Dragging brake

Topic: Dragging brake (Read 1237 times) previous topic - next topic

Dragging brake

February 01, 2015, 11:59:18 am

Here is my story. 97 U295 with about 65K miles. I have owned it since 2001 & it has been parked in garage since I have had it except for going on trips. We use to use every weekend. Use for last 8 years has been about 2 short trips a year (400 miles round trip)

In 2012 I put new tires on since they were getting old. While I was at tire place I noticed the driver side rear rotor was grooved up. I had no clue since never heard anything and unit stopped great. I check around and found a place in Houston that said they could work on these brakes. Company replaced rotor and shoes on that driver rear and replaced pads all the way around.

March of 2013 I took a trip and had a problem with the front brake dragging and overheating. We stopped, let ti cool, then went to a tire shop, where they took apart, and all looked great. Since then have had no problem with that break. When I got back from trip I took MH to another repair place to have the steering box replaced & to have them check all of the brakes.

Over Thanksgiving weekend 2013 we went up to Henderson TX to visit father-in-law. On the way wife when she walked to the back said it smelt like an electrical burning. I pulled over and the back driver side brake was smoking. We stopped to let it cool down and continued the rest of the way.

On the Saturday way back to Houston I stopped at Foretravel to check the brakes. Wish I had one of my temperature guns so I could have checked the rotor temp. All looked good and continued on. When we stopped at a light in Corrigan I looked back in the mirror and saw smoke coming from the wheel well. We had the brake checked out in Livingston after letting brake cool down and they said all was OK.

When I got home I got my temperature gun and checked all 4 rotors. Front right was 91. left front was 109, right rear was 109 & left rear (problem one) was 145 degrees.

I then took the MH back to the last place that worked on the RV. In talking to them it turned out they had no idea about the correct grease to use or the helper springs. The got some of the correct grease from the brake manufacture along with the helper springs.

Today I got to take out a short trip to check the brakes. I drove 20 miles and pulled over to check the rotor temps, RF 90, LF 100, RR 102, LR (problem one) 148. While I was at Buc ee filling up ($2.44 per gallon) I figured I would take the MH to Foretravel and have them fix it before the next big trip I go on. When I got back home I rechecked the rotor temps. RF 91, LF 100, RR 117,LR (problem one) 127

Now I need your opinion. Do I go to Foretravel to have then see what is wrong, or since the temperature was way closer to the other rotors is the new grease and helper springs getting worked in? Since I had traveled 40 miles total I figured the LF's temperature would have been over the previous high of 148.

Re: Dragging brake

Reply #1 – February 01, 2015, 12:39:36 pm

It could be the slack adjuster hanging up.

The procedure for replacing the grease involves backing off the slack adjuster. Sometimes that causes the slack adjuster to malfunction. I had that happen and replaced the slack adjuster and all is well now. (Replaced the slack adjusters on both sides to play it safe)

Re: Dragging brake

Reply #2 – February 01, 2015, 12:50:13 pm

Several things:

PROPER lube procedure is critical. If they were just greased and not properly purged, they will keep the lazy pad on the disk. The proper grease is also important.

Lubing the slide area is also important-- should be less important for you, since you drive frequently.

There are also helper springs from the brake manufacturer that I highly recommend when you have the brakes worked on. They help insure that the pads retract from the disks.

Re: Dragging brake

Reply #3 – February 01, 2015, 12:50:59 pm

Very frustrating I know! I had a similar problem over the last 3-7,000 miles in a similar senario and had the brakes replaced, no caliper problems so...rotors/pads ... 3 times, yes you read it right, and finallly the last shop to do the job confessed that (as I had confirmed on parts boxes anyway) these parts are all being made in China now and this is just what is available and to be expected. Now this was not air brakes & not a Foretravel, but the experience and information is offered as a thought regarding presently available parts and similar symptom to yours on my present Motorhome.

Re: Dragging brake

Reply #4 – February 01, 2015, 05:10:43 pm

Quote from: wolfe10 – February 01, 2015, 12:50:13 pm

Several things:

PROPER lube procedure is critical. If they were just greased and not properly purged, they will keep the lazy pad on the disk. The proper grease is also important.

Lubing the slide area is also important-- should be less important for you, since you drive frequently.

There are also helper springs from the brake manufacturer that I highly recommend when you have the brakes worked on. They help insure that the pads retract from the disks.

I gave them the manual that I downloaded as to the proper way to lube. They said they followed the manual to a T with grease they bought from Meritor.

They also put helper springs on.

I guess I will call Foretravel in the morning and see what they come up with. I should have just gone there in the first place.

Re: Dragging brake

Reply #5 – February 01, 2015, 09:31:28 pm

Turbo Jack,
I am not sure the manual speaks to the purge process. Also, just curious, were the pins in good condition?

Re: Dragging brake

Reply #6 – February 01, 2015, 09:37:13 pm

Quote from: turbojack – February 01, 2015, 05:10:43 pm

I guess I will call Foretravel in the morning and see what they come up with. I should have just gone there in the first place.

