#1 If the brakes are not acting weird, like surging when braking, or any other wobbling/squeaking/grinding..just the pads are worn, is it necessary to replace/turn the rotors?

#2 How does one know when to replace the rotors?

#3 Are OEM pads worth the price?

I realize this topic has been hashed out in the past, and I ve read a few of the old threads. I would like to get some recent thoughts on the subject.

The front left brake is making a soft sort of hum occasionally, like the starting of a "old school bus" noise I remember hearing from my youth. The brakes work just fine. In fact, I had to dynamite 'em yesterday and the anti lock kicked in on the front.

Thanks again,eh?

Brad

 

With non pulsating brakes as long as there are no deep grooves it's fine to continue to use the rotors as is. There will always be a slightly irregular surface due to the dispersion of abrasives in the friction material so new pads will take a day or so to wear into this pattern. The reduction in friction of the inconsistent contact is mostly made up by the increase in friction of the already established brown/gray transfer layer on the rotors vs turned rotors that have to build up the transfer layer to achieve full braking ability.

After a five year study there is no way that I could recommend to have the rotors turned on a bench lathe, only an on-car lathe gives consistent results in the most important aspect, rotor installed runout. This is why back around 2000 Ford gave on-car lathes to every dealership, something they never did before. And the brake manufacturers have been getting the aftermarket service people up to speed since.

The problem for DIY is by having a shop turn the rotors on a vehicle you might as well let them do the brake job. So for me I take the European approach. The rotors are just a wearable item like the pads, if they are damaged I just replace them.

I replace rotors if:

• They have pulsation (disc thickness variation, not warped)
• They are deeply grooved
• They are close to there minimum thickness
• The cooling vanes are excessively clogged by rust inhibiting cooling

You can't get OE production line pads anymore for your year vehicle, but you can get the Motorcraft versions. Those both standard and Super Duty are a better pad then what was OE for the 1999-2004 model years. Also a very good pad is the Hawk LTS formulation, which is a high metallic, higher friction pad. Due to the higher metallic content then what any OE engineer would accept today, there is a lower cold temperature friction level, but friction increases as the pads warm. With the high metallic content they also have good very high temperature fade resistance, so they are a good pad for people towing as most trailers are never set up with good balance to the truck, working the truck brakes more then they should.

Humming. If it's not that they are just happy I would check that the individual rubbing disks are even in thickness from the left to right side of the truck. It is normal for the rubbing disc to be of different thickness inner to outer on an individual rotor. But if there was a situation with a constantly rubbing brake pad against the rotor it would overly wear down a rubbing disc to the point where during braking the harmonics of going over the vanes can cause that noise. The OE rotors would not do that as they are a post vane design, but aftermarket rotors are a straight or curved vane design.

Humming can also come from a worn hub bearing that has developed gooves in its race, sometimes only heard with the addition forces while braking.

 

Good info, I was just discussing this the other day. I have NEVER seen a brake lathe or lathe operator at a parts house that I would trust to do precision work. I have also fount that turned rotors do not hold up well and there are issues sooner that if they where just replaced. There ARE cheap rotors out there and I would not buy the cheapest ones, but quality ones can are not too badly priced. I think I paid about $80 a piece for mid priced rotors from NAPA when I did my 2003.

 

When I did training classes decades ago I used to tell the group show a machinist how a parts store turns a rotor and ask them what they think. It's not as foolproof as the lathe manufacturers lead everyone to believe. The big problem is getting the rotor surfaces parallel to the hub mounting surface. The rotors that have a hub with bearings are not too bad depending if the lathes shaft haven't had too many rotors or drums roughly handled on them. Drum turning is fine as a drum brakes shoes walk with the drum rubbing surface, but rotors and pads do not.

The biggest issue with rotors is they are brought in to be turned to correct a pulsation issue and most of the time the rotor has developed hard spots, and those cannot be turned out on a lathe. So after about 5-10k miles the driver reports pulsation has returned and the myth of the rotors warped because they are thin. Not true, they have developed thickness variation as the hard spots won't wear as fast as the other softer area.

But as mentioned above about getting the rotor surfaces parallel to the hub mounting surface. Any excessive runout causes the high runout areas of the rotor to slightly touch the pads so those area wear down during off-brake driving. Thick to thin equals pulsation.

Now if everyone indexed the rotors to the hubs for lowest runout, and to spec (and the spec on these 4x4 trucks is 0.0015") then life would be easy.

But now without a test facility where I could turn my own rotor, yeah I just replace them as needed. The only warning about lower priced rotors is tight machining tolerances cost money. Before our aftermarket rotor manufacturing plant was moved to China the company spent $10mil to upgrade the machining side.

 

I researched rotors and pads and there are countless choices from cheap to extravagant.

Any suggestions on some good, reasonably priced rotors and pads?

Gracias,eh?

 

My oem ford were original at 161k. I would have still used them if I hadn't beat the snot out of them taking them off.

 

Brad,

I gave my pad recommendations above. The only rotors I'm buying for a Ford are the
Motorcraft, which are not OE but aftermarket. I have a stack of OE rotors for my '03 SD in my shed, but those are not in production from K-H anymore.

 

Older thread, I know, but looks like a brake job is due for my truck...

What is the minimum rotor thickness?

I'm on original rotors at 153k miles (with a 13,500 lb 5th wheel).

Last brake job done at local Ford dealership indicated 37.4mm remaining...that was in 2010.

 

2007 book says front disc minimum thickness 36.4mm/ 1.433in. Rear is 32.4mm/ 1.472in.

IMO replace them no matter what, they're cheap enough and with 150K+ you done good.

 

Thanks Tech...

Ford or aftermarket? If aftermarket, who makes a good rotor for heavy towing applications?

 

I have Power Slot Cryo rotors and Hawk LTS pads waiting to go on, but these stupid dust-maker AutoZone Gold pads are still hanging in at 65k miles with 110k mile stock rotors.

Hawk LTS or Motorcraft Super Duty (I think they make them for SDs) and Motorcraft rotors would be a good bet.

 

Geez...why can't Fordparts.com be more specific...

I see BRRF-100 and BRR-158 rotors that "match" my 2006 KR 4WD...which is it?

 

I would do the Motorcraft as they have the tightest control on runout and surface finish. The catalog, can't help with that. Both part numbers refer back to the OE assembly line rotor 7U2Z1V125A.

 

I have always received a quick response emailing the parts rep at:

Ford OEM Parts & Motorcraft Parts | Official Online Parts Store of AutoNation Ford White Bear Lake.

Pat Rawn - Parts Specialist

 

I called and got it sorted out...thanks!