Proper use of P30 brakes and transmission selection on long descents?

[Ericb760]

My wife and I took an exploratory run to Big Bear Lake in Southern California this week, mainly to get out of the house, but also to scope out RV parks in the area. We found a great park right on the water and plan on booking some time there this summer. Big Bear sits at about 8,000', and coming back down off the mountain is a series of tight switch backs. We were in our Honda Civic which was fine. I do have concerns coming down that mountain in my old RV, though. Before going up I plan to have the brakes serviced.

My question: What is the best advice one would give to a relatively new RVer in regards to downhill braking and transmission selection? I have a TH400 mated to a 454.

[Elandan2]

Nice pic. The old adage is "use the same gear down the hill as you used to get up the hill" The other consideration is not letting your speed climb so high that you have to ride the brakes to slow down and ultimately overheat them. You are better making less frequent applications to keep your speed down.

[Rickf1985]

First and foremost limit your speed coming down. Do not hit the top of the hill at 60 mph, be slowed down to 35 mph or so at the top at least the first time you do it so you can get a feel for the vehicle. You cannot ride the brakes the entire way down or you will lose them. You can downshift to second gear but listen to the engine. You have low gearing in the rear so you you will wind up the engine pretty good in second and then you will need to go to third (D). All the while you will be lightly applying the brakes on for a bit and off, on for a bit and off. If you have disc brakes all around they do not fade as bad or as fast as drum brakes but you still do not want to push them to the limits. You do not want to have to do a brake job every time you come down a mountain. once you do this one time you will have a much better feel for how the vehicle handles it. It is hard for anyone to tell you exactly what to do because we do not know the weight or brake package or your driving skills/experience. I don't know about the road there but most long steep grades have emergency run offs, they are well marked and if you lose your brakes use the first one you come to! Do not think you can ride it out, you can't!!!!

[ClydesdaleKevin]

Try to slow down to at least 35 at the top of the hill, and put on your flashers.  Shift down to 2nd gear.  When you speed gets up to around 45, hit the brakes until you slow down to 25, and then take your foot off the brakes so they don't get too hot.  Stay in 2nd with your flashers on the whole way down.  When you coast back up to 45, apply the brakes to bring you back down to 25...and keep doing that all the way to the bottom of the hill.  Make sure you have a Brake Buddy in your tow vehicle.


We put a LOT of miles on a P-30 chassis with a 454, loaded up HEAVY...and this is what always worked best and safest for us.


Kev

[Ericb760]

First and foremost limit your speed coming down. Do not hit the top of the hill at 60 mph, be slowed down to 35 mph or so at the top at least the first time you do it so you can get a feel for the vehicle. You cannot ride the brakes the entire way down or you will lose them. You can downshift to second gear but listen to the engine. You have low gearing in the rear so you you will wind up the engine pretty good in second and then you will need to go to third (D). All the while you will be lightly applying the brakes on for a bit and off, on for a bit and off. If you have disc brakes all around they do not fade as bad or as fast as drum brakes but you still do not want to push them to the limits. You do not want to have to do a brake job every time you come down a mountain. once you do this one time you will have a much better feel for how the vehicle handles it. It is hard for anyone to tell you exactly what to do because we do not know the weight or brake package or your driving skills/experience. I don't know about the road there but most long steep grades have emergency run offs, they are well marked and if you lose your brakes use the first one you come to! Do not think you can ride it out, you can't!!!!

I made a point of identifying the emergency runoffs all the way down the mountain, and they were plentiful although I would probably total the RV if I had to use one.


Question: We have similar rigs. I'm guessing that there are disks up front and drums in the back as a normal P30 1989 setup?

[Ericb760]

Try to slow down to at least 35 at the top of the hill, and put on your flashers.  Shift down to 2nd gear.  When you speed gets up to around 45, hit the brakes until you slow down to 25, and then take your foot off the brakes so they don't get too hot.  Stay in 2nd with your flashers on the whole way down.  When you coast back up to 45, apply the brakes to bring you back down to 25...and keep doing that all the way to the bottom of the hill.  Make sure you have a Brake Buddy in your tow vehicle.


We put a LOT of miles on a P-30 chassis with a 454, loaded up HEAVY...and this is what always worked best and safest for us.


Kev

Sounds like sage advice, although I doubt I'll be anywhere near 45 mph coming down that particular mountain.

[Rickf1985]

You have to look at the tag under the hood and see what brake option you have, I have discs all around.  Or just crawl under there and look behind the wheels, you will see drums or calipers. They are all discs on the front in the later years I believe but the rears could be drum or disc.  And yes, hitting a emergency runoff is going to do some damage. They are designed to stop a heavy vehicle going fast with no brakes so they are deep gravel and suck the vehicle in. It is a violent event but not likely one that will kill you. The alternative is likely to kill you. So, destroyed vehicle or dead people? I used to drive tractor trailers over those mountain passes and I saw more than one truck hit the runoff. They all walked away. Unfortunately I saw a few that thought they could drive through a brake failure also. Most did not survive. Gravity always wins. Like Kevin said, nice and slow, the others behind you can go around or get over it, too bad. it is your life not theirs.