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GinaParmesan · 02-10-2018, 03:37 PM

What’s the best way to brake going down a long, steep incline?

The reason I ask is because I’ve had 2 instances where the brakes froze up. Violet can’t move, and her pedal feels stuck. The first time, I had a mechanic look at it and he replaced the lines, fluid & front calipers. $600 and 4 months later, it happened again. This time I just let them “cool off” for 45 min. and they’ve been working normally since then.

Both times I was going down a long, steep hill not long after being parked for a week or so.

My theory is that maybe pumping the brakes is causing them to somehow get stuck...

jdalrymple · 02-10-2018, 04:00 PM

The best procedure is to use the transmission and engine to control speed.

Choose lower gears.

Apply brakes only when speed increases enough to require slowing down, holding them until speed is a little slower than safe speed, then release and allow the engine to keep braking.

Most hills will require little brake application, if the proper gear is chosen.

Repeat until the bottom of hill is reached.

Regards,

JD

brick1 · 02-10-2018, 04:08 PM

A second vote for using engine braking, and slow down before tou start the descent.
brick

Waipio Rim · 02-10-2018, 04:13 PM

And, another vote for using a lower gear. I have seen good advice here that you should use the same gear going down a hill that you would have to use going up that hill.

My brakes froze up on me to the point that I had to be towed out of traffic. Had the master cylinder and hydroboost unit replaced, and they have been fine since.

GinaParmesan · 02-10-2018, 04:19 PM

Hi JD. Thanks! I did that in my 5-speed car, but the P30 only has 3 gears, so doesn’t that mean going downhill in 2nd at 25-30 mph? On the freeway, that sounds a bit scary...

Foiled Again · 02-10-2018, 04:21 PM

Your profile says you have a 1987 Airstream 290 moho.

Put on your bus driver hat every time you get in it. It is a lot different than driving a car or pickup truck.... a lot more weight and not that much more power. And brakes that are strong enough... but no overkill.

Thinking a half mile ahead and slowing down, and downshifting before gravity grabs you are all good. The more moderate your speed as you come over the top of the hill, the easier your coach is to keep in control... I'd be scares spitless id i knew I neesed to downshift and I was already going 70.... 50 or 45 and no worries about ruined upholstery.

GinaParmesan · 02-10-2018, 04:28 PM

My experience has been that the 454 won’t downshift unless I’m already going a speed within that gear’s range. I read it’s a safety feature to keep the engine from jumping through the grill if it was shifted into 2nd while going 65 mph.

So what I’m hearing is to just take downhill slopes in 2nd gear. That way the transmission can regulate speed.

(And also a tip about potential parts to replace if the problem crops up again. Thanks for that too! Let’s hope it doesn’t come to that.)

bwoodtx · 02-10-2018, 05:38 PM

You are hearing correctly. Downshift first. Good rule of thumb: you go down the hill in the same gear you went up......if the trans shifted down to go up, then go ahead and shift the lever down, crest the hill and make a safe controlled decent. If you went up at 50, go down at fifty. I believe you also have a tachometer in that rig-I would not let it go over about 3500 up or down the hill.

A W Warn · 02-10-2018, 05:42 PM

Yes, at the top of the hill get in the right lane, slow down, then shift down to second. If there are speed restrictions for the big trucks, follow those. Use brakes as little as possible to avoid over heating them.

Reving the engine while going downhill in the lower gear is not harmful, when kept within the engine's specifications. Keep an eye on the engine speed as well as the vehicle speed (~4,000 rpm in second gear, on my truck is normal when I go down 8% grade maintaining 45 mph, while towing)

Going slow is better than blocking traffic when the brakes lock up. Or, even worse, having a wreck if the brakes fail and control is lost.

jdalrymple · 02-10-2018, 07:02 PM

An old P 30 simply isn’t a new modern vehicle. The chassis is near max load with these classic motor homes.

Stay in the slow lane, take things easy, slow down to about 45 a the top of the hill and manually shift to second. Let the rig ease down the hill.

These rigs were built when speed limits were 55 mph. I try to keep my max speed at 60. Just let traffic go around and enjoy the trip.

If I need to travel faster, we leave the motor home in the hanger and take the trailer.

