Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 09-22-2014, 09:15 AM   #1
Senior Member
 
Join Date: May 2014
Posts: 134
Steep grade - lesson learned

I think I know now why they have those Safety Pullouts at the top of steep grade. We live in northern AZ and make several trips a year to Phoenix for doctors and shopping. That requires a decent off of the Mogollan. I usually shift down to 4th gear and flip on the exhaust brake and can make it down with minor braking.

This time, as I breezed by that safety pullout, I flipped on the exhaust brake and nothing happened. We were going 55 in no time and headed into the first big curve. I managed to keep us under 65 and steer through 50 mph curves, praying I didn't smoke the air brakes. DW sensed that all was not well as she calmly asked why we were going so #%?! fast.

I pulled off at the bottom of the hill and spent the next half hour diagnosing the problem. I found the exhaust brake power wire had pulled out of a crimp connector. I got it connected and we were back in business. I spent the rest of the trip thinking that I could have done that simple repair in the safety pullout at the TOP of the hill rather than doing a white knuckle drive down the hill.

LESSON LEARNED: Make sure everything is working before plunging off down a steep grade!!
__________________

__________________
Al & Sue w/T-Bone & Rosco
Go Devils Bus, 1994 8.3 Cummins, Spartan Chassis
Climbon69 is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 09-22-2014, 09:28 AM   #2
Community Administrator
 
JohnRR's Avatar


 
Fleetwood Owners Club
Workhorse Chassis Owner
Join Date: Sep 2010
Location: Marquette, Michigan "Da UP"
Posts: 16,940
At least the outcome was good. Thank you for sharing.
__________________

__________________
John & Cathy R.
06 Pace Arrow 38L W24
08 14 Lincoln MKX AWD
See My RV Upgrades
JohnRR is offline   Reply With Quote
Old 09-22-2014, 09:28 AM   #3
Senior Member
 
450Donn's Avatar
 
Join Date: Jun 2006
Location: Dallas,OR
Posts: 2,553
Another lesson, leave the EB on ALL the time!
__________________
Don and Lorri
2007 Dodge 3500 dually
Resident Dummy.
450Donn is online now   Reply With Quote
Old 09-22-2014, 09:32 AM   #4
Senior Member
 
CampingCajun's Avatar
 
Join Date: Jul 2014
Location: Lafayette, La.
Posts: 1,144
When coming down a hill or mountain it is better to apply the brakes hard enough to shave 15 mph or so off of your speed vs. steadily riding the brakes to hold a consistent speed. Riding the brakes causes heat to build up which leads to brake fading. Try to come downhill at the speed which you topped the hill at.
__________________
2011 40' Monaco Cayman PBQ ISC 360
2013 Jeep Wrangler Unlimited
CampingCajun is online now   Reply With Quote
Old 09-22-2014, 10:52 AM   #5
Senior Member
 
RRDefector's Avatar
 
Join Date: Aug 2014
Posts: 346
Yes... Deploy ....cool.... Rinse and repeat. I had a brake failure in our infinity coming down a steep grade in North Western NC. Had to use a runaway ramp at 78 mph.. Hand brake was all i had and that was next to nothing. Have to say it scared the day lights out of me but did stop the car quick. Would hate to try it in a 56k # speeding bullet but know how they work now😳 Cracked brake line. I check everything close since that ugly day many years ago.


Robert & Jana Stanton... Birthing a 2015 Anthem or Cornerstone
__________________
Robert & Jana + fur baby rescues...Jimmie,Pepper,Pixie
2015 Entegra Anthem 44B
RRDefector is offline   Reply With Quote
Old 09-22-2014, 11:05 AM   #6
Senior Member
 
Papa_Jim's Avatar
 
Outdoors RV Owners Club
Join Date: Oct 2009
Location: Manitoba,Canada
Posts: 2,638
Quote:
Originally Posted by CampingCajun View Post
When coming down a hill or mountain it is better to apply the brakes hard enough to shave 15 mph or so off of your speed vs. steadily riding the brakes to hold a consistent speed. Riding the brakes causes heat to build up which leads to brake fading. Try to come downhill at the speed which you topped the hill at.
Others may say that I don't have to do this, but I try to determine what gear I will need to maintain the right speed for going down that hill before I start going down the hill. Before I begin the descent, I slow down to that speed and manually shift the transmission into that gear. I know it's slower, but I want to get to the bottom safely.

