Is it Always Necessary to Turn the Rotors when Replacing Brake Pads?

[dirty_mech]

I've got a 2000 Legacy wagon.  I'm about to replace the rear brake pads (and parking brake shoes while I'm at it) which are down to about 25% thickness.  The brakes make no noise and no grooving is visible.  Given this, is it really necessary to turn the rotors?

I've read a site on another thread where most people thought it would be unnecessary:

https://mechanics.stackexchange.com/questions/73/should-i-resurface-or-replace-my-rotors-everytime-i-replace-brake-pads

What is your opinion?

[Gloyale]

pads will wear more quickly if you don't resurface the rotors.

 

otherwise, no it's not necessary.  The brakes will still work just changing pads.

[montana tom]

If they are not grooved then just change pads.  If you are doing the parking brake consider changing out the spring / hardware pack at the same time.  

[heartless]

i have never had rotors turned on any car I have ever owned.

 

I have replaced them if they were heavily grooved or otherwise showing signs of excessive wear... like the one pictured (that one was pretty extreme)

 

I do agree with Montana Tom, tho - if doing the parking brake as well, do the hardware kit with it - cheap insurance it will continue to function properly.

Edited November 24, 2017 by heartless

[987687]

If you don't get a $7 hardware kit you'll be extremely pissed off trying to get the parking brake back together.

 

Rotors for cars are generally so cheap it's more expensive to have them turned than it is to replace them. If there's any question, just get new rotors, it's cheap and the proper way to do the job. 

 

The only time it's usually worth turning brakes is on 1-ton trucks and up where rotors can be over $100 for a pair. Cars don't usually even have enough meat on the rotors to turn them, they'll be too thin.

[ferp420]

And turning roters create thin spots and promote warping you can scratch them.up with sandpaper or a grinder with a flap wheel to knock off any glasing just make sure the rotor is spinning while you use the flap wheel

[Naked Buell]

I agree, if bad replace with new, fairly inexpensive and brakes are important like good tires. I thought turning would be ok on my truck but you are taking away mass that is used for the cooling process.

[GeneralDisorder]

Rotor turning is only done on big stuff with expensive parts. Subaru's are not that. The brake systems job is to turn motion into heat via friction thus slowing the vehicle. The rotor's heat dissapative ability is directly related to it's mass. If you have deeply grooved rotors and then remove more material to smooth them out you are compromising it's mass and therefore it's ability to absorb heat from pad friction. This will end up creating hot spots that will bake pad material onto the rotor surface creating "cementite" crystallization of the rotor in an uneven pattern - leading to brake pedal pulsation due to rotor thickness variations. Commonly referred to as "warpage". This is generally undesirable, and in *most* cases cannot be corrected by turning the rotor - the crystallization will still be present and will shortly present itself again as the softer material surrounding it wears and again leaves those spots proud of the surface. 

 

It's likely at least $10 to $15 per rotor to have them turned. Then you have to figure travel time and waiting - quite possibly two trips. When a rotor cost's about $30 - $40 new - maybe less from rockauto.com, etc. The risks, frustration, and inconvenience greatly outweigh the savings unless you have really expensive rotors. 

 

GD

[Gloyale]

It's likely at least $10 to $15 per rotor to have them turned. Then you have to figure travel time and waiting - quite possibly two trips. When a rotor cost's about $30 - $40 new - maybe less from rockauto.com, etc. The risks, frustration, and inconvenience greatly outweigh the savings unless you have really expensive rotors. 

 

GD

 

Rotors for cars are generally so cheap it's more expensive to have them turned than it is to replace them. If there's any question, just get new rotors, it's cheap and the proper way to do the job. 

 

Yes aftermarket rotors for subarus are cheap.  But you get what you pay for.

 

Factory Subaru rotors are made from a high grade steel, with higher resistance to rust and corrosion than cheap chinese Autozone garbage.  Also less likely to warp from rapid heat/cool cycles seen when driving in snow/rain often.

 

Subaru rotors are around $80+ a piece.  

 

They are stamped with a thickness limit. Usually they can be turned at least twice.  If there is room, I will ALWAYS turn an OE subie rotor before throwing it away for Rock Auto junk.

 

I have mine surfaced locally on a turntable.  Water cooled during the cut, leaves a precision crosshatch unlike an old "scratch needle" on a lathe.  Same machine that surfaces my Flywheels.

 

Costs $35 for a set.  You can't buy 2 new cheapo rotors for that price, let alone good ones from Subaru.  If you aren't spending over at least $40 buck a piece for rotors you are getting JUNK!

