On the GM Express Van forum, there are a lot of posts concerning severe vibration when braking (usually going downhill). On our first cross continent trip in our 2008 Roadtrek last year, it happened several times and again this year. This may be solved by replacing the front rotors with higher quality ones.
Has anyone experienced this vibration? Usually front brake.
Has anyone cured this vibration? How?
I know that Booster and Photog had a very interesting thread going regarding lifting the suspension, in 2010/2011. Did either of you prior to or after the suspension lift have brake vibration? Could it be that the factory delivered geometry is a factor?
I am going to have the Roadtrek serviced in the New Year and I am looking at doing whatever is necessary at that time.
"Drive with Care, Life has no Spare!"
2008 Roadtrek C190V 6.0L Hella Fog, Nighthawk Driving, Halogen Reverse Lights, Fiamma Air Horn, Firestone Air Bags, Custom Bed & Mattress, Custom O/Head Tray. website www.sen-f.ca
Front disc rotors are probably warped and need to be either machined back or replaced. If it is the rotor you will feel the pedal feel like it is pulsing. Generally they will warp from getting too hot.
Not a hard job if you have basic mechanical skills. I did the rear rotors and callipers on our MH and it took me an afternoon but I had to take the rotors and hubs down to a friend that has a big press to get the studs out and then press them back on. Fronts are generally much easier....
After the brakes cool down does the vibration go away. I believe, that in some rotors, that heating of the different metals will cause the brakes to shudder, but will go back to normal after the brakes have cooled. I had this happen a couple of times in my Chevy Rt while descending steep grades, even though I was using low gears. From what I have read, this is not uncommon for the brakes on the Chevy van conversions. I had the rotors checked, and they were fine, so I didnt replace them.
You have a lot of weight, and what would be normal braking in a passenger car, will heat the brakes on the vans. I tried to use even a lower gear, so to stay off the brakes even more. It's hard sometimes because of the cars dogging you, I would just pull over more, and let them go around.
* This post was
edited 12/04/11 12:21am by My Roadtrek *
My '02 C190P's brakes only overheated enough to vibrate one time. I used to picnic at the same spot on the Blus Ridge P'way above town almost every day in warm weather, and coming down the first time I was in too high a gear (3rd), using the brakes too much. Using 2nd for the steeper part was the cure.
From nearly a lifetime of mountain driving, my answer to "what's right gear to descend in with a heavy vehicle" is the one that's slightly too slow. Then you use the throttle to maintain speed, and accept the fact that the engine is going to rev up. Pull off to let faster traffic go by when the need arises.
Jim, "Mo' coffee!"
'06 Tiger CX 'C Minus' on a Silverado 2500HD 4x4, 8.1 & Allison (aka 'Loafer's Glory') www.tigervehicles.com
The brake vibration is very common on the Chevies. There was just a discussion about it on the Yahoo Roadtrek board. There is a difference of opinion on what causes it, warping of rotors or uneven transfer of pad material to the rotor (my preference), but that doesn't really matter.
The cure seems to be higher quality parts, both rotors and pads. The high performance brake folks almost all say that semi metallic pads are the best for this application, but they will really mess up your wheels. Folks have had success using good rotors like Brembo, drilled or slotted, with top line ceramic pads. That is what we intend to do.
Also be aware that the success of using new parts can be VERY dependent on the proper bedding procedure at breakin. It is very detailed and fairly extreme.
It is very scary the first time this happens on a long downgrade. One of the members of the Roadtrek group on Yahoo solved his problem with heavy duty, slotted and drilled rotors and ceramic pads. My '04 RT on the Chevy chasis will vibrate badly if I let the rotors get too hot but stops as soon as things cool down. After I figured out what was happening I started downshifting to maintain speed on long downgrades and had no more problems. My mechanic tells me I have about only about 20% wear on my brakes so I've been reluctant to spend the money for replacement now. As long as I can control it I'll be happy and do the heavy duty replacement when new brakes are needed.
my daughter did in her van, turned out it was cheap rotors used by the great GM company. they replaced them free.
My daughter had the problem with her Trail blazer and GM refused to replace them saying they had been overheated (though she'd never driven the car in the mountains)in the 30,000 or so miles she'd put on it. Had them resurfaced and the problem returned in about a year but when she then replaced them whatever the cause, the new ones never repeated the problem.
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Seems the quality of all rotors, oem and aftermarket are highly suspect these days. I have a mechanic friend who does a LOT of brakes, and he will turn fresh rotors right out of the box, says about 70% of them are not true right out of the box. Says this saves him a lot of money rather then having an unhappy customer return with a pulsing pedal and have to do it then anyway.
Now there is a lot of debate whether the pulsing is caused by uneven pad deposits, or warped rotors. I personally do not have enough experience to weigh in.
I recently put some Bendix Titanium mettallic2 pads on my van, for greatly increased stopping power. My previous pads were very anemic and nearly dangerous. I can now lock up the fronts if I have to. I'd rather wear the rotors faster and deal with more brake dust than rear end somebody. They are only 50$ a piece for my Van so not a big deal.
One thing I do now, is NOT leave the pads clamped tight to the rotors after a hard stop. I either stop early and slowly roll forward, or just use the parking brake. Leaving the hot pads clamped on the hot rotors will either cause pad deposits to form, or uneven heat distribution might cause the pads to warp, or perhaps both possibly resulting in the pulsing pedal.