brake pump thingy = Dashboard lights problem!

[lisalotus]

okay guys we,ve recently upgraded the front brakes to brembo,s, all went well. brakes were obviously bled, had trouble bleeding all air out of system, but eventually brakes went hard. Okay with me so far, started engine, pump accumulator thingy that charges the system wirred for approx 40 secs which I believe its supposed to do, then switches off okay. My question is, is it supposed to keep coming on when you pump the brakes, cos it is, I,ve never notice it before but to be honest I,ve usually got music blarring out all the time so may just not of noticed it, also the dash board lights go out after about 5 mins every time I go out in it at night, been like that forever, but of all the bizzare things they come on momentarily now when pump thingy is wirring

Any body any ideas???????????????

[Jonathan]

When you pump the brakes you de-pressureise the accumulator so the pump energises. With ABS you don't need / shouldn't pump the brakes. I found with my Esprits is the pump tends to run up briefly on start and then become quiet.

Bleeding should have been straight forward as the setup is nice and easy (unlike say the Elise system where the calipers have a natural air lock in them !). Makes me wonder if there is a slight problem somewhere.

Fully depressurise the system by pumping the brakes with the engine off for about 40 movements (as described on the reservoir lid) - open the reservoir and ensure both levels are correct (the details of which should be in the user manual). Leave the oil to settle - yes it is normal for the oil to look like a latte coffee head

When oil has settled crack the bleed nipple on the caliper and bleed some out of the system by pressing the brake in, use sharp rappid pumping and then smooth out once the oil is coming out with no air bubbles in it - on the last pump hold the pedal down and the person on the caliper needs to nip the nipple up again - the pedal should be pretty firm. Repeat on other side. Worth bleeding the system again imo.

Refill to correct levels on the reservoir - replace lid and turn the ignition on.

Should whir a bit, 10 secs is normal.

Did you fully replace the fluid or just top it up ?

Might be worth treating it with some new fluid if it hasn't been done for a while - a total system drain and re-fill (as opposed to a flush) might yield results.

[lisalotus]

Hi Jonathan

Thanks for reply. Yeh we,ve pretty much done all that you advise, as in totally drained system, replaced all fluid.

So is it normal for it to repressurize itself when the brakes are pumped????????????????, and have you any ideas why the dash board lights which dont work 90% of the time do work when pump is repressurizing, I mean to me it just doesn,t make sense, but then there,s many quiky things about my car that doesn,t make sense, I mean it is a lotus after all

[Jonathan]

Once you've bled, refilled and finished with the braking system you shouldn't need to pump the brakes at all....infact some manufacturers of ABS specify they should not be pumped.

The action of pumping de-pressurises the system and the accumulator the whirring is the pump motor re-pressurising the circuit. With the ignition on you might get the odd 1-2 secs of Whirr if you pump the brakes rapidly but no more than that. So yes it is normal for it to re-pressureise after pumping (not that you should be !).

Which lights are coming on ?

The amber ABS light is a little bit of a dark art, the ABS controller has it's own logic like the ECU so in order to interpret the ABS warning light you need to get it plugged in. The light can stay on solid or flash as well. As far as I know this simply idicates the styate of the ABS, flashing means you have ABS function but there is something you need to look at, solid (like mine) means the ABS function is disable for some reason.

The red brake tell tale dashboard light comes on when the system is below 1800 psi which is saying to you you're running low on fluid pressure to the calipers, the pump should cut in then and raise the pressure back to the required level.

Have you road tested the car yet ?

Does the car fade (ie get softer progressivly) or do you get pedal fluctuations ?

Wouldn't hurt to get the thing looked over and check any fault codes on the ABS controller, if you book it in tell them they need to have the equipment to look at these codes becuase only then might they spot potential problems.

Hard to tell at a distance - always said tyres and brakes are 2 things you must get 100% right.

[lisalotus]

Hi jonathan

Its the dashboard background illumination lights that arent, working right, the ones that come on when you have the headlights on.

Okay I understand that I should not pump the brakes, I,ve kinda got into the habit, cos its the only way to slow car down, also abs doesn,t work either, light on constantly.

Thanks for all Your help

A friend of mine is going to take a look at it tommorrow for me, I,ve got to go to Norfolk in it, in a couple of weeks, dont fancy going all that way with dodgy brakes.

[DanR]

Check your fader connections. One or more could be fraying or broken and making intermittent contact. Its a low voltage system. I'd suggest you re-solder all three of them. Then blob the connections with a hot glue gun so they're less likely to break again. Make sure the fader is firmly re-fitted.

[Jonathan]

Lisa !! You shouldn't be driving it with dodgy brakes !!

On a serious note probably the reason why you're having to pump them is to keep the pressure there - it would suggest there is a leak or malfunction in the ABS, the light being a good indication but if you're having to pump then the pedal pressure is not getting to the calipers (or it is dispersing under load).

