this post was submitted on 30 Sep 2024
29 points (93.9% liked)

Mechanic Advice

275 readers
1 users here now

This community is for getting help with vehicle or other mechanical problems.

Remember, there are no stupid questions, we want everyone to feel welcome. If you don't want to answer a question that you think is silly, then just move on and keep it to yourself.

Rules:

  1. Don't be a dick

That is all.

founded 1 year ago
MODERATORS
 

So it's come the time to break the pads on my car which is a Kia Rio. I've looked up a few things and the job seems doable by myself which saves a lot of money.

The only thing that I can't seem to find a concrete answer is if they actually need to be bled once the new pads are installed?

Thank you

top 24 comments
sorted by: hot top controversial new old
[–] [email protected] 15 points 1 month ago

You don't normally have to bleed the brakes after changing pads.

You WILL have to pump the brakes a few times before you start to get pedal feeling back, because you'll have pushed the pistons back in the calipers and they need to reset, so don't drive off until it feels good.

[–] Strath 9 points 1 month ago

No. If the brake line is not disconnected, no bleeding is needed.

[–] [email protected] 7 points 1 month ago (2 children)

And FYI you can rent brake spreaders from most auto parts stores which you need for the job.

[–] mvirts 2 points 1 month ago

And you can easily hurt yourself with crappy C clamps instead, but it does work 😅

[–] redline23 1 points 1 month ago

This. You will need some way to push the caliper piston back. I'm not familiar with the way KIA does it (push back in or some sort of twist to push in) since different manufacturers do different things.

If it's simple push piston back in, It will help to unscrew the cap from the brake reservoir to prevent pressure from undoing it. Make sure you don't overflow the reservoir since brake fluid does nasty stuff to paint.

[–] [email protected] 7 points 1 month ago* (last edited 1 month ago) (1 children)

You only will need to bleed, if you open the system, e.g. to replace the cylinder.
When you only change the brake pads, you are pushing the pistons back and thus, should keep an eye on the reservoir tank near the ~~motor~~ engine so that the brake liquid doesn't spill over.
However, every one or two years, you should also exchange the brake liquid. The liquid it is hygroscopic to avoid corosion in the system, but the water bounded by the liquid can create vapor bubbles if the liquid gets hot yielding to fading effectiveness of braking.

[–] [email protected] 2 points 1 month ago (1 children)

A brake is a device to stop or slow a vehicle, and braking is what you do when you apply the brakes. Brake pads are what OP is talking about replacing.

Breaking something is separating it into pieces or interrupting a sequence of events, like taking a break from work.

[–] [email protected] 1 points 1 month ago* (last edited 1 month ago)

Thanks. I must have had a blackout and blindly followed OPs spelling.

[–] knacht1 6 points 1 month ago (1 children)

First of all, Learn to spell "Brake".

[–] mvirts 5 points 1 month ago

Don't forget to check the slide pins and maybe grease them

[–] Graphy 4 points 1 month ago

No you won’t need to bleed your brakes unless you happen to take off the calipers which you shouldn’t need to do.

It’s a very easy job that shouldn’t take you too long.

Your biggest worry is probably going to be stripping bolts if they’re a bit rusted. Can get some PB blaster and spray down all your bolts ahead of time so that they’ll come off easy.

Don’t forget to check out a break-in procedure after you have the new pads installed.

[–] SirSamuel 4 points 1 month ago (1 children)

I don't know Jack about Kias, but this is how I change my pads.

I use a large C clamp to compress the brake cylinder into the caliper, which releases the pressure on the existing pads and gives room for the new pads going on. I take it slow, and have never had issues using this method

For bound bolts/nuts I use a 50/50 mix of acetone and transmission fluid on any offending parts. I wait a few minutes for it to soak in, and voila! Don't waste time with WD40, go straight to the good stuff

Since you haven't opened anything within the brake fluid system, there's no need to bleed. Except your knuckles. Wear gloves

[–] [email protected] 2 points 1 month ago* (last edited 1 month ago) (1 children)

To push the pistons of the rear brakes back, you probably need a special mechanical device that rotates the piston while simultaneously applying pressure to push it back.

[–] SirSamuel 2 points 1 month ago (1 children)

My Transit van will probably be the first vehicle I don't do my own brakes on. I've heard the rear brakes are a chore. Sounds like Kia rear brakes are similarly annoying

[–] [email protected] 1 points 1 month ago* (last edited 1 month ago)

I only know from the Kia Picanto and Ford Focus, both about 20 years old. It isn't overcomplicated and the "special" device isn't that expensive, a set that will work on (almost) any car costs about 20 €.

[–] [email protected] 3 points 1 month ago

You definitely don't need to bleed the brakes.

Take the old pads out and put the new ones in. It's painless.

You wouldn't even need to bleed the brakes if you were doing the fluid, Just use a one-way valve over the nipple.

On motorcycles I tend to pop out the piston and wipe all the crap off it then bleed the brakes. That's because the brakes get sticky and it's a bit of a nuisance, but other than that you wouldn't often need to bleed the brakes on a car unless you fuck something up.

[–] dyathinkhesaurus 2 points 1 month ago
[–] [email protected] 2 points 1 month ago

If you're only changing pads, there's no need to bleed the system. Only time that needs to be done is when fixing a fluid leak or replacing a hydraulic component such as a caliper, hose, or master cylinder.

[–] Death_Equity 0 points 1 month ago* (last edited 1 month ago) (3 children)

You should bleed the brakes, because brake fluid absorbs water over time and goes bad.

There are a few ways to do it by yourself, but the first step is making sure all 4 bleeders open and aren't seized.

Edit: Brake fluid should be replaced every 2 years or 20,000 miles. Brake pads need replacement every 20,000 to 40,000 miles. Average driver in the US goes 14k miles a year. Bleed your brakes until the fluid is clear when you replace brakes, even if the caliper wasn't replaced.

[–] [email protected] 3 points 1 month ago

You don't need to bleed brakes for a pad change. Change the fluid if it's time to be changed, which also happens to be convenient to do while the wheels are off. Brake pad wear might coincide with fluid change timing, but not always.

[–] [email protected] 1 points 1 month ago* (last edited 1 month ago)

Then, you should not only bleed, but actually replace the brake fluid, i.e. keep bleeding it until the fresh brake fluid, you have been filling into the reservoir, comes out of each bleeder.

[–] [email protected] 1 points 1 month ago

Yeah, you don't need to bleed the brakes here.

Changing the fluid is different from changing the pads.

And if you're changing the fluid you can just put a one way valve over the nipples and pump it out whilst the misses pours the new stuff in.