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07-16-2018, 11:07 PM
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#1
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Member
Join Date: Sep 2014
Location: KINGSTON, WA
Posts: 32
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2018 F-53 24K chassis brakes issue
I recently descended an 11 mile, 6% grade with lots of twists and turns posted down to 25MPH and very, very few places to turn out and narrow, to no shoulders. Ambient temperature was in the upper 90's. I was very thankful, and lucky, I had a tire pressure/temperature monitoring system because the front brakes overheated. I pulled off at the earliest opportunity and smoke was pouring off the front brakes. I was afraid the coach was going to catch fire. Tire valve stem/rim temp got up to 172F. I was also lucky I found a place to pull off as the brakes felt like they were starting to fade. The rear brakes were about 30-40F lower than the front. I realize that most of the braking load is on the front.
This is a brand new 2018 Tiffin 34PA with the 24K chassis pulling a Chev HHR. I am a right foot only driver (I don't ride the brakes), use the tow haul mode, only braking when excessive speed built up during engine braking. Even at that, the number of turns with a low recommended speed necessitated somewhat frequent application of brakes.
The measured weight of the coach is well under the GVWR, the toad has a functioning braking system and the combination is well under the GCWR
The only thing I can think of that caused this was the combination of high ambient temperature and road conditions as I am very aware of proper braking methodology and use engine braking as much as possible.
I noticed when crawling under the coach that the front brakes have a large funnel for air cooling of the brakes, which of course would be less effective at low speeds. This event scared the hell out of me, and my confidence level in the braking system is diminished. I will of course be talking to Ford, but I don't expect much help there ....
I've driven this combination on other steep grades around the western US Utah, and Arizona with no problems.
Anybody else experienced this?
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2018 Tiffin Allegro Open Road 34PA
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07-17-2018, 12:14 AM
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#2
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Senior Member
Join Date: Jul 2014
Posts: 35,317
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Did you manually downshift the transmission to help control your speed ?
In a situation like that, you want as much engine braking as you can get.
Pick a gear that forces the engine to rev up in the 4000 RPM range. That way you should need less foot braking.
PS: The braking load on MH chassis are about 50-50 front and rear. The more weight on the rear axle, the larger the brakes will be, and more work they will do.
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07-17-2018, 12:26 AM
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#3
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Senior Member
Join Date: Jun 2014
Location: Oregon
Posts: 1,052
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Without owning a gas class A I can't say for sure but I have a plenty heavy gas setup with 2500 Ram truck + 11,000# 5th wheel. I find on a 6% grade tow/haul alone isn't enough and I have to do as twinboat mentions - manually shift to the right gear for the conditions and let the engine scream. On a road like you mention I'd likely be locked into 1st and only hitting the brakes hard and fast going into corners.
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07-17-2018, 02:08 AM
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#4
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Senior Member
Join Date: Jul 2005
Posts: 1,679
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In most situations, the toad brakes are not coming on in a downhill situation, there isn't inertia trigger to be felt. That is adding 4,000 lbs to the braking effort of the brakes on the motorhome that are designed only for the weight of the motorhome.
Few auxiliary brake setups are tied to the brakes of a gas motorhome unlike many diesel pushers with air brakes. I chose a RVI 3 Brake system because I can, if I feel the need, press the Test Button and apply the toad brakes.
__________________
Dale & Mark Bruss
13 Years Full-Timing Now with a 2016 Bounder 33C
40' Travel Supreme winter residence
Lots of RV Information at www.dmbruss.com
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07-17-2018, 04:51 AM
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#5
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Senior Member
Ford Super Duty Owner
Join Date: Jan 2015
Location: NE Ohio - Near Cleveland
Posts: 741
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Get your front wheel hubs checked. Also do a search for front hub issues, there have been several reports for premature hub failures. With that much smoke I'm going to guess that it wasn't really a brake issue but the hub seal failed and grease leaked out. Once onto hot rotors you'll have tons of smoke.
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2015 Coachmen Encounter 37LS
2014 Ford F53 chassis pulling a 2010 Honda CRV toad
Co-pilots Bella and Frosty (don't tell the wife)
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07-17-2018, 09:50 AM
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#6
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Member
Join Date: Sep 2014
Location: KINGSTON, WA
Posts: 32
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Quote:
Originally Posted by Crankshaft
Get your front wheel hubs checked. Also do a search for front hub issues, there have been several reports for premature hub failures. With that much smoke I'm going to guess that it wasn't really a brake issue but the hub seal failed and grease leaked out. Once onto hot rotors you'll have tons of smoke.
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Now that is a possibility! I will definitely get that checked. That would explain why the fronts got so hot compared to the rears. Thanks!
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2018 Tiffin Allegro Open Road 34PA
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07-17-2018, 09:52 AM
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#7
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Member
Join Date: Sep 2014
Location: KINGSTON, WA
Posts: 32
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Quote:
Originally Posted by twinboat
Did you manually downshift the transmission to help control your speed ?
In a situation like that, you want as much engine braking as you can get.
Pick a gear that forces the engine to rev up in the 4000 RPM range. That way you should need less foot braking.
PS: The braking load on MH chassis are about 50-50 front and rear. The more weight on the rear axle, the larger the brakes will be, and more work they will do.
