Replacing Brake Pads

[stringbean]

i buy my brake pads and rotors from Lordco, a Canadian owned company since im in Canada and i do it all my self, i dont trust anyone in my town unless i personally know then and they are high up in the department at a dealership, body shop etc. im only 18 and can change my brakes its such a good way to save money, make sure you know how to do it though first lol

[gnegroni]

By 'frozen', he meant corroded/ rusted to the point of seizing. We're not talking temperature, here.

The normal resting position for the caliper and pads is only slightly backed off from the rotor. Think less than 1 mm.

Final thought-- it seems that the act of pressing the piston back into the caliper while replacing pads is the often the first time you will see the effects of a bad caliper. Remember, when you push that piston back in, it will now be operating in a different area of the caliper bore than it had been previous to the brake work. This part of the bore can become rusty over time and 'grab' the piston enough to prevent it from retracting normally.

Thanks for the input.

On the possibility of a frozen caliper (never happened on any vehicle of mine before), is there anything I could use to allow some "relief" on that caliper via brake cleaner or something?

[Black Bob]

^^^^In regards to frozen calipers (i.e. jammed sliding on the caliper pins), unjamming them is all dependent on how jammed up they are. Spray lube, WD-40, mallet etc. all have been used to free up a frozen caliper as a first resort (also the cheapest path). As a second resort, frozen calipers have been taken apart and rebuilt (mechanics hate busting their knuckles and will charge you out the "A" to do it). As a last resort frozen calipers can be just replaced (usually cheaper than a rebuild).

That being said, I agree with Youngblood, the piston inside the caliper seizing is more often than not the cause of rubbing--I would definitely check that. (If the piston doesn't retract it'll keep the brake pad in constant contact with the rotor.) Free movement of the piston can be checked by pushing the piston into the caliper with a C-clamp and then releasing it a few times. Pepboys "shoulda" checked this before installing the pads. Goodluck!

[gnegroni]

I bought the pads at PepBoys, but installed them with a local mechanic.

[Black Bob]

^^^One quick way to assess any rubbing without too much knuckle busting is to take the wheels off and see if a strip of paper can fit between the pad and the rotor. At rest, the pads should be separated at least ~1mm from the rotor. If not, then re-check caliper and piston movement. Also re-check any rotor warping. If all is good I would suggest moving on to checking the emergency brake springs in the hub (which was the problem I had) and that the E-brake cable does move.

[gnegroni]

^^^One quick way to assess any rubbing without too much knuckle busting is to take the wheels off and see if a strip of paper can fit between the pad and the rotor. At rest, the pads should be separated at least ~1mm from the rotor. If not, then re-check caliper and piston movement. Also re-check any rotor warping. If all is good I would suggest moving on to checking the emergency brake springs in the hub (which was the problem I had) and that the E-brake cable does move.

Bob, we rechecked piston movement with the pads and caliper removed. Piston retreated using the appropriate tool and did so with ease. The emergency brake system was AOK.

I'm thinking there could be a problem with the hydraulics (brake pump, distributor, ABS). The feeling I get is that once the braking force is applied, the system is not letting go of the pressure and thus the car feels as being held up.

I don't think its wise to turn the rotors since the problem is not solved, thus possibly giving me warped rotors once again and have them replaced (more $$$). I could be wrong, but I don't feel symptoms of warped rotors when I brake. Hope though, that by removing the wheels and having the nuts tightened with the appropriate star procedure and not rely heavily on the impact gun might solve the vibration problem at high speeds.

I purchased the Haynes manual since I can't find any particulars on the Toyota repair manual we have access to.

Help!?

[Black Bob]

Hmmm......nothing is popping up as the obvious culprit .......next suggestion is to see if a little air somehow got in the brake line during the pad install (it can happen), bleed and test. Any other suggestion is gonna involve someone with more intricate knowledge of brake fluid pressure, ABS system, etc.

Also, I'm still conflicted on whether or not the vibration problem is totally separate from the brake problem or not--might be a tire issue (balance, air pressure?)?

[gnegroni]

Hmmm......nothing is popping up as the obvious culprit .......next suggestion is to see if a little air somehow got in the brake line during the pad install (it can happen), bleed and test. Any other suggestion is gonna involve someone with more intricate knowledge of brake fluid pressure, ABS system, etc.

Also, I'm still conflicted on whether or not the vibration problem is totally separate from the brake problem or not--might be a tire issue (balance, air pressure?)?

Well, I think you mentioned to check the tire pressure and wheel nut tightness. Last night I took the Solara for a highway ride and I didn't notice the vibration, so those may have been the culprits.

Is there any chance of damaging any of the hydraulic components by bleeding the system? Does the ABS system need to be reset when changing pads (can't find any literature requesting this) or bleed vehicle with the key on the ON position?

[Black Bob]

Although I have caused a few air bubbles in my brake line back in the day, I never bled a brake line in my life so I can't safely comment on how. Usually a common symptom of air in the line is a "spongy" feel when pressing and depressing the brake pedal.

But in regards to torque on the lugnuts what I CAN tell you is that torque is a finicky thing. If the nuts are non-equally torqued you will get noticeable vibrations, however if you over-torque your nuts (ha!) you will get vibrations AND warped rotors. I used to be an "over-torque-er" 20 years ago (literally standing on a torque wrench set to max) because I thought more was better. After 4 broken lugs, 2 billion swear words and 4 warped rotors I found out more is not better. Following the manufacturers torque setting on all wheels is always best. Like lugnut torque, equal air pressure across all tires is also very important to prevent vibrations, not to mention uneven tire wear and steering wheel pull.