There is no such thing as a stupid question The theory being that you have almost three times the amount of time with the brakes in cool down mode as opposed to the three seconds of heating up the brakes. This is supposed to prevent brake fade; prevent overheating the brakes to the point where they smoke. When you smoke a brake, there is a danger that you will glaze the brake shoe making it virtually useless ever again. The second method, NOT government approved, is the way we did things in the old days. First you select the appropriate gear as above. Then as you launch into the descent, you apply a slight bit of brake application pressure; just enough to have the brake shoe touch the brake drum, causing a very slight amount of drag. As you require harder braking, you apply more brake application pressure then release as required but never allowing any air between the brake shoe and the brake drum. The theory is it’s oxygen that allows the heat to feed into that which is undesirable, brake fade and smoking and eventually fire. If there’s no oxygen, there’s nothing to feed the fire, so to speak. Can you glaze a set of brake shoes? Yes, with either method. It’s the skill level you develop by understanding the braking system of the truck and use of same over many experiences. The truth be told, both methods have their place. It’s the conditions under which you find yourself that will determine which method you use and sometimes you will find you can use both on the same hill on the same descent. The object of the exercise is to descend the hill safely without causing anyone, yourself included, any discomfort. I will give you a couple of examples that might help you figure out why both methods have their place. I will draw on some real life experience, not on what an engineer may say based on theory and testing. The scene: It’s Sunday afternoon on a busy summer weekend. You are proceeding south on Interstate 77 dropping from Virginia to North Carolina. The hill is called Fancy Gap. It’s a six percent grade for seven miles of winding road, with several “run away ramps” strategically located along the hill. At the bottom of the hill is a rest area, then just past the rest area is a North Carolina DOT scale. Being Sunday afternoon, there is bumper to bumper traffic in both lanes traveling about five miles per hour below the limit. As you descend the hill, you correctly leave adequate safety margin but because of the traffic, your safety margin to the car drivers looks like an invitation to invade this space in front of your heavy vehicle. Often these cars changing lanes in front of you are not leaving you much space, in fact the term “cut off” could apply. You are using the three second brake stab with the eight second release. What would happen in this scenario is you’d be crushing a large number of cars, undoubtedly with some loss of life, whereas if you’d known about and were using the constant application of brakes method, you would be in a much better position to react to the changing conditions as you descend the hill. Using the stab method, you risk overheating the brakes and risking enormous brake fade when you need your brakes most critically. In my experience, both methods work and work well if properly executed. My caveat is you have to learn the various conditions under which you will be operating and use whatever method is most suitable for that particular condition. Practice both methods where you find ideal conditions so you are competent when conditions are less than ideal. Safety is the highest priority. Then you have to consider appearing to the lay drivers out there who think they know everything. Then you have to consider your equipment and not doing damage especially the hidden damage. You can never tell you have glazed brake shoes. The brake shoes can look like there is lots of life left but if those shoes are glazed over, they are virtually useless. You can tell by the smell of the brake shoes if they’ve been overheated beyond reason, and if there’s a JULY / AUGUST 2014
