Soft Pedal, even after bleed. Polo 9N3.

[Blue Shell]

Hey, so I have an with my 10' Polo 9N3 issue; My pedal is way too soft and it isn't as sensitive from factory.

Now, the issue arised when I changed my front pads, they were very low and the disc had a big lip on it.
I changed the passenger side and pressed the brake to push the piston out, I then did the same for the drivers side although now the pedal was soft.

I bled the front callipers, where performance improved a little.

I then changed the rotors two weeks down the track, as they were causing a squeak.
After that I thought to myself it's time to get to the bottom of this soft pedal.
I've bled the conventional way (furthest from M/C), the workshop manual way (PF, DF, PR, DR)
and in random orders to no avail.

When bleeding I have monitored the clear hose while my assistant depresses the pedal about five times and no air has come out.

After scrounging the internet I have read I may need to cycle the ABS or use a vacuum bleeder, two things I have no idea how to do.

My question now is, am I doing something wrong?

Any advice is greatly appreciated and you have my thanks in advance.

[Transporter]

The brakes should be pressure bled, otherwise yeah you can end up with the soft brake pedal.
To cycle ABS, you can simply go on the road with a bit of soft surface and brake hard until you feel rumbling in the brake pedal, do it 3-5 times. Just make sure there is no car close behind you.

[Blue Shell]

Thanks for the quick reply. So I'm not the sorta guy that likes getting brake fluid everywhere, who is amirite?
Would that be best done in a brake shop? There are a few around my area, wouldn't be over a hundred bucks would it?
I just want my factory firmness back :(.

[Transporter]

It doesn't have to be a brake shop, a good independent VW specialist should have a pressure bleeding equipment.

I use ATE FB30 and ATE SL6+ESP brake fluid, it guarantees the factory brake pedal feel.

[Blue Shell]

Called up VWVillage and they quoted me 82 dollars. Guess I'll have to pay if I want it done properly, I'm still wondering what the difference is though. Logic tells me it should be bled using the simple way.

[brad]

Have you cleaned & lightly greased the slider pins; the rubber bushes the pins go through & cleaned/lubricated the slider tracks that the pads rest on.

I assume you have bedded the pads in? What brand/type pads & rotors did you use & what brake fluid have you been using?

That's all I can think of as my first thought was the lip on the rotors (both the outer edge & near the hub) but you say you fited new rotors?

[Blue Shell]

Yep, a new front reline. I'm using bendix for pads, dba for rotors and Nulon Super Dot 4 fluid.
I'm thinking now that it may be the one-man bleeder hose I'm using. The check valve is plastic and sorta old. I'm going to try once more with just clear tube the tedious way. Thanks for your advice guys.

[brad]

Try the pin sliders & pad sliders first. I recently regained 15mm of brakepedal when I ground off the rotor lips with an angle grinder (yes, dodgy) & dismantled/cleaned all the dirt/dust/rubish off the calipers. Did nothing else - still original pads didn't even look at the hydraulic side.

[h100vw]

Try the pin sliders & pad sliders first. I recently regained 15mm of brakepedal when I ground off the rotor lips with an angle grinder (yes, dodgy) & dismantled/cleaned all the dirt/dust/rubish off the calipers. Did nothing else - still original pads didn't even look at the hydraulic side.

I think at least part of the problem is the pads not run into the discs. I'd go and do some miles before blowing money on a pressure bleed. A few hard sops would show you how much of the disc is in contact with the pads.

Gavin

[Transporter]

Many newer brands today require pressure bleed while changing the brake fluid, the old fashion bleeding with an assistant will not give you the same nice firm pedal.

Also, I'd like to point out that using a cheap pressure bleeder, where the brake fluid comes in contact with the pressurised air will cause the moisture from the pressurised air and the micro bubbles to be introduced into the brake hydraulic system, causing the corrosion and other issues.

[seangti]

Hopefully not going off topic to the OP, so what's the best way for the DIY'er to do a fluid change? Using an air compressor and appropriate tooling to suck the new fluid through to the caliper?

[h100vw]

Hopefully not going off topic to the OP, so what's the best way for the DIY'er to do a fluid change? Using an air compressor and appropriate tooling to suck the new fluid through to the caliper?

I have one like that Sean but is f'ing noisy, with the compressor running and then blowing air out too. The best bit about it is collecting the old fluid.

Gavin

[Blue Shell]

So I don't know if anyone is still interested but I have now found something that may have contributed to a soft pedal.
My rear pads.
While the outers look fine the inner pads were down to the metal. I have replaced these over the course of the weekend and am ordering rotors on Monday. I'm just curious, would the piston run out of travel if the pads are worn down this bad or would it accommodate for the distance. Anyway, once the new rotors are on I'll give it a bleed and see how I go.

On a separate note, I have been utilizing ABS and it seemed to have reduce the force needed whilst braking. So that's good news too.

[brad]

Generally, if you run out of friction material & the piston is a bit short, it will pop the piston out. ie: There's nothing to stop the piston continuing to move toward the rotor. I've had almost nothing to do with handbrakes incorporated into the caliper so maybe I'm wrong.

If the inner has worn significantly more than the outer then I'd be having a good look at the caliper slider pins & the machined surfaces the pads sit on as it appears something is jamming