DIY brake job on a Scion xB

April 19, 2014

When her beloved Honda CRV became too old to drive safely on the highway my mother needed another car with easy access. The best we could find at the Honda dealership was a 2008 Scion xB from Florida which offered height-adjustable front seats and wide doors.

The Toyota controls on the air conditioning and lights were a chore for Mom to learn in her mid-eighties, but the rest of the car was just fine. Two years later the brakes had begun to grind, so I put it up on the hoist and took it apart.

After the wheels were off I realized that nothing looked familiar in there, so I took to You Tube for instructions. Disk brakes have come a long way since my all-too-frequent encounters with them on my 1979 Rabbit, but now there are lots of guys who demonstrate simple procedures on their websites.

On the Scion xB the caliper is separate from the part that holds the brake pads. On the fronts the holder hinges up for convenient maintenance if you remove the lower bolt.

The big problem with the rear calipers was that no amount of clamping pressure would make them retract, though the pins holding the brake pads were fine. Online I discovered that the emergency brake linkage holds the pads in position, so the piston of the caliper must be rotated clockwise under compression to get it into position for new pads. Charlie emailed me that Princess Auto had a tool for that on sale this week, a dice-shaped, hollow metal box with pins sticking out of it. After much fussing with C-clamp, hammer and screw driver, I learned to fit a 3/8″ socket extension into the appropriate slot on the new gadget and twist away.

I looked online for brake parts. None of the usual Canadian suppliers carry Scion brake parts. I phoned a Toronto-based eBay brake parts vendor. She firmly told me that 2008 Scion xB’s have drum rear brakes. Oh. Another told me the same thing. So much for the $200 brake job.

Toyota brake parts are usually pretty reasonable at the dealer, so I called Kingston Toyota and asked. The parts guy wanted a VIN number. I recovered 16 of the 17 digits from a liability slip in the glove box and his computer provided the rest. “Is it black?” he asked, by way of confirmation.

Another reason I was willing to pay four times the lowest Internet price for pads and rotors for this car was that the pads when I took them out seemed to have been jammed into the holders, unable to move. I suspected either a fit issue or crummy workmanship at some point. There was no need for Toyota brakes to fail in two years of light driving.

John had to order the rear rotors from Toronto, but assured me they would be in the following morning, so we planned a trip to Kingston to pick them up. For the $601 (including tax) John threw in two tubes of grease and a session with a technician who explained to me how to lubricate the pads in their slots so that they would work smoothly. Then he carried the rotors out to the car for me, and away we went.

By email I asked Charlie if the pins really needed to be re-lubricated if they were flexible under their rubber seals. He assured me that they did, but after I greased one with the special lubricant the dealer gave me I had trouble getting the rubber thing to seal again, so I left off for fear my clumsy fingers would do more harm than good to the other pins. Charlie’s done a lot of brake jobs on his track cars, but they were Porsches, and Porsche brakes go together very easily. Scion brakes don’t.

All in all the reassembly went pretty well. I had to figure out how to wiggle the pads into the holders so that they could move. Otherwise they’d jam. The lubricant and a goodly amount of elbow grease freed them up, but I still don’t understand why these little clips fit onto the bottom of the front pads. There weren’t enough to go around, so I put two on the left side and left the right ready for clip installation if they squeal or thump.

Apart from the pad-fitting the front brakes went together well, but the rears required that I remove the calipers in order to mount them on the rotors. No problem: Charlie’s tool box has two sets of vice grips for pinching brake lines, and banjo bolts are no big deal if you don’t lose the washers when you remove them. “Gravity bleeding” was mentioned on one of the videos, and it seemed to work. I added a few ounces of brake fluid at the top and wiped up the mess on the floor.

The car stops well now and the ABS works properly. With the summer tires installed (tire pressure sensors) no indicator lights complain on the dash. The parking brake works properly. The car shows no evidence of brake drag, but when I took the temperature of the rotors after a test drive, the right rear was a bit hotter than the others. That caliper had felt a bit tight when I put it together. It may need replacement.

I’ll try a couple of test drives and see if it loosens up with wear. Now that I know how to reassemble a set of modern disk brakes, the prospect of another session on the hoist isn’t bad at all.

BTW: I see this article is already getting some hits, so I should mention a trick I learned from a mechanic some years ago. Toyota brake rotors don’t flop loose from the hubs when the wheel comes off. There is, however, a pair of tapped holes drilled into the rotors which take a regular bolt, metric thread, a bit bigger than 1/4″. The correct bolt takes a 12 mm wrench, if I recall correctly. To remove the rotor, all you need do is locate a suitable bolt and twist it in against the hub. Pop. Works every time. Paint the bolt and keep it in your toolbox.

UPDATE: 20 April, 2014

After considerable thought, a downloaded service manual and email chats with Charlie, I went looking for the source of the friction on that right rear caliper.

There didn’t seem to be a lot of run-out on the rotor, though the pads had worn themselves looser than when I had forced them into place before.

Before long I found myself removing the piston from the caliper by turning it counter-clockwise with my little caliper tool and a 3/8″ ratchet. It felt as though some lube could help. When the piston came free I discovered a few bits of broken thread on the stud inside the caliper. I cleaned things up as well as I could, tried air to blow any remaining moving parts out onto the bench (there weren’t any), then buttered things up with the synthetic grease the dealer gave me and put them back together. The rubber “foreskin” of the piston was hard to get back in, though with persistence and the back of a dental pick I think I prevailed. Several trips in and out (with ratchet and tool) and the piston seemed freer than before. On a dry fit I noticed that it’s fairly easy to extend the piston in the caliper by judicious manipulation of the emergency brake lever (where it joins the cable at the wheel), though it’s wise to avoid pinching the web between one’s thumb and first finger during this exploratory exercise.

Little then remained but to torque the lug nuts and try a gentle test drive. My laser thermometer read 120F on the right rear rotor vs 100 or so on the others after the drive. But the gas mileage is back up on the digital display and there’s no puddle of brake fluid under the car, so I hope that the caliper has somehow become third-time-lucky.

UPDATE: 24 April, 2014

After several local expeditions to check local ice conditions, I have concluded that the brakes on the Scion are now considerably better than those of the other vehicles in the fleet, so this missive ends.

Advertisements

One Response to “DIY brake job on a Scion xB”

  1. Tom S Says:

    FWIW, twice, my mechanic tried to use after-market drums on my 2002 Tundra without success. Both sets (NAPA) were “warped” from new. We gave up and installed Toyota OEM drums and now my brake pedal doesn’t talk back to me when I step on it.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: