Bleedin' brakes

[ohgodwhathaveidone]

Hullo chaps

Just a quickie, have been bleeding my brakes after overhauling the brake master cylinder, but am still faced with spongy brakes. I have bleed as per instructions in the workshop manual - twice - but still have spongy brakes - any ideas, or is it a matter of bleed, bleed, bleed and bleed again, my friend...?

Cheers, Mark

[loudnproud]

Hi Mark

Rebuilding master cylinder is a difficult job, have you got it right that could be your problem, rubber flexable brake pipes are also another reason for spongy brakes if they are past ther sell buy date, replace with braided hoses. Bleeding brakes you should start with wheel furthest from master cylinder working towards master cylinder as you go, only press brake pedal about half way down or you will dislodge PWDA valve which can also lead to a spongy pedal.Good luck.

Peter

[ohgodwhathaveidone]

Thanks for that Peter, I suspect that it may be the PWDA valve as the front drivers side brake, when bleeding, did not seem to want to bleed with such enthusiasm as the rest of the brakes. I have searched the forum for the PWDA valve and it seems as though it may be a matter of removing the switch to get at the valve and then convincing it to return to the centre. If this is the case, would I have to disconnect the pipes (and then hae to re-bleed again) or can I just remove the switch, fiddle and replace? Unfortunately, the brake warning light bulb has blown so I can't ascertain whether the PWDA valve is centred without taking it apart......

Regards, Mark

[DJT]

Mark,
The PDWA splits the brake mcircuits front/back. If the front brakes are reluctant to bleed, then you may have to reset the valve by bleeding the rear again. There is a knack to getting it right. Another way is to make a little gadget like this:

DSC01567.JPG

This can be used to replace the switch whislt bleeding the brakes, It holds the shuttle valve in the central position no matter what.

[StagnJag]

Do you have rubber flexible hoses? They can break down inside and still look fine outside. This can sometimes lead to front calipers 'sticking' on, but It might also cause one corner to feel a bit stiff to bleed, or a piece got stuck behind the bleed valve.

Rgds

Dave