Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: dans96u295ft on May 10, 2020, 01:52:27 am

Title: Rear brake hanging up
Post by: dans96u295ft on May 10, 2020, 01:52:27 am
Had the rear brake pads and rotors replaced 200 miles ago. Took a 120 mile test run today all good until the last 10 miles. Started smelling gas from the stove so I pulled over and set the brakes to get out and shut the gas off at the tank. Continued home and the last 5 miles started smelling brake pads. Got home and the right rear was hot and smelling but not locked up and dragging in the gravel. when I moved it the brake popped and I drove it on down the driveway. It must not of released on that wheel when I got back in and drove home. Any ideas/ also I think the gas valve in the stove is shot. Anyone replaced that as that seems to be the source of the gas smell. It didn't set my gas alarm off but you could smell it. Not a very successful test ride!
Thanks
Title: Re: Rear brake hanging up
Post by: Pamela & Mike on May 10, 2020, 06:55:01 am
Did who ever do the brake job grease the calipers?
If so did they use proper grease?
Did they purge the old grease out of the purge vent so not over greased?
After a rebuild over greasing is the major reason for brake caliper non return. When the grease gets hot and expands it has no where to go except move the caliper.

What stove do you have as some have a standing pilot light that has a separate cut off valve.

Mike
Title: Re: Rear brake hanging up
Post by: wolfe10 on May 10, 2020, 09:10:08 am
Did who ever do the brake job grease the calipers?
If so did they use proper grease?
Did they purge the old grease out of the purge vent so not over greased?
After a rebuild over greasing is the major reason for brake caliper non return. When the grease gets hot and expands it has no where to go except move the caliper.

What stove do you have as some have a standing pilot light that has a separate cut off valve.

Mike


Spot ON!
Title: Re: Rear brake hanging up
Post by: Old Toolmaker on May 10, 2020, 09:39:31 am
Any ideas/ also I think the gas valve in the stove is shot. Anyone replaced that as that seems to be the source of the gas smell. It didn't set my gas alarm off but you could smell it. Not a very successful test ride!
Thanks

Did you arrive home on the hook of a tow truck?  No?  Then it was a successful trip.

The pilot light will also give off that propane smell if the tank is near empty.  The valve for the pilot light is a little metal rod with a roll pin for a handle.
Title: Re: Rear brake hanging up
Post by: dans96u295ft on May 10, 2020, 10:00:51 am
No pilot light on this 4 burner. It has the twist starter knob. Agree. Made it home was good. I'll soap bubble today and see if it is the stove valve.
What's the fix on the brakes. They told me they did clean and grease the caliper pins and charged me extra as it took additional labor time. It hasn't hung up until last night. What is the proper grease? I don't know what they did as I wasn't there. They are a heavy truck repair shop and do lots of air brakes but never an FT.
Can I roll under and visually look at the brake when the park is pulled on to see anything? or do the wheels need to come back off?
thanks
Title: Re: Rear brake hanging up
Post by: wolfe10 on May 10, 2020, 10:08:54 am
VERY few OTR trucks have air disk brakes, so most truck shops are not familiar with them.

Fire trucks are the other primary place you will find air disk brakes.
Title: Re: Rear brake hanging up
Post by: Chuck & Jeannie on May 10, 2020, 10:21:40 am
They told me they did clean and grease the caliper pins...
In addition to Mike's questions (up above):

1.  What kind of "grease" did they use on the slide pins?
2.  Did they install the "Helper Spring" kit?

See this thread for info on slide pin lube (pro or con) and helper springs:

Helper springs on Meritor disc brakes (https://www.foreforums.com/index.php?topic=16318)
Title: Re: Rear brake hanging up
Post by: Pamela & Mike on May 10, 2020, 01:20:09 pm
After reading the latest here is another thought. If they greased the slide pins with grease, you must live on a gravel drive per your statement in OP, you could have picked up some sand/dirt on  the guide pin and this could have cause the calipers to hang.

 Here is a link to the 4M brake book that you need to work on this type of brakes. https://www.foreforums.com/index.php?action=media;sa=media;in=1701    Look on page 42 of this book about slide pins.

Mike
Title: Re: Rear brake hanging up
Post by: dans96u295ft on May 10, 2020, 01:29:47 pm
I'll bet they didn't relieve the grease pressure after greasing. Printed out that page for them,
Thanks much all.
Title: Re: Rear brake hanging up
Post by: Old Toolmaker on May 10, 2020, 02:48:17 pm
I'll bet they didn't relieve the grease pressure after greasing. Printed out that page for them,
Thanks much all.

FWIW, IF you want or think you need to grease the slider pins, a dry lubricant, moly be damned is a great way to go, and second to that is 60% moly paste, but with the paste you still have the problem of dirt sticking to the pin.

You need a piece of metal harder than the pin to burnish the moly powder into the pin.  A pair of high speed steel tool bits intended for making lathe tools works great.

TS-001 Moly Powder, Super Fine grade (https://www.tsmoly.com/molybdenum-disulfide-powder-moly-powder-super-fine-grade-p-189.html)

"I" have wedge brakes.  Don't even ask.  I have a Stephens Truck Center across the street from where I live and I watched the guy's eyes when I did ask if they serviced wedge brakes.
Title: Re: Rear brake hanging up
Post by: wolfe10 on May 10, 2020, 02:59:11 pm
Bendix manual calls for clean DRY, UNLUBED slide pins. In fact even have a line in the manual saying to recheck and remove any grease from them.

