Replace calipers: yes or no?

It’s definitely time to replace front brake rotors in my 1999 Sienna. I’ll replace pads too, and completely flush out the old fluid, no telling how old that is. While I’m in there, I would likely replace the flex lines before they pick an inconvenient time to fail.

But what about calipers? Because they are expensive, I’m not sure if replacement is worth the cost. What happens to brake calipers over time, do they “wear out” or deteriorate in some way?

Should I just spring for new ones?

The car was evidently a one - owner for 15 years, dealer serviced during that time; then probably one other owner before I bought it in 2015. I have no records of prior service, so no way to know if the calipers were ever replaced.

Who has an opinion?

If you were able to compress the pistons back into calipers with no resistance, and the dust boots aren’t torn, there’s no reason to replace the calipers.



21 year old car… Calipers cost $32 exchange rebuilt from Rockauto. Not expensive at all. Plus bleeding the caliper may break off a bleed screw requiring replacement anyway…

Yes, I’d go ahead and replace them along with the rear wheel cylinders ($10) in the drum brakes and the brake hoses.

Pistons and cylinders get worn or dirty over time and get sticky causing uneven pad wear. Many times it’s because the rubber boots get damaged and allow contaminated. If none of this is happening I would take @Tester s advise.

@Mustangman: Thanks. They are about $58 at local Napa store. That’s less than my memory was reporting from when I priced them 5 months ago. So I’m less resistant, will decide when I get a good look at what I’ve got. I don’t need to pinch pennies, especially on brakes, considering how little this car has cost me in 5 years.

The price you got before may have been without returning the old ones, or maybe a different brand. Are the ones you priced at NAPA white box specials, or are they a decent name brand?

@jtsanders: I don’t have a good answer to your important question, but I’m glad you asked it. Thank you.

Chances are that the price I got on the phone this morning was their lowest price choice. That would be my strategy for answers to phone callers if I owned the store. Coincidentally, when I called, it was the same clerk who had printed out the quote last winter, and I was able to reference that, intending to show that I was a regular customer, which I am.

And as you suggest, core charge would account for a price difference too. The price I got today might have been with core returned, and the earlier quote might have been just the item cost.

My original question came from simply not knowing what can change over time on a caliper, and now I have gained knowledge on how to judge. If in doubt, I’ll buy new (or rebuilt) ones.

If you are DIY type and if you can get bleeder screws to unscrew, I would vote to keep calipers and simply replace the o-rings and rubber boots:,1999,sienna,3.0l+v6,1357534,brake+&+wheel+hub,caliper+repair+kit,1720,1999,sienna,3.0l+v6,1357534,brake+&+wheel+hub,caliper+guide+pin+boot+kit,11515

The rationale is: you have OEM calipers which were good for 20 years and likely they will not fall apart for another 10+

We’ve seen a number of complaints on this forum where “some/unknown” replacement calipers brought a number of problems on their “happy” buyers, resulting in repeating rework.

If your current calipers are not in badly rusted/stuck state, it is likely not that much work to replace their wearable parts and make them go for longer.

@thegreendrag0n: good point:

We’ve seen a number of complaints on this forum where “some/unknown” replacement calipers brought a number of problems on their “happy” buyers, resulting in repeating rework.

Agreed. I avoid “factory rebuilt” when I can, especially for starters and alternators. There’s a local electrical shop that has been rebuilding motors in-house for well more than 3 decades.

Back to brakes: you hit the core of my question by referring to replacing the o-rings and boots. If I do get the bleeders off (starting with PB Blaster and time), I’ll likely go with replacing the rubber parts only.

Thanks for your insight.

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Something ot keep in mind if you replace the piston seals in the brake calipers is that unless the brake fluid is changed now and then moisture in the fluid will pit the walls of the caliper piston bores. This means they need to be replaced or they likely fail sooner rather than later even with new seals.