[idosubaru]

I never replace rotors on subarus. It’s pointless. 285k on my OBW, yaaawwwnnn.

 

Rear are Pointless to turn. Fronts only if they vibrate while braking.

 

Even if they are grooved and scored it’s not a big deal. You’ll get 35,000 miles instead of 38,000 miles, an insignificant difference.

 

If they’re grooved, once pads wear in the rotors have a larger effective surface area and one could argue they improve braking due to “larger rotors”, haha. Granted the grooves would need to be perfectly concentric but it’s just an illustration how low grade and ignorant current brake maintenance norms are.

 

what’s the best thing you can do for life long brake maintenance? The answer is a list of things most shops don’t do = dumb.

 

1. Use high quality grease like SilGlyde or other. Not generic brake grease.

 

2. Replace the pad retaining clips. Depends on age, propensity to corrosion/rust/damage. I aim for once around 150k +\- 50k. Maybe it’s onjy necessary in the rust belt but I’ve seen pads also hang on built up black ridges too (brake dust, dirt, don’t know) or bent clips from multiple or past pad changes.

 

Do number 1 & 2 (jokes welcome), and Subaru rotors and calipers last 300,000 miles on daily drivers unless you’re really hard on front brakes or they sit too long in the rust belt, etc.

[idosubaru]

I’ve seen people (against my recommendations) pad slap shredded rotors where pad rivets or calipers had ground down the rotors with shavings everywhere. I wouldnt recommend that but again, it just doesn’t matter unless the rotors are structurally compromised due to thickness or heat.

[GeneralDisorder]

Costs $35 for a set.  You can't buy 2 new cheapo rotors for that price, let alone good ones from Subaru.  If you aren't spending over at least $40 buck a piece for rotors you are getting JUNK!

 

The cost is much higher than $35 for the resurfacing because your time is worth far more than the cost to do the surfacing. We get the highest quality rotors for most customers (Akebono is generally OE) and after 10 years and hundreds of brake jobs - not one has come back for rotor problems. Dust and noise issues with certain brands of pads yes, but haven't ever had a rotor complaint. It just isn't generally on the radar for these cars. Even inexpensive rotors seems to be fine under most usage. Subaru's are not that demanding on brake components - that's why the factory calipers often last the life of the car. 

 

GD

Edited November 24, 2017 by GeneralDisorder

[dirty_mech]

Thank you all for the great advice!

I will definitely buy a hardware kit for the parking brakes and probably just remove the glazing with light sandpaper from the current rotors, and also get some high quality brake grease. 

Back when I was a dumb kid I tried to "turn" a friends rotors by removing grooving with the side of a 7 1/4" circular saw metal blade.  The rotors must've come out uneven as his new brake pads wore down to the plates after a few hundred miles.  Wish I had known that grooving wasn't such a big deal; I would've left them as-is and avoided a big headache! 

EDIT:

I ended up buying:
 

CENTRIC 11847005 (118.47005) Parking Brake Hardware Kit

POWER STOP 17770 (17-770) Brake Pad  

WAGNER Z794 Parking Brake Shoe

 

 

Shelled out an extra $7 to get the Wagner parking brake shoe set over the Centric brand.  Not sure if it was worth it or not, but the company behind Wagner is about 15 times older and the warranty was 4 times longer (12 vs 3 months) so I decided to play it safe. 

Edited November 25, 2017 by dirty_mech

[Gloyale]

The cost is much higher than $35 for the resurfacing because your time is worth far more than the cost to do the surfacing. 

 

i don't do rush jobs.

 

the machine shop is close by and does rotors quickly.  I am dropping off stuff often enough he takes good care of me quickly.

 

Old timer, amazing shop.  Bob Forrest Engine Rebuilders.

 

I give him as much business as I possibly can because someday he'll be gone and that local resource will no longer be available.

 

Besides....it takes time to order and get parts too.

Edited November 25, 2017 by Gloyale

[idosubaru]

i'd get wagner over centric too.  

 

rockauto is a great source for reasonably priced brake pad retaining clips.  sometimes they're a couple bucks instead of the $20+ locally. 

[GeneralDisorder]

i don't do rush jobs.

 

the machine shop is close by and does rotors quickly.  I am dropping off stuff often enough he takes good care of me quickly.

 

Old timer, amazing shop.  Bob Forrest Engine Rebuilders.

 

I give him as much business as I possibly can because someday he'll be gone and that local resource will no longer be available.

 

Besides....it takes time to order and get parts too.

