Brakes, ABS think tank

[Jonathan]

Right, been driving around wth no ABS from day 1. Pedal has always been horrendous in my car, sometimes it can be rock hard, others you can go 1/2 way to the floor before it responds and you can feel the pedal back pressure changing (quite funny sometimes, you can fight it trying to push you back).

ABS pump runs here and there, esp at lights when you apply brakes and come to the stop, doesn't run for much more than 2-3 secs though. Wondering if I have a leaky accumulator or something ?

Fluid, lines, pads and disks are all A1 condition.

Changed the wheelspeed sensor the other day and finally got my ABS back online (not that you really need it atm). Thought this might cure the brakes but no joy.

Before I go into it and perhaps start taking parts off the car, has anoyone come accros this and rectified it - Delco Moraine system btw. I'm sort of considering turning it into a big project and re-doing the hydraulics on the brakes...anyone looked at this / done it ?

Never had a single prob with braking until this evening when the car pulled violently over the the left whilst mildly braking...very scarey, thought the bloody wheel had fallen off !!

Getting there, nearly perfect...

[esprits4de]

Hi,

I changed the accumulator and got rid of the exact same pedal problem. Pushing the brake pedal 4-5 times the pump should re pressurerize, if it does before that ther may be a problem with the acc.

Still I have the tell tale going, waiting to see what happens after the switch will be changed.

[Kato]

This one sounds like it could be a problem with the accumulator.

There is a Checking Procedure to determine if the Accumulator is defective.

It is in Section JF of the Service Notes (Delco Moraine ABS111A)

Also check setting of brake light switch at pedal. If this is not set

correctly it can have influence on brakes.

[Paul93Lotus]

Also check setting of brake light switch at pedal. If this is not set

correctly it can have influence on brakes.

<{POST_SNAPBACK}>

That was what was causing my abs light....only found out because a freind said "Hey...you know your brake lights aren't coming on!"

The switch was sticking...brake lights now come on, and no abs light now. Easy to check.

[Jonathan]

Going in to be sorted asap.

Light fine, ABS actually works nicely - its the back pressure on the pedal that is hugely inconsistant, sometimes it's really hard then the next foot in can go down a few inches....really unsettling when you expect the pedal to be at a certain place and they're not.

[hast2]

Never had a single prob with braking until this evening when the car pulled violently over the the left whilst mildly braking...very scarey, thought the bloody wheel had fallen off !!

I've got the same problem Very scary when pushing on and it decides to do it!!

And THAT abs light just keeps blinking at me, every day

Have reconned the rear calipers, the slides were sticking.

The fronts have been checked for being free.

All the brakes seem to work evenly when jacked up and very light pedal pressure applied.

When the accumulator was checked it appeared to be low in pressure, so fitted a new one.

Now my troubles are worse

It was ok for about 50 miles of gentle driving then THAT light came on again, 5 miles after that when ever I touch the brakes the red light comes on aswell

Theres no charge in the accumulator and the pump runs everytime you press the pedal, not good when driving because of the 1/4 sec delay in getting the power assist. Trying not to use the car so I don't burn out my pump.

Think I may have some sort of leak within the master cylinder but there expensive and i'm fed up throwing money at this system that seams to be nothing but bother.

Has anyone ever fitted a bias peddal box, I run one in my rally car and would like to know if anybody does a kit for the esprit?

Sorry for the long post and thanks in advance for any help

Gary

[Malc Holmes]

Hope its not so serious but if it comes to a re-build then I have a complete Kelsey Hayes setup available from a V8. ABS modulator, with control unit in near new condition, complete with the six pipes, Brake master and servo in good used condition (from an '98 V8 car). I am away for a week from tomorrow, but let me know if anyone is interested.

[fflyingdog]

I've got the same problem Very scary when pushing on and it decides to do it!!

And THAT abs light just keeps blinking at me, every day

Have reconned the rear calipers, the slides were sticking.