Brake fluid is hygroscopic (meaning it absorbs moisture) and the usual rate of absorption is around 2 to 3 percent a year. If the fluid has never been changed it’s likely a mess.

ok4450: I appreciate the heads up, but I’m not certain I understand your message exactly. I think you are describing just what I was intending, for the reason you explained.

I did know that brake fluid is hygroscopic, but thanks for mentioning it none-the-less. I’m assuming there’s rust and other contamination in the fluid as well, so I’ve been thinking that I’d start with fully flushing the entire system before I touch anything, especially if I replace the calipers, even though that requires a bit more brake fluid. I am certain that the fluid is a mess, as you wrote. That was my first thought about this project, aside from the worn rotors.

unless the brake fluid is changed now and then moisture in the fluid will pit the walls of the caliper piston bores

I think that flushing out all the old fluid first would avoid the problem you described. Am I understanding you correctly?

After all the fluid has been replaced, it should be fine to change those seals. Did I miss anything in what you advised?

Not quite. I mention the pitting due to the age of the car and what is quite likely contaminated brake fluid.
I suspect the piston bores are already pitted and new seals would likely be a waste of time and money.

It certainly does not hurt to pop the caliper pistons out and take a look at the bores. I don’t know if you have ever rebuilt a caliper and had to remove the piston but the easiest way is to fold a thick rag and place it against the face of the caliper piston. Remove the bleeder nipple and hit the caliper with a quick shot of compressed air. The piston should pop right out. The main thing is to keep the fingers away from the piston as it would be easy to crush or lose a fingertip.

As Tester mentioned earlier, if the pistons compress back into their bores easily and there are no signs of any leaks you could skip caliper rebuilds or replacements at this point. Usually if the piston seal is age hardened the piston will be difficult to turn and compress and that means replacement.

Got it. I’ll see what I have once I get the first caliper off. I’ve soaked the bleeder and the nut between brake line and hose, with PB Blaster, will let that work overnight or longer. These days, like most people, I’m rarely using my car, so there’s no hurry. I have some two wheelers for most errands.

If the caliper qualifies on Tester’s standard, then I’ll see if I can rebuild it, knowing that if I don’t succeed, I can still buy a new (rebuilt) one. If I do try the compressed air technique, I’ll be very careful with my fingers in the path of that piston.

I now have the right front wheel off just for inspection, and I see that the caliper is marked with a Toyota logo. So either it is the original part, or one replaced by the dealership which formerly serviced this car.

Thanks all for the helpful responses.

On my daughters’ old Nissan I was rebuilding her rear calipers at 11 years of car age and 70K miles over upstate NY roads (CarFax is handy sometimes) and the one which made me to go for rebuilds indeed had a frozen piston.
It took blowing it for several seconds at around 100 psi to pop it out, the moment of separation was like an explosion.
I had it caught by the piece of wood, not by rug, and it made something like half an inch deep crater on impact, probably would simply cut the rug through.
Caliper was indeed pitted inside, but not around the o-ring grove, piston was shiny chrome, so I cleaned that up and it worked fine for years after that.
Since @WesternRoadtripper1 calipers were not giving him trouble yet, IMHO he has a fair chance of successful rebuild.

Replace calipers?


After a continuing my “education” on Youtube, where two well filmed videos provided a visual understanding for what a worn piston and bore might look like, I decided to replace the calipers. The effort necessary to clean the mating surfaces just seemed like more than I wanted to get into. And I don’t have quite the right equipment to clean the surfaces adequately. In a pinch, I could have made it happen, I just decided it wasn’t a worthwhile use of my energy, nor was it cost effective. I’m guessing that they were in pretty bad shape, so my effort might have saved $90, cost me a couple hours, only to need new calipers in a couple of years.

So, I’ll install the new parts, replace all the fluid, and still have more satisfaction than if I’d just dropped it off somewhere for somebody else to do the job.

I’m grateful for the good advice offered above, thank you.

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