Citroen XM Forum

Ever since I've had the Cobalt car the front brakes have bound slightly. First time I looked at them both pads with pips on were fitted to one caliper, so I moved them to the correct positions, stripped the calipers down, including popping the pistons out, checked the handbrake mechanism, etc and things were better...but not right. Coming to a stop the brakes would hold for a second before fully releasing.

I've also noticed a bit of grabbing causing the front to brake before the rear and cause the rear to lift.

Today I fitted new Bendix pads, checked all the mechanism, loosened the parking brake cable by 1/2 turn (not that is was too tight), fitted new flexi hoses, bled all the brakes, checked the doseur linkage has free play and the bell crank is free and now everything is perfect.

Obviously not hearing a creak when the wheels just rotated on a slight incline is satisfying, but also the ride quality has improved.

I'm not actually sure what the final fix is, but am pleased it's sorted.

Last night I tried fitting LED dashboard lamps to the clock unit, but didn't like the high output, then finding they weren't dimming when the lights were switched on made me abandon that idea. It is filament lamps for me.

Since I've had the car, the plip hasn't worked, probably due to the receiver getting water in it...from the leaking sunroof..., so I obtained a replacement plip and receiver, but needed to sort a key blade.
Today I have received a key blade, made adjustments to it to get it to fit and fitted it to the key housing using the proper fitting kit. I now have a working plip with brand new blade.

Sometimes, the little things matter.

I ordered the fitting kit and gearbox plugs by number from a Peugeot dealer who sent them through to the local branch for me to collect.

Been looking at the possibililty of replacing the tungsten lamps on some of the dash displays with LEDs - particularly thr r.h. clock/temp/comp unit, which is illuminated all the time, and runs hot because of that.

Unlike switches, which are either on off, the displays and (radio) have to dim . . . and LEDs just don't respond in exactly the same and matching way as tungstens in this respect. I can think of slightly complicated ways of doing it - eg a voltage controlled PWM circuit, whereby a varying input voltage would modulate an output to the LEDs (and possibly only one of these for all the units) - but maybe someone has a smarter idea.

To be honest, it's hardly a priority - most of our display lamps have done almost 20yrs and 100k mi - but I would like to get rid of the heat behind the RH display, before it damages anything.

White Exec wrote:
To be honest, it's hardly a priority - most of our display lamps have done almost 20yrs and 100k mi - but I would like to get rid of the heat behind the RH display, before it damages anything.

It has gone nearly 20 years without damaging anything, why should it now?

You're right, of course.
TBH, it's only that it runs so flaming hot!

In fact, the display doesn't have to be continuously dimmable; just needs to operate at two levels of brightness. Have already thought of a simple way to do this, using one extra relay.

Would be nice if I had a spare display to play with, even a shot one, so long as the illumination works....anything unwanted lying around?

Maybe a CAT4004 driver? Six dim levels only, first level being 50%. Some additional circuitry would be needed to switch it to dim when the feed drops and reset otherwise.

Strange that nobody builds a straight automotive LED driver with just two levels or with direct voltage control. There would be a market.

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Hi Gabor,

Thanks for the CAT2004 lead. Also looked at a couple of other similar LED drivers, but component count looked a bit high.

This is what I brewed up earlier.
Just involves one miniature relay, LEDs, and not much else:

My odd thoughts.
LED's in parallel require selection for common properties to avoid brightness variations.
A 1 volt car battery voltage drop could be enough to switch the LED's out.
Altenator regulator failure could blow all the installed LED's.

John

Think you're being a bit over-cautious on this.

3 commercially identical LEDs operating in parallel, with their own Individual resistances are commonplace.
R1s could be individually selected, if anyone could be bothered.
The LEDs would also be behind the diffused LCD screen, and not directly visible, just like the OE tungsten lamps.
1v battery drop would not be critical; car is full of OE LEDs which do not drop out.
Similar situation with "alterrnator regulator failure".

Again, if anyone was that fussy, additional components could be added, e.g. voltage regulator, protection diode for relay coil, ...

Chris

Chris, you must have seen this already because it comes up quite at the top on Google. Too many components and the 10:1 brightness ratio seems to be off the mark but the idea itself is nice.

http://www.linear.com/docs/26508" onclick="window.open(this.href);return false;

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