 

It's not a matter of rushing the job. It's that I pay my guys hourly and for them to be delivering and picking up rotors will add significantly to the cost. They can go work on another job (5 bays full at all times) while I wait for rotors to be delivered. Sending people off site for any reason generally results in a lost hour one way or another. Especially if it's two trips. They always stop for food and screw off, etc. It's not economically viable *for us* to resurface rotors. With the discounts on parts that we get through our wholesale channels, and figureing the machine shop costs and additional labor costs not to mention tieing up a bay for much longer (if I need rotors I'll have them delivered before we even begin the job), it's just not worth it in any way. The cost to the customer plus the inferior product being delivered (thinner rotors) is a lose/lose for us and the customer. 

 

If you figure $35 for surfacing, plus and hour for two round trips to the machinist and other screwing off, then the lost time on other jobs, and the bay being tied up waiting on rotors. The cost to the customer for this would be approx $200 for surfacing. I can sell Brembo or Akebono (OEM) rotors for $65 to $85 per each. That's $130 to $170 a pair. The math doesn't play out for us sell surfacing to a customer. Now for a DIY'er who's time is worth basically nothing (though I would argue they probably [hopefully?] have a marketable skill they could be using to make money in place of doing their own brakes) it might be viable to resurface some rotors.... but in any case it's still an inferior end product to new OE quality rotors. 

 

GD

Edited November 25, 2017 by GeneralDisorder

[Gloyale]

The cost to the customer plus the inferior product being delivered (thinner rotors) is a lose/lose for us and the customer. 

 

GD

 

I think calling Non-OE inferior to properly turned, Within thickness according to SUBARU, is a stretch.  My wife had 3 sets of different "new" rotors put on her Forrester always making vibration.  My OE subaru rotors turned once or maybe twice, (IDK car has 240K) on my Forester never shake.

 

Aren't there any city delivery guys in your area that could make a run once a day?  Cheaper than the difference in buying quality rotors.

 

I get it.  It's not in your business interest.  But it is in the individual Subaru owners best interest I think to keep the quality, OE rotors when possible.  They aren't $85+ a piece for no reason.  You get what you pay for.  

 

I just think this forum and this in particular is geared toward DIY owners.  And for those that are far away from quality machine resources, new could be the way to go.  Or if the rotors are trashed from neglecting pad change, and too thin for spec, sure get new ones.

[987687]

I agree with GD. Even though I don't work as a mechanic anymore, I want to get my DIY work done as fast as I can. The less time I spend screwing around with my daily driver the happier my life is. Also, if you use all new brake parts and do the job properly you'll probably get another 60k out of them. Doing a halfassed job usually ends up costing more money in the long run if you plan on keeping the car.

[GeneralDisorder]

I feel the same way about it that I feel about honeing cylinders. If they are so screwed up that you are considering honeing then you need to bore it oversized with a bore plate and a plateau hone. Same goes for rotors - if they are grooved and have a wear edge, etc.... I would rather have new ones. The quality new rotors will be painted on the hub and fins for corrosion resistance, etc. 

 

On the subject - Raybestos came out with brand new calipers for Subaru applications that are properly painted, etc. They are made with all new castings due to the lack of quality cores. The price is good. I haven't tried one yet but my supplier brought one in and they look promising.

 

GD

Edited November 25, 2017 by GeneralDisorder

[Gloyale]

If you figure $35 for surfacing, plus and hour for two round trips to the machinist and other screwing off, then the lost time on other jobs, and the bay being tied up waiting on rotors. The cost to the customer for this would be approx $200 for surfacing.

 

GD

 

I have a hard time believing that sending out rotors to turn would force you to put a %600 mark up on them.

 

 

 

Run your shop how you want but sure smacks of rushing jobs, cut corners, and price gouging to me. I hope it's not.  I haven't heard of anyone complaining about your shop.  And you are knowledgable enough to know how to take good care of Subarus.  Maybe it's just the tone of this thread and I'm wrong.  The impression of you I've had for the past 10 years is that you do things right or not at all.

 

My customers leave paying $45 for the turning ($10 markup for handling) the price of their brake pads,(usually $40-50) and $40 labor for changing pads on most Subarus.  Usually less than $150 total.  I can't justify chargin anyone more than that for hangin pads.

 

 I would rather do easy jobs like brakes and axles for the lowest price possible for folks and get the return business when they need bigger work like Wheel bearings, Clutches, and HGs.

[forester2002s]

'There's more than one way to skin a cat.'

 

Can we leave it at that?

