Because if you get 2 calipers off the shelf at the same time, there’s already no guarantee that they’ll perform exactly the same, because one might be defective, or have different internal measurements than the other (but still within tolerances). In short, since it’s impossible to guarantee that both calipers will perform exactly the same in either scenario, might as well save the cash.
There’s no need to replace both. I’ve replaced one caliper and the other lasted another year before I had to replace it. It’s like the mentality of replacing headlights in pairs.
There is a need when it involves doing things the right way, customer satisfaction over the long term, and the legalities around liability for not doing it the right way are involved.
If a piston seal has hardened and is causing a problem (as is the case most of the time) then it’s reasonable to assume that the piston seal on the other side which is using the same fluid is also in the process of failing.
Bleeding and flushing are not the same thing. Flushing is a process of pushing fresh fluid into the master cylinder and releasing the old fluid out through the bleed screws in the calipers. Its a bit like flushing a toilet, the fresh water comes in the top and the dirty water goes down the trap.
Bleeding is a similar but the goal when bleeding is to get trapped air out of the system that gets in when you replace a caliper or brake line. If you have fresh brake fluid in the system and then have to replace another component, then you bleed, but you don’t necessarily replace all the brake fluid that is in the system.
The quotes you got seem fair to me. I do my own brakes so I would just replace one caliper, but doing both at the same time will save you about $100 over have both changed on separate occasions. The choice is yours.
Bleeding and flushing ARE the same thing. Only it shouldn’t be called flushing. It’s called Power Bleeding. http://www.motiveproducts.com/
Tester
It may just be a matter of semantics, but the difference between flush and bleed is the purpose. It is the same procedure and uses the same equipment, but if the purpose is to get air out of the system, its bleeding. If the purpose is just to replace the old brake fluid in the system with fresh, it is called a flush.
Power bleeding is a specific procedure that involves a pressurized tank. Not all bleeding or flushing is power bleeding. But I will agree that power bleeding is the best procedure to use. There is also gravity bleeding, vacuum bleeding, two man bleeding and one man bleeding procedures.
Power bleeding does the same thing as manual bleeding. It removes all the old fluid along with all the air in the system. The only difference is in what manner the pressure is produced.
The benefit of power bleeding is it only requires one person to do the job.
Tester
OP apparently got 84K miles from the original front brake pads. That’s very good, and means a careful driver is behind the wheel. I’m assuming this is a manual xmission. If an automatic, 84K on a set of pads would really be an accomplishment. Its sort of confusing that the OP reports the back brakes needed new components prior to this. Usually the front brake pads need to be replaced 2 or 3 times before anything needs to be done to the back brakes.
In any event, since this car is driven carefully, I think replacing just the one bad caliper is all that is needed, along with flushing/bleeding the lines – meaning all the air removed and fresh fluid throughout the brake system front brakes and back brakes. Like I said before, I wouldn’t resurface the rotors. If they need resurfacing, then they need replacing.
While new calipers may differ somewhat from each other, it’s reasonable to assume that a well-used one on the car, of the same vintage as the one that just failed, is going to perform differently than a new or rebuilt one, and may affect braking performance or fail fairly soon.
I’d still replace them both.
Gosh, thank you all so much for your continued responses! By the way, GeorgeSanJose, it’s an automatic, and I have no explanation whatsoever for the fact that this is the first time for the front brakes vs. having the rear ones done once in our 84K. So the tally leans toward having both calipers replaced at 7 to 4, with a few qualifications. It’s decision time tomorrow morning!
Certainly makes sense to replace BOTH sides together and at the same time, so your mechanic fellow sounds to me like he’s on the ball and knows his stuff!
A failing or failed caliper on one side will cause a front (or rear) brake IMBALANCE ( an MOT failure as well as being dangerous ). replacing only one side may shift the imbalance to the other side as the new caliper will be more efficient than any existing component. Braking force must be equal at both wheels. Change out the discs and flexys as well while your there, for a decent overhaul again on BOTH sides. Pads as a matter of course…a decent caliper kit will come with a set of pads anyways. Hope this helps.
How do you know that both replacement calipers are equally “efficient?” What if you get 2 new calipers, but one is slightly different than the other? Will you crash, and if so, who should you sue, the manufacturer for not making all brake calipers exactly the same, or the mechanic for not bench testing the calipers to be sure they’re exactly the same?
Brakes really aren’t that complicated. Fluid gets squeezed into the caliper, which presses against the piston, which presses against the pad, which presses against the rotor. Unless something is wrong with the caliper, the brake will work. So, unless the other caliper is also broken, it does not need to be replaced.
I agree! Change the affected caliper only unless the others one is bad also.
I think that after 4 years the problem has been solved.
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Four years or fourteen, the thread is still educational and informative. Even those who already know what they are doing, are not harmed by a review. And, many of our readers do not ever post here. It would be interesting to know how many views postings get in total.
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Yes, I guess its still a question one may have after so many years. I guess you could go either way. Pay me now or pay me later. I have replaced just one before but I don’t see a problem with replacing both if you want to be done with it for a while.
However, I disagree with turning the rotors. The rotors should just be replaced and forget the old practice of turning them down with the result of them being too thin, warping within a year and you’re back in the shop again for more brake work. If you pull the calipers, a couple more bolts and the rotors come off and the job is done right.
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I agree with @bing on turning rotors. Pointless. Rotors are cheap, just replace 'em. Thinning out the metal doesn’t exactly help the problem not come back.
This increases the price of a brake job by $150 to 200 per axle, how do you compare with the competition with pricing? Do you sell the rotors at cost?
You measure the rotor thickness, don’t you? Toyota rotors have .100" of service life.
I had a mixed bag of experience with “cheap rotors”, specifically ones for $25-35 ones I bought from Advance Autoparts.
I’m talking Subaru Outback (used to own 3 Outbacks before, had to redo brakes on 2 of them at some point).
They were made in China, shiny look, etc… One set worked just fine after burn-in and I was quite happy and drove them until car was sold out.
Another set warped in few weeks, but I retained the OEM ones, so I brought them to the machine shop and asked to turn them, which costs something like $15 a pair, replaced back and returned warped parts back to the store. OEM rotors were still in decent shape after 70K miles, not much metal to remove before they were looking like new.