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  1. As a lot of people are aware, the Delco ABS system used on the S4, S4s and S300 is not very popular with many and I feel misunderstood and mis maintained. Ive never been too impressed with its efficiency since day one of my ownership, but have been determined that it should be better and was no doubt better when new. So, as the car was off the road over the winter months for hibernation, I decided to spend quite literally a few months researching and tackling this system, with a view to getting it working as best as I could and correctly, before making a decision as to its efficiency and worth. Now, if I may, Id rather not turn this thread into a 'declo are rubbish what you need is.....or replace it with such and such...' I just want to share the work thats gone into this and the results Ive achieved so that we can have an informative and accurate guide to getting it working to its proper level of efficiency. OH and sorry if its a little long winded..I promise Ill put some pictures up too when I can to make it pretty The result of all the work, money spent and time etc came to fruition when yesterday I took the S4 out for a spirited run to see how they perform under heavy braking etc and around town in traffic. The bottom line is that they work and bloody well too! So if you want yours working, or you think yours are working, (and I can pretty much guarentee they are not regardless of how theyre currently functioning) read on....... Renowned these days for the unobtainable pressure switch that goes weak, inconsistant pedal feel, wooden feedback if any and non inspiring braking force, this system has been ousted by many and slated so I tackled things logically in my attack of this system. Lets start with the all important parts that are not available. THE ACCUMULATOR This is not available, and a suitable alternative is from an XJ6 Jaguar as we know, but these are becoming scarce too now and expensive. So, having looked at many types, which come in various sizes, capacities, pressures and screw threads, I settled on a Wabco unit which is very commonly available at a much lower price than the orginal was or the jag unit. Its and M14 thread, 200bar 0.3litre unit from a P38 Range Rover. THe original Lotus unit was a 207bar 0.25litre unit, however the system never ran at this 207bar pressure so this had a greater pressure capacity than required and so the 200bar unit is still above the systems working pressure, making it a perfect and cost effective alternative. THE PRESSURE SWITCH The carrot dangling infront of us for some time of a new switch being in the pipeline, research being done etc has led people to either scrapping off the system or finding an alternative way of getting it working, but do they know if it is functioning correctly really? I doubt it. Even if your switch is cutting in and out as its supposed to I will pretty much guarentee it is nt working right and is junk. I have had a custom switch made for me that enables my system to work at the correct original pressures, but more of that in a bit.... THE PUMP MOTOR THese are pretty much sound. Unless yours has been running all the time due to a badly functioning system, it shouldnt be worn so if it is running as it should according to the workshop manual its ok. Thats the main components, Ill look at ABS later on. What did I do? Well, having spent a lot of time looking at other vehicles using this system and seeing that pretty much everyone has had issues with poor braking efficiency these days, it would appear that this system has several areas that need monitoring, maintaining and replacing. A lot of it is common knowledge... When I made the decision to invest in the system I decided the first thing to do was to see what was actually happening whilst it was being used..ie what pressures were being created, at what pressures the pump cuts in and out, how much pressure is 'used up' out of the system each application of the pedal etc...I needed a visual interpretation of what was actually going on...so I decided that I was going to fit a pressure guage to the system, which I could then observe throughout the use of the system, ie from a depressurised system, watch it pressurise, see what happens when the pedal is applied, where does the pressure drop to, rise to etc.. I bought a 4000PSI pressure gauge along with various fitments from my local hose/hydraulic suppliers to enable me to fit a t-piece to the pump body between the original pressure switch and the pump, and fit the gauge to that. Ill deal with bleeding the system seperately later too...Then, I was able to observe the system functioning. What I found from this, that whilst my system was stop starting etc exactly as per the workshop manual, it was way out of spec.The switch was allowing the pump to run up to 2400 psi, and cut out as if it had reached its maximum pressure, and it would cut in when the pressure dropped to 1950psi. Now, the system is supposed to run at 2700psi top pressure, 2400psi lower pressure with the warning light on at 1800psi. So even though the switch appeared to function correctly, it was only with the gauge that I could see how out of spec and misleading this was actually. Instant indication of a weak pressure switch which I bet pretty much everyones is....So the search was on to find a new switch, or an alternative one. At