The fronts have been checked for being free.

All the brakes seem to work evenly when jacked up and very light pedal pressure applied.

When the accumulator was checked it appeared to be low in pressure, so fitted a new one.

Now my troubles are worse

It was ok for about 50 miles of gentle driving then THAT light came on again, 5 miles after that when ever I touch the brakes the red light comes on aswell

Theres no charge in the accumulator and the pump runs everytime you press the pedal, not good when driving because of the 1/4 sec delay in getting the power assist. Trying not to use the car so I don't burn out my pump.

Think I may have some sort of leak within the master cylinder but there expensive and i'm fed up throwing money at this system that seams to be nothing but bother.

Has anyone ever fitted a bias peddal box, I run one in my rally car and would like to know if anybody does a kit for the esprit?

Sorry for the long post and thanks in advance for any help

Gary

Hi Gary

Have you changed your pressure switch yet? Pound to a dollar its that.

Nick S4s

[hast2]

Hi Gary

Have you changed your pressure switch yet? Pound to a dollar its that.

Nick S4s

Gold star to you

When I shorted out the switch the pump runs.

When I went to take out the switch to try and give it a clean up or see If there was any visable fault, I accidently sorted it

The socket I had wouldn't clear the accumulator because the side wall was to thick, but it felt like it would go with a big push.

So I thought i would try and TAP the socket on with a hammer . Not wanting to crack the housing I gave up when it wouldn't go on with a few soft taps.

Later on doing some other work and switched on the ignition and heard the brake pump priming up Result

Now I need to see if it still pulls to the side when braking at speed, before the switch packs in again, which won't belong!!

[fflyingdog]

Gold star to you

When I shorted out the switch the pump runs.

When I went to take out the switch to try and give it a clean up or see If there was any visable fault, I accidently sorted it

The socket I had wouldn't clear the accumulator because the side wall was to thick, but it felt like it would go with a big push.

So I thought i would try and TAP the socket on with a hammer . Not wanting to crack the housing I gave up when it wouldn't go on with a few soft taps.

Later on doing some other work and switched on the ignition and heard the brake pump priming up Result

Now I need to see if it still pulls to the side when braking at speed, before the switch packs in again, which won't belong!!

Glad to be of help ......

Nick S4s

[Riddlemr2]

Mine is doing the same strange pedal feel thing where it feels like the pedal is pushing back at me and the brake pedal feel changes quite often. The ABS light had been blinking as well so the accumulator was replaced. The ABS light no longer illuminates, but the strange pedal feel is still apparent. Is this likely the pressure switch?

I've done some searching, but can't seem to find a picture of the pressure switch...I've looked cover to cover in my service parts list. Can anybody help me out with a picture of the thing? I'm probably staring right at it, but don't know what to look for!

Thanks again!

Edited January 14, 2007 by Riddlemr2

[fflyingdog]

Mine is doing the same strange pedal feel thing where it feels like the pedal is pushing back at me and the brake pedal feel changes quite often. The ABS light had been blinking as well so the accumulator was replaced. The ABS light no longer illuminates, but the strange pedal feel is still apparent. Is this likely the pressure switch?

I've done some searching, but can't seem to find a picture of the pressure switch...I've looked cover to cover in my service parts list. Can anybody help me out with a picture of the thing? I'm probably staring right at it, but don't know what to look for!

Thanks again!

If you have no "abs" lights either flashing or steady then as far as the abs computer is concerned the system is working as it should,having said that it doesnt know how your pedal "feel" is,the pressure switch is on the abs pump assembly bracketry at the front of the car very near to the accumulator that you replaced it will have a plug on it with 2 wires,it doesnt look unlike a oil pressure switch about the same size,and will either be grey or black (the uprated switch is grey),but to answer your question i dont think its the pressure switch that is causing your problem,my brake pedal pushes back at me on my S4s this quite normal by Lotus standards as for the feel changing i cant comment as i havnt suffered this,hope this was of some help.

