I boiled my brake fluid and lost my brakes in a 29 foot jamboree. A fella who works as a mechanic up there came up to the mountain and bled my brakes. Gave me the braking 101 lesson. Which is always use your transmission to hold your speed going down mountains. In a steep grade leave it in first and forget it. Thats what I did from there on out and never had a problem. Always use what ever gear holds your speed. I used that rig for many trips in the mountains after that. Hardly used the brakes at all when decending. My brake pedal went to the floor on switch backs up in the mountains, when I learned my lesson, believe me never again!
Your P30 Chevy 454 is the early version of my Vortec 8.1 L, now also obsolete. I have been on grades as steep as 13% and use 1st for all those descents over 6%. If the road is straight and we are slower than I feel we need to be then, and only then will we upshift to 2 or even 3. So our rule is start slow and let speed come up to where you feel comfortable and can control it with minimal short applications of the brake.
Clearly on grades we are familiar with we can start out at the speed we prefer and in the gear we need to be in, but NEVER on unknown roads, 40 mph may be fine on some roads, but a tight hairpin can be really frightening at that speed if you don;t know it's coming.
Paul
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All wisdom appreciated. Thank you! I lost the forum for almost 24 hours after I posted the OP, so I am very glad to see all the helpful feedback.
I will look at the autometer tach. Thanks for that tip More To See! I made a list of things to do of course, after my trip. New trans fluid is atop the list! thanks.
Clay, thank you very much for the maximums speed in gear 1 & 2 from the manual! I had a hunch that there was something about the 30 mph range based on the sound.
I don't have a tow/haul button but I've seen those and now I will know how to use them (always wondered), thanks zman.
Ace1001, I agree! that is a an excellent plan!
Dave, luckily my brake fluid was new in 2012 along with new a caliper resulting from an overall brake check for intended mountain driving. I will bleed and replace. thanks for the voice of experience in a similar rig.
xctraveler, thanks from a fellow P30 driver. 13%! wow. I can hardly imagine. That is extreme. 6% & steeper grades, use 1st gear. Good rule of thumb.
Arch, yes mountain driving certainly demands respect. 40 mph on a more wide open pass would be decent, but Teton Pass has a clearly posted 25 mph speed limit for trucks, and wisely so. 30 really felt kinda wild and it caused my DW to spasm her braking leg! you should see the runaway truck ramp - across the left side! On a two lane road!!! Very nutty drive in an RV.
Two things - a prayer at the summit would always be a great idea and maybe I should get brake vent duct/hose. I didnt think of ductwork on those huge rotors till I was up high. Has anyone done so?
OK one last thing sorry. I have sinned with my parking brake. I set it sometimes and I forget to release it and I drive off. I did that twice and you could smell it. The last time I did it there was no smell. Is the parking brake independent of the primary braking system? If it utilizes the primary brakes, I probably burned up a pad or a shoe. but the brakes worked fine, I must say. thanks again.
Your Chevy P30 chassis might have a brake drum behind the transmission that is part of the drive shaft system. Those would be the brake shoes that got worn down if you have the Chevy Auto Park system. A quick look under there will tell you pretty quick.
They is an adjustment that can be done but it involves lifting the rear wheels off the ground so you can spin the drive shaft.
I suspect we have all run with the parking brake set. They need a buzzer alarm system on that brake.
We were driving through some back roads in the Black Hills a few years ago. I spent most of it in 1st and 2nd on the downhills and didn't worry about how high the engine revs got. Suddenly on a steep downhill the tranny upshifted from 1st to 2nd. I still don't know why, I am pretty sure a 1993 Chevy chassis doesn't have an engine over-rev control in the tranny but maybe it does. Anyway, I still had plenty of brakes left so I kept it under control. A sudden unplanned upshift will make you have to clean out your drawers though!
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jvander wrote: We were driving through some back roads in the Black Hills a few years ago. I spent most of it in 1st and 2nd on the downhills and didn't worry about how high the engine revs got. Suddenly on a steep downhill the tranny upshifted from 1st to 2nd. I still don't know why, I am pretty sure a 1993 Chevy chassis doesn't have an engine over-rev control in the tranny but maybe it does. Anyway, I still had plenty of brakes left so I kept it under control. A sudden unplanned upshift will make you have to clean out your drawers though!
You probably inadvertantly touched the throttle. When using the engine for braking it will not shift up regardless of RPM, UNLESS you touch the throttle. If you touch the throttle at all, it will then shift up.
To the original poster, engine rev limits are for the engine under power as when going up the hill. When being used to brake the coach, the limit is much higher and is normally not indicated on a tach or otherwise.
Bottom line, an engine can safely and without damage turn significantly higher RPM while braking than while under power. Yes, it will sound loud and be much faster than you are used to hearing. But that is how you will remain safe and the coach will be fine. You should always be in low enough of a gear that the use of brakes is only very intermitant if at all.
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BigRabbitMan, thanks for the thought provoking post. My manual has little to say specifically on this issue. It does say that I can shift into 1st from any gear, at any speed. However first gear won't engage till the speed drops below 40 mph or 35 mph (depending on which manual page I read).
Apparently 30 or 35 mph are no problem descending with first gear engine braking. The only cautionary statement is one shouldn't brake too often or too hard.
There is quite a procedure for changing the ATF. I will drop the pan and get a new gasket and be prepared to replace any disposable filters w/new gaskets. It looks like I am right on, or ahead of schedule at 10,000 miles since last change. It calls for 12,000 mile interval, or sooner with severe use, which I would say describes the situation.
Also, I had a bobble ascending near the top of Teton Pass, where either the engine or the transmission briefly stuttered. When the fluid gets hot it expands, and more so the hotter you get it. When it expands excessively, you get bubbling and cavitation which cause slippage. It was attention getting but I got slippage but only briefly. To cool a transmission, you put it into neutral & idle. I should have spent more time at the summit in neutral. Good learning experience. After initially thinking that I would not want to do this pass again real soon, I won't hesitate now that I've learned a lot about it. I appreciate your help in my STEEP learning curve (so punny!)
oh, parking brake - I need to inspect my propeller shaft drum brakes for wear and adjust my cable, a process which sounds like a complete PITA (maybe it's not) but I really should have a functional parking brake. The manual isn't crystal clear for my comprehension level but it appears that the drive shaft has a brake drum, which is my parking brake. I don't think it was in completely perfect adjust when I got it, because when I tested it, it only provided a meager level of slowdown when in neutral. It was like a parking "booster."
Plus I need to rebleed brakes, because I smoked them on the Big Sky descent.
You've got it! The engine and transmission are for speed control both up and down hills. The brakes are for stopping, not speed control.
Regards the "parking brake". It is just what it says, it is designed to be used when parked and not as a "stopping" brake. That means that it is designed to keep the vehicle from rolling AFTER it is parked and not to bring it to a stop. This is true of all of the driveline parking brakes. If you use it while moving, you will smoke it. Think of two brake shoes doing what 8 normally do.
Yes, check the shoes and replace or adjust as necessary. It should be applied before placing the coach in Park to prevent "park lock" when the weight of the coach is trying to make the coach roll and holds the parking pawl in too tight to release. Before you leave the drivers seat, in your coach you should have the parking brake on and holding (release foot brake to check) and then place it into Park.
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