By Core Brake Parts Tech Team — Circleville, OH warehouse
Every Lotus Evora from 2009 to 2021 stops on four-piston AP Racing calipers at all four corners, so caliper trouble on this car is usually a seal, piston or slow-release problem rather than a worn-out casting. Most complaints trace back to calipers that sit unused, get cleaned with the wrong chemicals, or run hot on track, and most can be fixed with a reseal and fresh fluid before you ever need a new caliper.
How the Evora Brake System Is Built
The Evora uses fixed, opposed-piston calipers rather than the single-piston sliding calipers found on most road cars. A fixed caliper bolts rigidly to the upright and pushes pads from both sides with pistons on each side of the disc. There are no slide pins to seize, which removes one of the most common failure points on ordinary cars, but it means the pistons and their seals do all the work of applying and releasing the pads.
Lotus of Jacksonville describes the original cars as having four-piston Lotus-branded AP Racing calipers all around, with the later 400-series cars moving to AP Racing branded calipers in a revised configuration. The disc package changed with the calipers:
| Model | Calipers | Front disc | Rear disc |
|---|---|---|---|
| Original Evora and Evora S | AP Racing four-piston, front and rear | 350 x 32 mm one-piece, ventilated, cross-drilled | 332 mm one-piece, ventilated, cross-drilled |
| Evora 400, GT and GT430 | AP Racing four-piston, front and rear | 370 x 32 mm two-piece, ventilated, cross-drilled | 350 mm two-piece, ventilated, cross-drilled |
Because the caliper and disc sizes changed between generations, a caliper, pad or rotor for an early Evora is not a drop-in part for a 400 or GT. Always confirm the model and year before ordering. One more detail matters for rear caliper work: the parking brake is a cable-operated drum brake built into the hat of the rear disc, not a mechanism inside the caliper. A rear caliper on this car does not wind back like the screw-type rear pistons on many sedans, and parking brake problems are a separate diagnosis from caliper problems.
Common Evora Caliper Problems and Their Symptoms
An Evora is often a second car that sits for weeks at a time, and it is also a car owners take to track days. Both habits are hard on caliper seals, and the symptoms are predictable:
- Pull to one side under braking. One or more pistons on one corner is slow to move, so that wheel brakes harder or softer than its partner.
- Dragging or a hot wheel after a drive. A piston that does not retract keeps the pad in light contact with the disc. You will feel more heat from that wheel than the others and may smell hot brakes.
- Uneven pad wear. On a four-piston caliper, one sticky piston shows up as a pad that is tapered or worn thinner on one side, or an inner pad much thinner than the outer.
- Fluid weeping at the caliper. Damp streaks on the caliper body or wheel, or a slowly falling reservoir level, point to a failing piston seal or bleed screw. Treat this as urgent.
- A soft or longer pedal. Air or moisture in the fluid, or a leaking seal, lets the pedal travel further before the pads bite.
- Pads stuck to the discs after storage. Rust bonds the pad to the disc surface on a car left sitting damp, and the first drive breaks it free with a clunk or leaves a rust stripe on the disc.
What Causes Them
Heat and time at temperature
AP Racing states that seal life depends on time at temperature: the longer a seal sits hot, the faster it degrades. Its race guidance is to re-seal every other event for calipers that run up to 200 C, and to re-seal as soon as possible for calipers that reach 200 to 220 C or more. It also warns against holding the brakes on hard while stopped after a hot session, because heat soaking from the pads into the caliper pushes its temperature up. An Evora that sees regular track use should be treated closer to a race car than a commuter.
The wrong cleaner
AP Racing is blunt that its calipers should only be washed with soapy water or an alcohol-based cleaner, and that petrol, gasoline or any mineral oil based cleaner or lubricant will damage the seals. A generic spray degreaser or a petroleum-based grease on the pistons can swell the seals and cause the sticking it was meant to cure.
Storage and moisture
Brake fluid absorbs water over time, and water in the fluid corrodes pistons and bores from the inside. On the outside, a car parked wet lets the pads rust onto the discs. Lotus of Jacksonville advises making sure the brakes are dry before long-term parking and leaving the car in gear or in park with the handbrake off, so the pads do not stick to the discs.
Reseal, Rebuild or Replace?
A fixed AP Racing caliper is designed to be serviced. The body is rarely the part that fails, so the order of repair is:
- Fresh fluid and a bleed. If the pedal is soft but nothing is leaking, start here. Use the fluid specification in the Lotus owner's handbook.
