spally

iTrader: (1)

right had new brake pads/disc fitted, along with the brakes being bled. However i now have occasions that when i push the brake pedal it almost hits the floor. If i release and push again it's fine.

Have spoken with spec c and he believes it could be a wheel bearing. Next question, how do i find out if the bearing has gone??? dosent seem to be any excess play in the wheel?

cheers

bibo_boy

Hello mate,

I recently changed my bearing on my old Terzo. The only way of telling if the bearing is sound is to take off the whole hub then check for play.

I had a grinding noise but no play, when I went to switch hubs, the old one fell to bits on dis-assembly.

Buy an old hub (with a decent bearing, make sure it's a straight one) and switch it to see if it still does it?

To be honest, I'm not 100% sure it would be that though as do the bearings have any input to braking? (I'm nooooooo expert).

Would have thought it may be something like brakes need rebleeding, check hose connections etc......

Good luck mate.

Mark_B4

I'd be tempted to check the breaks again first to ensure they have been bled correctly, before going down the bearing route, as all it'll cost you is a bottle of break fluid.

spally

iTrader: (1)

cheers for the replies fella's.

will start off with the cheapest possible problem and work my way through a list

Milamber

iTrader: (2)

Shall we get you one of these?

spally

iTrader: (1)

would probably work better....

pete.300

That has nothing to do with the bearings mate brakes and bearing are NOT linked in any way apart from they are both on the wheels..
Sounds to me like you have an air lock in the brakes for the pedal to hit the floor.. get them rebled any by someone that knows what there doing..
Dont understand why you had to have them bled in the first place...?

frayz

iTrader: (7)

It IS possible for this to happen,

Basically a funked bearing can cause play to create pad "knock-off". I know Mrs Spec C's classic did it.

Id be inclined to check the brakes first though mate, Check that the pads are seated correctly and coppersliped in all the correct places.
Then re-bleed and try again. How long have your bearings been on the car?

Id change them if theyre older than 10k miles anyway. If you leave a damaged bearing, it will wreak the hubs too. This is exactly what i did at the ring. 4 laps was enough to kill the hubs with a bearing on its way out.

Check the brakes first.. then the bearings.

If you need anything.. bell me

spally

iTrader: (1)

the people that fitted the new disc and pads, know what they are doing and were the ones that bled the brakes, as after running the new pads in i was having the problem where they werent stopping the car, hence the reason for them being asked to bleed the brakes. However after the garage bleeding the brakes again i am still having the same issues!!!.

spally

iTrader: (1)

cheers matey, hubs have certainly done more than 10k miles. Yeah speccie told me of the problem with lins.

To tell you the truth i am not mechanicaly minded and would not know how to tell if the pads are seated correctly. Am going to get my brother-in-law to have a look as he is a mechanic.

Oh and cheers for the offers of help guys

Joely P

i cant see how the wheel wobbling from a fooked bearing will affect the braking in any way shape or form other than maybe a shaking steering wheel under braking, the caliper will operate the same regardless of the serviceability of the bearing...

also, it doesnt sound like your brakes have been bled incorrectly as it is an intermittent fault. if there was air in the system it would always feel spongey and as you say 'go to the floor'.

imo i think the problem will lie in the brake servo itself and thats where il be starting my fault finding

Joel.

spally

iTrader: (1)

right, starting to sound like a bearing........as when under heavy braking the steering wheel feels like it's about to shake away from the column.


cheers

frayz

iTrader: (7)

Mate,

Jack up the car and grab the wheel at 12/6 oclock and then and 3/9 oclock and feel for any play.

???

spally

iTrader: (1)

Frayz, will have to have a butchers at that later on mate. cheers

frayz

iTrader: (7)

If theres any play then i can say its 100% wheel bearing and you will also have deffo funked the hubs too.

The hubs wear like crazy as soon as a bearing goes.

spally

iTrader: (1)

ok mate. cheers

JohnD

iTrader: (5)

Frayz is right. If the bearing is bad and allows the wheel to wobble or have end float, it could cause pad knock-back. You press the brake and the pad has to move back into position before applying pressure to the disc. There would however, need to be a fair bit of play in the bearing for this to happen, which from what is described, could be the case.
As it's ABS, bleeding should, if at all possible, be by pressure into the fluid reserviour on the master cylinder. Make sure this is the method used.
JohnD

PS Steering wheel shake under braking could also indicate out-of-balance wheels.

mrs_b4

Or warped disks , had some of those in my time

FLAT ERIC

iTrader: (1)

When a wheel bearing flexes (and they all do to a lessor or greater degree) the disk will work against the pads and try to open the pads up. An opposed piston caliper will follow the disk, while a single side piston design will allow the pads to be pushed away from the rotor. With severe wheel bearing flex you can push the brake pedal down 1/8th to 1/2 the pedal travel just to bring the pads back into contact with the rotor.

Needs to be a fair bit of play though in a Subaru, because they have an unusually wide distance between the bearing pairs in the hub. Ever wonder why Subaru wheels have such huge offset? Now you know. If you tap a curb or hit a really big hole it is possible for pad knock back to develop. How much play is too much? Flexing the hub by hand the face of the rotor need only move .01" to cause a noticeably low pedal. Usually the maximum hand flex is .006".


Causes of Excessive pedal travel

Friction pad knocks-back after violent cornering
Pads not properly seated or positioned
Insufficient fluid in master cylinder reservoir
Loose wheel bearing
Damaged caliper piston seal

Mark

jay knowles

Sometimes when you bleed brakes and push the peddle to the floor it can show a weakness in the master cylinder as it doeasnt normally operate to the extremes of its travel,seen it plenty of times.JAY

Spec'c'57

iTrader: (1)

If you dont understand that best you speak to scoobyclinic as they solved the problem/rectified it for us....

Summers

I've had the same bearing problem with MY99 classic 3 years ago. Dealers replaced the master cylinder and then found the near side wheel bearing was causing the problem. Scary though when the break pedal goes soft. Hope you get it sorted mate.

Neil