Personally I would look for leaks / fractures around all the pipe joins (rigid and flexible) as well as around the caliper pistons (behind the pads) and fittings. If the calipers have been split at some point in their life this can cause them to leak as well - look for oil on the seem inbetween the 2 halves.

See if you can get it to a specialist asap - if anything just to look at the ABS fault code (they need to have a reader) because this will probably go a long way to solving the issue. From all you have said the system is losing pressure what with the pump running and the fact you're having to depress the pedal repeatedly to maintain braking.

On the dash lights - could be a manner of things, best to get a sparky look at it.

Be careful with driving it - if it's that bad don't take the chance !

[fmxa]

Lisa,

You may want to check http://lotusespritworld.com/EMaintenance/BleedingBrakes.html pretty good article on bleeding the brakes etc

[DBredS4]

Hi Lisa, I had a problem with dash lights, in fact with all lights I just noticed the dash ones fail. Basically they would blink like a connection was faulty and go out. Not confidence building when the only person who knows you aint got any lights on a lit motorway is YOU !!!!

I would twiddle with the switch and they would come on again only to go out when I was least expecting them to

Anyway, it turned out to be the light switch. It was so filled with grease from new that the connection it was making wasn't perfect. I removed the dashboard cover, an art in itself, and whipped the switch out, dismantled it, removed the almighty GOB of grease, rebuilt it and fitted it. Never had a problem since.

I have been using the new found grease for all sorts, lubricating the anchor chain on my yacht, doing the bearings on my Chieftan Tank, regulating the oil prices with OPEC etc etc... couldn't believe they put so much in.

Hope it helps

db

[lisalotus]

Hi every one

Thanks for all your help and advise.

Right Danny, with reference to your advise, there is no power at all getting to the fader so the problem is further back, there is a relay box thingy (sorry for terminology) that is getting power but no power is coming out, so I,m presumming that it is buggered

Jonathan when I say I pump the brakes, I dont mean I,m having to, its just the way I drive, kevins just said that I,m a dumb blonde trying to do the job of the abs , think I better retake my driving test . Friend who lives up the road and just happens to have rebuilt v8, so knows a thing or two, thinks that the reason brakes dont feel any different having just spent

[Jonathan]

Ahhh so it's you thats pumping the brakes on purpose then

I would suggest you probably need to stop doing that, lol, and yes if you're bedding in the pads wont bite as good until they have done a few miles. When bedding in I just drove my cars normally but use the brake ahead of usual and used it to cost up to the stop, that way the pad gently sweeps the disk over a longer period....also if you can don't allow them to bite all the way to the stop....lift off at about 10mph before the stop and then re-apply as this gives the pad chance to flick off the brake dust thats building up.

I also reakon the rheostat (fader) is on the negative -ve side of the illumination bulbs so unless they are on you will not see any power there anyways (car wiring is usually arse about face, everything is on the negative).

From the circuit drawing here does the clock work ?

Also check fuse 6 (5 amp) which actually feeds the rheostat module

TBH I'd opt to just bypass the thing (how often do you use the fader anyways ?)

The black yellow wire on the rheostat module pin 8 is the negative, if you ground this (pin 5 the black wire next to it) with the ignition on the lights should come on full brightness....make sure all your fuses are in 1st

[lisalotus]

TBH I'd opt to just bypass the thing (how often do you use the fader anyways ?)

The black yellow wire on the rheostat module pin 8 is the negative, if you ground this (pin 5 the black wire next to it) with the ignition on the lights should come on full brightness....make sure all your fuses are in 1st

Hi Jonathan

Are you sure pin 8 is neg, cos when we bulb test it to the chassis, its reading as positive .?????????????????

Yes the clock does work

Thanks again for all your help, I owe you a drink

[Jonathan]

Need to check the wiring colour.

TBH I've dpone a few wiring tricks on my car and found that the people who built it got more than a bit confused with the wiring diagram, wire colours and pin numbers

Pin 8 should be yellow / black and the -ve side of the bulbs....thats what the drawing says however it's been known to be wrong !

If the clock works then there should be live on the bulbs for the illumination cus this is paralleled to the live supply (red/orange - pin 6). Pin6 has a red/white wire coming out of it as well - this is the live supply wire to the bulbs. The other half as I say is the Black/yellow wire.

Of the lights are switched on but the bulbs don't work then this black/yellow wire will be +ve in comparison to ground which is probably what the bulb test you're doing is pointing out - try switching the side lights on and putting that bulb from pin8 to ground....do the dash lights come on (all be it dim) if so thats the one.

From the black/yellow wire I reakon (cant tell from the drawing) it goes onto the wiper of the rheostat and then back out from there to neutral - therefore the rheostat controls the current in the negative 1/2 of the circuit.

The rheostat colours are:

Grey = wiper

Yellow = positive

Blue = negative

You could try linking the grey to either the yellow or blue....one will give you no lights the other will give you bright lights....

