Bad brakes - spongy pedal - any advice?

[cupra-barn]

Hi everyone,

After some help.

Front brakes - Forge 6 pot 356mm setup yellow stuff pads
Rear brakes - LCR calipers with EBC discs and Pagid OE pads.

My brakes are extremely spongy, no pedal feel at all. Ive had them pressure bled on vagcom by 2 garages, the second of which I trust 100%.

Ive got new calipers all around with new fluid in the whole system. The pads have been bedded in but still I have a terrible pedal. The brakes do work, but only when the pedal is pushed a long way down and even then, there is no bite its a gradual loss of speed.
The car stays level when braking, I would expect it no 'nose dive' a bit considering how big the fronts are but nope.

The garages are at a loss, Im at a loss and the misses is going crazy with money being thrown at it.

Can anyone suggest anything?

 

[m0rk]

Bled the master cylinder? Faulty MC? Air in the ABS unit?

Too large a capacity calliper for the MC?

 

[cupra-barn]

Bled the master cylinder? Faulty MC? Air in the ABS unit?

Too large a capacity calliper for the MC?

Master and clutch has all been bled at the same time.

I wondered on the ABS unit but Ive been assured there is no air in the system.

I quizzed the garage on the master, but they are pretty sure the master is ok. They said that if the master was the issue it wouldnt have stood up to the pressure bleeding process.

Is there a way to check the servo do you know?

 

[m0rk]

If the servo wasn't working the pedal would be very firm

You've got spongy & long travel, so something is not right.

Have you got the old brakes to put on? I'd think about swapping the fronts back to OEM to diagnose anything else

 

[cupra-barn]

If the servo wasn't working the pedal would be very firm

You've got spongy & long travel, so something is not right.

Have you got the old brakes to put on? I'd think about swapping the fronts back to OEM to diagnose anything else

Hmm so servo and master have been rulled out.

That only leaves me the ABS pump which was my initial thought a few weeks ago.

Just plugged it in again, Im now showing:

01314 : Engine control unit. Control Modules. Brake electrics.

 

[cupra-barn]

From Ross Tech

01314 - Engine Control Module
01314 - Engine Control Module: No Communications
Possible Causes
CAN-Databus Wiring/Connectors from/to Engine Control Module faulty
Fault(s) stored in Engine Control Module
Engine Control Module recently flashed or re-mapped
Possible Solutions
Check CAN-Databus Wiring/Connectors from/to Engine Control Module
Check Measuring Value Blocks (MVB)
Usually Measuring Value Blocks (MVB) 125+ show the current Communication Status

 

[BoostHard]

Are the calipers fitted the correct way with the nipples at the top?

I have seen calipers fitted to the wrong side before so the nipples were not at the top. So when bleeding the trapped air couldn't escape. This wasn't on an LCR so Im not sure if the calipers can be fitted on the opposite side but worth checking all the same.

 

[Captain Cupra]

Did you bleed the rears with the handbrake engaged if not then that will be why I just had this issue yesterday fitting 4 pots and vented 256mm calipers, also if you let the fluid drain from the fronts you'll need to cycle the abs pump, also if they didn't pressure bleed and did it manually they will have minced the seals on the master cylinder!!!

My bet is bleed the rear with the handbrake ON!!!! Makes a huge difference!!

 

[Captain Cupra]

How did the garage bleed it? Pressure bleeder? If they didn't they want shooting as the mk4 chassis braking system must be pressure bled, was the abs cycled? Trick with these cars is direct swapping of lines to not allow fluid to be lost this will drain the system and let air into the abs unit, if I lived near you I'd sort it mate..

 

[cupra-barn]

Yes they pressure bled them.

I believe the handbrake was off but not 100% sure. Could you explain why that would make a difference? Don't mean that in a shitty way, I don't understand why.

Yeah porchester is a little bit too far lol but thanks for the offer

 

[Captain Cupra]

Well because it's a mechanical handbrake within the rear caliper piston on a worm drive that's self adjusting, if the handbrake is off and you bleed your only bleeding enough fluid to the caliper to fill the piston in the retracted handbrake off position thus the pedal having to push more fluid to compensate so you need the fluid to be there's for the full travel to be solid ad on disc, sorry it's hard to explain but I didn't bleed with the handbrake on and I had a soft pedal, halfway down then feel but vague, re bled with it on and bang firm pedal lethal brakes, it makes a difference trust me I'm not talking poo without having a clue like some people

 

[Captain Cupra]

And as mentioned with 4 or 6 pot calipers you need the bleed nipple on the top, easy mistake to make but you will never ever bleed them this way up..

 

[BigJase88]

I bled my brakes last week

But didnt have the handbrake on as i had just changed rear discs and pads

Will it make a difference if i re-do it with the handbrake applied?

Changed from 2 year old VAG dot 4 to ATE racing blue DOT 4??


Cheers

 

[Captain Cupra]

Definately trust me it will be considerably firmer, I promise!!!

 

[Captain Cupra]

Make sure you apply and release the handbrake to wind the piston out to the proper adjustment as stated the handbrake is self adjusting, once firm apply the handbrake then bleed the back left, back right, front left, front right, master cylinder nipples and clutch, firm responsive pedal awaits you.. If you've done it correctly

 

[paulbrem]

Check the seals on the master cylinder I have had to replace these before but on a nissan. I was able to get a kit, sorry dont know about seats

 

[cupra-barn]

Ok well give it a try and I'll come back to you. Thank you

 

[BigJase88]

Make sure you apply and release the handbrake to wind the piston out to the proper adjustment as stated the handbrake is self adjusting, once firm apply the handbrake then bleed the back left, back right, front left, front right, master cylinder nipples and clutch, firm responsive pedal awaits you.. If you've done it correctly

I havent bled master cylinder?
Howd you do that?

Ive bled all 4 calipers and the bleed nipple at the gearbox?

 

[Captain Cupra]

You using a pressure bleeder?

 

[tom t]

Some good I do there captain. Going to be changing rear brakes shortly. Just incase I need to bleed them again. When you say rear left etc. is that asif you standing at the front of the car. If you can u der stand what I mean lol. Cheers