Workhorse has found that drivers often overheat and damage their vehicle braking systems by improper braking in mountain areas or by "riding" the brakes on flat ground. The following includes suggestions from the Workhorse Technical Team as well as recommendations outlined in the DOT (Department of Transportation) commercial driver's license manual. Workhorse has included these DOT procedures in its owner's manual since 2007 and they apply to all types of motor homes.

In mountain driving, gravity plays a major role. On any upgrade, gravity slows you down. The steeper the grade, the longer the grade, and/or the heavier the load - the more you will have to use lower gears to climb hills or mountains. In coming down long, steep downgrades, gravity causes the speed of your vehicle to increase. You must select an appropriate safe speed, and then use a low gear and proper braking techniques.

You should plan ahead and obtain information about any long, steep grades along your planned route of travel. If possible, talk to other motor home or truck drivers who are familiar with the grades to find out what speeds are safe. You must utilize engine braking techniques to go slowly enough so your brakes can be utilized for speed reduction without getting too hot. If the brakes become too hot, they may start to "fade." This means you have to apply them harder and harder to get the same stopping power. If you continue to use the brakes hard, they can keep fading until you cannot slow down or stop at all.

Select a "safe" speed
Your most important consideration is to select a speed that is not too fast for the:

• Total vehicle and cargo weight.
• Length of grade.
• Steepness of grade.
• Road conditions.
• Weather.

If a speed limit is posted, or there is a sign indicating "Maximum Safe Speed," never exceed the speed shown. Also, look for and heed warning signs indicating the length and steepness of the grade.

You must use the braking effect of the engine as the principal way of controlling your speed. The braking effect of the engine is greatest when it is near the governed rpms and the transmission is in the lower gears. Save your brakes so you will be able to slow or stop as required by road and traffic conditions.

Select the right gear before starting down the grade
Shift the transmission to a low gear before starting down the grade. Pay close attention to the gear that is required to climb the grade prior to decent. For example if the gear required to climb the grade is 3rd gear, then 3rd gear should be selected prior to the decent as a base line to control your vehicle speed. Do not try to downshift after your speed has already built up above the safe posted speed limit. Once your speed has increased over the safe posted speed limit you may not be able to shift into a lower gear. You may not even be able to get back into any gear and all engine braking effect will be lost.

With motor homes, a rule for choosing gears has been to use the same gear going down a hill that you would to climb the hill. However, new motor homes have low friction parts and streamlined shapes for fuel economy. They may also have more powerful engines. This means they can go up hills in higher gears and have less friction and air drag to hold them back going down hills. For this reason, drivers of newer motor homes may have to use lower gears going down a hill than would be required to go up the hill. Usually you want the lowest gear that will keep the motor home at or near the speed you want in negotiating the downhill. For example, if you're going down a six percent grade and wanted to go 35 mph, you would start downshifting and using the brakes to get to an engine rpm that will enable you to maintain a speed at or near 35 mph.

Proper braking technique
Remember, the use of brakes on a long and/or steep downgrade is only a supplement to the braking effect of the engine. Once the vehicle is in the proper low gear, the following is the proper braking technique:

1. When your speed increases to or above your "safe" speed, apply the brakes aggressively enough to feel a definite slowdown.
2. When your speed has been reduced to approximately five mph below your safe speed, release the brakes. (This brake application should last for about three seconds.)
3. When your speed increases again to your safe speed, repeat steps 1 and 2.

For example, if your safe speed is 40 mph, you would not apply the brakes to any increase in speed until you reach 40 mph. Then you apply the brakes aggressively enough to gradually reduce your speed to 35 mph and then release the brakes. Repeat this as often as necessary until you have reached the end of the downgrade.

Brake fade or failure
Your brakes by design operate utilizing brake pads that rub against the brake disks to slow the vehicle during brake application. This braking function creates heat, which the brake system can dissipate during normal brake applications. However, brakes can fade or fail from excessive heat caused by improper use or dragging the brake to slow the vehicle on mountain grades rather than relying on the engine braking effect. To safely control a vehicle, every braking mechanism must do its share of the work. Brakes with excessively worn pads or rotors will not provide the same degree of braking power. If you are not sure about the condition of your braking system, have it inspected by qualified service center.

Escape ramps or runaway truck ramps
Escape ramps, also known as Runaway Truck Ramps, have been built on many steep mountain downgrades. Escape ramps are made to stop runaway vehicles safely without injuring drivers and passengers. Escape ramps use a long bed of loose, soft material to slow a runaway vehicle, sometimes in combination with an upgrade. Know escape ramp locations on your route. Signs show drivers where ramps are located. Escape ramps save lives.

