tires and brakes on my four winds chevy 3500 chassis

[wpatters1229]

Just to follow up on an old subject. All about tires. I bought 4 new tires for our class c rears from firestone. Inflated them to 80 and the fronts to 75. Ran over 8000 miles this last summer from west coast to east and back. Not one bit of trouble and only had to top off once after half way through the trip. Great tires and the 80/75 psi seems ideal for all the altitude changes, heat and rough roads.
Now my concern is with brakes. Does this rig have disk brakes in the back axle? It is a 2005/2006 Chevy Express 3500 chassis. On real steep down grades as much as I try with down shifting etc. the brakes sometimes get hot to the point where they really start to shimmy...I mean the rotors are warping bad...they seem to straighten out after they cool. Has anyone replaced the fronts with drilled and slotted rotors? I did that with a jeep and it really made a difference.
Let me know your thoughts on the brakes.

Thanks

[wpatters1229]

Did much more research and actually the industry states that semi-metalic pads are far better for heavy vehicles than ceramic and they stop better in high heat. That is why most kits containing a rotor and pads use these. That is what I am going with and heavy inspection of the calibers....I have had sticking calibers before on other vehicles along with bad and worn guides. Thanks Will look at the link Rolin sends.

[Rolin]

Hi wpaters1229,
I believe that you experienced the same problem we had with our 2003 Jayco Chevy Class C. We experienced uncomfortable brake shudder/shaking (caused steering to shake side to side) when the brakes are used hard (like on an extended downgrade). It was caused by rust and corrosion on the calipers.

We could see that one of the brake pads was worn more than the other. Found that this was not uncommon on Chevy class C's. You can see our journey to find the cause and effect a cure in the thread listed below. It includes some pictures. Took time to find the exact cause but after the fix our brakes worked great. Did not need any special slotted rotors or special disk pads. Amazing difference when the brakes work right.
http://forums.motorhomemagazine.com/index.cfm/fuseaction/thread/tid/25738198/srt/pa/pging/1/page/1

[carringb]

One cautionary note on ceramic pads: They have less friction when they are cold, like the first stop in the morning, or even after cruising on the highway in cool weather. They have great stopping power when warm, but I didn't like the excess distance when cold. Probably less of an issue in a motorhome, since they'll heat much quicker. Just be aware your first stop or two each trip will take a little more stomp power.

I would not expect sealed bearings to need replacing so soon, unless they were ever submerged in water.

[ron_dittmer]

wpatters1229 wrote:
The front hubs have a open hollow center that is big enough to stick you hand in and it reaches all the way to the rotor. It appears as though after taking off the lug nuts and then the hub nuts the rotor would just pull right off after taking off the caliper and pad assembly. I think if there is a bearing it is something at the rear of the spinal and not part of the hub or if it is it certainly is not anything you can just remove like the old cotter pinned bearings. I know what you mean. I had a 56 chevy for many years and they always had to be re-packed. Most of my cars over the years had packable bearings. Thanks

It seems the industry trend had been that front wheel drive vehicles introduced sealed bearings up front with non-fwd quickly following. I personally like sealed bearings and just replace the hub when it's time. There is too much vulnerability with packed bearings. From contamination, improper packing, and improper tightness, packed bearings is just too touchy to me. Just replaced a bolt-on sealed hub assembly and be done. Hub assemblies are very reasonable to purchase and relatively simple (non-skilled) to replace on non-fwd vehicles like a van/motor home. I wished we had sealed bearings on our 2007 E350 RV.

[wpatters1229]

The front hubs have a open hollow center that is big enough to stick you hand in and it reaches all the way to the rotor. It appears as though after taking off the lug nuts and then the hub nuts the rotor would just pull right off after taking off the caliper and pad assembly. I think if there is a bearing it is something at the rear of the spinal and not part of the hub or if it is it certainly is not anything you can just remove like the old cotter pinned bearings. I know what you mean. I had a 56 chevy for many years and they always had to be re-packed. Most of my cars over the years had packable bearings.

Thanks

[scroller95969]

The front bearings are sealed in the hub assembly from 2003 on.

[ron_dittmer]

If your front wheels have center hub caps with a cotter pin behind, then you have grease-packable bearings.

I would definitely repack them during a front brake job and also replace the inner grease seals in the process. They are very cheap in price and are critical for lasting protection from water and other contamination. They come out during the grease packing process so just put in new ones.

When repacking, do one wheel at a time as not to mix bearings right to left side for they wear uniquely into their mating race.

[wpatters1229]

I watched that video on youtube and he didn't have that much trouble getting the caliper bracket off...locktight does make it tough. Generally that stuff will break loose with a sharp rap on a breaker bar. Now if the wrong type was put on it can be very difficult....heat works...so does loosenut spray. The inner nuts on the hub is what I am concerned with since you have to cross jam the wheel with a bar across the lug nuts. Just takes time and muscle.
Thanks

[scroller95969]

If I remember right if you are replacing the rotors you have to take off the caliper bracket and I thing that it torques at 225#'s. I had a heck of a time getting the bolt loose. After I got it off I could see that there was some kind of locktite type material on the threads. If I were to do it again I would carefully apply some heat to the bolts and then replace them. When I reinstalled them I put some red locktite on the threads. I think that the pads only torqued at 80#'s.

[wpatters1229]

I found a youtube video that looks just like the front brakes on this RV https://www.youtube.com/watch?v=EJvCxxXCNbs Answers a lot of questions. I believe you are right on the bearings. Make sense. The person saying they might have to do the bearings is the secretary who takes reservations for work. I think that is a standard answer so no one is blind sided. I just need to make sure my air tools are strong enough to undo those inside nuts. The video does not show the torque on those but I would say they are probable the same as the lug nuts which is 140 ft lbs.

thanks

[j-d]

Looking at rockauto.com, it hints to me that Chevy went to sealed wheel bearings for the front wheels. Be that true, I'd question the integrity of a shop which says they need packing.
For anybody lurking, on many vehicles, the brake caliper bracket prevents removal of the rotor/hub, so they pack only the outer bearing. Job should be remove, clean, pack, install with new inner seals, both inner and outer bearings.

[wpatters1229]

OK I called an RV shop and they said I should also have the front wheel bearings packed. The wheels seem fine and in my haynes manual it only says anything about packing wheel bearings for 2002 and earlier. Does that mean I should leave the bearings alone? Also from what I can see I do not have to remove the bearings to remove the brake disks. Thanks

[wpatters1229]

I did find a cheaper solution at http://brakeperformance.com/brake-rotors/premium-dimpled-&-slotted-brake-kit-black-zinc-coating.php

[wpatters1229]

OK I am going with some ceramic but wow all these parts are expensive compared to rockauto listings. The rotors are almost $400 alone. Will have to think on this one. I keep hearing my late dad say, "They paid smart engineers to build these so why would you change from what they recommended?" How about money!!

[scroller95969]

I don't remember the pads. I'm almost sure that they were just the semi-metallic that I got them at the local parts store. Probably middle of the road price. I'm planning on putting on new pads this year.