Nick S4s

Edited January 14, 2007 by fflyingdog

[Riddlemr2]

Nick, thanks for the reply. I found the switch easily once you told me where to look. What I need to do is have another Esprit owner have a drive and see if it feels like theirs. You are not along telling me that the "push back" is normal. Perhaps I just need to get used to it, but it can be a bit strange in traffic as I'm sure I've looked like an idiot trying to come to a stop in traffic I tried unplugging the pressure switch completely and the ABS light came on constantly, but the pedal still felt odd - perhaps normal for a Lotus but very unlike my old MR2 or current daily-driver Acura Integra.

[alan]

Nick, thanks for the reply. I found the switch easily once you told me where to look. What I need to do is have another Esprit owner have a drive and see if it feels like theirs. You are not along telling me that the "push back" is normal. Perhaps I just need to get used to it, but it can be a bit strange in traffic as I'm sure I've looked like an idiot trying to come to a stop in traffic I tried unplugging the pressure switch completely and the ABS light came on constantly, but the pedal still felt odd - perhaps normal for a Lotus but very unlike my old MR2 or current daily-driver Acura Integra.

Hi,

Dont unplug the pressure switch as you will loose power assist to the brakes and once the accumulator discharges you will loose power assist to the brakes!

Read this web page instead - http://www.voicecrystal.com/Esprit/ABS_Disable/ its OK to disable to ABS, but not the pump!

BTW the pedal feel may also be effected slightly by whether you have one of the old or newer pressure switches. These control when the pump recharge the accumulator. There seems to be some confusion about the change in switch, on the Lotus technical bulletin - see http://www.espritfactfile.com/tsb.html#TSB18 it says "To lower system pressure and reduce brake pedal stiction. The new pressure switch, fitted into the pump/accumulator housing, has-been recalibrated in order to lower system pressure, and reduce seal friction in the booster/master cylinder assembly. One effect of this change is to lessen any tendency of the brake pedal to 'stick' and not fully return to its up stop. "

I was also told however by a normally reliable source that one of the reasons for the change was that with the old switch the brake pedal was too low down on some cars which could switch on the brake lights and flatten the battery. The new switch does not let the accumulator discharge as much and has less pedal movement.

HTH

Alan

[doct93]

I've had ongoing problems with my ABS and can only agree with trying a different pressure switch, swapping the accumulator (it's off a jag xj6 if that helps) and above all checking all the plugs on the master cylinder. When the ABS is malfunctioning (as mine was for a long time) the pedal feeling is incredibly variable. Now, with all the plugs attached properly, it feels the same all the time. (and I have a spare pressure switch!)

Tim B

[brucet]

I've had ongoing problems with my ABS and can only agree with trying a different pressure switch, swapping the accumulator (it's off a jag xj6 if that helps) and above all checking all the plugs on the master cylinder. When the ABS is malfunctioning (as mine was for a long time) the pedal feeling is incredibly variable. Now, with all the plugs attached properly, it feels the same all the time. (and I have a spare pressure switch!)

Tim B

Hang on to that spare pressure switch. They're getting to be as rare as hen's teeth! It took me weeks to find one when I needed it last summer. Finally found one at the dealer in Chicago ($171!), but he only had a couple.

The Accumulator is a lot easier to find--gmpartsdirect.com has them for $102 (part # 25528382). Replacing that cured my "spongey" feel in the pedal, and the pump now runs only every fourth or fifth time, instead of every time.

The only trouble with gmpartsdirect is that they only ship here in the US. If you're in Europe, PUK and Ramspott both have the accumulator, but at twice the price.

[esprits4de]

Hang on to that spare pressure switch. They're getting to be as rare as hen's teeth! It took me weeks to find one when I needed it last summer. Finally found one at the dealer in Chicago ($171!), but he only had a couple.

