My service truck is a square nose Dodge with the 1st gen cummins. Some say 50k mile truck w a 500k mile engine. Brakes survive one year on the front end; they pulse and vibrate terribly at the end of the pad life because they are suffering from runout and are also worn unevenly but smoothly (ie no grooves or ridges etc) such that the thickness is no longer consistent. Have read it is imperative to achieve zero or one mil runout on new rotors in order to prevent the runout from causing the uneven wear that in turn causes the shudder. Has anyone tried the rotor shims that correct this problem? Nucap and Raybestos offer this shim in three versions of "taper": three six and nine mils of correction. If I install the new rotors with the runout .... since they are new and the same thickness it will be ok for a while then it will start doing it again in about 6 months and about one year or 15-20k miles it will be pretty bad. Hate to have these new rotors turned to address the problem that is likely caused by the hub as theses new rotors are surfaced etc etc.
Can you post some photos of the calipers? Truck Shop
Will get some pics .... Having a bit of a challenge with the correction shim because of trying to figure out their part numbers so I can order them.... I have an email sent to the mfg (Nucap) requesting assistance in this regard. By the end of the day today it seems the most practical solution is to have the new rotors installed onto the hub and take em to a brake shop to have em turned to remove the runout in the hub and rotor assembly.
I gave up long ago on turning rotors, most come with only .060 room to adjust when new and once eaten up by pads are down to where you cannot get the warp and runout off them. I tried a few after market units, and not any better where my Ford would destroy them in 2/3 the miles. Dragging a 24' goose with a farm tractor and bush hog along with supplies of fuel, tools and gear for a weekend every two weeks 130 miles one way years ago ate it up.
Here are some pics of the front caliper and rotor. These new rotors are made by Centric and I checked em on my lathe (rotate part in chuck as well traverse the DI) with a DI (dial indicator) and they were 'perfect' as my DI can tell me. Looking cool air holes and slots too for no extra charge LOL. My Dodge [mfg by Budd] wheel hubs - another story. Using some 2 mil brass shimstock 'tween the rotor and the hub: I was able to get one rotor to a fat 3 mil RO (runout) and the other to 2 mil RO. The one pic shows the brass shim in the ply of the rotor to hub. I did find a mfg/source for full contact tapered rotor to hub shims, they are made by Nupac and also can be found under Raybestos, but no part number listing for my truck. Their catalog is 'application specific' as opposed to me asking for 8 lug, 1/2" diameter on 6.5" wheel centers. According to my OEM service manual, the brake caliper etc are mfg by Chrysler. The idea for this project is to get the rotor RO as small as possible to prevent uneven wear (non parallel rotor faces) to preclude the "judders". * In my quest to improve these brakes, I have found brake pressure gauges to be of great value: Example A have caught a master cylinder 'easing off' (internally bypassing) the brake pressure to the back axle. Example B I determined the RWAL (rear wheel anti lock) was also misbehaving. These brake pressure gauges mount right on the caliper and or the wheel cylinder as applicable. ** There is no doubt the weight pf the truck and the tools as well as the trailer plays a hard hand on these brakes, just aiming to optimize the part life as we tend to get busy and hard to find the time to work on the truck.
What's a "mil"? Is that some kind of slang? Typically we speak in terms of "thousandths" of and inch, or "tenths" of a millimeter. IMO, the problem with all Dodge trucks is the POS caliper design. They never float correctly and always wear worse on one side or the other. I don't know if Willwood or some other independent brake company has an upgrade available, but the Chrysler design is complete garbage. If you want perfect runout, you can take them to someone with an on car brake lathe. Or, if possible, turn them in your brake lathe with them already mounted to the hub.
A mil is a thou.
To a Millright!! I would not have shimmed between the hub/rotor, that needs to be a clean, tight, stuck together nothing squishable fit. Would have assembled and made any cleanup cuts to square on the lathe.
Dodge caliper brackets and calipers had a problem with crud getting in the caliper mounting slot of the bracket. If those are not cleaned out periodically the caliper will loose its floating ability and the rotors will wear unevenly. I had a Dodge D150 4X4, when I rotated tires I would remove the calipers and wire brush the contact areas and smear a thin film of anti-seize on the bracket. Or I just did it twice a year it just became part of the maintenance. I owned it 23 years never had brake issues. Truck Shop