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I was in tow/haul mode and the RPM was pushing 5K in places, so I was getting as much as I was going to get.
__________________
2018 Tiffin Allegro Open Road 34PA
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07-17-2018, 09:53 AM
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#8
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Member
Join Date: Sep 2014
Location: KINGSTON, WA
Posts: 32
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Quote:
Originally Posted by Dale & Mark Bruss
In most situations, the toad brakes are not coming on in a downhill situation, there isn't inertia trigger to be felt. That is adding 4,000 lbs to the braking effort of the brakes on the motorhome that are designed only for the weight of the motorhome.
Few auxiliary brake setups are tied to the brakes of a gas motorhome unlike many diesel pushers with air brakes. I chose a RVI 3 Brake system because I can, if I feel the need, press the Test Button and apply the toad brakes.
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Toad braking system is electric, not inertial, but even if they weren't working at all, my total combined weight was well under the GCWR for the vehicle.
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2018 Tiffin Allegro Open Road 34PA
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07-17-2018, 09:59 PM
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#9
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Senior Member
Join Date: May 2017
Location: A
Posts: 151
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Our very first trip in our 2017 Newmar Bay Star, we went to Yosemite and on the way back down we had the exact same experience. Ever since we installed the 5-Star tune our downshifting logic has been so competent that I have not been able to get the brakes to smoke like that again. Even coming down the 17 from Flagstaff To Phoenix - or going up/down the rockies into and out of south western Colorado couldn't fade our brakes.
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07-18-2018, 04:44 AM
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#10
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Senior Member
Thor Owners Club Ford Super Duty Owner
Join Date: Jul 2011
Posts: 3,788
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If you let Tow/Haul pick the gear the potential for overheating your brakes will be very high. Don't worry about inconveniencing other drivers for the short period of time during a decent and get the transmission into the lowest gear to hold the speed down. Your safety, and to some extend theirs, is dependant of you maintaining positive control of the coach to include not overheating your brakes.
https://youtu.be/Yi8BKesrYUE
The video is an 11% grade. Did the decent in second and the coach held a comfortable speed for the entire descent. You have to get the speed down at the top of the hill and manually shift into the lowest gear possible early. It's a lot easier to upshift if you feel going a bit faster is OK for the road but down shifting once rolling isn't going to be easy. Get aggressive with the transmission and get into the lowest gear. Engine braking works, even for gas engines.
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2006 Hurricane 31D built on a 2006 Ford F53
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07-18-2018, 09:17 AM
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#11
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Senior Member
Join Date: Nov 2005
Posts: 3,965
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Quote:
Originally Posted by FR3
Toad braking system is electric, not inertial, but even if they weren't working at all, my total combined weight was well under the GCWR for the vehicle.
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You may well be under the GCWR, but the brakes on the F53 chassis are rated for the GVWR (gross vehicle weight rating) in this case 24,000 lbs., not the GCWR (gross combined weight rating) which in this case is 30,000 lbs.
Here's a paragraph straight from the page 52 of the 2018 Ford F-Series Super Duty Class A Motorhome and Commercial Chassis Owner’s Manual:
http://www.fordservicecontent.com/Fo...CA_03_2017.pdf
The rating for the tow vehicle's braking system operation is at the gross vehicle weight rating, not the gross combined weight rating. Separate functioning brake systems are required for safe control of towed vehicles and trailers weighing more than 1500 pounds (680 kilograms) when loaded.
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Hikerdogs
2013 Adventurer 32H
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07-18-2018, 11:57 AM
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#12
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Senior Member
Ford Super Duty Owner
Join Date: Jan 2011
Location: Lowell, Arkansas
Posts: 7,297
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"You have to get the speed down at the top of the hill and manually shift into the lowest gear possible early. It's a lot easier to up shift if you feel going a bit faster is OK for the road but down shifting once rolling isn't going to be easy. Get aggressive with the transmission and get into the lowest gear. Engine braking works, even for gas engines."
Many good responses but Sweetbriars comments, above are by far the best advice to avoid the same situation.
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TeJay Auto Instructor/4-yrs USAF/ Liz: RN/ WBGO 2014 Vista 30T/ F-53/CHF/5-Star/Koni * Bella & Izzy * Golden /Cocker mix/ Louie The Cat* All Retired
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07-18-2018, 12:03 PM
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#13
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Senior Member
Tiffin Owners Club Nor'easters Club Appalachian Campers Carolina Campers
Join Date: Sep 2016
Posts: 673
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You are using tow/haul mode right?
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-Mike
2020 Tiffin Open Road 34PA
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07-19-2018, 05:17 PM
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#14
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Senior Member
Join Date: Jun 2016
Posts: 579
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Best to always start down the two lane mountain roads in the 8,000 ft and above range in first gear at 15 mph. If you feel the need to go faster there is always second gear. My dolly has surge brakes, so if I go much faster down a 7-10% grade, I burn up the dolly brakes.
If your brakes got that hot, the whole system needs to be checked: grease, bearings, rotors, calipers (seals) and fluid.
__________________
Jim & Roy Davis
2016 Hurricane 31S
1961 Chev Rampside toad
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