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Frequently asked questions 

 

Q. My Peugeot has just failed the ITV with a CO reading between 0.64 and 0.67 but passed on the lambda readings. Does it sound like the CAT needs replacing?

A. If all the other emission readings are within specifications then I would say that the cat needs replacing.

Q. I have a 2003 model Peugeot 307 SW 1.6 petrol and the brake fluid needs changing but I am looking to do the job myself. Can you give me any pointers?

A. It is a two person job as you will need to get an assistant to pump the brake pedal whilst you bleed the brakes one at a time. You will need a suitable ring spanner to release the bleed valves and a length of approx. 8mm transparent plastic pipe. It makes sense to have all 4 wheels off the ground if possible, then unless you know all is good with the brakes it’s the ideal opportunity to strip, clean and lubricate all the brakes and to push each piston all the way home (with bleed valve open preferably) and pump them back before you start the bleeding process. Using a length of clear pipe syphon as much old fluid as possible out of the master cylinder, then top up with fresh fluid and top it up again after each wheel is bled. Generally you start at the furthest wheel from the master cylinder. Fit a length of clear hose to the bleed valve and feed the open end into an old jar then crack open the bleed valve, get your assistant to pump the brakes full strokes at a reasonable pace, after each down stroke you can if you wish close the bleed valve for the duration of the up stroke, keep going until you see the new fluid flowing through then close the bleed valve whilst the pedal is down. Top up the fluid and repeat for the rest of the valves and then really put some pressure on the pedal to check for any leaks.

Q. I have a Qashqai with manual air con that is not working. I’m pretty sure the compressor clutch isn’t engaging and I have checked the relay fuse. I suspect therefore that there might be low refrigerant pressure that is preventing the clutch activating. To test this (momentarily) I was thinking of shorting out the low pressure switch. The sensor connector appears to have three pins, so which two do I short?

A. Modern pressure switches are not on/off contact devices. They produce a variable voltage according to the pressure in the system, so do not short out the switch or you could cause further damage. You really need to get the gas pressure system tested, as no gas means no a/c. There are no particular common faults, but the basics need to be checked first.

Please email your questions to graham@motorworldtenerife.com