Jim
__________________
Jim & Kate
2016 Creekside 23RKS
2014 Ram 1500 4X4 Eco Diesel
Canada, eh?
Papa_Jim is offline   Reply With Quote
Old 09-22-2014, 11:26 AM   #7
Registered User
 
Monaco Owners Club
Join Date: Oct 2009
Location: Varies Depending on The Weather
Posts: 8,517
Quote:
Originally Posted by 450Donn View Post

Another lesson, leave the EB on ALL the time!
Right ON!

No reason to turn it off.

Dr4Film ----- Richard
__________________
Dr4Film is offline   Reply With Quote
Old 09-22-2014, 03:23 PM   #8
Senior Member
 
Join Date: Feb 2010
Posts: 569
As the old saying goes

You can come down a mountain the right way 1,000 times
but you can only come down it the wrong way one time.
__________________
2008 Thor, Four Winds Mandalay 40G. Cummins 400 isl. Freightliner chassis
koda59 is offline   Reply With Quote
Old 09-22-2014, 03:27 PM   #9
Senior Member
 
Doc Hugh's Avatar
 
Triple E Owners Club
Freightliner Owners Club
Join Date: Dec 2011
Location: Winnipeg, MB, Canada
Posts: 133
Steep grade - lesson learned

Here's a copy of a slightly abridged article related to descending long downgrades recommending the brake "snubbing" method ("a service brake application made at intervals"). Although specifically referring to semi tractor/trailer combos with air brakes, I found it an interesting read on the subject.


"How To: Brake on long downgrades
BROOKE WISDOM | 11.1.09
AAA

The problem:

Descending a long downgrade can trigger a runaway even when your brake system is in good working order. Here’s why.

The treadle valve, under the pedal, sends only a small air signal. It activates a relay valve on each axle, which applies the brakes at a pressure that varies with the signal pressure.

Proper braking on severe grades will keep you from having to veer into the deep gravel of a runaway truck ramp...

Relay valves don’t send any pressure at all into the system until they reach a certain level, their crack pressure. And, especially if aftermarket valves have been used to replace original equipment valves, the crack pressures might not be the same on all axles.

Consequently, a light, steady braking pressure down a long grade often causes only three or four of the five axles to apply. Because those three or four axles are doing all the work, they get too hot. Once one or more axles overheat, the remaining axles may be unable to shed enough energy to keep the vehicle speed under control, even with maximum treadle pressure.

The solution:

• Shift to the lowest gear that allows the truck to run at the posted truck speed limit.

• Apply the engine brake at the highest setting that allows the speed limit to be maintained.

• As needed, apply the service brakes using the “snubbing” method. This means applying enough pressure – usually 10 to 30 psi – to cause the truck to slow gradually. That amount of air pressure will open all relay valves and apply all the brakes.

• After the truck has lost 5 to 6 mph, release the brakes, which enhances their cooling.

• As you regain the speed limit, reapply the brakes hard enough to reach the recommended pressure range. Repeat this procedure until the road levels."
__________________
Hugh & Judy with Golden Retrievers Lars, Kenzie & Arvy in 2009 Triple E Invitation 40' QSDP, FL-XCR, Cummins 8.9L ISL 400HP, Allison 3000MH towing 2009 Jeep Liberty
Doc Hugh is offline   Reply With Quote
Old 09-22-2014, 06:29 PM   #10
Senior Member
 
wa8yxm's Avatar
 
Damon Owners Club
Workhorse Chassis Owner
Join Date: Mar 2009
Posts: 22,799
Another feature of those steep long grades is the truck run out lane,, This is a lane with generally loose dirt or sand of increasing depth designed to stop a run-away truck with MINIMUM damage and no loss of life.

