My 2008 grand caravan needs new front brakes. They're squealing. I'd like to replace them myself. I watched a few videos and it looks easy enough.

However how do I know if the rotors need to be replaced as well?

Trying to save money and do things myself.

Thanks

 

I would replace the rotors too. Rather than resurface the rotors.

 

Rotors generally don't need replaced if you currently don't feel any brake pulsation and the surface is not gouged. Make sure to inspect all rubber parts for rips or cracks. Clean and grease the floating caliper pins so you don't experience premature brake wear out and poor braking from dragging, stuck brakes.

 

I disagree. Most pads and rotors wear their faces together. Nowadays, the rotors are designed to absorb more braking heat and hence wear faster than in years past.

I'd replace both, unless you have less than 5,000 miles on the rotors.

 

And I disagree with that. The quality of replacement rotors is spotty; maybe you'll get a good set, maybe not. That's true even of major brands; don't even think of using the cheap Chinese crap from your local parts store unless you plan to sell your car.
If your rotors aren't causing pulsation, i.e. they seem to be running true, I'd reuse them. I've done that many times on other cars, not even having them resurfaced, and had no problems. Just rough up the faces with some sandpaper to help the pads seat, then move on.

 

True that. Same goes for flywheel and clutch replacements. Unless the rotor or flywheel is visibly scorched, vibrates/pulsates or shows cracks from overheating or gouges, many will survive multiple wear-out cycles with good results. I have gone thru a set of rotors in a weekend BEFORE the pads wore out while had others last for 4-5 pad sets. Inspection and attention to symptoms are the key to deciding whether rotors need replaced. Pads have wildly varying compounds and rotor wear characteristics depending upon quality, driving behavior and duty cycle (weekend road racing, hilly terrain, commuter, heavy load, short trip, highway or pedestrian use). Some rotors are real losers from a quality and lifecycle standpoint while other's truly wear like premium iron. I stay away from typical economy rotors because they rust and can't withstand any heat....but you can't go wrong with $19 Bendix. I have seen Chinese discount rotors last less than 2 months under normal street use. The metallurgy was terrible...soft metal, wore fast, developed hot spots, cracks and rusted.

As far as new rotors wearing quicker and running hotter due to today's more aggressive pad compounds, I think that's a big generality and quite a stretch. The brakes on a 2008 to 2012 Grand Caravan are much larger than those found on an '80's vintage Corvette or 3/4 ton truck. The factory GC pads are no more aggressive than 30 year old semi-metallics. Putzing around town and highway cruising at the speed limit does not cook rotors like a weekend canyon run in a car seeing deep corner braking and high G forces lol.

One thing that HAS changed of late is new rotor thickness vs min thickness spec. Most rotors sold today are manufactured at or near min thickness which makes re-cutting illegal. Rotor defects can seldom be corrected thru resurfacing, so this change is a non-issue for me. When Bendix rotors can be bought for $20 each I can't see any sense in resurfacing a rotor in hopes of restoring it.

PS: I don't replace good parts with remaining life because I have better things to do with my money. I troubleshoot and replace parts that are defective or have seen better days. When someone else is doing the labor, it does make sense to take a conservative approach and replace more parts. Professional labor services are not cheap, so bad judgment may result in rework. That should be avoided.

 

One other thing that needs to be taken into account is the weight of the vehicle. By and large, today's vehicles weigh more than older models due to build quality and features that add weight (sound-deadening insulation, electronics, etc). That weight carries momentum, which is energy that needs to be dissipated (as heat) via the rotor. Thinner rotors can absorb less heat (less evenly) than thicker ones, and will warp considerably faster as a result.

I will concede that one should never use cheap Chinese rotors on any vehicle, unless used it's never being driven. There are better aftermarket rotors that last longer than OEM parts (Raybestos' is pretty good, I've had good luck with them on 5 different vehicles).

Also, driving patterns play a more significant role than more people would like to admit. Don't rush from 80-0 stop and then keep your foot down on the brake at the top of the exit ramp on new rotors...instant warping. All those things are magnified by newer, thinner rotor designs.

However, if $$ is an issue, keep the OEM rotors for now and set aside some money in case they do warp/wear faster than you'd like.

 

Agree on the quality of the Chinese rotors--been there, done that. But where do you find Bendix rotors for that price, and is there a specific one to ask for?

 

Bendix Premium PRT5844 rear rotors for my '08 T&C at rockauto.com are $19.84 each.

 

Very true, but the 12" rotors on the '08 Grand Caravan aren't exactly undersized when compared to 10" rotors found on commercial trucks and various 400+HP V8 muscle cars sold in the 70's and 80's. The difference in swept area is about double. Corvette 454 and 427 rotors were just over 10" back then, as were the rotors on some commerial trucks with dual wheels designed to carry and tow many tons. I own a 1979 Mustang Cobra with 9" factory rotors....just sayin'. Rotors have been upsized to improve braking performance and lifecycle, not just to compensate for progressively rising curb weights.

The same upsizing strategy has been taken by mfrs on clutch designs. Clutch swept area specs have risen by about 30% in the last couple decades to improve lifecycle and help prevent failures. The notable exception is BMW who stubbornly stuck with undersize clutches. They used 9-5/8" units on 400+ HP V8 vehicles while every other mfr migrated to multi-disc designs or 11" & greater. The M3, M5 and 5-er V8 clutches burn out way too often when driven by aggressive owners.