That is from the 1999 shop manual. I don't know if that is still considered "best practices".

Anyone with recent MOT brake service experience who can update?

And, agree with adding the Bendix helper springs.
Title: Re: Rear brake hanging up
Post by: Lon and Cheryl on May 10, 2020, 03:04:44 pm
I would also check the air brake chamber.
Title: Re: Rear brake hanging up
Post by: dans96u295ft on May 10, 2020, 03:48:36 pm
Super. Just ordered the helper springs for both axles. Napa on line has them. TWD kit-15018. $55 for both to door, Printed out the page how to purge the grease for the tech.
Thanks much
Title: Re: Rear brake hanging up
Post by: Chuck & Jeannie on May 10, 2020, 04:06:47 pm
Just ordered the helper springs for both axles...$55 for both to door...

Each spring kit contains 2 springs and services one brake caliper.

4 kits required to do all 4 brake calipers (both axles).
Title: Re: Rear brake hanging up
Post by: Hans&Marjet on May 10, 2020, 04:38:10 pm
Bendix manual calls for clean DRY, UNLUBED slide pins. In fact even have a line in the manual saying to recheck and remove any grease from them.

That is from the 1999 shop manual. I don't know if that is still considered "best practices".

Anyone with recent MOT brake service experience who can update?

And, agree with adding the Bendix helper springs.
We had MOT replace our pins and added the helper springs in March....they were assembled "dry" no lube used.
Title: Re: Rear brake hanging up
Post by: dans96u295ft on May 10, 2020, 05:24:31 pm
Yes. I'm just doing the rear as the fronts are fine and I didn't have them worked on. When they are ready, I'll order 2 more kits.
Who is MOT? I'm ignorant
Title: Re: Rear brake hanging up
Post by: wolfe10 on May 10, 2020, 05:27:29 pm
MOT= Motorhomes Of Texas in Nacogdoches

Motorhome Dealer In Nacogdoches, TX | Motorhomes of Texas (http://www.motorhomesoftexas.com/)
Title: Re: Rear brake hanging up
Post by: Pamela & Mike on May 10, 2020, 06:10:00 pm
Bendix manual calls for clean DRY, UNLUBED slide pins. In fact even have a line in the manual saying to recheck and remove any grease from them.

That is from the 1999 shop manual. I don't know if that is still considered "best practices".

The last brake class I attended DRY. My hard copy shop manual still is the same as yours.

Mike
Title: Re: Rear brake hanging up
Post by: Texhub on May 10, 2020, 06:58:13 pm
Fot = Foretravel of Texas
Title: Re: Rear brake hanging up
Post by: dans96u295ft on May 10, 2020, 06:59:16 pm
These are Meritor brakes. Dry? on the pins?
Title: Re: Rear brake hanging up
Post by: dans96u295ft on May 10, 2020, 07:01:03 pm
So which is better. FT service or MOT service?
Title: Re: Rear brake hanging up
Post by: bbeane on May 10, 2020, 08:04:25 pm
I would imagine one is no better than the other.
Title: Re: Rear brake hanging up
Post by: Jeff & Sandy on May 11, 2020, 07:20:14 am
MOT vs. FOT....personal preference but currently FOT is closed, MOT is open if you need service now.

I've had good experiences at both places. It's hard to describe the feeling in Nacogdoches for a FT owner. Everything is right there. Whatever your coach needs is right there.

I had an alignment done at FOT last year on the same equipment used when my coach was built. The tech was on the assembly line for my coach in 1993.

I'm a big MOT fan. I bought my coach there and have been back for service. All of my experiences there have been excellent. I find that MOT is all about excellent customer service at every level.


Title: Re: Rear brake hanging up
Post by: turbojack on May 11, 2020, 08:37:13 am
FOT Service was open last week.  I was told more employees were to come back this morning
Title: Re: Rear brake hanging up
Post by: Jeff & Sandy on May 11, 2020, 08:53:17 am
Good to hear that
Title: Re: Rear brake hanging up
Post by: Realmccoy on May 11, 2020, 08:56:42 am
My coach currently at FOT for windshields. Service and parts departments are open after being shut down for a week. After a lot of cancellations the phone is starting to warm up with new appointments being scheduled.
Title: Re: Rear brake hanging up
Post by: dans96u295ft on May 12, 2020, 02:41:46 pm
It's at the dealer that installed the rear brakes and I handed him the Meritor service pages. He agreed, different than most. He is going to purge the calipers of excess grease and I'll give it a try. Springs are on their way
Title: Re: Rear brake hanging up
Post by: Old Toolmaker on May 12, 2020, 04:54:53 pm
It's at the dealer that installed the rear brakes and I handed him the Meritor service pages. He agreed, different than most. He is going to purge the calipers of excess grease and I'll give it a try. Springs are on their way

Always watch the eyes.  When the eyes lose focus you know you've lost your mechanic.  Sometimes referred to as the deer in headlights look.
Title: Re: Rear brake hanging up
Post by: dans96u295ft on May 13, 2020, 12:16:20 am
Excellent. Time to get this country back in service