rdharper

This may seem like a dumb question. Gotta ask it anyway.

On changing brake pads, the FSM says, right before compressing the brake cylinder, to draw some brake fluid from the reservoir.

I assume that means from the reservoir on the firewall, before the master brake cylinder, what else, right?

Problem I have with that is, why would that work? It is before the Master cylinder. How could that help the brake cylinder loosen up to make its compression easier?

Thanks for any explaination. If it works, it is much easier than the methods I've used in the past on different vehicles.. opening bleeder valve, or a special compression tool etc.

Elvota

I believe they want you to remove some of the fluid because when you compress the brake piston, the fluid will overflow at the resevoir... but this is more of an educated guess than fact.

rdharper

Could be right... makes more sense than my guess. They state you can use a wooden handle of a hammer to move the piston back. That has not been my experience, but then I've never done the job on a Toyota... lol. Maybe their piston-cylinders are a bit more amenable to pushing the piston in.

amgraham

Yeah, the reason they say to take some fluid out is to prevent overflow since when you compress the caliper piston you are essentially making the system capacity smaller.

The easiest way I have found for compressing calipers is using a big pair of channel locks. Just adjust it and put one jaw on the piston and the other on the back of the caliper and squeeze. Vice-grip makes a tool that works well for most calipers too (wide jaws with adjustable pads). Wow, I never realized how hard that is to explain... I hope you can picture some of that

CJM

Just opent he brake fluid reservoir cap, it wont overflow unless the reservir is filled to the brim.

A big c-clamp works the best to compress the pistons too.

rdharper

Thanks CJ... c-clamps I've got, all sizes and then some.. lol. Good idea.

CJM

Yea, tried and true. Thats the way I always do my brake jobs and we never spilled any brake fluid.

86SR522REEFI

I use a handy dandy snap on piston spreader type deal. Before that i used channell locks. Both work the same, one cost Muchos Dineros more though. Ive done brakes alot and none of them have overflown due to compressing the piston.

rdharper

Haven't done a lot, but probably 6 over the years. Never had overflow either, but it might explain the FSM's comment. Its there in black and white: "Draw out a small amount of brake fluid from the reservoir."

Maybe its a mystical thing... like throwing salt over your shoulder.

rdharper

Well, the laugh is on me (as usual). I finally noticed I was reading the 2WD front disk brake instructions. 4wd disk-pad replacement instruction appear to even simpler, as one only removes the anti-rattle springs, 2 anti-rattle pins, and an anti-rattle clip. No removal of caliper assemply. And no comment about fluid removal...

Egads... how simple can it get!

rdharper

Well, changing disk pads was never as easy as this! Since you don't need to remove the piston assemble (only on the 4wd, not 2wd) the job is really simple.

The actual work was about 20' on the first side, and probably 10' on the second. If I were any good, it would be 20' for the whole job.

The springs and clips go right back with no hassle. Toyota, you guys are good.

Not that I recommend them, but the Kragen online price was 17.99, which I called in and got, picked up later in the day. They had about 6 different sets, so I've no idea which are really "best". I just went with the least expensive in-stock. My racing days are long gone, I can't see the logic in paying twice the price. I'd rather have them wear down a bit sooner, and save the wear on the rotor, which was in beautiful shape.

And with a light rear-end (long-bed pickup), and no abs in the rear such as my '94 4runner has, the breaking is always governed by not locking up the drums in the rear anyway... anyway, for what its worth, the job is simple and inexpensive, and no risk of some clown bending the rotors with two much torque when the wheel is put back on.

Should have done the shocks at the same time... they look to be very easy as well.. oh well. Next week.

rdharper

The 2wd admonition which was left off of the 4wd front disk brakes instructions in the FSM was correct, in my case. I did get some overflow of the brake reservoir.. probably a tablespoon or two.

Makes a bit of a mess, which could be avoided by putting a rag around the thing. Since most people claim it doesn't happen, that is a simple solution, and avoids opening the brake reservoir. You know, wiping off dust, guessing at how much to remove etc. Not necessary.

The other thing I wonder about is whether the rubber around the pistons is successfully in place without pinching it etc. There is almost zero space even if the pistons are totally retracted, so you kind of have to guess. Probably wouldn't hurt to put a very small amount of lubricant to let it slip in place, then push the pads in just beyond where they will sit, and pull it back into place. That lubricant is on the opposite side of the pads, so it should be safe.

But I worry too much, as you can plainly see. The brakes seem to work great, and I'm happy for now... lol.

toyota_mdt_tech

I doesnt help pushing the pistons back in at all, it just keep the brake fluid from running all over the engine room as the piston displaces all the fluid behind it.