[GeneralDisorder]

It's not price gouging - the customer is getting new parts and they are happy for it. You cater to a different type of customer. I get that. But a $10 markup only shows how naive you are at running this type of business. Once you get to running a real shop with real overhead you simply cannot do that. Most shops markup between 200 and 300% for parts being delivered to them. And it's not correct to view it as a 600% markup because you are talking about labor for the pickup and delivery portion of it - which is $99 per hour. It's about a 100% markup plus labor. 

 

I have had to work my way up through the customer ranks - some of the people that came to me when I was a guy in my garage have stayed through all the changes but many didn't because I don't change $35 an hour and 10% parts markup anymore. No matter - word got around and now I have customers that are happy to pay my current rates. They would likely never have considered taking their car to somones garage though so those aren't the people you start out with as a customer base. The customers I have now want a brick and mortar with a warranty and a comfy lobby with popcorn and Wi-Fi. Naturally this creates overhead and they understand that.

 

GD

[Gloyale]

It's not price gouging - the customer is getting new parts and they are happy for it. You cater to a different type of customer. I get that. But a $10 markup only shows how naive you are at running this type of business. Once you get to running a real shop with real overhead you simply cannot do that. Most shops markup between 200 and 300% for parts being delivered to them. And it's not correct to view it as a 600% markup because you are talking about labor for the pickup and delivery portion of it - which is $99 per hour. It's about a 100% markup plus labor. 

 

I have had to work my way up through the customer ranks - some of the people that came to me when I was a guy in my garage have stayed through all the changes but many didn't because I don't change $35 an hour and 10% parts markup anymore. No matter - word got around and now I have customers that are happy to pay my current rates. They would likely never have considered taking their car to somones garage though so those aren't the people you start out with as a customer base. The customers I have now want a brick and mortar with a warranty and a comfy lobby with popcorn and Wi-Fi. Naturally this creates overhead and they understand that.

 

GD

 

I want to find this $99 dollar an hour DELIVERY JOB!!! haha  I will quit working as a mechanic!  Get outta here with that BS.

 

Schedule brake drop offs in the morn, have a courier take them over and back (i can recommend several who don't charge $99 for 2 cross town trips.  Hell call a F@#@ing Uber!  If you can't figure that one out IDK what to say but it's a poor excuse to make people spend more money than they need to.  EVER!

 

I do run a "real" shop

 

It exists in 3-dimensions and persists in space time.  I carry garage keepers insurance.

 

What I don't do is have employees, advertising, uniforms, and a waiting area or pay rent on my shop space.

 

My customers are not much different than yours other than they live in a smaller town and are comfortable with a "no-overhead" operation like mine.  I hope you weren't implying that they are somehow poor, uncultured yokules who can't afford to take care of their cars so they need a "buddy" to fix er up.

 

That is NOT what I do. I like you value my time. I am professional and I stand by all my work.  I charge $75 hour.  Every customer gets a recipt and a description of the work done.

 

I've actually been doing this for 10 years as my only income source.  I am doing fine.  I have ZERO debt.  Can you say that?  If not than I am wealthier man than you so tell me again how I am naive?

 

My customers are loyal and appreciative and I know all their names.

 

Run your shop how you want.  I am just gonna call it like I see it.  YOU are the type of shop that drives customers to me.  Thank you.

Edited November 27, 2017 by Gloyale

[GeneralDisorder]

Labor is labor. Doesn't matter that it's a pickup/delivery, it all has to be figured into the bottom line, and the hourly rate is $99. 

 

I don't pay rent. I pay a mortgage on my commercial building, and what I owe is less than 1/3 the value (~$1,000,0000) of the building. My house(s) are paid for. So are all my cars. I have no outstanding credit cards other than revolving credit that is used for business purposes due to fraud protection, etc. So there ya go - you be the judge.

 

What I do have is employees that I provide a living wage. I have never required advertising since word of mouth keeps me a month+ deep at all times. 

 

I don't have problems with customer loyalty or satisfaction. On the contrary it's all the other shops that drive customers to me. I'm one of the good guys running a full time production shop.

 

GD

[idosubaru]

I see different business models, not gouging or naivety. And I see two highiy respected persons I’m usually hoping reply to my questions!

 

I’d prefer options be explained, given recommendations, and I choose, but that doesn’t often work in the business or customer world. When I try I to explain Subaru options to people I’m helping I often get blank stares and realize they really can’t and don’t want to decide. So I have too.

 

I appreciate Gloyales attention to finances but understand GDs model, which is common in urban areas.

 

Customers and scaling force decisions about cost, approaches, and the paradox of choice of customers unfamiliar with automotive world.