- Reseal. If a piston is sticking or a seal is weeping, the caliper can be stripped, cleaned and fitted with new seals. AP Racing's procedure: extend the pistons with hydraulic or air pressure against a block, remove the old seals with a blunt tool, clean the bores, grooves and pistons with an alcohol-based cleaner only, soak the new seals in brake fluid for 30 minutes, and seat each one without twisting it.
- New pistons. A piston with pitting or scoring on its sealing surface will chew through new seals. Replace it rather than polish it.
- Replace the caliper. Only when a bore is corroded or damaged, a thread is stripped, or the body is cracked. Lotus of Jacksonville puts replacement calipers at a significant cost per corner, so a reseal is worth trying first on a caliper that is only sticking.
If you are not comfortable dismantling a hydraulic caliper, send the calipers to a shop that rebuilds AP Racing units. AP Racing itself offers reconditioning through its distributors.
What to Replace at the Same Time
A sticking caliper almost always damages what it clamps. When one Evora caliper has been dragging, inspect both calipers on that axle and plan to replace:
- Pads, as an axle set. A glazed or taper-worn pad will not bed in properly against a fresh caliper. For road and fast-road use, see our brake pads. For track days we carry the EBC RP-1 race pads for the 2009-2016 Evora and the DBA DB1938RP race pad set for the 2010-2015 Evora, plus the EBC RP-1 front set for 2015 and newer cars.
- Discs, if they are blued, heat-checked or worn unevenly. A dragging pad overheats the disc. For the early cars there is the DBA 4000 Series T3 slotted front rotor and the DBA 4000 Series T3 slotted rear rotor. Confirm the listed fitment against your car, since the 400 and GT use larger two-piece discs.
- Brake fluid, fully flushed. Old fluid is often the reason the seals failed.
- Hoses, if they are cracked or swollen. A collapsed flexible hose can hold pressure on a caliper and mimic a stuck piston. Browse brake hoses and brake lines.
How Hard Is the Job?
Pad changes on the Evora are straightforward on a fixed caliper: the pads usually come out after removing the retaining pins without unbolting the caliper. Removing a caliper for a reseal means opening the hydraulic system, so you will need to bleed the brakes afterward, and on an ABS car that bleed should be done carefully with fresh fluid. Torque the caliper mounting bolts and bleed screws to the values in the Lotus service manual; do not guess on bolts that hold a fixed caliper to the upright. The reseal itself is bench work that rewards patience and cleanliness more than special tools. Most owners who do their own pads can do a reseal; anyone unsure should leave the hydraulic side to a specialist.
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Shop Brake Calipers →Frequently Asked Questions
Does the Evora use the same calipers front and rear?
Every Evora uses AP Racing four-piston calipers at both ends, but the front and rear units are different parts sized for different discs, and the 400 and GT calipers differ from the early cars.
Can I put Evora 400 brakes on an early Evora?
Not as a simple swap. The 400 and GT run larger two-piece discs with different calipers, so a conversion needs the matching calipers, discs, and wheels that clear them.
Why does my Evora's handbrake feel weak when the calipers are fine?
The parking brake is a separate cable-operated drum inside the rear disc hat. A weak handbrake points to the drum shoes, the cable or its adjustment, not the rear calipers.
Can I clean my AP Racing calipers with brake cleaner?
AP Racing says to use soapy water or an alcohol-based cleaner only and to avoid petrol or any mineral oil based cleaner or lubricant, which damages the seals. Check the label of any spray before using it near the pistons.
How often should the calipers be resealed?
For a road car, reseal when you see sticking, weeping or uneven pad wear. For a car that sees hard track use, AP Racing's guidance is to reseal far more often, and immediately if the calipers have run above about 200 C.
Sources
- Lotus of Jacksonville - Evora brakes, wheels and tyres - caliper and disc specs by generation, drum-in-hat parking brake, storage advice
- Lotus Evora GT press release (2020) - AP Racing four-piston calipers front and rear, 370 x 32 mm front disc
- Lotus Palm Beach - Evora GT specifications - servo-assisted two-piece discs with AP Racing four-piston calipers
- AP Racing - Caliper Servicing and Reconditioning - cleaning agents, seal replacement procedure, seal soak time
- AP Racing - Brake Caliper Seals and Temperature - time-at-temperature seal life and re-seal intervals
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