Whatever you do, do NOT let them talk you out of the helper springs. There seems to be a mis/lack of understanding at the factory regarding what those springs are for. We had to press the issue to get ours installed. If for some reason you need any of the slide pins replaced, make sure they reinstall the helper springs.

Re: Dragging brake

Reply #7 – February 01, 2015, 09:38:00 pm

Most fire departments have Meritor only. Go pick their brains and see it the master mechanic will moonlight off duty. Your Foretravel should have the Meritor maintenance book as part of the included manuals. Has all the part numbers as well as procedures.

Pierce

Re: Dragging brake

Reply #8 – February 02, 2015, 07:26:04 am

I took mine to a cummins shop who works on fire trucks. They redid all my brakes, purged them and adjusted them too. New pads and helper springs as well.

Re: Dragging brake

Reply #9 – February 02, 2015, 07:46:41 am

Quote from: Pierce & Gaylie Stewart – February 01, 2015, 09:38:00 pm

Most fire departments have Meritor only. Go pick their brains and see it the master mechanic will moonlight off duty. Your Foretravel should have the Meritor maintenance book as part of the included manuals. Has all the part numbers as well as procedures.

Pierce

The company that worked on it does a lot of Houston Fire Department trucks. Their solution was to replace the complete brake caliper, since that is what they would do for Houston. They did not know about springs, grease, or correct way to do it, until I showed them all the information as to how to do. After I though about it, most fire trucks do not drive long distances at one time so not really a chance to heat up from dragging.

The mechanic that worked on the brakes said that he purged the excess grease, for what it's worth.

Re: Dragging brake

Reply #10 – February 02, 2015, 03:20:25 pm

Turbojack,

I had a dragging brake a few years ago and fixed it myself. I replaced the pins and bushings for that brake using the instructions in the Meritor manual. I had a machinist replace the bushings, I didn't have that equipment. The pins can get pitted and the bushings worn causing a pad/s to drag. It's been okay since then, but I check the pins for pad wear. If the pins are flush with the bushings time for new pads or if the length of the exposed pin pair is different something is wrong. In my case only one pad was dragging and it was worn at an angle almost to the point of metal to metal contact on one end of the pad. The pins were pitted and I didn't like the looks of the old bushings for that brake. Proper grease and purging is necessary. Some folks put a plastic wire ties on the brake fittings to keep the grease monkeys when lubing the chassis from greasing those fittings.

Re: Dragging brake

Reply #11 – February 05, 2015, 08:23:39 pm

I've had the same problem with the left rear, and had them redone and the springs added. I've had the slack adjusters checked/adjusted. The best guy I found was at Yuma Diesel in Yuma, AZ. He said the equipment is very good. He told me to be sure that after the rig set for a few weeks, I should be sure to pump the brakes five times before I moved it to allow the brakes to go thru the on/off motions. I've not had a brake drag, or other issue with them since I've paid attention to doing that before each trip.

Re: Dragging brake

Reply #12 – February 06, 2015, 12:21:26 am

I noticed that the chrome plating on the pins seems to be crappy and pits. I couldn't get new pins when I replaced my rear rotor, so I just ground and smoothed the bubbles away so the caliper wouldn't hang up on the bubbles.

Re: Dragging brake

Reply #13 – February 06, 2015, 02:47:09 am

Quote from: Bob Thomas – February 05, 2015, 08:23:39 pm

. . . He told me to be sure that after the rig set for a few weeks, I should be sure to pump the brakes five times before I moved it to allow the brakes to go thru the on/off motions. I've not had a brake drag, or other issue with them since I've paid attention to doing that before each trip.

I do that regularly before starting off, and do 5 heavy brake pumps after releasing the parking brake.

Need to be very sure that the parking brake (spring brakes) are off before heavy brake application, since if the parking brake is still on, you add the service brake pressure to that of the spring brakes and can possibly overload the rear slack adjusters. Commercial air brake handbooks emphasize that.

(This is not a problem if you just apply normal brake pressure before releasing the parking brake.)

Re: Dragging brake

Reply #14 – February 27, 2015, 06:13:10 pm

Update
After taking a number of test trips, and testing rotor temp, I felt the dragging brake problem had not been fixed. I did not know if I should buy the Jacks & impact or take it to MOT. I made appointment with MOT. On trip from Houston to Naco the night before, the air temps were in the low 40, high 30. I made 3 stops to let the brakes cool. At every stop the Left Rear was way hotter then any other brake. This last Wednesday morning they started going thru the brakes. First problem they found was the brakes were adjusted wrong. The one brake I was having problems with was adjusted tighter so it was doing most of the braking. So after applying the brakes to make a stop and check temp is was going to be hotter then the rest since it was doing most of the work. They said the grease that was showing up outside did not look like the correct grease. (The company I had just work on them in Houston swore they had put in the correct grease, and had done everything correct per the manual I had sent them) They also showed me a slide pin and it was pitted bad in spots and suggested they be replaced. I had agreed to replacing anything that needed to be replaced since I was tired of having problems with smoking brakes on trips. MOT replaced all of the pins, put new grease in all of the brakes and adjusted all of them. The said they test drove and rotor temps were the same. I headed back to Houston. I stopped at the rest area somewhere around Livingston and checked the rotor temps, all looked good. Continued on to the house with no problems. I was so happy making a trip without an overheating brake in the last 2 years.