Finally Pin 5 is the neutral (black).

Thats about as much as I can help really - without seeing the car I wouldn't wanna tell you to do something that could be dangerous given that the cct drawings are not always correct ! You wouldn't wanna know what they've called the clock on my drawing !!! If you're unsure leave it be and sort it at a later date.

If you're handy with electrics the best thing to do is to get a piece of wire and cut it in 2 - put a 3-5 amp car fuse in line with the wire and use that to test your grounds & lives - that way if you go directly from live to ground the fuse will blow and save you a potential fire hazard, you do have to be very careful.

Incidently does the clock light work ?

[s4simon]

Think you're gonna have to start up one of those premium rate number thingys Jonathan - You'd make a killing.

0906-ASKJON

[lisalotus]

Hi Jonathan

Are you sure pin 8 is neg, cos when we bulb test it to the chassis, its reading as positive .?????????????????

Yes the clock does work

Thanks again for all your help, I owe you a drink

<{POST_SNAPBACK}>

Hi Jonathan

Done what you suggested with pin 8, we,ve linked pin 8 with pin 5 , and we now have dashboard lights , so hopefully that,ll be the end of it, jesus I,ve got a headache

Thanks again for all your help

[Jonathan]

and we now have dashboard lights

<{POST_SNAPBACK}>

Wahooo !

Nice 1 !

Simon - thats not a bad idea actually B)

[ragingfool35]

did you replace the rheostat module in the front relay box that controls the instrument panel lights?

[lisalotus]

"and we now have dashboard lights"

no we dont, we did have, but after about 1 min they go out again

I give up, going out to buy miners lamp

[Jonathan]

Check that earth and the fuse.

It might need some resistance from the rheostat which was bypassed (unlikely but this is a Lotus).

Should have + battery voltage on Pin 6 (red / orange wire)

Could be a lose connection somewhere.

If you have a multi meter there test pin 8/5 to ground (on ohms, should get about 1 ohm) and pin 6 to ground (on volts, should be battery voltage) obviously with the side lights on.

[Guest teigan]

you may have a bad grounding connection period. try wiggling the groundpoint being used; that's where a bar is bolted through the fiberglas into the metal chassis. either vibration loosened the hardware, or contact points are corroded. if that doesn't work, can we get a photo of you wearing just the miner's lamp?

[fflyingdog]

you may have a bad grounding connection period.  try wiggling the groundpoint being used; that's where a bar is bolted through the fiberglas into the metal chassis.  either vibration loosened the hardware, or contact points are corroded.  if that doesn't work, can we get a photo of you wearing just the miner's lamp?

<{POST_SNAPBACK}>

You are such a wag

[DanR]

I'm not very confident with electrics. Not sure but I think the operating voltage for the fader is stepped down from 12v. Consequently you may need to use a meter instead of a 12v test lamp. Maybe with 12v something in the solid state circuitry has burnt out.

Edited December 10, 2005 by DanR1201

[lisalotus]

Thanks for all the advise, I will get to the bottom of this electric problem eventually. Its seems to me that its shorting out when it gets warm, if that makes any sense, because it works fine for about a minute then goes off every time at the same time.

Its a nightmare to work on because you have to sit in the seat upside down with your legs up in the air, head up the backside of the dashboard , theres just no room down there in the footwell. I,m sure who ever designed the electrics was some sadistic, masochistic guy (definatly a guy, woman would have made it much easier to work on, I mean women never complicate things, eh guys??????

We,ll have another go at fixing it at the weekend.

The brakes seem to have resolved themselves, I think they just needed to bed themselves in (bless em), they still feel borderline crap but then they always have, so no change there.

Apparently that accumulator wirry thingy is supposed to come on about every 3 to 5 times of brake depression.

Were not having a very good time with cars at the moment, Kevs ( a shogan) keeps breaking down in the morning on the way to work at exactly the same place. It has a 1 minute rest and then starts no trouble and runs fine all day "how bizzare"

My advise: Maybe it doesn,t like that journey so take another route to work

[hovgaard]

you have to sit in the seat upside down with your legs up in the air, head up the backside of the dashboard

<{POST_SNAPBACK}>

Can we get a picture of that, then?

[Jonathan]

Its a nightmare to work on because you have to sit in the seat upside down with your legs up in the air, head up the backside of the dashboard

<{POST_SNAPBACK}>

AKA the Lotus position

Spent many an hour like that, hurts my arms the most !

The electrical prob seems a bit odd though, if you're at Donny next year I'll gladly have a look at it, although having looked at the cct drawing it's not a complicated system so I'm a bit miffed. Have another look later, I'd be tempted to remove the rheostat incase it has a thermal cut out in it somewhere, shouldn't do and even if it does it shouldn't cut the lights but you never know - if you cut anything be sure to fully insulate the wires propperly !