another automotive question


rodger.

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Well, I finally braved changing the brakepads on my wife's Yaris, and it went well.  I had a buddy over who is very automechanically inclined, and he walked me through it.  Put new front rotors on, new front brakepads, and cleaned up things in general.  It was a great learning experience for me.

 

I had one problem, however.  One of the caliper sliding pins is sticking.  Its not "bouncing back" very well, though it does so slowly.  We cleaned the pin and put some new grease on it, and it improved, but is still not where it should be.

 

Any advice on this?  The pin is not broken or damaged. 

 

Later this week I will take it off again, clean it, scrub it with a metal wire brish, and reinstall.  Is the thing "shot" and the whole unit needs to be replaced, or is there a common fix here that a rookie like me doesnt know about?

 

Thanks!

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What's the cost of a new one?  If you're going to take it apart anyway, might be good to just replace it.

i new Toyota caliper runs about 400, i believe.  I will have to check in the morning.  I think an aftermarket caliper is closer to 125.  Again, just approximate numbers.

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Ouch..  Forgot it was a Toyota..  Great long lasting vehicles but, they're sure proud of them!

yup, pricey parts but they last a long time.  I just changed the pads in the yaris, and they were from 2007.  Lots of material left too, just the rotors got rusty.

 

The rotors and brake pads from toyota were actually 3 dollars cheaper than wagner, so I just went with Toyota rotors and brakepads.

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There seems to be a law of physics that says if there are N nuts, bolts, pins, whatever, there will be 1 that will be frozen, stripped, stuck, broken, whatever. Applies to plumbing and mechanical. Or, the part needs a tool you don't have to remove, unstick, unfreeze, whatever. If that law didn't exist, life would be easier....

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Franklin, you said the pin isn't "frozen" just that it doesn't "bounce back" like the other. AS LONG as the pin slides FREELY all is good. There is nothing inside of the caliper bracket pushing the pin out out (except trapped air). 

 

If the pin doesn't slide smoothly, you will have brake wear problems, but if it were frozen, you would have known when you weren't able to remove the pin to grease it.

 

Brake pads are always in contact with the rotor. Always. Brake fluid applies pressure to the caliper piston, that pushes onto the inside pad, that pulls the outside pad in. 

 

The caliper piston has an O-ring that keeps brake fluid from leaking but ALSO pulls the piston BACK ever so slightly so that it release the pressure on the brake pad. 

 

If the pins slide smoothly, your good to go. Don't worry about how much they "bounce back" Just worry about smoothness.

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Franklin, you said the pin isn't "frozen" just that it doesn't "bounce back" like the other. AS LONG as the pin slides FREELY all is good. There is nothing inside of the caliper bracket pushing the pin out out (except trapped air). 

 

If the pin doesn't slide smoothly, you will have brake wear problems, but if it were frozen, you would have known when you weren't able to remove the pin to grease it.

 

Brake pads are always in contact with the rotor. Always. Brake fluid applies pressure to the caliper piston, that pushes onto the inside pad, that pulls the outside pad in. 

 

The caliper piston has an O-ring that keeps brake fluid from leaking but ALSO pulls the piston BACK ever so slightly so that it release the pressure on the brake pad. 

 

If the pins slide smoothly, your good to go. Don't worry about how much they "bounce back" Just worry about smoothness.

Thanks - I value your advice very much.

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I had one brake repair go very badly.  (I've been doing brakes on my rides off and on for the past twenty years.  It's the one repair I feel confident enough to handle.  Doesn't mean I know everything about it.)

 

It started out fine, but this one bolt on the caliper just refused to let go.  It had become rusted in place, but not so that the caliper wouldn't rotate out of position.  Except that as soon as the caliper came out, the piston extended and would not go back in.  The caliper needed to be replaced, because the backer plate of the pad got wedged in a wrong place, and the edge of the piston essentially ground the back of the rotor so that the entire assembly needed to be replaced.

 

I couldn't get anything off.  I couldn't put it back on.  I had to walk to the local parts supplier (only two blocks) to find out they could order the part, but it would take a few days.  I spent several hours running around, waiting on busses and family, and finally got all the parts.  By 10:00 PM, I had finished.  (I started at 9:00 AM.)

 

Turns out the previous brake job did not lube the parts properly.  That grease that you applied to the pin was needed to help keep the bolt from rusting and seizing.  Don't get me wrong, rust will happen regardless of grease.  But regular maintenance and preventative measures go a long way to keeping that pin from becoming a problem.  If you are worried about it, check on it every so often.  (I wouldn't worry about it more than monthly.)  Make it a part of your oil change routine, if you feel strongly enough about it.  But like Pat said, if it's sliding, you're still in good shape and shouldn't have to worry.

 

(It was also this repair that made me appreciate my mechanic, and the rates he charges for repairs.)

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+1 one hiring out the brake jobs. My best solution is to adjust my driving style to avoid using the brakes as much as possible. 125k miles on my current front brake pads, no problems. Unknown mileage over and above that on the rears, they were on the truck when I bought it with 100k + miles.

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+1 one hiring out the brake jobs. My best solution is to adjust my driving style to avoid using the brakes as much as possible. 125k miles on my current front brake pads, no problems. Unknown mileage over and above that on the rears, they were on the truck when I bought it with 100k + miles.

Works good for me, but wife is hard on the car.

Do u at least inspect your brakes? That's a long spell with no pad replacement for the rear.

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Check the fluid in your master cylinder periodically.  And double check the bleeder valves at the wheel cylinders.  

 

I have mentioned I've done brake repairs... one of my repair jobs was to replace a wheel cylinder.  The second repair job on it was to replace the wheel cylinder again because I didn't seat it correctly.  (Happens when it's 15 below, snowing, and 7:00 PM at night.)  Short version, I lost a lot of brake fluid to a tiny leak.  Made the pedal feel softer than it really was, because I was sucking air into the line.  Didn't have to (re)replace the brakes like I was afraid, but did have to bleed the brakes.  Don't get the cheap "one man" kit.  (sometimes, you don't even need that much: Lowes has clear plastic line for pennies, and an older brake fluid bottle with a little left works wonders.)

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  • 2 weeks later...

The amount of 'bounce' in the slide pins is relative to how much air (or vacuum) is trapped behind the pin due to the seal caused by the grease/boot.  As someone mentioned, the main point is that the pin needs to slide smoothly.  A couple points.. when you cleaned the slide pin (and socket) be sure to avoid any water-based products.. or if you use them then be 100% sure that they have fully evaporated prior to installing fresh grease.  Otherwise, the water will be sealed in by the grease and it's almost a guarantee that it'll end up rust-locking.

 

Aside from the pin, it's also important that the boot be free of tears and compresses normally.  If the boot rips then water will eventually get into the socket.  If you do find that you need a replacement due to the slide pins then note that you don't actually need an entire caliper.  Rather, you just need the caliper bracket. The brackets are much cheaper and easily found at a junk yard for 20-40$.  There may also be other models that use the same parts (i wouldn't be surprised if a scion matched up).

 

For bleeding the brakes, i've always done the two-man simple setup.  One guy pumps the pedal to build up pressure and holds the pedal down while the other loosens the valve.  I just hold a rag over the valve and only have it open for 1-2 seconds.  As long as the person keeps pressure on the brake pedal and you don't leave the valve open too long you wont have to mess with kits, bottles, tubes, etc.  Just add fluid to the reservoir every so often so it doesn't dip too low and press air into the line.  Oh, and start with the longest lines first (usually rear passenger, then rear driver, front pass, front drv).

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