Pulled spark plug - how does it look?

NGK came installed with my Prius. I bought a new set online from a Toyota dealer and got Denso plugs in Toyota boxes. So both are used by Toyota for Prius.

 

A couple of cautions regarding spark plugs:

1. Some of the pricey ones warn that they should not be regapped. It will damage them, I assume.

2. Cleaning should ideally be with chemical solvent only, no wire brushing or sand blasting.

 

When the serpentine belt was off, I hope that you rotated the coolant pump by hand to verify the bearing is in good condition. If that is true and you don't see any coolant seepage then no worries.

Although I normally would be among the first to replace a part at the slightest hint of trouble, in the case of the mechanical engine coolant pump I would say that you'll have plenty of warning with regards to coolant seepage at the pump shaft. Hence there is no need to replace the pump until you see this.

 

I don't know if this is your specific problem, but the mechanical brakes on the Prius are often only used at very low speed (*usually about 7 MPH and under, where the regenerative braking is not very effective).

So it's pretty common for the drums/discs to build up a bit of rust scale simply because they get so little use. I sometimes get a little bit of squeaky brake happening at low speed.

*Of course if you need to brake hard then the mechanical brakes can be used at any speed.

 

In my experience what squeaks is the points of contact between the shoes and backing plate: typically 3 points per shoe. I've not had a Toyota with drum brakes, but usually:

There's a clip around the centre of each shoe's web, holding the shoe tight against the backing plate. There are tools to help release that clip, but you can do it with pliers.

With the clip released it should be possible to lift the shoe a bit clear of the backing plate. What I'll typically do:

1. Pull the shoes away from the backing plate and clean out any residue from previous lubricant. A flat blade screw driver with a thin wrap of cloth works. Try to avoid getting lubricant on the shoe's braking surface.

2. Get a small amount of molybdenum anti-seize compound on a slim spatula or brush, and put a little dab on the contact points (typically 3) between the shoe and the backing plate. Again, be careful to avoid getting lubricant on the shoe's braking surface.

This will usually do it. There are also contact points at the tops of the shoes, between the shoe and hydraulic cylinder, and similar points of contact at the bottoms of the shoes. But the movement at these points is insignicant, and I usually just leave them alone.

Don't forget to put the clips back on when re-assembling. It's even more fun putting them on then taking them off. Might be worth looking for that tool. Again, it can be done with pliers, but it's always a bit of a fight.