Changing front brake discs

[RedWitch]

I made an attempt at changing the front brake pads and discs today, using the excellent guide in the KB section.

I managed to do the offside set, on the nearside the 17mm bolts were seized too tight and I didn't have either a lump hammer or a cheater bar to release them. Will do this side tomorrow.

Anyway, a couple of questions/comments:

Why the need to bleed off brake fluid and open up bleed nipples when replacing the caliper - surely this is asking for air to get into the system? All you are doing by winding the piston back in is pushing the brake fluid uphill and since you are not adding additional fluid, it's unlikely to overflow.

Second, I found it just as easy to use a water pump wrench to squeeze the piston back in, a bit cheaper than having to buy a caliper windback tool.

Anyway - good guide!

[JohnnyC]

Why the need to bleed off brake fluid and open up bleed nipples when replacing the caliper - surely this is asking for air to get into the system? All you are doing by winding the piston back in is pushing the brake fluid uphill and since you are not adding additional fluid, it's unlikely to overflow.

But the brake fluid is likely to overflow if you're changing the pads (which you should be doing too if you're changing the discs), assuming that the level has been topped up as your pads wear down.
What I did was to remove the cap from the brake fluid resevoir though. The other (better, but bit of a pain) method is to open the bleed nipples on the caliper.

Second, I found it just as easy to use a water pump wrench to squeeze the piston back in, a bit cheaper than having to buy a caliper windback tool.

Yeah, a wrench or spanner is just as good IMHO.

[crazylegs]

get one of those sucky syringy things.take out most of the fluid but not all ,sort the brakes and top up with nice fresh fluid.no bleeding and most of the fluid is renewed.

[Lauren]

I just do it by pushing/winding the piston back in the with the top off the brake fluid reservoir. Have never had it overflow yet.

[System-G]

Have a read here:
Photographic Brake Change "How-To"

It's a comprehensive "How-To" I did for TOC with my Corolla GTi, but it's exactly the same for most Toyotas including the MKI & MKII.

[Blokey]

...on the seized or tightened to ft + a quarter turn bolts/nuts - soaking the thing in a proper penetrating oil the night before and then having a pop at it the following morning works for me.

By proper penetrating oil I mean something like PlusGas or 3in1 Penetrating fluid. Another trick I've heard of is to get a socket and breaker bar on there, get someone to lean on the breaker bar whilst someone else taps the socket with a hammer (ideally dead-weight) and it'll usually move.

The front disks should just push back they don't need to be wound back in. When changing the pads/disks I take out fluid from the reservoir, push the pistons in, fit the new pads/disks and then flush all the old fluid out and put new stuff in.

B.