vI kmzor hox qoN bc jwxgIAW[ izAwdw grm hox qoN bcwA hovygw Aqy DUMAW vI nhIN inklygw[ jdoN qusIN brykW lw ky DUMAW k`F idMdy ho qW iesdy SUA kMm krn dy smrQ nhIN rihMdy[ dUjw FMg jo srkwr duAwrw pRvwinq nhIN ieh hY ik aus qrHW krIey ijvyN pihly simAW ‘c krdy huMdy sI[jwxI ik pihlW TIk gyAr dI cox kro Aqy jdoN qusIN auqrweI ‘c ho qW hlkw ijhw bRyk nUM d`bo, ieMnw ku ik bRyk SUA bRyk frMm nwL l`g jwvy Aqy hlkI ijhI iK`c hovy[ jdoN quhwnUM sKq bryk dI loV hovy qW bryk pRYSr ku`J vDw idE pr kdy vI bryk SUA Aqy bryk frMm ‘c hvw nw Awx idE[ AsUl ieh hY ik ieh AwksIjn hI hY jo aus ‘c byloVI hIt jwx idMdI hY Aqy ijs nwL bRyk kmzor huMdI hY, pr DUMAW inkldw hY Aqy AMq A`g bx jWdI hY[ is`DI g`l jy AwksIjn hI nw bxUM qW A`g bxn dw koeI kwrn hI nhIN[ kI qusIN bryk SUA dy sY`t nUM glyz kr skdy ho[ hW, dovW ‘coN iksy vI FMg nwl[ieh quhwfI kwrIgrI dw lYvl hY ijhVw quhwnUM tr`k dy bryikMg isstm nUM keI vwr vrqx dy qjrby nwL pRwpq hoieAw hY[ scweI qW ieh hY ik dovyN FMg Awpxy Awpxy QW TIk hn[ieh qW hwlqW ‘qy inrBr krdw hY[ keI vwr ie`k hI phwVI dI auqrweI ‘qy quhwnUM dovyN FMg vrqxy pYNdy hn[pr mMqv dohW FMgW dw ie`ko hY ik sur`iKAq FMg nwl quhwfy smyq ibnw koeI nukswn kIqy Arwm nwL cVHweI qoN hyTW auqirAw jwvy[ mYN ku`J audwhrxW idMdw hW ijs nwL quhwnUM ieh smJ Aw jwvygI ik dovyN qrIky Awpxy Awpxy QW ikvyN TIk hn[ mYN AslI qjrby dI g`l krWgw iksy isDWq Aqy tYst ‘qy ADwrq iksy ieMjnIAr dI d`sI hoeI nhIN[ idRS:grmIAW dy ie`k AYqvwr dI ie`k KwsI tRYiPk vwlI Swm[qusIN ivrjInIAw qoN ieMtrstyt 77 dI auqrweI ‘qy nOrQ kYrolInw nUM jw rhy ho[ies ih`l dw nWA hY PYNsI gYp[ moV GyV vwLI ies sVk dI s`q mIl q`k 6% auqrweI hY[ies ‘c phwVI dy nwL keI ‘rMn Avy rYNp’ vI hn[ auqrweI dy AYnH hyTW ie`k rYst eyrIAw vI hY[ ies dy nwL hI nwrQ kYrolInw fI E tI skyl hY[ AYqvwr dI Swm hox krky ie`Qy imQI spIf qoN 5 mIl G`t hI spIf rihMdI hY ikauN ik g`fI ‘qy g`fI cVHI huMdI hY[ auqrweI hox krky qusIN Agly hYvI vhIkl qoN Awpxw tr`k kwPI ip`Cy r`iKAw huMdw hY pr kwrW vwly ies C`fI hoeI QW ‘c kwrW ilAw GusyVdy hn[Asl ‘c ieh kwrW vwly quhwfy A`gy ieMnI QW nhIN C`fdy ik ‘k`t AwP’ dw inXm lwgU ho sky[ qusIN iqMn sikMt bRyk lw ky 8 sikMt bRyk C`fx dw inXm Apxw rhy ho[ ies qrHW krn nwl hovygw ieh ik qusIN keI kwrW nUM drV skdy ho[ ies qrHW krn nwL koeI jwn vI jw skdI hY[ jdoN ik jy qusIN lgwqr bryk d`bx dw FMg vrqogy qW ieh izAwdw vDIAw rhygw[ikauN ik ies nwL qusIN auqrweI ‘c auqrdy smyN sVkI hwlqW nwL vDIAw FMg nwl nij`T skdy ho[ stYb FMg vrqx nwL quhwfIAW brykW izAwdw grm ho jwxgIAW Aqy jdoN quhwnUM ienHW dI vDyry loV hY ieh brykW Pyf vI ho skdIAW hn[ ij`QoN q`k myrw qjrbw hY jy shI FMg nwL vrqoN kIqI jwvy qW qrIky dovyN hI vDIAw FMg nwL kMm krdy hn[ myrI slwh qW ieh hI hY ik quhwnUM v`K v`K hwlqW dI jwxkwrI hoxI cwhIdI hY Aqy loV Anuswr ijhVw Fu`kvW vDIAw FMg hY auh hI vrqo[ ij`Qy quhwnUM l`gy ik sVk ‘qy hwlwq TIk hn au`Qy dovyN FMg vrqo[ sB qoN mu`K pihl hY sur`iKAw[ quhwnUM aunHW frweIvrW dw iDAwn vI r`Kxw pvygw ijhVy smJdy hn ik aunHW nUM sB ku`J pqw hY[ Awpxy smwn dw vI iDAwn r`Ko ik ies dw nukswn 15