MGF Brakes Service Guide

Your MGF or MG TF braking system is one of the most critical safety components on your vehicle. This guide takes you through a logical diagnostic process, starting with the simplest checks, working through each component systematically, and using process of elimination to identify problems before carrying out targeted repairs.

Recognising the Warning Signs

Before diving into diagnostics, you need to identify what brought you here. Brake problems typically announce themselves through three categories of symptoms.

Audible indicators include squealing or grinding noises during braking, scraping sounds when moving off, or unusual clicking from the calliper area.

Visual indicators include brake fluid below the minimum mark on the reservoir, uneven tyre wear patterns or visible scoring on the disc surface through the wheel spokes.

Performance indicators include a spongy or soft brake pedal, the vehicle pulling to one side under braking, increased stopping distances or a pulsating brake pedal.

Note which symptoms you're experiencing before proceeding. This information will guide your diagnostic path.

Understanding the MGF Braking System

Before diagnosing any fault, you need to understand what you're working with. The MGF and MG TF models feature a hydraulic braking system with disc brakes on all four corners. Standard models use 240mm ventilated front discs with sliding callipers, paired with 240mm solid rear discs. Performance variants such as the MGF Trophy, MG TF 160 and models equipped with Sportpack 2 use larger 304mm front discs with AP Racing four-piston callipers for enhanced stopping power.

Both models incorporate an ABS (Anti-lock Braking System) as standard, a vacuum-assisted servo for reduced pedal effort, and a cable-operated rear handbrake integrated into the rear callipers. Understanding your specific model's brake configuration is essential before beginning any diagnostic work.

Stage One: The Simplest Checks First

Always begin with the easiest inspections that require no tools and take only moments. These simple checks eliminate the most common causes before you invest time in more involved diagnosis.

Check the brake fluid level. Open the bonnet and locate the brake fluid reservoir. The level should sit between the minimum and maximum marks. A low level could indicate a leak or simply that your pads have worn, pushing more fluid into the callipers. Top up with DOT 4 fluid if low, but note that a sudden drop requires immediate investigation.

Listen during a short test drive. Drive at low speed in a quiet area and apply the brakes gently. Note any squealing (often worn pads), grinding (metal-on-metal contact indicating critically worn pads) or scraping (possible debris or dragging component).

Feel the brake pedal. With the engine running, press the brake pedal. It should feel firm and consistent. A spongy pedal suggests air in the system. A pedal that sinks slowly to the floor indicates a hydraulic leak or failing master cylinder. A pulsating pedal points toward warped discs.

Check for pulling. During braking, does the vehicle pull to one side? This indicates uneven braking force, typically caused by a seized calliper, contaminated pad or hydraulic restriction on one side.

Stage Two: Visual Inspection of Components

If the simple checks haven't identified your problem, proceed to visual inspection. You'll need to remove the wheels, so gather a trolley jack rated for at least 1.5 tonnes, axle stands, and a wheel brace.

Inspecting Brake Pads

With the wheel removed, examine the pad thickness through the calliper inspection window or by looking at the pad edge. Check the friction material thickness on both the inner and outer pads.

Condition	Diagnosis	Action Required
Friction material above 3mm, even wear	Normal	Continue monitoring
Friction material at or below 3mm	Worn pads	Replace pads (axle set)
Inner pad significantly thinner than outer	Seized slider pins	Service or replace calliper
Outer pad significantly thinner than inner	Seized piston	Service or replace calliper
Uneven wear across pad face	Warped disc or calliper issue	Inspect disc, service calliper

Condition

Friction material above 3mm, even wear

Diagnosis

Normal

Action Required

Continue monitoring

Condition

Friction material at or below 3mm

Diagnosis

Worn pads

Action Required

Replace pads (axle set)

Condition

Inner pad significantly thinner than outer

Diagnosis

Seized slider pins

Action Required

Service or replace calliper

Condition

Outer pad significantly thinner than inner

Diagnosis

Seized piston

Action Required

Service or replace calliper

Condition

Uneven wear across pad face

Diagnosis

Warped disc or calliper issue

Action Required

Inspect disc, service calliper

Inspecting Brake Discs

Run your fingernail across the disc surface to feel for grooves. Light scoring is normal; grooves deeper than 0.5mm indicate replacement is needed. Check for cracks, particularly around ventilation holes on front discs. Look for a pronounced lip at the disc edge, which indicates significant wear.

