[ramjet]

I had the same issue with bubbles returning into the rear section of the reservoir.

There are people on here that have owned these cars for far longer than me, so understand that this is my opinion.

I went through all the tests that others have outlined above. i.e. counting how many pushes to depressurise, how many seconds to repressurise, how many pushes between pump runs, attempting to clean the switch, pushing and holding to see if I had a leak.

Based on most of the tests, most things appeared pretty good. However, I then ended up with the pump running on every press. ABS flashing all the time.

I forked out about $50 for a test rig which screws into where the pressure bulb goes and the bulb goes into the other end of the hose. There is a gauge on this hose as well.

Firstly, the system was incredibly clean, fluid-wise. Trying to clean the switch achieved nothing. Analysing the drawings and cross sections of the Delco system, if you have a leak from the pressure bulb, it will show up as bubbles in the rear section of the reservoir.

After hooking up the test rig, I got the following. Pump switching in at the correct pressure, but switching off about 70% of full operating pressure. This switch off occurred after about 35~40 seconds from zero pressure. See the problem here without a way to measure the pressure? I was getting what looked like the correct run time, but I had a pressure bulb which was basically at zero pressure, a switch that has gone soft on the high pressure side and a run time that looked ok.

My assist is no worse now than when I first got the car, but I expect it to get better when I replace the switch as I am currently never getting to the peak operating pressure.

My advice - buy yourself the pressure test rig. It will take out the guesswork and you'll use it more than once. If you don't think you will, sell it to someone else for half the price. Any brake issue, I won't hesitate to bolt it on to check things. You are never going to pick a system pressure drop by measuring the run time of the pump when there are other variables.

[Rich H]

I know nothing about the Esprit ABS system but is the V8 Esprit at Douglas Vally Breakers going to have anything useful in it? the front end looks OK but the back end was gutted by fire.

Being DVB it'll be expensive but just thought it might be a useful donor for someone.

Just a thought...

Rich

[CarlC]

Michael

Really good info. Gives me another avenue to investigate...

Rich.

I'm afriad not, the whole system was dumped and replaced with the Kelsey Hayes Brake and ABS Setup on the V8's.

Edited June 29, 2010 by CarlC

[Jonathan]

The pump run time test is not an indication of pressure - more over if the system is totally de-pressurised and you switch the unit back on the pump run time will actually give you a reasonable idea of how much pressure a bled system is charging to.

If the pump should run for 40 seconds, anything under that is likely to suggest the pressure switch is defective - anything above that generally means the system has a leak / accumulator is duff or switch again.

You dont just go on 1 method and discount the rest - these test are a guide and used in conjunction can tell you a lot if you're good at fault finding.

[ramjet]

I've reread my post Jonathon and it does come across a bit harsh. You are right that the tests are indicative. However, if you look at my circumstances again, I had two variables change. They both changed in the direction that from the tests made everything still look ok, but I still got a fault every time I drove the car. Actually, everytime I pressed the brake pedal.

The only sure fire way to diagnose the system is the pressure test rig.

[MartinL]

OK, finally took the plunge and give up on the whole lot and ripped it out!!

Removed master cylinder, resevoir and pump, associated pipes and electics.

Replaced with Toyota MR2 (non turbo) master cylinder and servo, new pipes made up and fitted as req. with a Wilwood pressure limiter in line to rear brakes, just bled the system and leak checked, best pedal feel i have ever had on this car and the best brakes ever, best feel ever, even before I connect the servo, still need to run pipe under car and connect into inlet manifold, will report back soon as i grt a chance to do this.

Best part is parts cost less than £70 so far!!

[nodemgr]

Here's my experience. Shortly after I bought my car one of the first things I did was replace the accumulator due to the low accumulator code. After a thorough bleed my ABS light stayed off for about a week or so but then the pedal would get a little mushy and the blinking ABS light would return. Then I tried bleeding again and the same thing, light off for a week then mushy pedal and light back on. I can't tell you how many times I bled my brakes. I put up with this for a few years and then I got PNM's front brake kit so I decided to fix the system. I cleaned the pressure switch myself(and it was sticking, so that was part of the problem), but l decided to have the ABS unit refurbished because I always wondered about internal seals. I sent the whole system off including the accumulator, pump, switch, and master cylinder. I got it back a week later refurbed and fully tested. The internal seals were "swelled" and had to be replaced. The only other thing was some filter had detached itself and probably got in the way of the stroke of the cylinder occasionally, according to the tech. I don't recall feeling anything like this when using the brakes but he said it probably happened. The refurb comes with a year warranty and cost $575USD. It is a lot but I believe this includes a refurb switch and accumulator if yours are bad, since the price is fixed. Unfortunately mine weren't bad so the profit margin was high on my refurb.

Best part is the ABS light is gone and my pedal is rock hard. I haven't had it to the track yet, but I've got time with the year warranty. Actually I haven't even tried to invoke ABS yet., but I am confident in the system with no warning lights. It's crazy to think of how much brake fluid I went through over the years.

