Heads Up for Diesel Owners

[Tom S.]

I had a scary situation yesterday. While driving, my engine fan suddenly came on. Since it was only 35 degrees outside, I knew there had to be an issue. I looked at the dash and the temp looked ok. Then I noticed the battery light. At 50 mph, you don't immediately notice the lack of power steering, but when I applied the brakes to pull over and check things out, I noticed not only the steering, but my brakes were practically useless! Diesels don't produce the vacuum needed for power brakes. That power is supplied by a pump driven by the serpentine belt. My belt had come off, leaving me with manual steering and almost no brakes. The only fortunate things about this incident was A: no accidents occurred and B: I was only a few blocks from my favorite parts store. I always carry an extra belt, but I didn't have the tools to put it on. That will change!

I was on my way to work out, but the work out I received steering that monster around and trying to stop it was enough for me! Some day, if you can find a large empty parking lot, try shutting off your motor at around 25 mph and try stopping and steering. Then call your cardiologist!

[camper4]

I have basically the same truck.
Thanks for the heads up. Glad no one was hurt! Imagine that happening while towing!!!

[southern thunder]

Wow, good information. Thanks.

[1retired06]

you didnt say how old that serpentine belt was? On my Ford, not an easy job to replace.

[richfaa]

Never happen on the truck but did on a 30K bus I was driving..very scary

[DQDick]

Glad it worked out well for you. Good thing the Monty wasn't on the back going down a long grade. Just the thought of that is enough to scare the poop out of me. Check the belt for cracks before mountain trips is now another thing on my list. Thanks for sharing!!!

[priceml]

My old 1997 Chevy 454 (gas) had power steering with a hydro boost run off the belt.It had no vacuum to it.So it is not just diesels.

[Tom S.]

quote:Originally posted by 1retired06

you didnt say how old that serpentine belt was? On my Ford, not an easy job to replace.

Turns out it wasn't the belt's fault. I lost the idler pully, and when it went it took the belt with it. BTW, the belt was original with 55,000 miles on it.

[1retired06]

Bad luck with that pully. I traded in two previous Ford diesels, (2002 and 2005) each with 100+K mileage, and with original belt and hoses on both. I did inspect routinely after 60K mark. Lots of variables in life, heat is one.

[Sky]

This is good information to know and thank the man above that no accident occured and no one was hurt. I'm not a mechanic but on cars the power brakes and the emergency brake work seperately from each other so you have brakes if something like this occurs. Wouldn't this be true on diesel trucks....at least one would think so and it should be a common sense thing to have. Or am I wrong on the information I was told many years ago in reference to the brakes being seperate from each other?

[Champ_49]

I have always been told, when you change that serpentine belt you also change that idler pully as that is what usually takes out the belt first. The bearing in them things take a beating. So for safety and piece of mind always change that idler pully!!

Dave

[1retired06]

Roger that on the pully replacement!

[Tom S.]

quote:Originally posted by Sky

This is good information to know and thank the man above that no accident occured and no one was hurt. I'm not a mechanic but on cars the power brakes and the emergency brake work seperately from each other so you have brakes if something like this occurs. Wouldn't this be true on diesel trucks....at least one would think so and it should be a common sense thing to have. Or am I wrong on the information I was told many years ago in reference to the brakes being seperate from each other?

Cars and trucks do not come with emergency brakes - a misconception that persists today from over 50 years ago. What you have is a parking brake. If you ever have taken the rear rotors of a Chevy/GMC, you find a tiny set of drum brake pads and a drum built into the rotor. Try to use to stop the truck, even at slow speeds will pretty much fry those shoes very quickly, maybe even in seconds. They are only designed to hold the vehicle when parked, especially on a steep incline.

[Dave Nowlin]

I would think that when all this starts, that turning on the tow haul mode would help some with the braking. Both transmission and exhaust breaking would be brought to bear, depending on what truck & year you have.

[Illini Trekker]

I'm guessing that not very many mile on the idler for it to lock-up. Tom have you had any noise changes in the motor that may give us a clue something's up? I'm looking at 85K on mine, changed the belt last fall to be on the save side?

[CBTraveler]

Thanks for the warning! I just might have my idler and belt replaced as a precaution. 87,000 miles so far without a problem and i'd like to keep the good luck going- especially downhill with the Monty attached.

[kab449]

When you do your under hood inspection pay close attention to the edges of the serpentine belt. When the bearing in the idler loosens up the pulley is not in alignment any more and it subjects the microgrooves to side forces that can cause the rubber coating on the belt to disintegrate and then the cords will show. Just one sign of impending trouble. Wish I had 5 bucks for everyone I replaced, Oh I did but I spent it.

[farmboy]

I have a question. Are you saying the electric motor backup pump had no effect on your braking power? Just wondering.

[brooksider]

Tom S you are right that vehicles have a parking brake. At one time it was an emergency brake but when they went to a split master cyl, one for the front and one for the rear, then they went to a parking brake.
Joe

[Phil P]

Hi

Richfaa's bus should have had the electric backup pump but the light duty trucks we use for 5th wheel RV’s don’t. How ever there is a HydroBoost unit available with the pump and additional switches to install it.

Phil P