Component	Standard Models	Trophy/TF 160
Front disc diameter	240mm	304mm
Front disc minimum thickness	18mm	25mm
Rear disc diameter	240mm	240mm
Rear disc minimum thickness	9mm	9mm
Minimum pad thickness	3mm	3mm

Component

Front disc diameter

Standard Models

240mm

Trophy/TF 160

304mm

Component

Front disc minimum thickness

Standard Models

18mm

Trophy/TF 160

25mm

Component

Rear disc diameter

Standard Models

240mm

Trophy/TF 160

240mm

Component

Rear disc minimum thickness

Standard Models

9mm

Trophy/TF 160

9mm

Component

Minimum pad thickness

Standard Models

3mm

Trophy/TF 160

3mm

Inspecting Callipers and Hoses

Examine the rubber brake hoses for cracking, bulging or chafing. Check around the calliper pistons and bleed nipples for fluid weeping. Look at the slider pins (where the calliper bolts pass through rubber boots) for torn boots or corrosion.

Stage Three: Diagnosing Specific Symptoms

Having completed your inspections, use this section to work through your specific symptom and identify the root cause through process of elimination.

Symptom: Squealing or Grinding Noise

Start with the simplest cause: Worn brake pads are the most common reason for brake noise. If your visual inspection revealed pads at or below 3mm, this is almost certainly your problem. Replace the pads.

If pads have adequate material: Check for glazed pad surfaces (shiny appearance) caused by overheating. Lightly sand the pad surface or replace. Examine the disc for embedded debris or foreign material. Check that anti-squeal shims are present and correctly fitted.

If noise persists after pad replacement: The disc surface may be damaged or contaminated. Replace discs alongside new pads.

Symptom: Spongy or Soft Brake Pedal

Start with the simplest cause: Air in the hydraulic system is the most common reason for a spongy pedal. Bleed all four corners following the correct sequence for the MGF: left rear, right rear, left front, right front.

If bleeding doesn't resolve the issue: Check all brake hoses for swelling under pressure (have an assistant press the pedal while you observe). Swollen hoses absorb pedal pressure. Inspect the master cylinder for external leaks around the pushrod. Check the brake servo vacuum hose for cracks or disconnection.

If problem remains: The master cylinder seals may have failed internally, allowing fluid to bypass. Replacement is required.

Symptom: Vehicle Pulls to One Side Under Braking

Start with the simplest cause: Check tyre pressures on both sides. Uneven pressures cause pulling that's most noticeable during braking.

If tyres are correctly inflated: Compare pad wear side to side. Significantly more wear on one side indicates that side is doing more work, likely due to a seized calliper on the opposite side.

Check for seized components: On the side the vehicle pulls away from, check the slider pins for free movement. Check that the piston retracts when the brake is released (the disc should spin freely by hand with minimal drag). On the MGF, rear brake callipers are particularly prone to seizure due to the integrated handbrake mechanism.

If callipers appear to function correctly: Check for contaminated pads (oil or brake fluid on the friction surface) which reduces braking force on that side. Contaminated pads must be replaced.

Symptom: Pulsating Brake Pedal or Steering Vibration During Braking

Start with the simplest cause: Warped brake discs are the most common cause of brake judder. This typically results from overheating, uneven wheel bolt torque or corrosion on vehicles that sit unused.

Confirm the diagnosis: With the wheel removed, spin the disc by hand and observe any visible wobble. If you have access to a dial gauge, measure runout against the disc face and compare to the specification in your workshop manual.

If discs appear true: Check for uneven pad deposits on the disc surface (visible as darker patches). This occurs when pads overheat and transfer material unevenly. The disc may be salvageable by fitting new pads and bedding in carefully.

If discs are warped: Replace discs and pads together. Ensure wheel bolts are torqued evenly in a star pattern to the correct specification to prevent recurrence.

Symptom: Handbrake Ineffective or Stuck

Start with the simplest cause: The handbrake cable may need adjustment. Check the adjuster mechanism in the centre console.

If adjustment doesn't help: The rear calliper handbrake mechanism is likely seized. This is extremely common on the MGF and MG TF due to corrosion of the threaded adjuster within the calliper. Inspect the handbrake components for visible damage.

Confirming calliper seizure: With the rear wheel removed, try to turn the disc by hand with the handbrake released. Excessive resistance indicates a seized mechanism. The calliper requires removal and either refurbishment or replacement.

Symptom: ABS Warning Light Illuminated

Start with the simplest cause: Check the brake fluid level. Low fluid can trigger the ABS warning.

If fluid level is correct: Visually inspect the wheel speed sensors at each corner. Check for damage to the sensor or its wiring, and ensure the sensor is securely mounted. Examine the reluctor rings (toothed rings the sensors read) for damage or contamination with metallic debris.

If visual inspection reveals nothing: Diagnosis requires specialist equipment to read fault codes from the ABS system. However, the vehicle remains safe to drive with standard braking; only the ABS assistance is unavailable.

Stage Four: Carrying Out Targeted Repairs

Once you've identified the root cause through the diagnostic process above, proceed with the appropriate repair. Gather the necessary tools before starting.

