7 replies to this topic

[DClarke1954]

Sorry for what might seem a fatuous unnecessary post but I am a bit puzzled by the performance (or lack thereof) of the servo-assisted brakes on my MkIII.

For a system that is "Servo-Assisted" it seems..well... nowhere near as aggressive as I imagined it ought to be.

My 2+ Ton Range Rover P38 brakes much more effectively.

This little vehicle that is <1/3rd the mass seems to not really respond sharply when I hit the anchors.

 

When I press the pedal with the engine off it isn't spongey at all, so I don't think it's full of air.

 

To be fair, the Rangie has a brake accumulator that stores lots of "pedal force" that gets released when you tap the brakes and it has a proper WABCO "Truck Braking" system so I am probably unfairly comparing chalk with cheese.

 

 

Now it is a long time since I drove a Mini for any length of time and maybe I am just not attuned to it yet or just how hard you have to tromp on the pedal to get "Max Braking".

 

Don't get me wrong, I'm not a tailgating maniac desperately needing to get out of trouble, but if I am ever going to put my grand-kids in the Mini I want decent braking efficiency.

 

Maybe the MOT on Wednesday will answer my question and tell me the Servo is FUBAR or the whole system is "below-par", or its all fine and I need to acclimatise to it.

 

It is the lack of a personal "Yardstick" of how it should be that is causing me to question things I think.

 

 

 

[imack]

With the engine turned off, pump the brake pedal a dozen or so times to deplete the vacuum from the servo. Then, while keeping a steady pressure on the brake pedal, start the engine. You should feel the brake pedal drop slightly if the servo is working correctly.

[Quinlan minor]

While it is possible that your expectations of the aggressiveness of the brakes may need recalibration, there is a wide variability of pads available.

On a system designed to run with asbestos in the pads, some modern compounds feel extremely wooden, to say the least.

It'd be worth examining your discs and pads, perhaps investing in some new high quality pads, remembering to bed them in properly.

[alpder]

Almost all the brake effort comes from the front: disks in your case. The car's new to you and is far from standard and has had all sorts of engine work on it. So see if someone has also fitted "race" pads, because they'll be b-all use until they're hot. Off-the-shelf Mintex just work, but are boring. Which is so much better than exciting.

[nicklouse]

Have the brakes been bedded in yet?

 

as to effectiveness cheap and cheerful pads will often give more bite.  The biggest problem is getting heat into them.

[sonscar]

Modern servos run 6 or more time's pedal pressure assistance,your mini may be as low as 1.6 and the diameter is likely to be smaller so less leverage.This said pressing harder should have effective brakes when in good condition.Steve..

[coopertaz]

if the mini servo is not working brakes are almost none existant, mot brake force results are useful it may just be the rear brakes need adjusting. Servo assisted 8.4 set up right and with good road spec. pads are good all rounders, if you get fade with very spirited driving then look at upgrades.

Edited by coopertaz, 25 February 2025 - 11:20 AM.

[Ethel]

Could be worth giving them a bit of a service. Take a pad out at a time & push the pedal to get the piston moving. Start on the driver's side & you can see the piston to gauge how much to press the pedal. A large flat spanner is useful to stop you ejecting the piston from the caliper & to lever it back until it pumps with next to no effort. Clean the discs & deglaze the pads on a flat sheet of sand paper. Tapping with a hammer, or spinning against the edge of file, will remove rust from the disc's edge. A light smear of copper slip on the backs & edge of the pad backing plate can help.