[CarlC]

Martin,

Very interested to hear your thoughts once your replacement setup is complete with Servo. It was looking like at least £400 to get the brakes sorted on my car and that was if the problem only turned out to be the accumulator. I've already had the pressure switch issue and sorted that. I'd love to get a refurb but with our Delco system being rearly used in the UK, Im thinking a Refurb is going to be costly if I can find someone to do it and the fear that I'll stil be left with a crap feel and brake solution.

The brakes are a massive disappointment on the S4. So the MR2 system swap you've done is of great interest. N/Yorks isn't that far from me, if you've got a spare half hour some time soon, I'd love to pop over and take a look at your solution with a view to implementing the same on mine.

[MartinL]

Hi Carl, you are welcome any time or we could meet up if need be, let me try to get the servo all workinkg then you are welcome to try it out for yourself and see if its to your liking.........

I am iust of the A66/A1 near Scotch Corner if thats any help, we work from home so most times are good.

[CarlC]

Thanks Martin,

I look forward to hearing your thoughts once you've got the servo sorted and I will certainly have a ride over to take a look at your new setup once its completed.

In the mean time I'll see if i can get some quotes for a refurb so I can look at both options.

Cheers,

[MartinL]

Servo now up and running.............................AMAZING!!!!!! after a few problems with brackets and location etc the time taken has been well worth it, the brakes now feel light and instant, ver unlike any Esprit I have driven but more like my over servoed Astra, wont be to everyones liking as no ABS, but OMG THEY REALLY STOP THE CAR

I think it would be possible to do this conversion in an afternoon if all the parts were to hand, I have taken out the wilwood limiter to thr rear as i managed to fix the original in line with a good clean out so parts wise i bought a master/servo for £15 of Ebay, brake pipes I made up myself from stock parts and the biggest expense was some copper small bore heating pipe to run the length of the car and somesilicone vacuum hose and clips about £35 brackets and nuts n bolts all found in the garage!

I will report once I get a few miles on with town/motorway testing once I am happy with the pedal position and adjustment

[davevr6car]

Hi Martin,

where are you getting your vacuum from. If you connect it to the manifold on a turbo car would you not be getting pressurised air instead of vacuum.

Sounds like you have sorted one of the biggest let downs in the esprit. Good work. A few pictures of your install would be great.

cheers

Dave

[MartinL]

David, you are correct, I failed to mention one of the most important parts in the conversion, a non return vacuum valve needs to be in line to prevent pressure build up. I have adapted a Rover (dont know what car???) Turbo manifold valve direct into the inlet port used for the dump valve take off ...........works for me!!

[Rich H]

As long as there is a working one way valve in the booster vauum line (Which there should be!) it won't be a problem. When the boost comes on the valve shuts and the booster retains vac..

All boosters have them as a safety thing so if the engine cuts you still have brakes for a couple of goes.

Clearly it'll only regenerate when off boost but it'll only take a brief bit of vac to replen and when braking you are generally off the throttle anyway.

Needs pics!

Edit: Too slow!!

Edited August 16, 2010 by Rich H

[davevr6car]

Hi Martin,

Sounds like a great upgrade. The brakes on my S4s are crap, I have fitted the S350 AP racing brakes front and rear and they are still not up to scratch. I would like to scrap the ABS system and fit a servo like you did.

Can you forward me any photos or a step by step guide.

cheers

Dave

[MartinL]

Hi Dave, Pics. to follow and a step by step guide to braking heaven!! ( well at least a massive improvement on S4 brakes!!!)

I have done about 500ml with new set up and all seems good, i am just sorting pedal travel now as I feel its a bit long although its all very progressive and light even with "hard" pads . I do need to alter the mounting brackets to something a lot stiffer than I have fitted now as I feel a bit sponginess is caused by flexing............. ............... its all good but I know I can get it even better, just need to get some time to play

watch this space..................

[Jonathan]

Sounds like something is wrong - I have APs on ym GT3 and it stops like you're hitting a brick wall

I do have good tyres though....

Tip = disable the ABS, when I put them on I found the ABS was coming in almost instantly, pull the fuses and you can actually stop as the ABS computer isnt thinking you're decelerating too quick and there must be a lockup occoring.

[MartinL]

Sorted................MR2 master and Servo.Hi Spec front calipers, disabled ABS, now I have brakes that really work.

Pics as promised,

[IanQ]

I had all this problem back in February complete with the caramel coloured brake fluid. Since I have given up playing with things I don't really understand ( although servicing my wife's Matra Bagheera is incredibly easy ) I sent my S4s to Gerald Turner. He soon fixed it and now the car goes and stops when it should.

I really admire you folks who have made your own solutions to this problem.

[G_Reaper]

Hi Everyone.

Does anyone know if Lotus have sourced a replacement presure switch yet????? Or are they too busy opening shops in the center of London instead of dealing with important things such as their aftersales support.

Cheers Mike

Bibs maybe you coulod let us know the latest please?

[Bibs]

They're testing it Mike on an S4s they've had at the factory for some time.

Would you believe that the clever and experienced engineers working on solutions for decades old cars don't get involved in opening shops!