brakes spongy

[skinz]

Hi peeps, I've changed my rear disk and pads cause on 1 side the pads had worn all the way down and also did a front wheel bearing at the same time, but after fitting them i found 1 of my rear callipers was binding so had to change that as well but now my brakes are really spongy and have loads of travel on my brake pedal, I've bled the brakes and that, when the engine is off the brake pedals bite is high an stiff as it should be but when I turn the engine on it goes all spongy, has any1 got any ideas on what to do cheers skinz

 

[hyphon12]

How did you bleed it? As manually bleeding these cars can damage seals in the master cylinder/servo

 

[skinz]

Cheers for the reply, Yea had 1 on the pedal while the other bled, how should have done it and how would I check to see if something is damaged

 

[skinz]

Cheers for the reply, Yea had 1 on the pedal while the other bled, how should have I done it and how would I check to see if something is damaged

 

[hyphon12]

The safe way is pressure or vacuum bleed. You would need to split the master off the servo iirc (not sure though as I'm just going by what's been posted in the past).

 

[aymen_a22]

Many people complain of a spongy brake pedal or a pedal that slowly creeps to the floor (with moderate to high pressure).

I assume you still have good stopping capability though.

Apparently it is the master cylinder seals that can get damaged if you go past your normal pedal travel (ie when manual bleeding).

The symptom causes a small amount of brake fluid to pass the seal and leak into the servo, however my pedal slowly drops to the floor and I have not had any brake fluid loss (by looking at the reservoir).

Another issue could be your ABS, apparently there is a brake bias (which all cars have) to distribute the correct brake force between the front and rear wheels. I have heard that these have a pressure release system which fills upon heavy braking (not sure how of if that is correct though). On our cars I believe it is located in the ABS module.

Lots to consider however I would probably start by rebleeding the whole system with a pressure bleeder (Motive, EZeebleed or similar) and then check again.

If you let a lot of air into the system it can find its way into the ABS module which then needs to be activated to release the air (usually though Vagcom but some people bleed the brakes then take it for a drive and activate the ABS on the road and then rebleed again).

Sorry for the essay, hope it helps in some way. Let us know how you get on.

 

[towcester vag]

i would pressure bleed the brakes and do a abs bleed using vcds
if you have teves 60 abs this system will have a long feel on the pedal and can feel like the pedal goes to the floor if car is running and you are pushing the pedal it will go to about 40mm from floor

 

[skinz]

Ive seen a couple of thread's on here about spongy brakes like me and they said that the brakes need bleeding in a certain order then do the servo then do the clutch, does any1 know what order this is

 

[aymen_a22]

There are two different ABS modules fitted to the Leon, you need to know which one you have.

The Mark 20 has all SIX pipes on the same side of the ABS unit.

The Mark 60 has four pipes on one side and two pipes on the top of the ABS unit.

The bleeding sequence (according to the bentley manual) is as follows:




Connect hose from bleeder collection bottle to first brake bleeder valve at caliper.

WARNING
The brake fluid level in the reservoir must not fall below the MIN mark during bleeding.

Have a helper pump the brake pedal several times and then hold pedal down firmly.

Open bleeder screw at the caliper and allow fluid to run out into collection bottle.

Close bleeder screw and then release brake pedal. Repeat operation until brake fluid runs clear and flows without air bubbles.

Repeat the above procedure at each remaining wheel.

Observe the correct sequence for each system type:

ITT Mark 20 IE Systems:
• Right rear caliper
• Left rear caliper
• Right front caliper
• Left front caliper

ITT Mark 60 IE Systems:
• Left front caliper
• Right front caliper
• Left rear caliper
• Right rear caliper

NOTE
To determine which brake system the vehicle has see 45 Anti-Lock Brakes (ASS).

Upon completion of repairs, always road test the vehicle so that the ABS is felt to engage through pulsing of brake pedal.

 

[kr1s77]

what size spanner do i need for the bleed nipple? also if i have this right, when pressure bleeding the brakes, will it push it through the abs or do i have to use vcds. if so do i use vcds with the eeziee bleed connected?

thanks

 

[skinz]

The nipple bleed is a 10mm I think, I did sort mine out but not sure how, we spent ages trying to sort it but while it was up on the ramp it still felt spongy, we was gonna leave it for the night and try again the next day, so my mate drove it out his unit and into the yard and slammed on the brakes activating the abs, I jumped in and set off home, driving down the rd and some idiot pulled out in front of me so I stomped on the pedal expecting it to be spongy and nearly ended up kissing the window screen lol