How to properly brake on mountain passes (1 Viewer)

[MDarius]

Oh! And RPM's. There have been several discussions about what happens when you run it at high RPM's. I'm probably out of my league on this one, but my understanding is these engines, when in good condition, can run at 4000 RPM's without a problem. When I'm on a hill I let it run up to 4500 or so, brake, let it run up for a while, brake, and repeat.

I think the risk is blowing a hole in your exhaust, blowing a weak head gasket, throwing a rod (I don't know what conditions would lead to this). Maybe someone with more knowledge can clarify or point to a good thread?

 

[Tools R Us]

I am adamantly opposed to braking in most cases.



I use the shifter a lot. Let your engine do most of the braking. I'm driving Sierra passes almost weekly now, in snowy/icy conditions. If you're on your brakes, you're out of control in a lot of cases. And I cringe at all the idiots out there...

Also agree with everyone here about flushing the fluid system. Mine needed it a LOT.

This is also the first automatic transmission vehicle I've ever owned, though.

Yep, if the plan is for less than ~30mph, shift low range. On road this is all I have even needed. Off road, most including Black Bear, are good, some really steep, need added brake, but due to the slow speed, not a problem.

That said, mine has crawler gears and have tuned the trans, cable and system pressure, so likely holds better than most?

 

[LINUS]

I'm w/ @surfpig & @SmokingRocks on this - I stay off the brakes as best as possible, and I shift manually to control speed.

Rocks made a comment I know lots of peep forget - that OD button under the handle. That's your 3rd gear before dropping down to 2 on the stick.

The post above @NLXTACY about brake health & mods is good too (& J's comment about good E-brakes for that all out, oh $hit moment) - but starting out slow & with OD off is a great way to control it, then 2 & 1 as it gets steeper/technical.

You may want to look at Hawk, EBC, etc - for pads that can handle whatever you are planning. I'm on EBC yellows since I spin 315's & seemed like a good idea.

 

[bloc]

Maybe a rear parachute? But seriously I was thinking the same thing as I am planning some trips like Black Bear Pass, etc. The brakes on these heavy trucks don't seem to be on par with the weight especially going downhill.

I don't remember even beginning to think about my brakes being an issue on black bear pass. The really steep, technical stuff is so slow that it's just a matter of traction and ultimate holding power (bite).. as in be way more worried about your brake booster/master cylinder than overheating anything.

Oh! And RPM's. There have been several discussions about what happens when you run it at high RPM's. I'm probably out of my league on this one, but my understanding is these engines, when in good condition, can run at 4000 RPM's without a problem. When I'm on a hill I let it run up to 4500 or so, brake, let it run up for a while, brake, and repeat.

I think the risk is blowing a hole in your exhaust, blowing a weak head gasket, throwing a rod (I don't know what conditions would lead to this). Maybe someone with more knowledge can clarify or point to a good thread?

My thoughts as well. I've always preferred letting the engine do as much braking as possible with intermittent "stabs" of the brake pedal to scrub speed, vs long periods of mild braking with no chance to let the rotors/pads cool off. Personally.

And, as long as the oil isn't getting too hot (unlikely on a downhill section) there's no reason the engine can't spin at 4k for HOURS. Even a very short stint at redline/5k would introduce higher forces than 4k sustained.. and as long as the oil/pump/coolant continue to do their jobs it SHOULD just sing away happily.

That doesn't mean I like doing that in my 300k mile engine.. it just feels cruel.. but I will if I have to.




One other strategy is to simply find the terminal velocity of the truck for the given slope. Why not let the refrigerator-like aero signature work to your advantage? Drag increases by the square of increased velocity..

 

[Heckraiser]

Lots of things already discussed here, but my $.02:

Yes, put the shifter wherever it needs to be for you to not have to ride the brakes. 1st gear, low range, whatever. Riding the brakes is the problem.