this stage, I spoke to PAULGT3 as I know he had problems last year with his switch failing, to see if he had solved it. It turns out he had made a temporary solution but was still searching, so we had a meet up and a good chinwag over coffee and came to the conclusion that we had both spent november and december last year researching the net etc to find a solution, so exchanging info we decided to use my car as the experiment to get this sorted.. Paul had purchased a switch from a Reatta which looked the same, but when it turned up it was MASSIVE so not a suitable replacement! But he and I had also been looking at possible solutions from the same companies, and after contacting several I found one that would make me a switch to function as I wanted, but without the pressure circuit. More of this in a bit... So, the switch is faulty...but I discovered something else, which I dont think has ever been mentioned before and that is what happens when the pump turns off. When the pressure reached 2400psi, the pump shut off. But then the pressure dropped, and settled after say15 seconds to 2100psi or there abouts....where it stayed constant until obviously the pedal was pressed. Now, I had two thoughts initially, one was that I had a leak and secondly that my accumulator was weak and not holding the brake fluid under pressure, and so allowing the system to loose pressure. In order to test the leak theory, I left the system pressurised at the 'settled' pressure of 2100psi for a week. I came back to the car and the pressure was still reading 2100psi. Ok, if there was a leak it would drop and creep down over that length of time even only a small bit, but nothing. So, my attention turned to the accumulator. As we know, this is a pressurised ball with a rubber diaphram inside. On one side it has nitrogen gas, on the other side the brake fluid is pumped in against the diaphram, which then expands against the nitrogen and results in the fluid being held under pressure. Naturally the nitrogen will seep through a weak diaphram resulting in a poor performing accumulator. Manufacturers recomend these are replaced regularly. This is a maintenance side of this system that seems to not get done, contributing towards poor brake performance. As a matter of course these should be changed after 5 years if I remember reading correctly, but of course it may be that they last 10! Prevention is better than cure.. So I researched into the accumulator now, and resulted after some time with the P38 unit. Slightly bigger, but as mentioned a good match. The only other difference between this and the Lotus unit is the way it seals when screwed into the pump housing. Both have an 0-ring, but the Lotus unit has a shoulder machined on it that fits snugly inside the pump threaded opening, sealing the o-ring against the body. The Wabco unit has no such shoulder. So, either machine a step in it to match the Lotus unit or more simply use a suitable copper washer to fit and seal. This is what I have done with no problems. So with this fitted, the system fired up again, the pressure rose as before, 2400psi, cut out pump and then....pressure drops to 2100psi as before. Well, that mystery was solved a little later... Onto the switch, I had ordered a custom switch which took 5 weeks to arrive unfortunately, but when it did I fitted it to my adapter piece on the end of the T-piece with the pressure gauge on, and fired up the system! Pressure rose to 2400 psi, settled down to 2100psi and cut out??!! Pressed the pedal and the pump cuts in immediately, up to 2400psi, settles to 2100psi again. OK not impressed. Long story short, I spoke to the company who then admitted they had failed to set the hysterises of the switch as I had ordered and said to send it back. Instead I obtained instructions from them allowing me to adjust it myself, which I did. I set the upper level to 2700psi, as per the workshop manual and luckily they had set the lower limit to 2400psi as requested. SO fired it up again and it went straight up to 2700psi! I was so happy, until it then dropped again to 2400psi.... The reason I believe this is, is that it is a natural 'give and settle' in the system. Basically, it is the nitrogen in the accumulator settling down after the initial force of fluid against it, gas will compact more so than fluid, so the fluid compresses the nitrogen slightly further resulting in a lower fluid pressure as the nitrogen isnt holding its density as much against the diaphram.. The solution here was to adjust the switch to over pump to a higher pressure, ie 3000psi which would then allow it to settle to the required 2700psi. Now two things to note here, the pressure safety valve in the booster master is set at 3400psi to vent excessive pressured fluid back into the reserviour, so this pressure is not a problem to pump up to initially, as the system settles quickly down to its correct functioning pressure. Secondly, the original black plastic pressure switches used on these system were functioning at a higher 2900psi to 3000psi pressure, the replacement grey ones were lowered to 2700psi. All Delco units had these switches change no matter what vehicle they were fitted to. They were changed under warranty as there were fears of excessive and premature failures of components in the booster system. The switches were made by GE Captial for anyone interested too.... So now Ive got a