Bleeding brakes !!!

So the problem goes i changed all the brake pipes today. Bleed all the brakes starting with the passenger side rear then driver rear / passenger front followed by driver front all went well brakes felt fine until i started it. There firm but if u hold pressure on them the pedal slowly goes to the floor like theres a leak but theres no leak. Ive put about 2 litres of fluid through it to make sure theres no air in the system and its still the same.


Has anyone had a similar problem like this ?

Because am stumped


Mark

Start with the front passenger side 1st,then drivers front,left hand rear and finally right hand rear.
I also find it helps to raise the rear of the car up when doing the rears.Helps get the air out.
Unless the master cylinders failed,you have still got air in the system.

I had a problem getting air out of the rear wheel cylinders a couple of months ago. The reason turned out to be air being drawn in past the threads on the bleed nipples. The fix is to wrap a couple of turns of PTFE tape (The stuff plumbers use) round the threaded part of the bleed nipple, taking care not to get it on the cone ended section where the hole is. It worked a treat for me. I used a pressure bleeder as well.
An added advantage of using the PTFE is that it helps prevent the bleed nipple threads seizing into the caliper/cylinder, it acts as a barrier to prevent corrosion. You don't need to remove it afterwards, just leave it on.

Cheers for your replys guys

As i say the the engine is off the foot brake holds preasure no problem but when its started the foot brake holds preasure but slowly sinks if u get what i mean. Ive had it out a drive and they seem to work the pedal just dont feel right



Mark

Is it a diesel? If so it's called diesel creep. Basically diesels differ to petrols by using a vacuum pump. When sitting idling and applying a lot of pressure to the brakes too much pressure builds up giving much more pressure than you need and allowing fluid to push past the seals. Whilst sitting still you should only apply as much force as is necessary to hold the vehicle and not press hard on the pedal.

You can read more about it here: look at number 202. Pedal creep on diesel car

Brakeparts.co.uk | Car Brakes, Calipers, Pads, Discs & Parts

Cheers mark

Mark151151 said:

Is it a diesel? If so it's called diesel creep. Basically diesels differ to petrols by using a vacuum pump. When sitting idling and applying a lot of pressure to the brakes too much pressure builds up giving much more pressure than you need and allowing fluid to push past the seals. Whilst sitting still you should only apply as much force as is necessary to hold the vehicle and not press hard on the pedal.

You can read more about it here: look at number 202. Pedal creep on diesel car

Brakeparts.co.uk | Car Brakes, Calipers, Pads, Discs & Parts

Cheers mark

Click to expand...

cheers for that info mark. Yes its a diesel. And makes perfect sence the pedal is solid when the engine isnt running. Ive never noticed this before but with doing the pipes it has made me realise this

Mark

As other posts,sounds like the master cylinder is passing.

mark666freelander said:

cheers for that info mark. Yes its a diesel. And makes perfect sence the pedal is solid when the engine isnt running. Ive never noticed this before but with doing the pipes it has made me realise this

Mark

Click to expand...

I hadn't heard of it before until I started reading up about it, I have a new Renault trafic and noticed the pedal creep when sitting at trafic lights etc after reading up about it I've noticed that I was just putting far too much force on the pedal for the brake effort needed to hold the van. I barely touch the pedal now and the van never moves.

I would think that this theory is only valid for a relatively slow pedal creep tho. If you we're hack b to pump the pedal at lights to keep pressure then it will be a problem somewhere.

Cheers mark

Aye my work van does this,transit tipper,never really thought of it as a problem though

cheers guys never really noticed it before until now i guess doing the brake pipes made me aware of it now tho. when u hit the brakes doing 40mph it stops fast no pulling to one side etc so it all good

cheers for everyone input

mark