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Tag Brake Dragging
On my last trip to Oregon coast, left overnight campsite heading to US border had only driven a couple of miles when the TPMS went into alarm, Pass Tag tire, pressure was normal but temp was very high, pulled off road and the passenger Tag brake was very hot, blocked the coach and jacked tag up, sure enough could not turn the wheel, a very light tap on the actuator arm at the clevis pin freed the brake immediately, repeated park and service brake applications with the wheel jacked up could not get the brake to stick again, so continued to Pacific shores without incident, once there i decided to cage that brake to avoid possible further issues.
Today removed the caliper and stripped it, pictures are what i found,was a bit of a mess with the old grease, no wear or unusual areas that could cause it to hang up, the grease nipple next to the bleed/vent screw had been broken off some time in its past, so i do not know when the shaft had last been greased by previous owner.
From the condition of old grease internally , i can only assume that it was causing the shaft and Helix on the power shaft to hang up,
Caliper return spring is in good condition.
Operating the brake lever by hand felt normal with little resistance to return to fully off position, but the fact that it started dragging after an overnight stop makes me think that the additional pressure applied by park brake operation may have caused the sticking.
I replaced the Tag Brake Chambers at the beginning of the year as routine maintenance, items along with the flexible hoses,R12 & R14 relay valves and Air Dryer, brakes all have approx 1.5 inches of travel
Tomorrow i will reassemble with new grease and anti sieze,
Doesanybody have any other thoughts that i should check whilst reassembling ?
Thanks
Gordon
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3 Replies
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Caliper slide pins and their bushings?
The slide pin Meritor part# is: KIT15013
These kits normally sell for more than $200 each, but there are 3 new kits on ebay right now for $80 eachThe bushings are not included.
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Gordon, good catch. You likely saved the bus.
Tom and I preach about the issues associated with overgreasing that style of brake because the end result is often a brake hung up. Tom actually had that experience from someone over greasing his.
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Don
The pins came out ok, not loose and not over tight, i have checked the fit of the pin in the support housing and its good, also not too tight where the caliper slides on it, thanks for the advice. I will take my time on re assembly and give everything a good look over.
Jon
I was reading up on the over greasing issue and will make sure that does not contribute to my problem, Thanks
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