Went for a COF last week. Apart from a tire I also had a little bit of freeplay on my king pin on the right hand side. So the front brakes go on the brake roller tester with no problem, but testing person notes down front brakes need to be retested. So get new king pin fitted over 1/ 1/2 days and take it back. This time king pin is all good(no play) go to retest front brakes, but lacked substantial balance on right side only. Went back to the mechanic and one of them told me they had the same problem the other week, but the other truck went back a few days later and passed apparently. The front brakes are disc, they have been replaced once and have no problems with front brakes in the last seven years. Has anyone else had this!
skull,
Mar 2, 5:51pm
What year Kenworth is it! 2006!
philltauranga,
Mar 2, 6:47pm
Grease on disks and pads from hands when kingpin being done! maby thats why they passed the other guys truck a few days later on the other one they fluked up, after it burnt off! or they may have not being bleed properley if they were dissasembled. When doing ballance fail on drum shoes in the past I just take to the shoe with the disk sander on the grinder and take the "glaze" off the shoe, put it on run it up till hot on way to tester,its smoking when I get to VTNZ and drifting into the workshop haha. PASS.
legacy1992,
Mar 2, 6:54pm
The left brake is fine, so there should be any air in the lines. It's a hydraulic brake. But I'm thinking there is a reason why the brakes need to be re tested after something is taken off around the brake. It's a pain in the arse thou.
philltauranga,
Mar 2, 6:58pm
Air could be trapped around caliper area on right side only. I would say most likley it wasnt degreased after the work being done tho.
v8power,
Mar 3, 5:17am
The COF tester is just covering basis. Generally it is "at the time of inspection" meaning if your brakes have already passed there should be no retest for the brakes after replacing the kingpin. BUT, the COF tester knows the brakes are pulled apart to do the job so might have written a brake retest down for yours and his piece of mind.
If brakes were fine prior to the kingpin replacement I would bleed again, as stated before, air can get trapped in the caliper. Thats why I prefer pressure bleeding over vacuum bleeding. After that take for a good drive as mentioned too remove any contaminants left on brake components and all should be fine.
mrfxit,
Mar 3, 6:19am
Std practice for pre brake test is to give the brakes HELL on the way to the COF/WOF to get them up to working temperature after sitting overnight.
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