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I replaced my rear brake pads and rotors by DIY, and the rubber cover for the cylinder in the caliper couldn't retract to the original place, so after I installed the brake pad and put it back, I'm sure the cover was pressed under the cylinder edge. I'm worried that the rubber cover will break soon or later.

I forgot to take a picture, so I grab a picture from internet and hope you can understand.

My question is: Is this a safety issue, can this cause brake fluid leak or other problems?

Thank you very much.
 

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I replaced my rear brake pads and rotors by DIY, and the rubber cover for the cylinder in the caliper couldn't retract to the original place, so after I installed the brake pad and put it back, I'm sure the cover was pressed under the cylinder edge. I'm worried that the rubber cover will break soon or later.
I had the same problem, as well as our member Vanib. Here is a link to his solution. Click Here
 

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Discussion Starter · #3 ·
Thank you so much, Rickl.

Do you mean just lift the boot up, and the air will go out?
I already drove the car 2 days after I replaced the Brake Pads, should I do that now?

And can this be a safety issue? I think it's might just a cover to prevent dust.
 

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Do you mean just lift the boot up, and the air will go out?
I already drove the car 2 days after I replaced the Brake Pads, should I do that now?
And can this be a safety issue? I think it's might just a cover to prevent dust.
By the time I read Vanib's solution, it had already been several weeks since I had changed the rear brakes. The next time I examined the brakes I expected the boots to be torn, but to my surprise they seemed to have retracted by themselves, and no damage was visible. I guess the air had leaked out after a period of use. I suggest you "burp" the boots as suggested though, rather than take a chance they will retract on their own.

As far as safety goes, well these boots do not hold in the hydraulic fluid, so there is no immediate safety risk. However if the boot gets torn, then dirt/water can get under it and cause scoring/corrosion after a period of time which will result in early caliper replacement.
 

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Discussion Starter · #5 · (Edited)


I guess I had a bad luck, I checked the piston boot tonight, and found that it was broken, I use a screw driver to push it back, since it's broken, so it's easy to push back and the broken part was hid and everything looks normal.

Since the brake pad is new, so the boot will not extend too much recently, it's probably OK for now, but I think it needs to be replaced next time.

Do you know if the piston boot can be replaced separately and where can I buy the piston boot?
Or the calliper should be replaced?

Thanks for your reply.
 

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Replace it now.
Especially from the appearance of your piston, I have a hard time believing that is a 2013+
 

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Discussion Starter · #7 ·
Replace it now.
Especially from the appearance of your piston, I have a hard time believing that is a 2013+
Sorry, I posted on the wrong place, It's a 2007 Rav4.
So you mean replace the caliper, should I replace only the left rear one or both of the rear caliper?
Thanks.
 

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I was going to say replace the seal, but it looks like there's some corrosion on the piston at around 11:00 that's on the edge and outside.
That means at least the piston, and maybe the caliper as well, unless it is actually clean on the boot seating surface.

The rubber seal is only there to keep dirt and water away from the piston and caliper.
The fluid is sealed quite well by the piston-to-caliper bore fit. Yes, the tolerances are that tight, which is why the dust boot is so important.
A small amount of rust, or scoring from dirt will quickly lead to the piston sticking in the bore, causing uneven and accelerated pad wear, as well as overheating that will lead to the rotor warping.
 

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Whether 2007, or 2013 don't take any chances, replace the entire assembly - and any other that looks to be in similar condition (I would replace on all 4 corners myself).
 

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Discussion Starter · #11 ·
CB91710. I'll go to the dealer and see if they have the seal. will update if I got the seal. thanks.
 

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Can I just replace the rubber boot without taking the piston out?
Thanks.
I don't believe so.
I have not pulled a Toyota caliper apart, but on my motorcycle, there is a groove around the inside of the cylinder just below the edge that the seal seats into.
The piston can not be pushed back enough to clear it.
 

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Discussion Starter · #15 ·
I did some research and I think it's impossible to replace a boot without piston out, so I will try to replace the calliper.

And the price is:
Left rear calliper price in Dealer: $26x + tax.
I found another store they provide calliper was rebuilt by a used one, so I can exchange one by my old calliper + $75.

Still thinking which one I should choice.
Thanks.
 

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It's really not a big deal.

Get a quart of fluid and a catch pan.
Pump the brakes until the piston comes out (yes, it will be a mess).
Replace the boot, reinsert the piston, compress the piston, bleed the caliper.
 
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