I live in Indiana (at 700ft. above sea level) and recently took my buggy to the rocky mountains and encountered a couple interesting "pressure-change" problems that I thought I would share with anyone who plans on taking their buggy to the mountains...

My CV-boots have always held fine with heavy load zip ties in Indiana. Going to the top of the mountain (11,500 ft above where I installed my CV-boots) they all blew up like balloons (and I mean HUGE ) and one completely blew off the flange. The other 3 had to have the small tie cut and then be "burped" back down to size. The opposite happened on the way down and at the bottom they looked vacuum-sealed. BTW... Zip Ties and CV Grease are NOT some of the things the Alpine Center Gift Shop (the only thing at the top of Rocky Mountain National Park and approx 60 miles from nearest hardware store) keeps in their inventory. Many thanks to the guy who was packed to the gills for a long camping trip who had some because I didn't... But I used to have some in there.... But I got a bunch in the buggy box again now.

My master cylinders encountered similar problems... The sea-level air pressure still trapped in my master cylinders activated my brakes just enough to eat halfway through my pads. I never smelled brakes once so I guess the race brakes work good. It also explains why my buggy felt power limited at the top. It was less the "thin air" in the motor and more the "fat air" in the brake master cylinder. I spent the whole week at 7,000 ft or above and put almost 700 miles on my buggy so that was a lot of slight braking. Some where along the way the loss of pad equaled out to the gain in pressure and they let up. Then when I got home it was the opposite as well. Had to pump my brakes 3 times to have pedal. Opened Master Cylinders and the boots were under a vacuum and were pulling my now worn pads all the way in.

I know it's all simple science NOW and maybe obvious to some, but I wasn't expecting it and found it quite interesting and frustrating at the same time. Just thought it would make for a good story for anyone else considering some high altitude play with their buggy.

Pretty cool information. Bet its something you will never forget!

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WTFO
We ride together, We die together, Bad Boys for Life
Loud pipes save lives.

Moral of this story... all you guys that can't get your brakes to work and have to pump them 10 times... which we have heard a hundred times... need to move into the Northern Rockies region and it will solve your problems! The sad part is that when you are fighting brakes and have tried anything and everything to get them to bleed out, you would contemplate this option if you let your emotions get the best of you!

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“Life is hard; it's harder if you're stupid.” - John Wayne -

I went there thinking: "As long as I don't have carbs... It will be fine..." Makes me wonder what the cv boots and master cylinders on all the Illinois and Iowa cars I saw there were doing. I bet alot of people who vacation in Colorado end up doing brakes and half-shafts afterward.

Magine that ... I need to take my wifey up that way to peronally experience this pressure change in as many ways possible !

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Theirs no replacement for displacement !

Sounds like the vent on you M/C cap is plugged ? I lived in Estes Park, and never experienced what your describing. Even when I'd ride from Loveland, about 6000', up to the Park entrance, I never saw a difference on my boots either. Yuo'd think everyone in Colorado would have blown boots, since everyone there drives a Suby ?

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Don't sweat the petty stuff, pet the sweaty stuff.

You are right... Every third car in Colorado is a Subie. My MC vent is in the lid. It only accomodates for the air between the lid and the rubber boot. If there is positive pressure in there the boot will just be smashed against the lid. If I would have just opened the master cylinder and let the pressure out it would have fixed it. I just didn't catch it until it was too late. My father in-law's brand new pickup did the same thing. Pulled buggy all the way out there in OD. I got about a mile up and it wouldn't pull in OD anymore. Sometimes it was even downshifting from OD on a road that was noticeably down-hill and I couldn't figure out why. Again I thought... Thin air = No Power... But down-shifting DOWN A HILL??? I figured out why when I saw how much brake dust was on the wheels. It wasn't from down-hill braking because the truck has electronic trans-braking built in with the tow-haul feature.

I don't think the CV"s would have been as much of a problem if I had the PROPER steel zip ties on them. I think most cars just adjust to it after a couple weeks because the pressure was even pushing the grease out around the bolt heads on the cv. It wouldn't take very long for the pressure to equal out. I bet there are a lot of FWD Cars with grease all over the underside. Besides that any newer car would have the cv's greased by a robot machine that puts the perfect amount of grease in there with almost NO air to expand in the first place. My power steering system is also sealed. when I got back to Indiana I burped everything but my steering res. and first couple times I started buggy PS pump would sound like it was dry starting. Took off cap and it was pulling a vacuum. Put cap back on and started buggy. No PS noises anymore.

It wasn't just car stuff either. I bought a quart of oil in Estes Park and the bottle was round it had so much air pressure in it. All my wifes makeup blew up in her travel bag on trip up to Estes Park (she was convinced I had set something on it and smashed it at first). The bags of potato chips at the gas station in Estes Park were all as big as my CV Boots. If you buy a non-carbonated drink in a can it still sprays you when you open it. Once I knew what I was looking for the symptoms are everywhere.