An example of brake-friendly driving technique in Death Valley
On a recent trip to California we made notes on driving technique when descending a mountain pass.

Background:
The motor home was built on a Workhorse W22 gas chassis, fully laden to 22,000 lb. GVWR. The driver, let's call him Mike, is an experienced driver with a valid Commercial Driver's License and is also a professional automotive technician. We asked Mike to drive the vehicle in a fashion that would conserve the brakes, but also be reasonable in using the engine and transmission for braking (i.e. drive it like you own it!).

We were traveling in a south-westerly direction into Death Valley National Park from the Nevada side on SR-374, with a planned stop at Stovepipe Wells Village in the park. This is quite a steep descent with almost 10 miles of 7 percent grade and 4 miles of 5 percent grade, with a total drop of around 4,000 foot over 12 miles of driving. The speed limit on some road sections inside the National Park on this road is 45 mph, so Mike shifted down to second gear as soon as we hit the down-grade. The motor home was a 2005 model with the 5 speed Allison transmission and equipped with the "Grade-Brake" feature, but Mike elected not to use the Grade Brake, instead preferring to manually shift down using the column shift.

Mike would allow the vehicle to run against engine compression with the engine speed varying between 4,000 rpm to 5,200 rpm, depending on the grade. Each time we hit 5,200 rpm the transmission would force a shift to 3rd in order to protect the engine. Each time this happened Mike applied the brake for a few seconds to scrub off speed and this allowed the transmission to downshift to 2nd gear again, allowing maximum engine braking in the safe speed range. Drivers should not be concerned about the high rpms in this situation because, as noted, the transmission will automatically adjust when needed to protect the engine. Also, if Mike had elected to use the Grade Brake feature, the down- and up-shifting would have happened automatically once he touched the brake pedal.

Overall, Mike applied the brake only seven times during the 14-mile descent and this includes the final stop at the T-junction with the North Highway! Most of the applications were of short duration, with less than 5 seconds of brake pedal application required to control the vehicle speed.

Only once did Mike use the brake pedal for longer on a twisty section to ensure we remained at a safe speed. The total time of brake application was only around 45 seconds. This was quite an enlightening illustration of how driving technique learned on heavy trucks (where brakes simply do not have the huge excess capacity found on passenger cars) can allow for safe navigation of the most demanding descents with no danger of overheating and damaging the brakes on your motor home.

In May 2009 Workhorse mailed an "interim notice" to alert affected Workhorse owners of a defect in certain Bosch brake caliper assemblies used on Workhorse W20, W21 and W22 motor home chassis models. Pending an approved recall remedy for the problem, the interim notice described the authorized interim repair procedure, at no cost to the customer, for those brake problems related to the defect. However, brake repairs related to typical wear and tear or other issues are still the financial responsibility of the customer. As with any recall, misunderstandings about the defect and about who is responsible for what often arise. This article will briefly explain the nature of the problem and how owners and technicians can determine whether a brake problem is related to the defect or not.

Warning signs

Signs of the problem may include:

• A distinct brake burning smell.
• Having to apply more engine power to overcome an unaccounted for slowing of the vehicle commonly associated with brake drag.
• An ABS light that is continually on.
• Smoke coming from the wheel end.
• A soft or spongy feel when applying the brakes.

Owners of the affected chassis models who experience any of the signs indicated above should have their brakes inspected at an authorized Workhorse service center. The inspection is at their expense; however, if the problem is related to the Bosch defect, Workhorse will provide an interim repair at no cost to the chassis owner.

Caliper assembly at fault

The piston clearances in the caliper are fairly small - the specified clearance of a new phenolic piston is .004 to .008 of an inch. Measurements of certain phenolic pistons taken from motor homes that have been in service for several years have shown an increase in diameter of up to .0035 inches.

The caliper piston is designed for some expansion due to normal heat absorption during braking. During normal operation, the internal piston caliper seal pulls the piston back into the caliper bore when the brakes are released. However, if the phenolic piston expands due to moisture absorption and heat, the seal may not be able to pull the piston back (called "binding"), which may result in the brake pad dragging on the rotor.

This can be hard for a technician to diagnose because if the brake pad drags as above and then the motor home is parked for a period of time (as short as 20 minutes), the piston may cool and decrease in diameter, releasing the piston from its binding condition.