Regards,

JD

tevake · 02-10-2018, 08:08 PM

They really are vintage old busses, I like the buss drivers hat comment.
Got to think differently when driving them. You get to enjoy the view for longer too.
Good tips above about cover it for you.

Even the big mountains of Colo only last a short while in the scope of a long trip.
Take it easy, your rig will thank you!

Cheers Richard

WayneG · 02-11-2018, 03:53 AM

I am curious on how well the Turbo hydramatic handles 2nd gear going down hill for long periods?
Somewhat related, I also wondered what source if hill grade maps everyone uses for plotting routes?
I was trying to find the grade of the Mass Pike just west of I91.
I can do that hill in 3rd both ways with only touching the breaks occasionally.

sallye · 02-11-2018, 09:21 AM

So what do you do if you have automatic brakes?

My TV does have "under drive," but I don't know if I can shift into it while traveling, and the manual says that you aren't supposed to use it while towing.

So, I'm confused. . . . . Up to now I've just been slowing down as needed before the grade and braking as needed.

A W Warn · 02-11-2018, 09:35 AM

Quote:

Originally Posted by sallye

So what do you do if you have automatic brakes?

My TV does have "under drive," but I don't know if I can shift into it while traveling, and the manual says that you aren't supposed to use it while towing.

So, I'm confused. . . . . Up to now I've just been slowing down as needed before the grade and braking as needed.

Not a dumb question.
The OP asked about a 1987 motor home. The posts above are generally discussing that motor home braking and use of an old 3 speed automatic transmission to help control the speed. Those old transmission do not function like the newer vehicles with an automatic engine brake, so they have to be downshifted by the driver using the shift lever.

add edit:
Maybe someone else will comment about shifting the transmission in your Durango. I'm not familiar with the term "under drive".

HowieE · 02-11-2018, 09:47 AM

The rule has always been go down a hill in the gear you went up the hill in. That hold true for All transmissions. Yes you will not fly down the hill with an older 3 speed transmission in first or second gear but you stand a better chance of living through the experience. You don't see trucks going down the steeper hills at the posted speed limit.

When it come to braking on a long hill it is better to ride the brakes than to periodically stab them. less heat build up.

If you have a vehicle that state not to use engine braking while going down hill consider getting another TV.

jack9443 · 02-11-2018, 09:49 AM

down shift if you cant your going to fast towing over 60 is wasting fuel and your safety

Nightmare67 · 02-11-2018, 09:58 AM

In a jet, carbon ceramic brakes, we were trained, during taxi, let speed build then apply a constant brake pressure application, slow down as much as traffic allows, them release and allow the aircraft to accelerate. Giving the brakes time to cool. This was especially important at places like Vegas and Phoenix. We had a system called BTMS, brake temp monitoring system. So I could see how this technique worked.

Now, if you’ve stuck with me this far, that was for carbon brakes. I can’t say positivity that that technique works with our brakes but it’s how I used to brake with a trailer until I got a diesel with exhaust brake.

sallye · 02-11-2018, 10:00 AM

Sorry - I meant to write "automatic transmission" . . . .

sallye · 02-11-2018, 10:03 AM

Quote:

Originally Posted by A W Warn

Maybe someone else will comment about shifting the transmission in your Durango. I'm not familiar with the term "under drive".

Actually, I think it's called "Over drive" . . . I'd have to look at the manual again.

WayneG · 02-11-2018, 10:05 AM

Quote:

Originally Posted by Nightmare67

In a jet, carbon ceramic brakes, we were trained, during taxi, let speed build then apply a constant brake pressure application, slow down as much as traffic allows, them release and allow the aircraft to accelerate. Giving the brakes time to cool. This was especially important at places like Vegas and Phoenix. We had a system called BTMS, brake temp monitoring system. So I could see how this technique worked.

Now, if you’ve stuck with me this far, that was for carbon brakes. I can’t say positivity that that technique works with our brakes but it’s how I used to brake with a trailer until I got a diesel with exhaust brake.

Sorry for sidetracking, yet again, but now you give me flashbacks of EOR duty at Nellis AFB. Hot breaks on a F111 were not fun to deal with! Especially with live munitions on board!