20 replies to this topic

[sheddd]

as title once again.
its been a while now, but earlier i was driving rouund a long sweeping left hand bend, on a 50 road and a car infront decided to slam on, so i had to too, now the back end locked up and just span me up ino the high curb, bent some stuff under car as trackings way out and what not.
but why the back end lock and just spin?
before i take the rear drums off id like to know what im looking for? lol
thanks

[lrostoke]

Think I'd be checking the fronts most of the braking should be through the front wheels, did the rears actually lock solid

[jaydee]

Have you adjusted rear drums? Are the front brakes working correctly?

[sheddd]

fronts working fine though, just the backs working too well?
handbrakes fine, 4 clicks and stops,

just locked up solid and span me right around hit curb flew over into a fence and into the nice scenery lol

[jaydee]

Adjust rear drums, thers a little bolt in the bakcplate, release it a little bit, then check if they lock up again.

[sheddd]

aight thankss, shall do it in abit after changingg the oil

[lrostoke]

Could be a problem with the brake bias, not the actual rear brakes.

I always adjust rear brakes so the wheel is stiff to turn then back off a qtr turn, never had a problem.
The rear brake is designed so that it can't exert more force than the front if the system is working correct.

Fronts may be working but not exerting enough force.

Also check the rears are releasing properly, the quadrants seizing can cause them to stick on, and also the handbrake scissor bit inside the drum can rust up.

Edited by lrostoke, 10 March 2010 - 02:05 PM.

[R1minimagic]

Do you have a servo?

[sheddd]

nope no servo?
i always thought it was odd having discs at front and no servo lol
but thats standard i assume?

[jaydee]

Dont worry, servo is useless, it just reduces brake pedal effort a little bit. The big servo vauum unit become standard in 89/90.

[stickycreambun]

the 8.4" discs were fitted for a few years before a servo was added, nothing unusual there.

[sheddd]

ah thats ok then, that that worry over lol
adjusted em and its not made a difference.
god knows lol

[998dave]

Are you sure the rear locked up and that it wasn't just lots of lift-off oversteer? (Which mini's do).

Do not back off the rear brakes, sorting out your brake balance by making the rear worse is almost as crazy as sorting out the understeer by making the rear slide.

Check the front's over, make sure they're breaking, you should have a recording of braking effort from your last MOT, check that it's front biased, or if you want to be sure take it for another check up at the MOT station.

That's the end of my technical answer... condescending advice warning.

Another alternative response could be don't drive as close to the car in front, that way when they slam on their brakes you've time to come to a controlled stop, rather then spinning yourself into a ditch...

[jaydee]

Minis tend to lock rear easily due to the lighter rear, thats why most of them are fitted with a bias valve that you can find on the bulkhead. Usually if the front discs are doing their job, you can adjust rear drums to avoid locking.
What tyre pressure you inflate tyres?
Is suspension setting ok?

[sheddd]

nah its done it before under breaking just not as bad, granted th road was dusty but still shouldnt do that.
not sure about exact tyre pressure though.

and car infront was a caterham seven with 6 pots and i wasnt close to be fair, just stops ALOT quicker then a mini lol.

god knows about suspention, probs not as its been stood for years.

i have a few things in boot so thats weight on back wheels? dunno if that'll make a diff though?