The Accumulator is a lot easier to find--gmpartsdirect.com has them for $102 (part # 25528382). Replacing that cured my "spongey" feel in the pedal, and the pump now runs only every fourth or fifth time, instead of every time.

The only trouble with gmpartsdirect is that they only ship here in the US. If you're in Europe, PUK and Ramspott both have the accumulator, but at twice the price.

Tell me, still looking for one, could you check if they still got one for me ?

[Jonathan]

I've had ongoing problems with my ABS and can only agree with trying a different pressure switch, swapping the accumulator (it's off a jag xj6 if that helps) and above all checking all the plugs on the master cylinder. When the ABS is malfunctioning (as mine was for a long time) the pedal feeling is incredibly variable. Now, with all the plugs attached properly, it feels the same all the time. (and I have a spare pressure switch!)

Tim B

Do you mean the solenoid valves that are fitted in the top of the master cylinder ?

I haven't tried that but tbh it seems like another avenue to try as sometimes (esp after HARD Braking) the pedal is fine and rock solid.

The pump runs ever so and often so unless the pressure switch is up the wrong'un the system is pressurising.

When you say fitted correctly - again how do you mean ?

[Riddlemr2]

Hi,

Dont unplug the pressure switch as you will loose power assist to the brakes and once the accumulator discharges you will loose power assist to the brakes!

Read this web page instead - http://www.voicecrystal.com/Esprit/ABS_Disable/ its OK to disable to ABS, but not the pump!

BTW the pedal feel may also be effected slightly by whether you have one of the old or newer pressure switches. These control when the pump recharge the accumulator. There seems to be some confusion about the change in switch, on the Lotus technical bulletin - see http://www.espritfactfile.com/tsb.html#TSB18 it says "To lower system pressure and reduce brake pedal stiction. The new pressure switch, fitted into the pump/accumulator housing, has-been recalibrated in order to lower system pressure, and reduce seal friction in the booster/master cylinder assembly. One effect of this change is to lessen any tendency of the brake pedal to 'stick' and not fully return to its up stop. "

I was also told however by a normally reliable source that one of the reasons for the change was that with the old switch the brake pedal was too low down on some cars which could switch on the brake lights and flatten the battery. The new switch does not let the accumulator discharge as much and has less pedal movement.

HTH

Alan

Alan, after reading your post, I think I might be on to something. I noticed that my brake pedal actually has a bungee cord (like an elastic band) wrapped around it to keep it in contact with the brake light switch! I think I will pick up a pressure switch soon as even if this is not the cause, it seems like a good idea to get one. Since the accumulator has already been replaced, the only remaining culprit is the switch. Is the GM part number for the switch I have seen on the forum applicable to all Stevens Esprits (including Brembo S4s)?

Tim B mentioned "plugs in the master cylinder." What do these plugs look like?

Also, quick edit...can somebody confirm the GM part number? Thanks!

Edited January 17, 2007 by Riddlemr2

[doct93]

The plugs in the master cylinder?

There are two or three of those funny electrical plugs Lotus use on the inboard side of the master cylinder, under the reservoir as I recall. They have little green locking pins that stop them coming out accidently. Turns out one of mine was unplugged, with the locking pin neatly replaced (ie it hadn't fallen out!). As I hadn't unplugged it, I'm guessing it was a standard Hethel "Friday afternoon" job, just like the passenger demister trunking which I found neatly tied in a knot under the dashboard! Anyway, after much ABS - related harassment, I plugged it back in and all has been perfect for the last 8 months (touch wood).

As to the bungee cord, Lotus did release a service bulletin suggesting an extra spring to return the pedal so the brake lights go off - I found it easier to use an elastic band!

Tim B

[Jonathan]

Yep these are the solenoid valves, there are 3 infact for front left / right and rear.

From reading they have 3 functions, normal, pressure hold and pressure relief, it's possible they could get stuck or something like that.

Another thing to check I suppose but I don't think this is the cause of my prob at least.