What technicians will look for, what is covered

Diagnostic signs of the defect include:

• Piston dust seals/boots that are cracked or appear discolored (white powder markings).
• Front wheel seals that show signs of damage.
• Front spindle caps that show signs of heat damage or leaking.
• Heat damaged ABS sensors and wheel speed sensors; ABS sensors that have stopped functioning at various speeds and may have intermittent loss of function and associated fault codes.

Rotors with radial cracks are NOT considered recall related damage unless there is other evidence of damage. Such cracks are typical of "riding" the brakes downhill, absence of a tow car brake system and continued hard braking. If the cracks are severe enough to merit replacement, that would be at the owner's expense.

Rotor colors also vary from vehicle to vehicle, and some discoloration and transfer of brake pad material along with brake pad wear is normal. However, if the rotor exhibits significant transfer of brake pad material, that may be related to the Bosch defect. Similarly, if the brake pads show a rough and damaged surface associated with significant material transfer, that would be considered defect related damage. Replacement of both rotors and pads in this case would be covered by the interim repair procedure.

Affected owners will be contacted

From the Workhorse Technical Team
With new diesel emissions technology comes new things for motor home owners to learn. There is one set of new warning lights for particulate buildup that it is especially important for those driving new diesel Class As to monitor - or risk damaging their engine.

Workhorse Custom Chassis, a leading manufacturer of chassis for Class A motor homes, has noticed instances of driver failure in this regard. Unfortunately, when this happens there is no warranty coverage for repairs and towing, not to mention the potential hazard to the driver and others. So it pays for drivers to read the manual and pay attention. They need to know what their gauges and warning lights mean.

All diesel engines produced after Jan. 1, 2007, must comply with the new regulations requiring the reduction of nitrogen oxide (NOx) and hydrocarbons (HC) by 50% and particulate matter (PM) by 90+% over the previous 2004 emission standards. To reduce particulate matter, a Diesel Particulate Filter (DPF) is used on all Class A diesel motor homes.

The DPF captures soot and larger sulfate particles in a series of ceramic honeycomb channels as gas passes through the porous material, and the particulates are trapped and accumulate on the channel walls. After thousands of miles, the DPF will eventually become clogged if nothing is done.

To prevent the DPF from clogging, the trapped particulates are burned off, and the filter is cleaned using a high temperature (around 1,700 degrees Fahrenheit in the Particulate Filter) regeneration process that leaves a harmless ash and residue. There are different regeneration processes for different diesel platforms, including automatic regeneration, manual regeneration, and DPF removal for an exchange or off-vehicle regeneration.

Workhorse's new W16D, W20D and W22D chassis with MaxxForce™ diesel engines are examples of how both manual and automatic regeneration are used. The driver must monitor a series of instrument cluster system lamps that indicate various levels of low to full soot load with the DPF as determined by engine exhaust back pressure. For motor home owners who drive their rigs mostly at highway speeds, automatic regeneration will kick in. However, if much low speed driving occurs, manual regeneration may be needed.

For this typical system, there are four levels of warning indicators that signal potential hazards and the action needed:

• Low soot load buildup: requires the driver to get up to highway speed to engage the automatic regeneration or to safely pull over and engage in manual Parked Regeneration.
• Exhaust filter is full: requires the driver to safely pull over and begin Parked Regeneration to prevent loss of power.
• Exhaust filter is full and engine performance is limited: Driver needs to safely pull over and begin manual regeneration to prevent engine shutdown.
• Soot overload: a serious engine problem has occurred and the engine may shutdown soon. Safely pull off the road, turn on flashers, place warning devices and stop engine. DO NOT USE Parked Regeneration but call for service.

Manual Parked Regeneration is a simple process of hitting a switch that increases the engine speed to a set RPM that achieves the temperature needed to burn off the soot. Needless to say, this will make the exhaust very hot, so the driver needs to take care to park away from people or combustible materials and vapors. This process takes about 30 minutes. To thoroughly clean the DPF system, the motor home should also be run at highway speeds for 20 minutes after a manual regeneration.

As we mentioned, this soot buildup happens over thousands of miles, so the regeneration process does not happen very often to the typical motor home owner. However, if the warning lights do go on, it is very important that drivers know what to do if they want to avoid crippling their rig with serious engine damage.

Download Workhorse Diesel Emissions Regeneration Card

For additional information about Workhorse call 877-294-6773 or visit www.workhorse.com.