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Brake Calipers
Been reading up on the problems associated with over-greasing of brake calipers and thought i would pass on what happened with mine.
After purchasing the coach i did a few trips without issue, probably in excess of two thousand miles, then after an overnight stop within 5 miles of setting off my TPMS on the kerb side tag tire went into alarm on high temp which turned out to be the Tag Brake dragging, I caged that brake and continued with my trip.
This winter i have removed / cleaned and rebuilt all 4 disc calipers, the attached pics show the quantity and condition of the grease in the calipers.
My calipers did not have grease nipples installed, just 2 blanking plugs and the breather vent fitting, so over the years somebody must have been installing and removing grease nipples to lube the calipers ? or the grease as pictured had been in there for years ?
Meritor call for a grease of NLGI grade 1 or better for caliper lubrication, this is not what was found in my calipers
All calipers removed and cleaned looked the same when opened but only 1 had dragged, which i find surprising looking at the quantity and condition of grease removed
Due to the extended grease interval and minimum movement of travel in operation of these parts i am trying a different method of lubrication, upon reassembly i coated all moving parts with a high temp anti- sieze compound, the caliper operation was extremely free and returned to the off position without any external force, this was not the case prior to cleaning.
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10 Replies
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Good job. I’ve never taken a Meritor caliper apart. Does someone make a rebuild kit?
Here is how I grease my calipers.
a) remove the poppet fitting
b) pump Meritor pt# A1779W283, which is NLGI#1 grease into the 2 grease fittings until fresh grease comes out the poppet fitting hole.
c) release the pawl on the slack adjuster and adjust or loosen it(lengthen stroke) fully which is about 4 or 5 360 turns of the adjuster. This will force excess grease out of the poppet fitting hole.
d) reinstall the poppet valve/fitting
e) re tighten(shorten stroke) of slack adjuster fully until pads are clamping the rotor, then release the pawl again and loosen/release(lengthen) stroke 1/2 to 3/4 turn. DONE -
I have never had an issue with overgreasing, but my procedure has been simple.
I squeeze the trigger on my air operated grease gun and when I hear the pump pulse once, I am done greasing.
I’m lazy and getting lazier and I want to avoid making work for myself so to protect my moving parts but not create work I only assure myself the part I am lubricating has the bare minimum of grease. So far, so good, no locked calipers, no split dust boots, no need to take stuff apart to clean up a mess I created for myself.
“Professional” grease jockeys will not listen to any advice about over greasing.
BTW, on edit it should be noted each fitting on my bus gets is required shot(s) of grease every 5000 miles so I am meeting or exceeding the Prevost schedule.
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Don
Dust seals and shaft grease seals are available from Meritor, i made up a spring compressor that’s needed to compress the return spring, not a very difficult job to strip and clean.
Gordon
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After talking to Gordon from Canada and looking at his pictures I decided to do the same as Gordon. Yesterday I pulled off the passenger tag caliper and took it apart, to my amazement the grease looked great it was clean and were loose and everything looked really good, the seals were a little hard and 0-rings a little flat so I started to put it back together and I decided to freshen it up while it was out, I found a minor rebuild kit, Meritor part #15001 so I ordered it. The kit is pretty complete springs-seals-piston boot-lots more. be here this weekend.
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1st one done right tag caliper rebuilt seals-piston boot-return spring- 0-rings- greased adjusted
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Got another ADB 1560 caliper rebuilt with the KIT 15001 basic rebuild kit all cleaned out new seals-piston boot-return spring- 0-rings-retainers new clay base Meritor grease, just waiting for pads for tags
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Owners that have others lube their coaches should make the grease monkey aware of the procedure for lubing the two grease fittings shown in the bottom photo Art posted.
The grease fittings keep the rotating shaft free to turn. But if they are overgreased trouble begins. On my previous coach with the Meritor brakes I gave each a single shot. I barely pulled the trigger on the gun, and in 250,000 miles never had an issue.
Overgreasing those fittings has the potential to inhibit the full release of the calipers and the result can be a dragging and overheated brake.
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Yes Jon now that I’ve taking the calipers apart I can see why If you pumped a bunch of grease in without purging the excess out, your going to have a problem, The 1st grease fitting to power shaft closest to slack adjuster it lubes power shaft and the big gear (power shaft nut) 2nd grease fitting by green piston boot it fills up behind piston bore , if you don’t purge out extra it will not return. It’s pretty easy to do it correct just follow the instructions . Using the Meritor clay base grease # A1779W283 it is very slick and it operates very smooth. I can see you would not have to grease it very often.
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
We never think of the importance of proper greasing techniques. We turn our cars and bus over to the lowest paid guy on the totem pole, and because he doesn’t know better every grease fitting is pumped full of grease until it comes out somewhere. After all, how do you know grease went into the fitting if you cannot see it come out somewhere else???????
But the problems from that practice range from ripped or torn rubber dust covers from being over inflated with grease, to a fire that will destroy a bus because a dragging brake, locked due to a hydraulic lock can and will start a fire as the brake disc gets so hot it is cherry red.
Our coaches need grease, but only very little at each point to provide lubricant between the moving parts. Any grease in excess of that is unnecessary.
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Well with what’s going in the world I’ve been doing projects around the house and on the bus, last couple of days I pulled front wheels off and then calipers off and rebuilt the ADB 1560 calipers I ordered new Disk Pads so front hopefully will be good. After rebuilding 4 calipers now I understand how they work, with the new piston seals and return spring on the bench you turn power shaft and it pops right off much better. while I wait for pads i think I will do some cleaning on front suspension , that’s being bored .
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