Story goes that the guy in the car in front of the truck was managing to stay ahead of the rig... Just, when they got to the run out the trucker thought AT LAST, The guy in the car drove into the sand and.. Well the trucker had no choice but to follow.

Let the guy behind you take that lane if he needs it and you don't.
__________________
Home is where I park it!
wa8yxm is offline   Reply With Quote
Old 09-22-2014, 06:54 PM   #11
Senior Member
 
BFlinn181's Avatar
 
Gulf Streamers Club
Join Date: Jan 2012
Location: Cincinnati
Posts: 16,238
Light, steady braking is bad for any brake system, air, hydraulic, or even antique mechanical brakes. I've never heard the reason given in the trucker's story, but driven a lot on hills. Downshift and apply brakes hard to drop speed by 10-15 mph, then take foot of the brake until next application to drop speed again by 10-15 mph. I've observed many folks riding the brake all the way down a hill, often accompanied by burning brake lining smell. It's true for 18 wheelers, buses, RVs, pick ups and autos, from Cadillacs to Minis. Don't ride the brakes. The OP had his exhaust brake malfunction, but I wondered why he didn't stop when he discovered it instead at the bottom of the hill.
__________________

Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI
BFlinn181 is online now   Reply With Quote
Old 09-22-2014, 07:54 PM   #12
Senior Member
 
ImagineIF's Avatar
 
Join Date: May 2010
Posts: 1,045
Quote:
Originally Posted by 450Donn View Post
Another lesson, leave the EB on ALL the time!
Just remember you can get an expensive ticket in a lot of cities that don't allow exhaust brakes.
__________________
Gil
99 Country Coach
Prevost XL 45 Conversion
ImagineIF is offline   Reply With Quote
Old 09-22-2014, 08:01 PM   #13
Registered User
 
Monaco Owners Club
Join Date: Oct 2009
Location: Varies Depending on The Weather
Posts: 8,517
Quote:
Originally Posted by ImagineIF View Post

Just remember you can get an expensive ticket in a lot of cities that don't allow exhaust brakes.
That's another over-stated myth regarding Exhaust Brakes.

If your coach has an Engine Brake and it is as noisy as the ones used by the OTR truckers that sound like a 50 mm machine gun then YES you may get a very expensive ticket.

So when was the last time you heard a motorcoach with an Engine Brake sounded like a MAC Truck?

Dr4Film ----- Richard
__________________
Dr4Film is offline   Reply With Quote
Old 09-22-2014, 08:01 PM   #14
Senior Member
 
BFlinn181's Avatar
 
Gulf Streamers Club
Join Date: Jan 2012
Location: Cincinnati
Posts: 16,238
Quote:
Originally Posted by ImagineIF View Post
Just remember you can get an expensive ticket in a lot of cities that don't allow exhaust brakes.
I've seen plenty of "No Jake Brakes" and "No Engine Brakes" but nothing prohibiting exhaust brakes. They certainly don't make the kind of noise a Jake brake does. Also, they are lots quieter than hitting something!
__________________

__________________

Bob & Donna
'98 Gulf Stream Sun Voyager DP being pushed by a '00 Beetle TDI
BFlinn181 is online now   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Steep grade Rogersslt Ford Motorhome Chassis Forum 7 07-22-2014 06:31 AM
Lesson I learned on fuel filter change.. blkcloud Class A Motorhome Discussions 5 06-25-2014 01:17 PM
How to level on steep grade? JACKAL0PE MH-General Discussions & Problems 22 04-07-2014 06:17 AM
Lesson Learned .... I Think scubastevee Class B Motorhome Discussions 9 08-04-2013 05:08 PM
Lesson Learned - Check Low Clearances tnrzryd Entegra Owner's Forum 21 07-29-2013 09:36 PM

» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 01:28 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.