Put some new front pads in a two days ago. Opened up the bleed nipples quickly at the same time as pushing the pistons back. However i forgot to clamp the lines.

 

Anyhow I didn't test it with the engine on until yesterday - cue the problem that I can push the brake pedal to the end of its travel with not much effort. *****cks says I, must have gotten some air in the lines when i opened the nipples to push the pistons back.

 

So today I have been bleeding the system. I've followed the procedure in the 95 manual. It tells me to bleed the abs actuator too, which is bloody hilarious because 94+ zeds have no bleed nipples on the abs... Anyhow I've bled and bled the system today, there is no air coming out the calliper nipples, no gurgling noises from the abs actuator. Started the engine several times to build pressure in the booster. I even disconnected the bat & abs like the manual says. 3 litres of Dot4 has gone into the system. I've checked the inside the firewall where the rod pases through to the booster - all dry etc.

 

Problem is the pedal still reaches the limit when pushed. There is resistance obviously as the pads start to clamp the disc, but then it just sponges all the way to the physical end of the pedals travel - was never able to even push the pedal that far before I changed the pads. Brake booster holds pressure just fine.

 

 

What to do next? Either there is *still* air trapped inside? Or could it be because the new pads have not bedded to the surface of the disc (there is a lot of movement as the pistons clamp the pads on the front calipers..)

 

 

Help me please because after 6 bleeding hours today i'm getting short on hair. :P

 

 

jay

You still have air in the system, are you bleeding them in the correct order, search brake bleeding.

 

Paul

Well this is just it - I've had 3/4 of a litre come out all four corners now with no air bubbles etc. :/

 

Followed the guides people have posted on here and been reading all the search results under brake bleeding, how the smeg do I get this trapped air out?

Brake bleed proceedure

http://www.ttzd.com/tech/lines/lines.html

It's possible that disturbing the system has fooked up the master cylinder seals, causing the fluid to bypass. Whats the flow like when you open up the bleed nipple?

Flow out the nipples is good mate, like I said i bled 3/4 of a litre through each corner with no bubbles in etc.

 

Just been out in it and while I do have braking it's certainly not as good as before. New pads I know, but foot to the floor = serious 'I can't stop' emergency stop! Roughly I would say i'm putting 5x less force onto the pedal and it's bottoming out it's travel.

That aint good!

 

Could still be a master cylinder problem, even with a good flow at the nipples, the fluid will take the path of least resistance.

 

But then it could be a number of other things. Ive seen as you say a change of brake pads causing similar problems, with the pedal really spongy until the pads had been given a good bed in.

 

Something else you could try is clamping off the brake hoses to see what your pedal is like, if its really hard you will know the master cylinder is ok, the fault will be at a caliper, a process of elimination should pin point the offending corner. If the pedal is still spongy the fault is either likely to be the master cylinder or air trapped in the abs unit.

did you remove the calipers? I once fitted a pair of 300ZX front calipers to my 200SX and put them on the wrong sides, this located the bleed nipple BELOW the brake hose input and obviously air rises... Best of luck

You probably have air trapped in the master cylinder. Is yours the type with the bleed nipple on the end ? If not then it can be a real struggle to get it out, due to the angle at which it sits.

The pedal will be spongey with new pads on old discs,Opening the nipples when pushing the pistons back is a good idea as some four pot calipers can flip the seals in the master with the volume of fluid being returned.It should not make a difference that you didnt clamp the lines off unless the fluid ran for ages and let the resovoir run dry.Does it have any pedal whatsoever? Normally when bedding in pads the pedal height wil be low at first till they settle and the biting point will rise.