Essential Tools and Equipment

You will need a trolley jack rated for at least 1.5 tonnes, axle stands (never work under a vehicle supported only by a jack), a wheel brace or impact wrench, and a torque wrench for proper fastener tightening.

For brake component work, you will also require a brake calliper piston wind-back tool (essential for rear callipers with integrated handbrake), a brake bleeding kit or assistant for two-person bleeding, copper grease for slider pins and pad backing plates, brake cleaner spray, and fresh DOT 4 brake fluid.

Replacing Brake Pads

Front Pad Replacement: Loosen the wheel bolts with the vehicle on the ground, then raise and support the vehicle securely on axle stands. Remove the wheel to access the calliper. For standard sliding callipers, remove the two slider pin bolts and lift the calliper away from the disc. Support it with a wire hook to avoid straining the brake hose.

Push the piston back into the calliper bore using a C-clamp or dedicated piston tool. This makes room for the new, thicker pads. Remove the old pads from the carrier and clean the carrier with brake cleaner. Apply copper grease to the pad backing plates and carrier contact points, then fit the new pads. Refit the calliper, torque the slider bolts to specification, and refit the wheel.

Rear Pad Replacement: The rear brakes require a special wind-back tool because the pistons must be rotated clockwise as they are pushed back. This is due to the integrated handbrake mechanism. Using a standard C-clamp will damage the calliper. Follow the same general procedure as the front, but use the wind-back tool and rotate the piston as you push it in.

After fitting new pads, pump the brake pedal several times before driving to restore pedal pressure. Bed in new pads gradually over the first 100 miles, avoiding heavy braking wherever possible.

Bleeding the Brake System

The MGF requires bleeding in a specific sequence due to the mid-engine layout and brake hydraulic line routing. Bleed in this order: left rear, right rear, left front, right front. Use either a pressure bleeder, vacuum bleeder or the traditional two-person method.

For each calliper, attach a clear tube to the bleed nipple and place the other end in a container with fresh fluid. Have your assistant pump the brake pedal several times, then hold it firmly down. Open the bleed nipple until fluid flow stops, then close it before your assistant releases the pedal. Repeat until no air bubbles appear in the fluid.

Servicing or Replacing Seized Callipers

For slider pin seizure, remove the calliper and extract the slider pins. Clean corrosion with a wire brush and brake cleaner. Apply fresh high-temperature grease and reassemble. If pins are pitted or damaged, replacement is necessary.

For piston or handbrake mechanism seizure in rear callipers, refurbishment kits are available but replacement is often more cost-effective given labour time. When fitting a replacement calliper, always bleed the system thoroughly.

Preventative Maintenance

Regular maintenance prevents many brake problems before they develop.

Fluid replacement: Brake fluid is hygroscopic, absorbing moisture over time. This lowers the boiling point and promotes internal corrosion. Replace fluid every two years regardless of mileage, using only DOT 4 as specified.

Handbrake exercise: Use the handbrake regularly, even if you normally park on flat ground. Apply and release it several times weekly to keep the rear calliper mechanism moving freely and prevent seizure.

Post-winter cleaning: After winter driving, wash the underside of the vehicle to remove salt deposits that accelerate corrosion of brake components.

Regular inspection: Check pads and discs visually every 10,000 miles or at each service interval. Catching wear early prevents damage to more expensive components.

Upgrading Your Brakes

For spirited driving or track day use, consider upgrading to performance brake components. Brake kits offer a convenient way to improve stopping power with matched disc and pad sets. EBC Turbo Groove discs paired with Greenstuff pads provide a noticeable improvement over standard components for fast road use.

For more serious upgrades, brake conversion kits with 304mm discs and AP Racing callipers deliver track-ready performance. These kits may require larger diameter wheels to clear the bigger callipers, so check compatibility with your current wheels before ordering.

SAFETY CONSIDERATIONS

Brakes are a critical safety system. If you are unsure about any aspect of brake maintenance, consult a qualified technician. Never drive a vehicle with suspected brake problems, and always perform a careful low-speed test after any brake work before returning to normal driving.

When working on your brakes, wear appropriate safety glasses and gloves. Brake dust may contain harmful particles, so avoid breathing it in and wash your hands thoroughly after completing work. Dispose of used brake fluid responsibly, as it is harmful to the environment.

DISCLAIMER

This guide provides general information for educational purposes. Always refer to the official workshop manual for your specific model and consult a qualified mechanic if you are uncertain about any procedure. Rimmer Bros accepts no liability for work carried out based on this guide. Brake systems are safety-critical, and improper maintenance can result in serious injury or death.

Browse our full range of MGF and MG TF brake parts

Frequently Asked Questions

How often should I replace the brake pads on my MGF or MG TF?

