Bedding in Brakes

[wsnaith]

Hi Guys

SVA two weeks today!

I'm concerned about my brakes. All brand new parts from Dax although they have been fitted for over a year.

Have bled them a number of times and not a bubble of air in sight. Have a never used country lane next to home which I will try to use to bed them in.

At the moment (up and down the drive) I can push the brake lever all the way down with very limited stopping power. However, if I release the brake and apply again immediately it stops great. Is this usual and will it sort itself out after a fews miles of use?

Confused about SVA passing brake test if you don't get a chance to bed them in.

Cheers

Warren

[lutman]

Originally Posted by wsnaith

Hi Guys

SVA two weeks today!

I'm concerned about my brakes. All brand new parts from Dax although they have been fitted for over a year.

Have bled them a number of times and not a bubble of air in sight. Have a never used country lane next to home which I will try to use to bed them in.

At the moment (up and down the drive) I can push the brake lever all the way down with very limited stopping power. However, if I release the brake and apply again immediately it stops great. Is this usual and will it sort itself out after a fews miles of use?

Confused about SVA passing brake test if you don't get a chance to bed them in.

Cheers

Warren

Would strongly suggest you get a hard pedal prior any country lane jaunts !
What you quote, where the pedal goes full travel and when released next immediate application is good does not sound like brake pads bedding in to me,
willing to be proved wrong,
sounds more like air trapped or perhaps a master/slave cylinder is sticking due fitted some time ago without regular use.
Your current situation would fail SVA as they would pick up on the full travel and poor stopping at first application.

[wilf]

They should improve as they bed in - mine seemingly had no stopping power at all until they got used. If the pedal feel does not improve very quickly, you may still have air in the system as Lutman suggests. Are the bleed nipples on all calipers uppermost?

[wsnaith]

Yes Wilf

The rear calipers hat to be rotated so that the bleed nipple was at the top

Warren

[JonnyT]

Does it do this repeatedly?

Had problems to start with as a result of air in the system (Jag brakes are a pain to bleed in this set up). Pedal was soft until I bled the system many times. Never went to the floor though - if it does it repeatedly then it may be another problem.

One issue that we did have is that the one way valve on the vac hose to the servo has instructions and markings which are pretty confusing (Simon and I read it before and after finding the problem and it is by no means clear). Try turning the one way valve round and seeing if that makes a difference. Before we did it the brakes were not good.

Bedding in has made a huge difference though to our brakes.

[wsnaith]

Thanks Jonny

I'll check the valve

Warren

[wsnaith]

This is a photo of the valve it has an arrow pointing towards the servo unit - is this correct?

Also I still have the white plastic cover attached - does this need to be removed?

Cheers

Warren

[JonnyT]

I think that pointing towards the servo is the right way round.

[craggle]

Hi Warren

Car looks good now

You can test the one way valve by removing the pipe from the manifold and giving it a suck! You should be able to suck through it but you can't blow through it.

Does sound like possible air in the system or the pads are getting pushed back in the calipers after being pressed. This could be badly seated brake discs given a wobble as they rotate and pushing the pads back or the master cylinder could be faulty.

If you jack up each wheel and give them a turn the pads should be lightly rubbing the discs. Get someone to press the pedal and see if they stop the wheel and then continue to lightly rub after releasing the pedal.

If this all looks good and you are convinced there is no air then I would look at the master cylinder to make sure it is not sucking the caliper pistons back when the pedal is released.

Craig.

[wsnaith]

Thanks again Craig

I'll give that a go

Warren