Two years ago when I had new tires installed and saw the grooved rear rotor I should have just taken it to MOT then. I would have saved a lot of aggravation, having to leave at repair shops in Houston, 3 times, and having roadside work on them twice.

Re: Dragging brake

Reply #15 – February 27, 2015, 09:55:56 pm

Did they install the helper springs?

Re: Dragging brake

Reply #16 – February 28, 2015, 05:50:12 pm

Quote from: wolfe10 – February 27, 2015, 09:55:56 pm

Did they install the helper springs?

The helper springs I had added at the Houston repair shop. They did not know anything about them and I had to give them the part number of them. It looked like they did not fix the problem but with the rear brakes being adjusted different when I put my temp gun on the rotors I was having my problem child 25-50 degrees hotter then the other rear one, making me think I still had a dragging brake. Since my problem child was adjusted tighter then the rest, it was doing most of the braking so it would be hotter then the others.

Re: Dragging brake

Reply #17 – February 28, 2015, 05:59:10 pm

Yes, helper springs will not overcome poor maintenance (over-greasing, under-greasing, wrong purge procedure, wrong grease, seized or badly pitted caliper slide pins, etc).

Very good braking system if not killed by an idiot tech.

Many fire trucks have the same brakes. A good place to start is "where do the fire trucks get serviced?"

And I would want to be sure that the tech (actual person, not just shop) know the brakes. I do NOT, repeat NOT believe in OJT for Bubba on a coach!

Re: Dragging brake

Reply #18 – February 28, 2015, 06:17:13 pm

Quote from: wolfe10 – February 28, 2015, 05:59:10 pm

Many fire trucks have the same brakes. A good place to start is "where do the fire trucks get serviced?"

Brett,

If you read back in the thread, you'll see that Turbojack did originally use a shop that works on the Houston fire trucks....

Re: Dragging brake

Reply #19 – February 28, 2015, 06:51:32 pm

Michelle,

Sad news, not only for Turbojack but for the Houston Fire Department. Assuming this was not the tech's first experience with this brake system, probably some other vehicles that need attention.

Re: Dragging brake

Reply #20 – March 01, 2015, 10:27:25 am

Quote from: Dave Katsuki – February 06, 2015, 02:47:09 am

Need to be very sure that the parking brake (spring brakes) are off before heavy brake application, since if the parking brake is still on, you add the service brake pressure to that of the spring brakes and can possibly overload the rear slack adjusters.

I have never seen the Foretravel brake system so I'm not sure this applies but all commercial trucks and buses, and my Wanderlodge have Anti-Compounding Valves in the air brake system to keep the above from happening. Here is a simplified diagram:

http://www.truckt.com Tractor Air Brake System Explained

TOM

Re: Dragging brake

Reply #21 – March 01, 2015, 11:00:59 am

Tom, Foretravels are unique among motorhomes in that they have an AIR DISC brake system, kind of a supersized small car system. Brakes drag on these Meritor Disc systems because of poor maintenance, where a S CAM or other truck brake system release readily and there is a great deal of room between the shoe and drum this is not true of DISC's. The clearance between pad and rotor is as little as 1/16 inch so it does not take much to drag. Usual cause is pitted slide pins and poor lubrication of calipers that does not allow calipers to retract. .
Lots of info on Meritors web site and a search here will also give much info.

Gary B

Re: Dragging brake

Reply #22 – March 02, 2015, 06:40:19 pm

Quote from: wolfe10 – February 28, 2015, 06:51:32 pm

Michelle,

Sad news, not only for Turbojack but for the Houston Fire Department. Assuming this was not the tech's first experience with this brake system, probably some other vehicles that need attention.

If you think about it, the fire truck and a motor home may have the same brake but they are used alot different. In the motor home the coach is run for many miles without touching the brakes since most of the use is highway and when it is used it is most of the time a slow decent. A fire truck most trips are less then 5-30 miles. When they are going to a fire they are on the throttle hard and then on the brakes hard. If the brakes are hot when they get to a fire it most likely not from dragging. If they have dragging brakes due to bad repair, it might never show up on the short trips they make.

I have been told that the brake jobs some of the fire departments are getting are costing in the 10-15K range. I have asked to see some of the invoices. I do not have a clue how they can be that high unless they have waited too long and have the rotors destroyed. The Houston repair shop I was at wanted to change me $5000.00 to fix my dragging brake by replacing the caliper. That is when I told them I would take it to Naco to get repaired.

Re: Dragging brake

Reply #23 – March 02, 2015, 06:47:37 pm

WOW. THose are crazy prices. Have had rears replaced at Parliament (yup, dragging brake caused by sticky pins.) $2K with pads and rotors and one caliper as I recall

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