Skip to main content ↑ ↓
Topic: Emergency Brakes Dragging (Read 1291 times) previous topic - next topic

Emergency Brakes Dragging

I had my wife back up our motorhome so I could listen to the rear brakes which I had felt dragging. Both brakes squealed loudly. Both air pressure gauges registered normally. We are scheduled for some repairs at MOT next week and I hope to be able to get there.
We have a lot of problems with dirt daubers making their nests in the ports (holes) of the leveling system. We clear these by poking a straight bent paper clip into those ports. I am wondering if that could be a similar solution here and if so where are the ports located?
If this is not the solution what else could be going wrong?
Thanks, Robert


Re: Emergency Brakes Dragging

Reply #1 –
Did you recently have any chassis work done, specifically greasing the chassis? If the brake calipers are not properly purged after greasing, this can cause brake pads to drag.

Re: Emergency Brakes Dragging

Reply #2 –
No, we've owned the coach since 2002 and I have always greased it myself. I never grease the fittings on the brakes.

Re: Emergency Brakes Dragging

Reply #3 –
Quote from: Rob & Di –
No, we've owned the coach since 2000 and I have always greased it myself. I never grease the fittings on the brakes.

When's the last time you pulled the slide pins and cleaned them/checked them for pitting/replaced them if needed?  Do you have the helper springs installed?

A quick forum search for brakes dragging pulled up a couple of references to the slide pins hanging up.

ETA - if your brakes are dragging and you can't get it serviced locally, stop and check temperatures often.  You can do some costly damage if things get too hot.

Re: Emergency Brakes Dragging

Reply #4 –
I will take a guess and point you towards the slide pins also, as Michelle says.  Many posts here re slide pins.
I changed mine last year and they were not giving me problems, but were horribly corroded and would have very soon.
Speedbird 1.

Re: Emergency Brakes Dragging

Reply #5 –
I think I've lucked out. I called MOT this morning and they suggested driving it a little and see what happens. After a short drive it went away except just when the coach comes to a stop. I'm adding to our list for our visit there next week.

Re: Emergency Brakes Dragging

Reply #6 –
I also have a 2001 coach and we just recently had a similar issue.  Keith at MOT looked it over and we pulled all the pins, which were original, 16 years old with 139000 miles on them.  All were pitted so all were replaced with new pins, cleaned up the brakes, all is good now.  Glad I had it done before a serious problem like a brake fire developed.

Keith will make sure you are ready for the road................... ^.^d

Re: Emergency Brakes Dragging

Reply #7 –
I couldn't agree more. Keith has done a lot of work on our coach.

Re: Emergency Brakes Dragging

Reply #8 –
Quote from: Rob & Di –
I think I've lucked out. I called MOT this morning and they suggested driving it a little and see what happens. After a short drive it went away except just when the coach comes to a stop. I'm adding to our list for our visit there next week.
Please post the cause and remedy, it might help someone with the same problem.

Re: Emergency Brakes Dragging

Reply #9 –
We left for MOT on Monday morning (Memorial Day). It started smelling like something was burning and we drove 15 miles to the first spot in the road wide enough to stop at. The smell was coming from the right front wheel. I shot the wheel caliper with my laser thermometer and it indicated 354 degrees. The left caliper measured around 240 degrees. We called Coach-Net but they couldn't find anyone to come until that evening and that mechanic wanted to charge us $698 to come plus $180/hour to work on it. We declined his "generous" offer and waited for a couple of hours for it to cool down. Then we backtracked to a grocery store about 2 miles back. The manager gave us permission to overnight there. After about 5 hours of bemoaning this we decided to return to our cabin, making several temperature measuring stops and then we backed the coach into its carport.
I discussed the problem with the Coach-Net technician and told him that I thought the problem was with a stuck caliper but he insisted that it had to be a wheel bearing. When I called MOT on Tuesday morning the technician agreed that it was a stuck caliper and together we agreed that we could drive the 170 miles there if we carefully monitored the caliper temperature. The temperature varied from about 250 to 270 degrees. We arrived there in about 5 hours.
After jacking, Keith pulled on the wheel and he could not turn it. He had a real hard time getting the slide pins out using a slide hammer, air hammer and a lot of Corrosion-X. They finished the job on both front wheels at 6:15, replacing the pins/bushings and caliper pads. They are doing the back ones tomorrow.
We purchased the coach in 2002 with 13k miles on it. It now has 193k miles on it. The calipers look to be a bit over half worn out and the slide pins look scarred and pitted.

