Heat from below

[rossbell]

There seems to be an unusual heat coming from under the body of the car. I've read elsewhere (Yahoo) that this could be related to brake problems. Norrie's also posted a reply on this in some personal comms, which he'll post here too.

[noz]

Hi Ross,

Yep, if the heat is coming from the front wheels area it's most likely binding brakes.

The most common cause is the linkage between the pedal and the master cylinder. The right hand drive cars didn't have enough room to mount the master cylinder(brake valve) behind the pedal so they mounted it up top under the scuttle panel at the bottom of the windscreen. Unfortunately the joints in the linkage are open to the elements and rust/sieze over time.

It's very easy to check. Just remove the scuttle to expose the brake valve and linkage next to the wiper motor. With the brake pedal released, pull the linkage up. If there's more than 5mmm movement it means that the return spring pressure isn't enough to overcome the friction caused buy the corrosion.

If so, undo the bolt through the top linkage union and withdraw. Sandpaper and grease all the components and reassemble. The joint should be free and the return spring should permit enough travel to fully release the brake valve.

Sometimes the stickyness is so slight that you don't notice. The only sign may be premature wear of pads and discs. If it get's worse it'll eventually fry the grease in the wheel bearings and they'll fail too. All in all a very expensive exercise.

Of course if the brakes are dragging it won't do much for the old fuel consumption figures.

Take a tip and check this today. It costs nothing, it's very easy to do and could save you a fortune in the long run.

happy motoring

cheers

noz

[rossbell]

Hi Noz

Finally getting around to looking at the brakes as discussed.

How does one remove the scuttle?

Also, my ABS light now lights constantly - could the heat and the ABS problem be related?

[noz]

Ross,

The screws which hold the scuttle on are hidden beneath the odd shaped bits of plastic at the bottom corners of the screen. Just push them down the way and unhook the bottom first then unhinge the top fixings. Sometimes you have to be a bit brutal with them. Once off the fixing screws are obvious.

The ABS light may have something to do with it but only if the dragging brakes has generated enough heat to cook the caliper and hence the ABS Sensor.

I can give you the wiring diagram for the ECU with the pinouts. By putting a resistance meter across each of the terminal pairs in turn you can check out all the sensors. They should read approx 1000 OHM's each.

Cheers

noz

[rossbell]

Hi Noz

That would be great. Could you email it? Or have you already posted it on the Yahoo XM site (which I'm signed up for too).

If email send to my junk email ross_bell at hotmail dot com

Cheers
Ross

This post has been edited by rossbell on May 20, 2004 06:19 am

[noz]

Ross,

As usual nothing is ever simple. There seems to be two possible ECU manufacturers and some variants of each.

Can you identify the ECU? Is it Teves or Bendix? Are there any markings on the box saying what the model number is?

I have what looks like most of the wiring diagrams but hey are in .pdf/.jpg format and are about 300KB for each A4 sheet. There are too many to send you them all by e-mail. If we can narrow it down I'll send the appropriate diagrams.

Cheers

noz

[rossbell]

Hi Noz

Just to prove how much of a Citroen novice I am: I don't even know where the ECU is, or how to do fault tests, etc.

[noz]

HI Ross,

Sorry, I've forgotten which model you have. On my 2.5 TD there's a black plastic box on the inner wing on the off-side. It's approx 200 mm in every direction. It contains 3 ECU's - 1 for the engine, 1 for the Suspension and 1 for the ABS.

You need to find them and look for manufacturers labels and/or model numbers. They should all have a label.

Let me know how you get on.

Cheers

noz

[rossbell]

Hi Noz

1993 2.0 turbo

Does this make sense? I fiddled around with the brake stuff as outlined above. The ABS warning light remained lit, but now, a few days later that warning light does not remain on. Does the car re-set itself or something, and if so, does that take some time?