Brake pad replacement intervals vary considerably depending on your driving style, typical journey types, and the pad compound fitted. Under normal road driving conditions, you can expect front pads to last between 20,000 and 40,000 miles, with rear pads typically lasting longer due to the front-biased brake balance inherent in the MGF design. However, several factors can significantly reduce pad life. Frequent town driving with constant stop-start traffic accelerates wear compared to motorway cruising. Spirited driving on country roads or track day use will wear pads much faster. Performance pad compounds often sacrifice longevity for improved bite and fade resistance. Dragging callipers caused by seized slider pins or sticky pistons cause rapid, uneven wear. Rather than relying on mileage alone, inspect your pads visually every 10,000 miles or during each service interval. Most front brake and rear brake callipers allow you to check pad thickness through an inspection window without removing the calliper. When the friction material reaches 3mm thickness, plan replacement soon. Some pads include wear indicators that produce a squealing noise when the material becomes critically thin, though you should not rely on this alone.

Can I replace MGF brake discs without changing the pads at the same time?

Technically, you can replace discs without changing pads, but this approach is rarely advisable and may compromise braking performance. New discs have a fresh, flat friction surface, whereas used pads develop a wear pattern matched to the old disc's surface profile, any grooves, and minor irregularities. Fitting worn pads to new discs creates several problems. The pad surface will not mate properly with the new disc, reducing the effective contact area and initial braking performance. Uneven contact can cause hot spots on the new disc, potentially leading to warping. The bedding-in process becomes unpredictable, and you may experience noise, judder, or inconsistent pedal feel. From a cost perspective, replacing pads alongside discs makes sense. Labour represents the majority of the job cost if you are paying a garage, and pads are relatively inexpensive. Brake kits from Rimmer Bros bundle discs and pads together at a reduced price compared to buying separately. This ensures matched components designed to work together, simplifies ordering, and guarantees optimal performance from first application. The only scenario where disc-only replacement might be appropriate is if you fitted brand new pads very recently (within 1,000 miles) and subsequently damaged a disc through impact or discovered a manufacturing defect.

What causes the rear brakes on my MGF to seize, and how can I prevent this?

Rear calliper seizure is one of the most common brake problems affecting the MGF and MG TF, and understanding the causes helps you take preventative action. The rear brake callipers incorporate a mechanical handbrake mechanism alongside the hydraulic service brake. This combined design creates additional complexity and potential failure points. The handbrake mechanism relies on a threaded adjuster that turns the piston to apply the brake when the handbrake lever is pulled. Over time, corrosion builds up on this threaded section, particularly if the handbrake is rarely used. Infrequent use allows moisture to settle and corrosion to form. Ironically, not using the handbrake accelerates this problem. Road salt and general exposure compound the issue, especially on vehicles driven through winter without thorough cleaning. Slider pins on the calliper carrier can also seize. These allow the calliper body to float and self-centre on the disc. When they corrode or lose lubrication, the calliper drags on one side, causing uneven pad wear, overheating, and eventually complete seizure. Prevention involves regular handbrake use, even if you normally park on flat ground. Apply and release the handbrake several times weekly to keep the mechanism moving freely. During routine service intervals, clean and lubricate the slider pins with appropriate high-temperature grease. After winter driving, wash the underside of the vehicle to remove salt deposits. Address any dragging or binding promptly before complete seizure occurs.

Is it worth upgrading to larger brakes on a standard MGF or MG TF?

Whether a big brake upgrade represents good value depends on your driving style, performance expectations, and budget. The standard 240mm front brakes are perfectly adequate for normal road driving and offer predictable, safe stopping power in everyday conditions. Upgrading to a 304mm brake conversion kit provides several benefits. The larger disc diameter increases the leverage acting on the wheel, improving overall stopping force. Greater disc mass absorbs more heat energy before fade occurs, making the brakes more resistant to repeated heavy stops. Multi-piston callipers distribute clamping force more evenly across the pad surface, improving pad wear and feel. These improvements become most apparent during track days, spirited driving on twisty roads, or towing situations where the standard brakes work harder. However, there are important considerations. The larger callipers require wheels with sufficient clearance, typically 16-inch diameter minimum. Check your current wheels for compatibility before ordering. The conversion adds unsprung weight, though the performance benefits generally outweigh this. Replacement pads and discs for the bigger system cost more than standard components. For occasional track use, you may achieve better value by fitting uprated pads and performance discs to the standard calliper setup. EBC Greenstuff pads with Turbo Groove discs, available in our brake kits, offer a noticeable improvement at lower cost. Save the full big brake conversion for regular track use or high-performance road driving where the additional capability will be fully used.

Chris Wrigley

Commercial Manager

Chris has been a car enthusiast since the early 1990’s and got his first Triumph Spitfire in 1996, one of many classics that followed!