Replacing Rear Rotors on Esprits
with Inboard Disc Brakes
Article and Picture by Atwell Haines
Eventually you will need to remove
and replace the rear brake rotors on your Esprit.
While the outboard front brakes are just like any of a thousand makes of cars, the inboard
rear setup makes the job seem a bit daunting to the novice. The following are my experiences
with the repair. It's not really a bad job at all as long as you know a few tricks. As usual, the
Lotus Service Notes only mention the procedure in passing.
rotors were originals, and I had warped them by applying the parking brake after
lapping session at the racetrack <tsk-tsk> NEVER do that always let the brakes cool
before applying the parking brake! So, I decided to replace them. I obtained a pair of
cryogenically frozen rotors from Diversified Cryogenics (www.frozenrotors.com) to
match my front set of rotors that I installed last autumn.
8mm Allen Key or socket
Penetrating Oil (I use Armor-All)
Ratchet and sockets
Spray Can of Brake-Cleaner
I put the car on my parking lift for this procedure if you don't have one, lift the back
of the car with a floor jack on the rear frame hoop, then let the car rest on jack stands
placed under the rear jacking reinforcements on the body sills. Be safe!
The first thing to do is to make
your life easy by spraying the hardware with a penetrating
release agent. As I use Armor-All, I killed some time waiting for it to do its thing by
cleaning and soaking the axle's rubber constant velocity joint boots. These should be
inspected carefully! If they are cracked get some new ones, as it is convenient to change
these while the axles are out.
The first thing to do is to release
the six 8 mm allen head capscrews that hold the inboard
end of the driveshafts in place. (I marked the position so that I could put everything together
the same as it was, although the shop manual doesn't mandate it.) I was using an allen wrench so I had to apply more breaking torque by putting a pipe on the end of the wrench for more leverage. Some of the capscrews could only be turned a flat at a time due to the position of the suspension. This was the most tedious part of the procedure.
Luckily only the inboard set of screws, nearest the brake rotors, need to be removed. Once the axle was free it was wired to the trailing arm to keep it out of the way during the rest of the procedure.
The three 17mm nuts on the brake
rotors should be loosened two turns next. It helps
to have the parking brake applied here to prevent everything from turning while you are
breaking the nuts free. Don't remove the nuts at this time.
Next the two brake calipers can be unbolted and moved aside. There are only two 19mm bolts and they can be reached with various combinations of sockets and wrenches. (Once again I found that my set of Gearwrenches made the job go MUCH easier ) Hang the calipers out of harms way with a length of coat hangers. Don't put stress on the rubber brake line!
After both bolts are withdrawn,
the calipers should be wiggled back and forth to spread
the calipers a bit. (Remember the new rotors will be wider than the old ones!) Opening the
cap on the brake master makes it a bit easier for the fluid to return to the reservoir.
Then the three bolts on each
caliper may be removed. You may find that the studs come
out with the nuts. That is OK. In fact, if one stud comes out it makes replacing the
Now remove the three nuts from
the rotors all the way. If a stud comes out, rotate this
position to be at the top. Then remove the old rotor.
Clean up all the mounting surfaces
so that you get a nice flush mount before fitting the new rotors. And don't
forget - new rotors come treated with an anti-corrosive coating, so be
sure to remove this with Brake Cleaner. I coat the mating surfaces and all threaded areas
with anti-seize before reassembly.
I replaced the rear pads with
Mintex formula 1144 race/street binders. This required that
the caliper pistons be retracted into the caliper. A ¼" inch ratchet extension does the trick
here. Make sure you orient the slot properly according to the instructions in the Service Notes.
Now came the tricky bit: repositioning
the new rotors onto the hubs. If the top rotor stud
is missing, the job is a lot easier. Once loosely in position the caliper can be mounted next. Now you will know if you retracted the caliper enough. The loose rotor allows you to angle the loaded calipers into position to slip over the rotors.
You can then loosely start the
caliper mounting bolts. Then you can tighten the rotor nuts. (Do any studs you
have removed first, simply double-nut the long (rotor) end of the stud to crank
them in.) Torque everything according to the manual. This is especially important
on the rotors, as you don't want to warp them!
The last thing is to replace
the driveshaft into the inboard rotor. Torque with a torque
wrench with allen key sockets. After a few miles of driving I re-checked all the hardware to
make sure it was still tight. The other side rotor is nearly the same as the first.
Some of the approach angles for the tools were different, but it wasn't any harder.