working switch, new accumulator and the system is at the right pressures. Now I mentioned this switch doesnt have the warning light function but this is not a problem at the moment the system will still work as it should. More on that later. When replacing these components, I followed the workshop manual exactly as per its bleeding methods. I ran the brakes over a weekend covering some 380miles of motorway and town and country lane driving and felt there was an improvement, but not as good as I thought it should be. Until last week.... I decided that I would bleed the system again, using a vacuum bleeder, but absolutely meticulously and slowly...the system is a pig to bleed. Basically, on a completely depressurised system starting at the front right caliper, then front left, then rear right then rear left. then the inboard booster cylinder bleed nipple, then the outboard nipple, then the inboard again, then the outboard again. I spent about 40 mins each bleed nipple, allowing minimal fluid through to ensure no air was being pulled up the thread of the bleed nipple...it was slow but neccassary. The booster nipples seem to draw air badly, as soon as they are fractionally slackened off they become loose in their thread, so i squirted washing up liquid over the the thread and this stopped them drawing up air this way, with a reapplication of washing up liquid every so often. Then, I turned on the ignition and pressurised the system, then ignition off then pressed the pedal lightly, ignition on for three seconds, then off then on then off, ten times as stated in the manual, for three seconds each with the pedal held on constantly. Youll hear the solenoids click on the three second mark. This will cycle the ABS solenoids. Then its done. Ok it took hours to bleed, but the results were worth it. I currently run my system with the two ten amp fuses removed from the ABS system to disable it, as I want to test the braked with my own skills. I went for a run yesterday having finished and they were brilliant. Its important to note that I run yellowstuff pads, which is not the best choice for this system. I can explain later as my fingers are tired now! But basically once theyre warm they were biting and applying some suprising pressure that I didnt have before. I was able to shave 110 down to 70 in a second or two, the wheels were locking at 50 to 70mph with a sharp stab of the pedal...never before was this happening! Obviously with the ABS enabled they wouldnt lock as such but continue braking as the system allowed... So the result of a hell of a lot of research which has been very sharply summed up here, time, experimentation, effort and determination I feel I have a set of braked I would be very comfortable with on a track, I have confidence in them at speed to pull me up if an emergence happens and to work under hard driving without failing me. This is how the system should be working. And Im sure no one here has driven the Delco system on the Esprit when new to know how they actually were and how they are now is so different. Now there are more details to be had of the fitments Ive used, pictures to post etc but Ill thank anyone reading this far! Sorry it was so long winded but the explanations are needed to make everything clear for others to hopefully use....obviously any questions Im happy to talk through These systems need to be kept going, or what will happen to the S300's? Theyll get butchered. Who wants that really....
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  2. no, your lucks not come to an end, because you have stumbled across a super rare car with wonderful handling... I'd presume that Atlanta isn't all that wet? (I know nothing about the US climate) so hopefully the chassis is probably ok. Do a quick search on eclat sprint through the forum archive, there is some good info in there. lastly - please sent an email to [email protected] and I will send you a sheet for you to return if you want your cars details to go on the list of survivors and to be added to our mailings.
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  3. Click for full article
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  4. I'm liking the not being able to see predictions, much better
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  5. Latest from Paul Matty's is that the pressure switches will be with them in around two weeks. So hopefully the supply of switches is sorted again now.
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  6. Must admit I thought it was the most pointless episode yet. The only good part was the first 10 minutes and even then they ridiculed the Merc immediately and we never got to see it compete against the other 2! I fast forwarded the bike bit too....and he Porker test. Which was just as pointless. All it was was Hammond driving round a track saying "Arrrgggghhhh this is good".
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  7. The bike piece was pointless, not even funny, not interesting, not wanted, dimwitted and made me go "Gahhhhhhh" show wasted!
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  8. Its gone!!!!!!!!!!!!!!!!!!!!! I am now an EX Esprit owner again....and properly sad. The new owner Keith is a nice guy and I have pointed him this way so if you see "my car" pop up again he has promised to look after it.
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