Things that have helped me with brake fade in race/track vehicles (IMO the heat stress of racing events is similar to a mega-steep switchback trail): thoroughly flush brake fluid and replace with a fluid with higher boiling point. I'm not sure what's available in CZ, but DOT4 Valvoline did the trick for me. And steel braided lines. Both of these made a HUGE difference in brake fade for my little honda. I would look at both of those options before pads because those wont hurt the brakes under normal conditions, but often pads designed for high heat don't work that great when cold (and are noisy, dusty, etc). But there are plenty of good all-around performance pads available that are a good compromise.

 

[scottryana]

These will likely be overkill for an 80 but I would use

From cheaper to most expensive
Motul RBF600
ATE Blue
Motul RBF660
Castrol SRF

Any good high quality fluid will be ok, the biggest problem with brake fluid is that it is hydrophilic and as it gets more infiltrated with water the boiling point comes down from as high as 600-610f to 200-300f, once it's boiling you have no brakes. So go cheaper and change more often if that's what you can afford.

The 'best fluid'? What do you recommend?

The 'best fluid'? What do you recommend?

 

[SmokingRocks]

Also selecting od off automatically locks the torque convert. Atleast on the a442F

 

[richardlillard1]

These will likely be overkill for an 80 but I would use

From cheaper to most expensive
Motul RBF600
ATE Blue
Motul RBF660
Castrol SRF

Any good high quality fluid will be ok, the biggest problem with brake fluid is that it is hydrophilic and as it gets more infiltrated with water the boiling point comes down from as high as 600-610f to 200-300f, once it's boiling you have no brakes. So go cheaper and change more often if that's what you can afford.

I use SuperTech from Walmart. Is that bad?

 

[bug616]

What about this :
West Coast Cruisers

Manual Control Lock-Up Unit Toyota with A442F, A343F, A750F, and soon for the B02A(6 speed auto) transmissions. Designed to manually control the Lock-Up convertor in All forward gears and reverse(Require Extreme Valve Body for 1st and Reverse Lock-Up). Eliminates all convertor slippage and convertor runaway on steep downhill descents allowing full 100% engine braking. These are must for Off-road Enthusiasts as well is those who Tow.

$210.00 USD (In Stock)


Have anybody installed that ?

I have this from Wholesale Automatics. Simple thing but totally transforms the ability to both ascend and descend steep hills. Effectively the same benefit as having a manual (on hills).

 

[snowglobe]

Boiling points
Motul RBF600: dry 594°F (312°C), wet 420°F (216°C), ~$39/liter
Motul RBF660: dry 617°F (325°C), wet 400°F (204°C), ~$56/liter
Castrol SRF: dry 590°F (310°C), wet 518°F (270°C), ~$62/liter.

Compared to
ATE Type 200: dry 536°F (280°C), wet 388°F (198°C) ~$14.5/liter
ATE Type SL.6: dry 509°F (265°C), wet 347°F (175°C) ~$13.5/liter
Castrol LMA/12509/12614: dry 509°F (265°C), wet 329°F (165°C) ~$9.5/liter
Lucas Oil 10826: dry 401°F (205°C), wet ? ~$12/liter
Toyota 00475-1BF03: dry ? , wet ? ~$28/liter

These will likely be overkill for an 80 but I would use

From cheaper to most expensive
Motul RBF600
ATE Blue
Motul RBF660
Castrol SRF

Any good high quality fluid will be ok, the biggest problem with brake fluid is that it is hydrophilic and as it gets more infiltrated with water the boiling point comes down from as high as 600-610f to 200-300f, once it's boiling you have no brakes. So go cheaper and change more often if that's what you can afford.

 

[leonard_nemoy]

I think your a couple years late

 

[BILT4ME]

I think your a couple years late

Maybe, but SOMEONE will use the info later on if thy're doing their searches!

Nice addition @snowglobe !

 

[SNLC]

Hello,

having 1996 FZJ80 with automatic transmission I struggled when descending mountain passes. Do you guys have any tricks how to properly brake when going down very steep mountain pass ? Put in low and first ?

I was almost without breaks on this pass:


Any other options then just stop and wait to cool the brakes ?

Yes, I lived in the heart of the Rockies for two decades.

As stated multiple times down shift. On top of that tap your brakes, don’t just ride them down the mountain. This helps keep them cool and prevent warpage.

