Brake parts cleaner advice needed

[2009Prius]

DIY 5K service newbie questions: How does brake parts cleaner work? Where do I spray (any places to avoid)? Do I need to wipe after spraying? Which brand is the best? Thanks!

[firepa63]

You don't need it. If you get a slight buildup of rust, just take the car up to about 40 MPH (where it's safe to do so), shift into N and apply the brakes to slow down to a stop. With the car in N the regenerative brakes are out of the picture and only the friction brakes will be used. The will clean the rust off the rotors.

[Patrick Wong]

A can of brake parts cleaner is a great addition to your garage supply cabinet. It is basically an all-purpose degreaser that does not leave a residue. It will dry quickly so there is no need to wipe the surfaces. Generally, it is not a good idea to get the cleaner on paint or rubber parts (other than rubber brake parts.)

However at 5K miles you don't need to worry about your brakes. When you get up to 30K miles or more, and feel like cleaning the rear brake shoes and drums, then you can pull the drums and spray down the exposed parts. I suggest catching the runoff on newspaper, then discard the used paper in a plastic bag.

[2009Prius]

Originally Posted by Patrick Wong

...
However at 5K miles you don't need to worry about your brakes. ...

I thought so too, until I saw in the 5K maintenance schedule an item listed to visually inspect the brakes, which means I need to pull the rear brake drums off, which then made me wonder if I might as well do a cleaning.

By the way what I should look out for other than the brake pad and the surface that rub against it? Thanks!

[Patrick Wong]

To remove the rear brake drum, if it doesn't just pull off when you have the parking brake released, you'll need a couple of 6 mm bolts (say ~25 mm long or more) to insert into the two threaded holes. This will force the drum off.

Regarding rear brake inspection, look at shoe thickness. The thickness of a new shoe is 4 mm, and it needs to be replaced when the thickness gets down to 1 mm.

Look at the brake shoes and the inside of the brake drums to see if they look glazed. If so, then you may need to replace them. (This would be unusual to see on Prius where the brakes are generally lightly used.)

Look for brake fluid leaks at the wheel cylinder.

That's about it unless you decide the parking brake needs to be adjusted.

Regarding the front brakes, look at pad thickness. New thickness is 11 mm and they must be replaced at 1 mm. Look for brake fluid leakage at the calipers. Look at the discs to see if they show any rust, esp the inside if you live in an area where winter salt is applied to the roads.

Measurement of brake pad and lining thickness excludes the steel backing plate.

When your car gets up to ~100K miles and you want to start worrying about the thickness of the front discs and rear drums, note that the spec for the front discs is 22 mm new and they should be replaced at 20 mm. (This is for NA, the Europe new spec is 25 mm IIRC.) The rear drum inside diameter is 200 mm when new and it should be replaced when the diameter becomes 201 mm. (Europe has rear brake discs.)

[2009Prius]

Originally Posted by Patrick Wong

To remove the rear brake drum, if it doesn't just pull off when you have the parking brake released, you'll need a couple of 6 mm bolts (say ~25 mm long or more) to insert into the two threaded holes. This will force the drum off.

Regarding rear brake inspection, look at shoe thickness. The thickness of a new shoe is 4 mm, and it needs to be replaced when the thickness gets down to 1 mm.

Look at the brake shoes and the inside of the brake drums to see if they look glazed. If so, then you may need to replace them. (This would be unusual to see on Prius where the brakes are generally lightly used.)

Look for brake fluid leaks at the wheel cylinder.

That's about it unless you decide the parking brake needs to be adjusted.

Regarding the front brakes, look at pad thickness. New thickness is 11 mm and they must be replaced at 1 mm. Look for brake fluid leakage at the calipers. Look at the discs to see if they show any rust, esp the inside if you live in an area where winter salt is applied to the roads.

Measurement of brake pad and lining thickness excludes the steel backing plate.

When your car gets up to ~100K miles and you want to start worrying about the thickness of the front discs and rear drums, note that the spec for the front discs is 22 mm new and they should be replaced at 20 mm. (This is for NA, the Europe new spec is 25 mm IIRC.) The rear drum inside diameter is 200 mm when new and it should be replaced when the diameter becomes 201 mm. (Europe has rear brake discs.)

Thank you! This is very helpful as always.