REPAIRS PAGE 12
BRAKE CHECK AND OVERHAUL
Toyota recommends that the brake fluid is changed every 24,000 miles or two years. Brake
fluid is hydroscopic which means that it absorbs water which can rust the brake
pipes. Start by jacking up the car and supporting it on four axle stands, remove
all four wheels. Starting at the rear near side brake calliper loosen the bleed
nipple and using a length of clear plastic tubing into a jar get your assistant
to pump the brake pedal several times. Tighten the nipple and repeat the process
with the other three brakes then return to the rear near side and ask your
assistant to pump out all the remaining fluid. When this is done remove the
bleed nipple entirely and clean it with a wire brush, using a length of fine
wire to clean out the hole. Repeat this with the other three brakes. As you work
round the car clean away dirt around the brake pipes and check for corrosion and
any cracks or chafing of the flexible rubber pipes. Fill the reservoir with new
brake fluid and bleed all the brakes in the same order as before.
Whilst doing this messy but necessary job it is a good opportunity to check both the
brake pads and the discs themselves. Wire brush off any loose rust and check for
scoring - which can be easily be skimmed out if not too deep, and look
especially to see if the pads are polishing the whole swept area of the disc.
Any unpolished region may indicate that the sliding bushes on the calliper are
in need of a clean and new copper grease, check also that the rubber boots are
not cracked. Don’t forget to check the rear of each disc by feeling them around
their entire circumference. If new pads are to be fitted don’t forget to decant
some fluid from the reservoir as the thicker pads will displace a certain amount
of fluid. Check the piston seals as these sometimes dry out and stick to the
pistons - release them gently with a small blunt screwdriver and lubricate with
a little brake fluid remembering to remove any excess. Wire brush all the fixing
bolts and torque back as specified in the manual.
RICHARD MORGAN
BRAKES – DISCS AND PADS
Brake discs often become scored and wear unevenly especially on cars as old as the
MR2, now 12 to 18 years old. New Toyota discs in common with most other replacement parts
can be horrifyingly expensive, but there is a much cheaper solution - skimming. My
local machine shop charges £15 to refinish a pair of brake discs, and with new
pads available at around £16 a set the whole car can be done for as little as
£62. I was recently quoted over £500 to supply and fit new discs and pads by a
well known national chain of tyre depots! Do it yourself is very straightforward
on the MR2, with the car jacked up and secured, once the two caliper bolts
have been taken out from the bracket the brake assembly can be removed together
with the old pads which can then be replaced. Next remove the two bolts holding
the piston assembly which should be tied with a piece of wire so it does
not hang by the brake hose. The brake disc or rotor should now be easily
pulled off, if it is stiff use two appropriately sized bolts in the
threaded holes provided, gently tightening these in turn will release the
disc. The rear of the car is treated in a similar manner. I recommend
following the steps outlined in the Haynes manual ( available from the
Club Shop
, not available from Halfords etc.) The minimum thickness that the disc
can be machined to is marked on each disc, don't forget that brake fluid
should be changed periodically and that if your old pads are very worn replacing
them with new ones will displace a lot of fluid back into the master
cylinder reservoir which should be siphoned off.
Although this is a very easy D.I.Y. job, for safety's sake DO follow all the jacking and securing
procedures.
RICHARD MORGAN