Re: Emergency Brakes Dragging

Reply #10 –
You went way beyond the amount of miles that I would inspect and service the brakes. Our '99 has just over 96,000 mi. at this point. I serviced them earlier this month. All the pins cleaned up an I added the helper springs. I will be checking them every 3 years from now on as we do not put the mileage on that you do.

Re: Emergency Brakes Dragging

Reply #11 –
Quote from: Rob & Di –
We left for MOT on Monday morning (Memorial Day). It started smelling like something was burning and we drove 15 miles to the first spot in the road wide enough to stop at. The smell was coming from the right front wheel. I shot the wheel caliper with my laser thermometer and it indicated 354 degrees. The left caliper measured around 240 degrees.

They finished the job on both front wheels at 6:15, replacing the pins/bushings and caliper pads. They are doing the back ones tomorrow.

We purchased the coach in 2002 with 13k miles on it. It now has 193k miles on it. The calipers look to be a bit over half worn out and the slide pins look scarred and pitted.


With those temperatures, you might want to check the front wheel bearings and at minimum replace the hub lube and Stemco plugs. 

I can't find my maintenance spreadsheet at the moment, but I'm pretty sure brakes/slack adjuster inspection and slide pin inspection/cleaning was every 2 years.

Re: Emergency Brakes Dragging

Reply #12 –
We put most of the miles on the coach some years ago. We drove it to Alaska and to Newfoundland four times each, not to mention numerous shorter trips. Our last long trip was to eastern Pennsylvania in March. When we returned we got caught in a blizzard on the tollway. The road was covered with whatever they used to clear it (salt solution?). The undercarriage and body of the coach and tow vehicle were drenched with this ugly white stuff. When we got home we cleaned everything as best we could. I think that this incident contributed to the problem. Also, as I'm going on 83 the coach is not used as much.
When I parked at the grocery store I stuck my finger into the wheel bearing oil and was surprised that it was only warm. I've always changed it regularly but I'll take care of that when I get home.

Re: Emergency Brakes Dragging

Reply #13 –
If you must drive in an area where salt products are used, use oil to spray into the exposed areas to protect it. Avoid areas where the oil can create problems, brakes, rubber etc......  I have been using oil to protect my cars for years and they look brand new, no rust in Ohio. I do not drive the coach in salt covered roads so I did not need to spray it with oil.

Re: Emergency Brakes Dragging

Reply #14 –
Been debating whether to add to this thread - don't want to "side-track" the discussion.  I decided that my info might help another Forum member if they get stuck in a situation similar to that just experienced by Rob & Di.

Background: a while back, we had some extensive brake work done to all 4 corners of our coach.  A inexperienced tech failed to purge the grease properly from one of the front brakes.  On the way home, our right front brake was dragging - overheated to the point that it was smoking heavily by the time I got stopped on the side of the road.  We wanted to return to the shop, but I was afraid to drive the coach in that condition.  A Forum member suggested a temporary fix, and a friendly truck driver stopped and offered to help me with the same advice.  After he did what was suggested (while I watched), we were able to get back on the road and return to the shop, where the mistake was corrected.

This isn't exactly the same as Rob & Di's problem, because I only had one brake dragging, caused by excessive grease in the caliper.  They apparently had multiple stuck brakes, caused by sticking slide pins.  The solution shown below might not have worked in their situation, and even if it did, would not have been ideal because it disables the brake.  However, it is still good to know, IF it can be safely applied.  Might get you out of a bad spot and back to where help is available.

UP TO YOU to decide if it would be safe to use this EMERGENCY procedure.  Here is my prior post in it's entirity:

Quote from: rsihnhold  -  6 months ago
"You could crawl underneath and manually back the slack adjuster off a bit if needed.  You'll likely need the Meritor Maintenance Manual from Barry's site if you aren't familiar with what to do."

As promised, here is what "the friendly truck driver" did to get me back on the road.  It is exactly what Robert suggested in his post (above).

First, he asked me if I had chocks, because he said it was safer working under the coach with them installed.  Being a well prepared owner, I did, and we put them in place at the rear wheels.

Then he asked for a screw driver and a Crescent wrench, which I was also able to provide.  We both slid under the front of the coach (so I could see what he was doing).  Looking at the brake (photo #1), he pointed out the auto slack adjuster (black greasy object in center of photo #2).  He used the screw driver to lift up on the "pull pawl" (spring-loaded button in photo #3).  Doing this disengages the gear in the slack adjuster, allowing you to adjust it.  Holding up the "pull pawl" with the screw driver (I had to drop the screw driver so I could hold the wrench and my camera), he then turned the square adjuster screw in a clockwise direction with the Crescent wrench (photo #4).  Doing this rotates the upper part of the slack adjuster away from the air chamber, and releases the excess pressure on the brake pads.

THAT'S ALL THERE IS TO IT.  ^.^d

WARNING:  This procedure renders the brake inoperative, so use caution when driving, cuz you'll only have 3 brakes!

The steps for doing this procedure are all contained in the Meritor Maintenance Manual mentioned in Robert's post (above), but they are not specifically listed as a "emergency procedure".  Instead, they are scattered around in various sections.  If you knew nothing about these brakes (pretty much described me before this incident), it might take you a while to figure out this solution.  Being shown what to do makes it simple!  I owe the "friendly truck driver" a big debt of gratitude.

I have since been studying the manual, and I now have a pretty good understanding of how these stoppers work.  The next time I have a "brake emergency", I will be much better prepared.  8)

http://beamalarm.com/foretravel-links/PDF/brakes-maintenance-manual-mm4m.pdf

Re: Emergency Brakes Dragging

Reply #15 –
One other thing - a lesson I learned from my "brake ordeal".  Anytime you have brake work done, no matter what tech does it, and how good the reputation of the shop, be cautious!  When you leave the shop to go home, make several stops along the way at frequent intervals, and check the temp of your wheels and brake components.  Carry a non-contact infrared thermometer for this purpose.  It doesn't have to be a super-expensive model - all you are looking for is a gross deviation in the temperature of one brake or wheel.  If you DO have a problem with your new brakes, take it from me, you would definitely rather catch it sooner than later!

Re: Emergency Brakes Dragging

Reply #16 –
They finished with the brakes yesterday afternoon but we are still parked in their lot. I watched the whole procedure. All of the slide pins were hard to get out but the right front one was the most difficult. This was the only axle where they had to replace the stainless steel slide pin bushings and this was a bear of a job. In addition to the slide pins, another much smaller pin which allows the assembly to flex (my assumption) was frozen and replaced. They suggested we replace the front calipers. They were about 2/3 worn.  The left one which was where the small pin froze was the thinnest.
The next job was to replace our rusted out muffler with a resonator. They needed a few parts for this but continued working until 6:15 (they close at 5). The last thing on our list is the dash A/C. We were hoping to get out of here but it doesn't seem promising as they are closing for the day at 11:30 for a company function. Even though this will be an inconvenience to us I feel that this is valuable to their employee's morale.
Robert
 

Re: Emergency Brakes Dragging

Reply #17 –
What is wore on the calipers? Or do you mean rotors. Calipers only hold the pistons to engage the brakes. Any chance of a picture of the small pin you are talking about.

Re: Emergency Brakes Dragging

Reply #18 –
No rotors were replaced. The caliper repair parts come with the lining bonded on the calipers, two per wheel. The pin I mentioned is small and looks to be about 3/8 inches in diameter and an inch or so long. It connects the air chamber to the brake actuating arm and is held in with a cotter key.
Robert

Re: Emergency Brakes Dragging

Reply #19 –
Rob is saying "calipers", but I believe he is actually talking about the brake "pads".  I.E., they replaced the pads in his calipers.

The pin in question sounds like the one at the top of the slack adjuster (see photos reply #14).