Cheers

 

[inkpot]

Two years ago I made a 2 week trip back up to Colorado and Wyoming. Hit Pikes Peak @ mid morning on a week day, so got to drive it with very little traffic. Ran it hard. Low range, 3rd and 4th gear all the way except dropped into 2nd for few hairpin turns. Made it from entry gate to train station in 50 minutes! Yes. You can Rally an 80.
Ran the same way going down. Staying in low range. Rarely even touched my brakes. Mid mountain in n the Park Rangers check yur brake temps with an infrared pistol. My brakes were 85 degrees. He did a double check because EVERYBODIES brakes are way hot coming down, so he makes them park and cool down. Bu TV not me. I think the 80 has grea TV compression braking for an automatic. Just shift down and do it.

 

[Broski]

I'm w/ @surfpig & @SmokingRocks on this - I stay off the brakes as best as possible, and I shift manually to control speed.

Rocks made a comment I know lots of peep forget - that OD button under the handle. That's your 3rd gear before dropping down to 2 on the stick.

The post above @NLXTACY about brake health & mods is good too (& J's comment about good E-brakes for that all out, oh $hit moment) - but starting out slow & with OD off is a great way to control it, then 2 & 1 as it gets steeper/technical.

You may want to look at Hawk, EBC, etc - for pads that can handle whatever you are planning. I'm on EBC yellows since I spin 315's & seemed like a good idea.

What is a peep ? Someone from the PNW or maybe posters with nearly 5000 posts,

 

[LINUS]

What is a peep ? Someone from the PNW or maybe posters with nearly 5000 posts,

Peep(s) = people(s)

Dang, I’m a old fart.
You never heard peep(s) before? -or did I spell it wrong?-

 

[Broski]

Linus
I going to guess that at 60 years of age that I'm am the old Fart, and no I never herd the term Peeps before, Except for the derogatory use of it in your Post's on this forum's. Just saying

 

[ZackR]

On top of that tap your brakes, don’t just ride them down the mountain.

This part is key and often overlooked. The brakes will run cooler with a firm but short application rather than a gentle but long application.

 

[SNLC]

This part is key and often overlooked. The brakes will run cooler with a firm but short application rather than a gentle but long application.

I lived in Wyoming for 20yrs. Wilson, Wyoming is at the bottom of Teton Pass. Five months a year the town completely stinks like burning brakes from all the tourist riding their brakes down that pass. Super annoying too when you have to follow them down the mountain and they force you to ride your brakes because they are doing it and going 15mph down the pass.

I don’t miss that at all about Wyoming.

Cheers

 

[Grench]

Just because you have an automatic transmission doesn't mean you can't downshift. Do it -before- you 'need to'. I.e. when you see signs saying 'trucks use low gear' and grade markers.

On paved roads...
I'll usually come over the crest of what is going to be a long steep downhill at or under the posted limit. Release the overdrive button on the side of the shifter (going from 4th to 3rd) - somewhere between 45-60 mph and foot off the gas. If that still accelerates due to the grade, I'll brake down to 40mph and drop the shifter into 2nd. Foot off the brake. If still accelerating due to grade, then this is a really steep thing you're going down - like 15% grade steep. Hit the brakes hard to bring it under 25 mph, downshift to 1st, let off the brake. If you're still accelerating in 1st, you're going down something that is going to seem like they paved over a wall. I haven't seen any stretch of paved road so steep that 1st gear won't hold from accelerating past 25ish outside of a national park where the speed limit is already posted to 20-25mph.

Offroad, if you're already in low range, the 80 with the transmission in 1st can generally keep itself 'slow' up to where the wheels start slipping due to gravity - at which point braking doesn't do much more than lock the tires and eliminate steering - which means uncontrolled ballistic descent...

There is a brake temp station at the bottom of Pikes Peak. I went there a few years ago. We came down the mountain in one continuous drive, stopped at the brake check, the guy laser temp tested the brakes then asked me if I'd used 'em at all on the way down. My reply was, "not much".

Note: My truck is supercharged and running 315/75R16 tires on 4.88 diff gears. YMMV