Kia Picanto's

Customer arrived this morning complaining of brake bind. You could not push the car with brakes off. Each wheel temperature was elevated and could be smelt of brake fade. The front brake pads were recently renewed. A visual inspection today shows that the drivers side front and passengers side rear pads are worn to the limit. The nearside and offside front and rear pads are worn but not as bad. All wheels felt like they were binding when rotated by hand. 

I put the scanner on and no fault codes. I tested the ABS unit pump and that works. I tested the front and rear ABS input/output solenoid valves and must admit the scanner function does not make it clear how you are supposed to know for sure if one if faulty. I did a comparison test across the front brakes and both seem to function the same, i.e. a clicking noise from the ABS unit can be heard when I activate the control unit. The rear solenoids don't seem to make a noise when activated.

I tried to bleed the hydraulic system and the nearside front brake bleeds okay. The offside front brake does not expel any brake fluid at all.

I did not try to bleed the rear brakes once I realised I could not loosen the brake bleed valves without causing damage. My primary concern is the offside front brake and nearside rear brake. Given that no brake fluid is expelled from the offside front brake, I don't think any would be expelled from the nearside rear brake either!

I loosend the hydraulic pipes at the master cylinder one at a time and got the boss to depress the foot brake on/off repeatedly. 

The front chamber of the master cylinder I suspect to be controlling the nearside front and offside rear brakes. The rear chamber of the master cylinder I think controls the nearside rear and offside front brake.

The master cylinder front chamber appears to spirt brake fluid out each time the foot brake is operated on/off repeatedly.

The master cylinder rear chamber appears to spit occassionally brake fluid out but not for long.

Its not an accurate test I know, but given I'd need hydraulic gauges to test the proper working pressures its the best I can do at the moment. 

My boss told me to connect the mitivac pump to the brake master cylinder and test it with that??

I do have a hydraulics test kit at home but am not sure about the connections/threads as when I bought it many years ago I did not realise it came front America, where they do not use the same types of threads as us. I do remember having some dies made for it but never used it. I'll see if I can find it tonight for experiments tomorrow.

has anyone seen this problem on Kias. I would not like to blame the master cylinder only to find that the ABS pump unit is the true cause?